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 #include "jfr/jfrEvents.hpp"
42 #include "memory/filemap.hpp"
43 #include "memory/gcLocker.hpp"
44 #include "memory/oopFactory.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/instanceRefKlass.hpp"
47 #include "oops/klass.inline.hpp"
48 #include "oops/methodData.hpp"
49 #include "oops/objArrayKlass.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "oops/oop.inline2.hpp"
52 #include "oops/typeArrayKlass.hpp"
53 #include "prims/jvmtiEnvBase.hpp"
54 #include "prims/methodHandles.hpp"
55 #include "runtime/arguments.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/fieldType.hpp"
58 #include "runtime/handles.inline.hpp"
59 #include "runtime/java.hpp"
60 #include "runtime/javaCalls.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/signature.hpp"
64 #include "services/classLoadingService.hpp"
65 #include "services/threadService.hpp"
66 #include "utilities/macros.hpp"
67 #include "utilities/ticks.hpp"
68
69 Dictionary* SystemDictionary::_dictionary = NULL;
70 PlaceholderTable* SystemDictionary::_placeholders = NULL;
71 Dictionary* SystemDictionary::_shared_dictionary = NULL;
72 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
73 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
74 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
75
76
77 int SystemDictionary::_number_of_modifications = 0;
78 int SystemDictionary::_sdgeneration = 0;
79 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
80 20201,40423,99991};
81
82 oop SystemDictionary::_system_loader_lock_obj = NULL;
83
84 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
85 = { NULL /*, NULL...*/ };
86
87 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
88
89 oop SystemDictionary::_java_system_loader = NULL;
90
91 bool SystemDictionary::_has_loadClassInternal = false;
92 bool SystemDictionary::_has_checkPackageAccess = false;
93
94 // lazily initialized klass variables
95 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
96
97
98 // ----------------------------------------------------------------------------
99 // Java-level SystemLoader
100
101 oop SystemDictionary::java_system_loader() {
102 return _java_system_loader;
103 }
104
105 void SystemDictionary::compute_java_system_loader(TRAPS) {
106 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
107 JavaValue result(T_OBJECT);
108 JavaCalls::call_static(&result,
109 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
110 vmSymbols::getSystemClassLoader_name(),
111 vmSymbols::void_classloader_signature(),
112 CHECK);
113
114 _java_system_loader = (oop)result.get_jobject();
115
116 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
117 }
118
119
120 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
121 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
122 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
123 }
124
125 // ----------------------------------------------------------------------------
126 // debugging
127
128 #ifdef ASSERT
129
130 // return true if class_name contains no '.' (internal format is '/')
131 bool SystemDictionary::is_internal_format(Symbol* class_name) {
132 if (class_name != NULL) {
133 ResourceMark rm;
134 char* name = class_name->as_C_string();
135 return strchr(name, '.') == NULL;
136 } else {
137 return true;
138 }
139 }
140
141 #endif
142 #if INCLUDE_JFR
143 #include "jfr/jfr.hpp"
144 #endif
145
146 // ----------------------------------------------------------------------------
147 // Parallel class loading check
148
149 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
150 if (UnsyncloadClass || class_loader.is_null()) return true;
151 if (AlwaysLockClassLoader) return false;
152 return java_lang_ClassLoader::parallelCapable(class_loader());
153 }
154 // ----------------------------------------------------------------------------
155 // ParallelDefineClass flag does not apply to bootclass loader
156 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
157 if (class_loader.is_null()) return false;
158 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
159 return true;
160 }
161 return false;
162 }
163
164 /**
165 * Returns true if the passed class loader is the extension class loader.
166 */
167 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
168 if (class_loader.is_null()) {
169 return false;
170 }
171 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
172 }
173
174 // ----------------------------------------------------------------------------
175 // Resolving of classes
176
177 // Forwards to resolve_or_null
178
179 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
180 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
181 if (HAS_PENDING_EXCEPTION || klass == NULL) {
182 KlassHandle k_h(THREAD, klass);
183 // can return a null klass
184 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
185 }
186 return klass;
187 }
188
189 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
190 if (HAS_PENDING_EXCEPTION) {
191 // If we have a pending exception we forward it to the caller, unless throw_error is true,
192 // in which case we have to check whether the pending exception is a ClassNotFoundException,
193 // and if so convert it to a NoClassDefFoundError
194 // And chain the original ClassNotFoundException
195 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
196 ResourceMark rm(THREAD);
197 assert(klass_h() == NULL, "Should not have result with exception pending");
198 Handle e(THREAD, PENDING_EXCEPTION);
199 CLEAR_PENDING_EXCEPTION;
200 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
201 } else {
202 return NULL;
203 }
204 }
205 // Class not found, throw appropriate error or exception depending on value of throw_error
206 if (klass_h() == NULL) {
207 ResourceMark rm(THREAD);
208 if (throw_error) {
209 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
210 } else {
211 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
212 }
213 }
214 return (Klass*)klass_h();
215 }
216
217
218 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
219 bool throw_error, TRAPS)
220 {
221 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
222 }
223
224
225 // Forwards to resolve_instance_class_or_null
226
227 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
228 assert(!THREAD->is_Compiler_thread(),
229 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
230 class_name->as_C_string(),
231 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
232 if (FieldType::is_array(class_name)) {
233 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
234 } else if (FieldType::is_obj(class_name)) {
235 ResourceMark rm(THREAD);
236 // Ignore wrapping L and ;.
237 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
238 class_name->utf8_length() - 2, CHECK_NULL);
239 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
240 } else {
241 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
242 }
243 }
244
245 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
246 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
247 }
248
249 // Forwards to resolve_instance_class_or_null
250
251 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
252 Handle class_loader,
253 Handle protection_domain,
254 TRAPS) {
255 assert(FieldType::is_array(class_name), "must be array");
256 Klass* k = NULL;
257 FieldArrayInfo fd;
258 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
259 // of this call
260 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
261 if (t == T_OBJECT) {
262 // naked oop "k" is OK here -- we assign back into it
263 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
264 class_loader,
265 protection_domain,
266 CHECK_NULL);
267 if (k != NULL) {
268 k = k->array_klass(fd.dimension(), CHECK_NULL);
269 }
270 } else {
271 k = Universe::typeArrayKlassObj(t);
272 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
273 }
274 return k;
275 }
276
277
278 // Must be called for any super-class or super-interface resolution
279 // during class definition to allow class circularity checking
280 // super-interface callers:
281 // parse_interfaces - for defineClass & jvmtiRedefineClasses
282 // super-class callers:
283 // ClassFileParser - for defineClass & jvmtiRedefineClasses
284 // load_shared_class - while loading a class from shared archive
285 // resolve_instance_class_or_null:
286 // via: handle_parallel_super_load
287 // when resolving a class that has an existing placeholder with
288 // a saved superclass [i.e. a defineClass is currently in progress]
289 // if another thread is trying to resolve the class, it must do
290 // super-class checks on its own thread to catch class circularity
291 // This last call is critical in class circularity checking for cases
292 // where classloading is delegated to different threads and the
293 // classloader lock is released.
294 // Take the case: Base->Super->Base
295 // 1. If thread T1 tries to do a defineClass of class Base
296 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
297 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
298 // so it tries to load Super
299 // 3. If we load the class internally, or user classloader uses same thread
300 // loadClassFromxxx or defineClass via parseClassFile Super ...
301 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
302 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
303 // 3.4 calls resolve_super_or_fail Base
304 // 3.5 finds T1,Base -> throws class circularity
305 //OR 4. If T2 tries to resolve Super via defineClass Super ...
306 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
307 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
308 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
309 // 4.4 finds T2, Super -> throws class circularity
310 // Must be called, even if superclass is null, since this is
311 // where the placeholder entry is created which claims this
312 // thread is loading this class/classloader.
313 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
314 Symbol* class_name,
315 Handle class_loader,
316 Handle protection_domain,
317 bool is_superclass,
318 TRAPS) {
319 // Double-check, if child class is already loaded, just return super-class,interface
320 // Don't add a placedholder if already loaded, i.e. already in system dictionary
321 // Make sure there's a placeholder for the *child* before resolving.
322 // Used as a claim that this thread is currently loading superclass/classloader
323 // Used here for ClassCircularity checks and also for heap verification
324 // (every InstanceKlass in the heap needs to be in the system dictionary
325 // or have a placeholder).
326 // Must check ClassCircularity before checking if super class is already loaded
327 //
328 // We might not already have a placeholder if this child_name was
329 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
330 // the name of the class might not be known until the stream is actually
331 // parsed.
332 // Bugs 4643874, 4715493
333 // compute_hash can have a safepoint
334
335 ClassLoaderData* loader_data = class_loader_data(class_loader);
336 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
337 int d_index = dictionary()->hash_to_index(d_hash);
338 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
339 int p_index = placeholders()->hash_to_index(p_hash);
340 // can't throw error holding a lock
341 bool child_already_loaded = false;
342 bool throw_circularity_error = false;
343 {
344 MutexLocker mu(SystemDictionary_lock, THREAD);
345 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
346 Klass* quicksuperk;
347 // to support // loading: if child done loading, just return superclass
348 // if class_name, & class_loader don't match:
349 // if initial define, SD update will give LinkageError
350 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
351 // so we don't throw an exception here.
352 // see: nsk redefclass014 & java.lang.instrument Instrument032
353 if ((childk != NULL ) && (is_superclass) &&
354 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
355
356 ((quicksuperk->name() == class_name) &&
357 (quicksuperk->class_loader() == class_loader()))) {
358 return quicksuperk;
359 } else {
360 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
361 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
362 throw_circularity_error = true;
363 }
364 }
365 if (!throw_circularity_error) {
366 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
367 }
368 }
369 if (throw_circularity_error) {
370 ResourceMark rm(THREAD);
371 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
372 }
373
374 // java.lang.Object should have been found above
375 assert(class_name != NULL, "null super class for resolving");
376 // Resolve the super class or interface, check results on return
377 Klass* superk = SystemDictionary::resolve_or_null(class_name,
378 class_loader,
379 protection_domain,
380 THREAD);
381
382 KlassHandle superk_h(THREAD, superk);
383
384 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
385 // It is no longer necessary to keep the placeholder table alive until update_dictionary
386 // or error. GC used to walk the placeholder table as strong roots.
387 // The instanceKlass is kept alive because the class loader is on the stack,
388 // which keeps the loader_data alive, as well as all instanceKlasses in
389 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
390 {
391 MutexLocker mu(SystemDictionary_lock, THREAD);
392 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
393 SystemDictionary_lock->notify_all();
394 }
395 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
396 // can null superk
397 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
398 }
399
400 return superk_h();
401 }
402
403 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
404 Handle class_loader,
405 Handle protection_domain,
406 TRAPS) {
407 if(!has_checkPackageAccess()) return;
408
409 // Now we have to call back to java to check if the initating class has access
410 JavaValue result(T_VOID);
411 if (TraceProtectionDomainVerification) {
412 // Print out trace information
413 tty->print_cr("Checking package access");
414 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
415 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
416 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
417 }
418
419 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
420 JavaCalls::call_special(&result,
421 class_loader,
422 system_loader,
423 vmSymbols::checkPackageAccess_name(),
424 vmSymbols::class_protectiondomain_signature(),
425 Handle(THREAD, klass->java_mirror()),
426 protection_domain,
427 THREAD);
428
429 if (TraceProtectionDomainVerification) {
430 if (HAS_PENDING_EXCEPTION) {
431 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
432 } else {
433 tty->print_cr(" -> granted");
434 }
435 tty->cr();
436 }
437
438 if (HAS_PENDING_EXCEPTION) return;
439
440 // If no exception has been thrown, we have validated the protection domain
441 // Insert the protection domain of the initiating class into the set.
442 {
443 // We recalculate the entry here -- we've called out to java since
444 // the last time it was calculated.
445 ClassLoaderData* loader_data = class_loader_data(class_loader);
446
447 Symbol* kn = klass->name();
448 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
449 int d_index = dictionary()->hash_to_index(d_hash);
450
451 MutexLocker mu(SystemDictionary_lock, THREAD);
452 {
453 // Note that we have an entry, and entries can be deleted only during GC,
454 // so we cannot allow GC to occur while we're holding this entry.
455
456 // We're using a No_Safepoint_Verifier to catch any place where we
457 // might potentially do a GC at all.
458 // Dictionary::do_unloading() asserts that classes in SD are only
459 // unloaded at a safepoint. Anonymous classes are not in SD.
460 No_Safepoint_Verifier nosafepoint;
461 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
462 protection_domain, THREAD);
463 }
464 }
465 }
466
467 // We only get here if this thread finds that another thread
468 // has already claimed the placeholder token for the current operation,
469 // but that other thread either never owned or gave up the
470 // object lock
471 // Waits on SystemDictionary_lock to indicate placeholder table updated
472 // On return, caller must recheck placeholder table state
473 //
474 // We only get here if
475 // 1) custom classLoader, i.e. not bootstrap classloader
476 // 2) UnsyncloadClass not set
477 // 3) custom classLoader has broken the class loader objectLock
478 // so another thread got here in parallel
479 //
480 // lockObject must be held.
481 // Complicated dance due to lock ordering:
482 // Must first release the classloader object lock to
483 // allow initial definer to complete the class definition
484 // and to avoid deadlock
485 // Reclaim classloader lock object with same original recursion count
486 // Must release SystemDictionary_lock after notify, since
487 // class loader lock must be claimed before SystemDictionary_lock
488 // to prevent deadlocks
489 //
490 // The notify allows applications that did an untimed wait() on
491 // the classloader object lock to not hang.
492 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
493 assert_lock_strong(SystemDictionary_lock);
494
495 bool calledholdinglock
496 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
497 assert(calledholdinglock,"must hold lock for notify");
498 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
499 ObjectSynchronizer::notifyall(lockObject, THREAD);
500 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
501 SystemDictionary_lock->wait();
502 SystemDictionary_lock->unlock();
503 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
504 SystemDictionary_lock->lock();
505 }
506
507 // If the class in is in the placeholder table, class loading is in progress
508 // For cases where the application changes threads to load classes, it
509 // is critical to ClassCircularity detection that we try loading
510 // the superclass on the same thread internally, so we do parallel
511 // super class loading here.
512 // This also is critical in cases where the original thread gets stalled
513 // even in non-circularity situations.
514 // Note: must call resolve_super_or_fail even if null super -
515 // to force placeholder entry creation for this class for circularity detection
516 // Caller must check for pending exception
517 // Returns non-null Klass* if other thread has completed load
518 // and we are done,
519 // If return null Klass* and no pending exception, the caller must load the class
520 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
521 Symbol* name, Symbol* superclassname, Handle class_loader,
522 Handle protection_domain, Handle lockObject, TRAPS) {
523
524 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
525 ClassLoaderData* loader_data = class_loader_data(class_loader);
526 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
527 int d_index = dictionary()->hash_to_index(d_hash);
528 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
529 int p_index = placeholders()->hash_to_index(p_hash);
530
531 // superk is not used, resolve_super called for circularity check only
532 // This code is reached in two situations. One if this thread
533 // is loading the same class twice (e.g. ClassCircularity, or
534 // java.lang.instrument).
535 // The second is if another thread started the resolve_super first
536 // and has not yet finished.
537 // In both cases the original caller will clean up the placeholder
538 // entry on error.
539 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
540 superclassname,
541 class_loader,
542 protection_domain,
543 true,
544 CHECK_(nh));
545
546 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
547 // Serial class loaders and bootstrap classloader do wait for superclass loads
548 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
549 MutexLocker mu(SystemDictionary_lock, THREAD);
550 // Check if classloading completed while we were loading superclass or waiting
551 Klass* check = find_class(d_index, d_hash, name, loader_data);
552 if (check != NULL) {
553 // Klass is already loaded, so just return it
554 return(instanceKlassHandle(THREAD, check));
555 } else {
556 return nh;
557 }
558 }
559
560 // must loop to both handle other placeholder updates
561 // and spurious notifications
562 bool super_load_in_progress = true;
563 PlaceholderEntry* placeholder;
564 while (super_load_in_progress) {
565 MutexLocker mu(SystemDictionary_lock, THREAD);
566 // Check if classloading completed while we were loading superclass or waiting
567 Klass* check = find_class(d_index, d_hash, name, loader_data);
568 if (check != NULL) {
569 // Klass is already loaded, so just return it
570 return(instanceKlassHandle(THREAD, check));
571 } else {
572 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
573 if (placeholder && placeholder->super_load_in_progress() ){
574 // Before UnsyncloadClass:
575 // We only get here if the application has released the
576 // classloader lock when another thread was in the middle of loading a
577 // superclass/superinterface for this class, and now
578 // this thread is also trying to load this class.
579 // To minimize surprises, the first thread that started to
580 // load a class should be the one to complete the loading
581 // with the classfile it initially expected.
582 // This logic has the current thread wait once it has done
583 // all the superclass/superinterface loading it can, until
584 // the original thread completes the class loading or fails
585 // If it completes we will use the resulting InstanceKlass
586 // which we will find below in the systemDictionary.
587 // We also get here for parallel bootstrap classloader
588 if (class_loader.is_null()) {
589 SystemDictionary_lock->wait();
590 } else {
591 double_lock_wait(lockObject, THREAD);
592 }
593 } else {
594 // If not in SD and not in PH, other thread's load must have failed
595 super_load_in_progress = false;
596 }
597 }
598 }
599 return (nh);
600 }
601
602 // utility function for class load event
603 static void post_class_load_event(EventClassLoad &event,
604 instanceKlassHandle k,
605 Handle initiating_loader) {
606 #if INCLUDE_JFR
607 if (event.should_commit()) {
608 event.set_loadedClass(k());
609 event.set_definingClassLoader(k->class_loader_data());
610 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
611 event.set_initiatingClassLoader(class_loader != NULL ?
612 ClassLoaderData::class_loader_data_or_null(class_loader) :
613 (ClassLoaderData*)NULL);
614 event.commit();
615 }
616 #endif // INCLUDE_JFR
617 }
618
619 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
620 Handle class_loader,
621 Handle protection_domain,
622 TRAPS) {
623 assert(name != NULL && !FieldType::is_array(name) &&
624 !FieldType::is_obj(name), "invalid class name");
625
626 EventClassLoad class_load_start_event;
627
628 // UseNewReflection
629 // Fix for 4474172; see evaluation for more details
630 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
631 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
632
633 // Do lookup to see if class already exist and the protection domain
634 // has the right access
635 // This call uses find which checks protection domain already matches
636 // All subsequent calls use find_class, and set has_loaded_class so that
637 // before we return a result we call out to java to check for valid protection domain
638 // to allow returning the Klass* and add it to the pd_set if it is valid
639 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
640 int d_index = dictionary()->hash_to_index(d_hash);
641 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
642 protection_domain, THREAD);
643 if (probe != NULL) return probe;
644
645
646 // Non-bootstrap class loaders will call out to class loader and
647 // define via jvm/jni_DefineClass which will acquire the
648 // class loader object lock to protect against multiple threads
649 // defining the class in parallel by accident.
650 // This lock must be acquired here so the waiter will find
651 // any successful result in the SystemDictionary and not attempt
652 // the define
653 // ParallelCapable Classloaders and the bootstrap classloader,
654 // or all classloaders with UnsyncloadClass do not acquire lock here
655 bool DoObjectLock = true;
656 if (is_parallelCapable(class_loader)) {
657 DoObjectLock = false;
658 }
659
660 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
661 int p_index = placeholders()->hash_to_index(p_hash);
662
663 // Class is not in SystemDictionary so we have to do loading.
664 // Make sure we are synchronized on the class loader before we proceed
665 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
666 check_loader_lock_contention(lockObject, THREAD);
667 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
668
669 // Check again (after locking) if class already exist in SystemDictionary
670 bool class_has_been_loaded = false;
671 bool super_load_in_progress = false;
672 bool havesupername = false;
673 instanceKlassHandle k;
674 PlaceholderEntry* placeholder;
675 Symbol* superclassname = NULL;
676
677 {
678 MutexLocker mu(SystemDictionary_lock, THREAD);
679 Klass* check = find_class(d_index, d_hash, name, loader_data);
680 if (check != NULL) {
681 // Klass is already loaded, so just return it
682 class_has_been_loaded = true;
683 k = instanceKlassHandle(THREAD, check);
684 } else {
685 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
686 if (placeholder && placeholder->super_load_in_progress()) {
687 super_load_in_progress = true;
688 if (placeholder->havesupername() == true) {
689 superclassname = placeholder->supername();
690 havesupername = true;
691 }
692 }
693 }
694 }
695
696 // If the class is in the placeholder table, class loading is in progress
697 if (super_load_in_progress && havesupername==true) {
698 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
699 class_loader, protection_domain, lockObject, THREAD);
700 if (HAS_PENDING_EXCEPTION) {
701 return NULL;
702 }
703 if (!k.is_null()) {
704 class_has_been_loaded = true;
705 }
706 }
707
708 bool throw_circularity_error = false;
709 if (!class_has_been_loaded) {
710 bool load_instance_added = false;
711
712 // add placeholder entry to record loading instance class
713 // Five cases:
714 // All cases need to prevent modifying bootclasssearchpath
715 // in parallel with a classload of same classname
716 // Redefineclasses uses existence of the placeholder for the duration
717 // of the class load to prevent concurrent redefinition of not completely
718 // defined classes.
719 // case 1. traditional classloaders that rely on the classloader object lock
720 // - no other need for LOAD_INSTANCE
721 // case 2. traditional classloaders that break the classloader object lock
722 // as a deadlock workaround. Detection of this case requires that
723 // this check is done while holding the classloader object lock,
724 // and that lock is still held when calling classloader's loadClass.
725 // For these classloaders, we ensure that the first requestor
726 // completes the load and other requestors wait for completion.
727 // case 3. UnsyncloadClass - don't use objectLocker
728 // With this flag, we allow parallel classloading of a
729 // class/classloader pair
730 // case4. Bootstrap classloader - don't own objectLocker
731 // This classloader supports parallelism at the classloader level,
732 // but only allows a single load of a class/classloader pair.
733 // No performance benefit and no deadlock issues.
734 // case 5. parallelCapable user level classloaders - without objectLocker
735 // Allow parallel classloading of a class/classloader pair
736
737 {
738 MutexLocker mu(SystemDictionary_lock, THREAD);
739 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
740 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
741 if (oldprobe) {
742 // only need check_seen_thread once, not on each loop
743 // 6341374 java/lang/Instrument with -Xcomp
744 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
745 throw_circularity_error = true;
746 } else {
747 // case 1: traditional: should never see load_in_progress.
748 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
749
750 // case 4: bootstrap classloader: prevent futile classloading,
751 // wait on first requestor
752 if (class_loader.is_null()) {
753 SystemDictionary_lock->wait();
754 } else {
755 // case 2: traditional with broken classloader lock. wait on first
756 // requestor.
757 double_lock_wait(lockObject, THREAD);
758 }
759 // Check if classloading completed while we were waiting
760 Klass* check = find_class(d_index, d_hash, name, loader_data);
761 if (check != NULL) {
762 // Klass is already loaded, so just return it
763 k = instanceKlassHandle(THREAD, check);
764 class_has_been_loaded = true;
765 }
766 // check if other thread failed to load and cleaned up
767 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
768 }
769 }
770 }
771 }
772 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
773 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
774 // LOAD_INSTANCE in parallel
775
776 if (!throw_circularity_error && !class_has_been_loaded) {
777 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
778 load_instance_added = true;
779 // For class loaders that do not acquire the classloader object lock,
780 // if they did not catch another thread holding LOAD_INSTANCE,
781 // need a check analogous to the acquire ObjectLocker/find_class
782 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
783 // one final check if the load has already completed
784 // class loaders holding the ObjectLock shouldn't find the class here
785 Klass* check = find_class(d_index, d_hash, name, loader_data);
786 if (check != NULL) {
787 // Klass is already loaded, so return it after checking/adding protection domain
788 k = instanceKlassHandle(THREAD, check);
789 class_has_been_loaded = true;
790 }
791 }
792 }
793
794 // must throw error outside of owning lock
795 if (throw_circularity_error) {
796 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
797 ResourceMark rm(THREAD);
798 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
799 }
800
801 if (!class_has_been_loaded) {
802
803 // Do actual loading
804 k = load_instance_class(name, class_loader, THREAD);
805
806 // For UnsyncloadClass only
807 // If they got a linkageError, check if a parallel class load succeeded.
808 // If it did, then for bytecode resolution the specification requires
809 // that we return the same result we did for the other thread, i.e. the
810 // successfully loaded InstanceKlass
811 // Should not get here for classloaders that support parallelism
812 // with the new cleaner mechanism, even with AllowParallelDefineClass
813 // Bootstrap goes through here to allow for an extra guarantee check
814 if (UnsyncloadClass || (class_loader.is_null())) {
815 if (k.is_null() && HAS_PENDING_EXCEPTION
816 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
817 MutexLocker mu(SystemDictionary_lock, THREAD);
818 Klass* check = find_class(d_index, d_hash, name, loader_data);
819 if (check != NULL) {
820 // Klass is already loaded, so just use it
821 k = instanceKlassHandle(THREAD, check);
822 CLEAR_PENDING_EXCEPTION;
823 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
824 }
825 }
826 }
827
828 // If everything was OK (no exceptions, no null return value), and
829 // class_loader is NOT the defining loader, do a little more bookkeeping.
830 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
831 k->class_loader() != class_loader()) {
832
833 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
834
835 // Need to check for a PENDING_EXCEPTION again; check_constraints
836 // can throw but we may have to remove entry from the placeholder table below.
837 if (!HAS_PENDING_EXCEPTION) {
838 // Record dependency for non-parent delegation.
839 // This recording keeps the defining class loader of the klass (k) found
840 // from being unloaded while the initiating class loader is loaded
841 // even if the reference to the defining class loader is dropped
842 // before references to the initiating class loader.
843 loader_data->record_dependency(k(), THREAD);
844 }
845
846 if (!HAS_PENDING_EXCEPTION) {
847 { // Grabbing the Compile_lock prevents systemDictionary updates
848 // during compilations.
849 MutexLocker mu(Compile_lock, THREAD);
850 update_dictionary(d_index, d_hash, p_index, p_hash,
851 k, class_loader, THREAD);
852 }
853
854 if (JvmtiExport::should_post_class_load()) {
855 Thread *thread = THREAD;
856 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
857 JvmtiExport::post_class_load((JavaThread *) thread, k());
858 }
859 }
860 }
861 } // load_instance_class loop
862
863 if (load_instance_added == true) {
864 // clean up placeholder entries for LOAD_INSTANCE success or error
865 // This brackets the SystemDictionary updates for both defining
866 // and initiating loaders
867 MutexLocker mu(SystemDictionary_lock, THREAD);
868 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
869 SystemDictionary_lock->notify_all();
870 }
871 }
872
873 if (HAS_PENDING_EXCEPTION || k.is_null()) {
874 return NULL;
875 }
876
877 post_class_load_event(class_load_start_event, k, class_loader);
878
879 #ifdef ASSERT
880 {
881 ClassLoaderData* loader_data = k->class_loader_data();
882 MutexLocker mu(SystemDictionary_lock, THREAD);
883 Klass* kk = find_class(name, loader_data);
884 assert(kk == k(), "should be present in dictionary");
885 }
886 #endif
887
888 // return if the protection domain in NULL
889 if (protection_domain() == NULL) return k();
890
891 // Check the protection domain has the right access
892 {
893 MutexLocker mu(SystemDictionary_lock, THREAD);
894 // Note that we have an entry, and entries can be deleted only during GC,
895 // so we cannot allow GC to occur while we're holding this entry.
896 // We're using a No_Safepoint_Verifier to catch any place where we
897 // might potentially do a GC at all.
898 // Dictionary::do_unloading() asserts that classes in SD are only
899 // unloaded at a safepoint. Anonymous classes are not in SD.
900 No_Safepoint_Verifier nosafepoint;
901 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
902 loader_data,
903 protection_domain)) {
904 return k();
905 }
906 }
907
908 // Verify protection domain. If it fails an exception is thrown
909 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
910
911 return k();
912 }
913
914
915 // This routine does not lock the system dictionary.
916 //
917 // Since readers don't hold a lock, we must make sure that system
918 // dictionary entries are only removed at a safepoint (when only one
919 // thread is running), and are added to in a safe way (all links must
920 // be updated in an MT-safe manner).
921 //
922 // Callers should be aware that an entry could be added just after
923 // _dictionary->bucket(index) is read here, so the caller will not see
924 // the new entry.
925
926 Klass* SystemDictionary::find(Symbol* class_name,
927 Handle class_loader,
928 Handle protection_domain,
929 TRAPS) {
930
931 // UseNewReflection
932 // The result of this call should be consistent with the result
933 // of the call to resolve_instance_class_or_null().
934 // See evaluation 6790209 and 4474172 for more details.
935 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
936 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
937
938 if (loader_data == NULL) {
939 // If the ClassLoaderData has not been setup,
940 // then the class loader has no entries in the dictionary.
941 return NULL;
942 }
943
944 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
945 int d_index = dictionary()->hash_to_index(d_hash);
946
947 {
948 // Note that we have an entry, and entries can be deleted only during GC,
949 // so we cannot allow GC to occur while we're holding this entry.
950 // We're using a No_Safepoint_Verifier to catch any place where we
951 // might potentially do a GC at all.
952 // Dictionary::do_unloading() asserts that classes in SD are only
953 // unloaded at a safepoint. Anonymous classes are not in SD.
954 No_Safepoint_Verifier nosafepoint;
955 return dictionary()->find(d_index, d_hash, class_name, loader_data,
956 protection_domain, THREAD);
957 }
958 }
959
960
961 // Look for a loaded instance or array klass by name. Do not do any loading.
962 // return NULL in case of error.
963 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
964 Handle class_loader,
965 Handle protection_domain,
966 TRAPS) {
967 Klass* k = NULL;
968 assert(class_name != NULL, "class name must be non NULL");
969
970 if (FieldType::is_array(class_name)) {
971 // The name refers to an array. Parse the name.
972 // dimension and object_key in FieldArrayInfo are assigned as a
973 // side-effect of this call
974 FieldArrayInfo fd;
975 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
976 if (t != T_OBJECT) {
977 k = Universe::typeArrayKlassObj(t);
978 } else {
979 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
980 }
981 if (k != NULL) {
982 k = k->array_klass_or_null(fd.dimension());
983 }
984 } else {
985 k = find(class_name, class_loader, protection_domain, THREAD);
986 }
987 return k;
988 }
989
990 // Note: this method is much like resolve_from_stream, but
991 // updates no supplemental data structures.
992 // TODO consolidate the two methods with a helper routine?
993 Klass* SystemDictionary::parse_stream(Symbol* class_name,
994 Handle class_loader,
995 Handle protection_domain,
996 ClassFileStream* st,
997 KlassHandle host_klass,
998 GrowableArray<Handle>* cp_patches,
999 TRAPS) {
1000 TempNewSymbol parsed_name = NULL;
1001
1002 EventClassLoad class_load_start_event;
1003
1004 ClassLoaderData* loader_data;
1005 if (host_klass.not_null()) {
1006 // Create a new CLD for anonymous class, that uses the same class loader
1007 // as the host_klass
1008 assert(EnableInvokeDynamic, "");
1009 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1010 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1011 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1012 loader_data->record_dependency(host_klass(), CHECK_NULL);
1013 } else {
1014 loader_data = ClassLoaderData::class_loader_data(class_loader());
1015 }
1016
1017 // Parse the stream. Note that we do this even though this klass might
1018 // already be present in the SystemDictionary, otherwise we would not
1019 // throw potential ClassFormatErrors.
1020 //
1021 // Note: "name" is updated.
1022
1023 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1024 loader_data,
1025 protection_domain,
1026 host_klass,
1027 cp_patches,
1028 parsed_name,
1029 true,
1030 THREAD);
1031
1032
1033 if (host_klass.not_null() && k.not_null()) {
1034 assert(EnableInvokeDynamic, "");
1035 // If it's anonymous, initialize it now, since nobody else will.
1036
1037 {
1038 MutexLocker mu_r(Compile_lock, THREAD);
1039
1040 // Add to class hierarchy, initialize vtables, and do possible
1041 // deoptimizations.
1042 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1043
1044 // But, do not add to system dictionary.
1045
1046 // compiled code dependencies need to be validated anyway
1047 notice_modification();
1048 }
1049
1050 // Rewrite and patch constant pool here.
1051 k->link_class(CHECK_NULL);
1052 if (cp_patches != NULL) {
1053 k->constants()->patch_resolved_references(cp_patches);
1054 }
1055 k->eager_initialize(CHECK_NULL);
1056
1057 // notify jvmti
1058 if (JvmtiExport::should_post_class_load()) {
1059 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1060 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1061 }
1062
1063 post_class_load_event(class_load_start_event, k, class_loader);
1064 }
1065 assert(host_klass.not_null() || cp_patches == NULL,
1066 "cp_patches only found with host_klass");
1067
1068 return k();
1069 }
1070
1071 // Add a klass to the system from a stream (called by jni_DefineClass and
1072 // JVM_DefineClass).
1073 // Note: class_name can be NULL. In that case we do not know the name of
1074 // the class until we have parsed the stream.
1075
1076 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1077 Handle class_loader,
1078 Handle protection_domain,
1079 ClassFileStream* st,
1080 bool verify,
1081 TRAPS) {
1082
1083 // Classloaders that support parallelism, e.g. bootstrap classloader,
1084 // or all classloaders with UnsyncloadClass do not acquire lock here
1085 bool DoObjectLock = true;
1086 if (is_parallelCapable(class_loader)) {
1087 DoObjectLock = false;
1088 }
1089
1090 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1091
1092 // Make sure we are synchronized on the class loader before we proceed
1093 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1094 check_loader_lock_contention(lockObject, THREAD);
1095 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1096
1097 TempNewSymbol parsed_name = NULL;
1098
1099 // Parse the stream. Note that we do this even though this klass might
1100 // already be present in the SystemDictionary, otherwise we would not
1101 // throw potential ClassFormatErrors.
1102 //
1103 // Note: "name" is updated.
1104
1105 ClassFileParser parser(st);
1106 instanceKlassHandle k = parser.parseClassFile(class_name,
1107 loader_data,
1108 protection_domain,
1109 parsed_name,
1110 verify,
1111 THREAD);
1112
1113 const char* pkg = "java/";
1114 size_t pkglen = strlen(pkg);
1115 if (!HAS_PENDING_EXCEPTION &&
1116 !class_loader.is_null() &&
1117 parsed_name != NULL &&
1118 parsed_name->utf8_length() >= (int)pkglen &&
1119 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1120 // It is illegal to define classes in the "java." package from
1121 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1122 ResourceMark rm(THREAD);
1123 char* name = parsed_name->as_C_string();
1124 char* index = strrchr(name, '/');
1125 assert(index != NULL, "must be");
1126 *index = '\0'; // chop to just the package name
1127 while ((index = strchr(name, '/')) != NULL) {
1128 *index = '.'; // replace '/' with '.' in package name
1129 }
1130 const char* fmt = "Prohibited package name: %s";
1131 size_t len = strlen(fmt) + strlen(name);
1132 char* message = NEW_RESOURCE_ARRAY(char, len);
1133 jio_snprintf(message, len, fmt, name);
1134 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1135 vmSymbols::java_lang_SecurityException(), message);
1136 }
1137
1138 if (!HAS_PENDING_EXCEPTION) {
1139 assert(parsed_name != NULL, "Sanity");
1140 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1141 // Verification prevents us from creating names with dots in them, this
1142 // asserts that that's the case.
1143 assert(is_internal_format(parsed_name),
1144 "external class name format used internally");
1145
1146 #if INCLUDE_JFR
1147 {
1148 InstanceKlass* ik = k();
1149 ON_KLASS_CREATION(ik, parser, THREAD);
1150 k = instanceKlassHandle(ik);
1151 }
1152 #endif
1153
1154 // Add class just loaded
1155 // If a class loader supports parallel classloading handle parallel define requests
1156 // find_or_define_instance_class may return a different InstanceKlass
1157 if (is_parallelCapable(class_loader)) {
1158 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1159 } else {
1160 define_instance_class(k, THREAD);
1161 }
1162 }
1163
1164 // Make sure we have an entry in the SystemDictionary on success
1165 debug_only( {
1166 if (!HAS_PENDING_EXCEPTION) {
1167 assert(parsed_name != NULL, "parsed_name is still null?");
1168 Symbol* h_name = k->name();
1169 ClassLoaderData *defining_loader_data = k->class_loader_data();
1170
1171 MutexLocker mu(SystemDictionary_lock, THREAD);
1172
1173 Klass* check = find_class(parsed_name, loader_data);
1174 assert(check == k(), "should be present in the dictionary");
1175
1176 Klass* check2 = find_class(h_name, defining_loader_data);
1177 assert(check == check2, "name inconsistancy in SystemDictionary");
1178 }
1179 } );
1180
1181 return k();
1182 }
1183
1184 #if INCLUDE_CDS
1185 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1186 int number_of_entries) {
1187 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1188 "bad shared dictionary size.");
1189 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1190 }
1191
1192
1193 // If there is a shared dictionary, then find the entry for the
1194 // given shared system class, if any.
1195
1196 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1197 if (shared_dictionary() != NULL) {
1198 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1199 int d_index = shared_dictionary()->hash_to_index(d_hash);
1200
1201 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1202 } else {
1203 return NULL;
1204 }
1205 }
1206
1207
1208 // Load a class from the shared spaces (found through the shared system
1209 // dictionary). Force the superclass and all interfaces to be loaded.
1210 // Update the class definition to include sibling classes and no
1211 // subclasses (yet). [Classes in the shared space are not part of the
1212 // object hierarchy until loaded.]
1213
1214 instanceKlassHandle SystemDictionary::load_shared_class(
1215 Symbol* class_name, Handle class_loader, TRAPS) {
1216 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1217 // Make sure we only return the boot class for the NULL classloader.
1218 if (ik.not_null() &&
1219 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1220 Handle protection_domain;
1221 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1222 }
1223 return instanceKlassHandle();
1224 }
1225
1226 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1227 Handle class_loader,
1228 Handle protection_domain, TRAPS) {
1229 if (ik.not_null()) {
1230 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1231 Symbol* class_name = ik->name();
1232
1233 // Found the class, now load the superclass and interfaces. If they
1234 // are shared, add them to the main system dictionary and reset
1235 // their hierarchy references (supers, subs, and interfaces).
1236
1237 if (ik->super() != NULL) {
1238 Symbol* cn = ik->super()->name();
1239 Klass *s = resolve_super_or_fail(class_name, cn,
1240 class_loader, protection_domain, true, CHECK_(nh));
1241 if (s != ik->super()) {
1242 // The dynamically resolved super class is not the same as the one we used during dump time,
1243 // so we cannot use ik.
1244 return nh;
1245 }
1246 }
1247
1248 Array<Klass*>* interfaces = ik->local_interfaces();
1249 int num_interfaces = interfaces->length();
1250 for (int index = 0; index < num_interfaces; index++) {
1251 Klass* k = interfaces->at(index);
1252
1253 // Note: can not use InstanceKlass::cast here because
1254 // interfaces' InstanceKlass's C++ vtbls haven't been
1255 // reinitialized yet (they will be once the interface classes
1256 // are loaded)
1257 Symbol* name = k->name();
1258 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1259 if (k != i) {
1260 // The dynamically resolved interface class is not the same as the one we used during dump time,
1261 // so we cannot use ik.
1262 return nh;
1263 }
1264 }
1265
1266 // Adjust methods to recover missing data. They need addresses for
1267 // interpreter entry points and their default native method address
1268 // must be reset.
1269
1270 // Updating methods must be done under a lock so multiple
1271 // threads don't update these in parallel
1272 //
1273 // Shared classes are all currently loaded by either the bootstrap or
1274 // internal parallel class loaders, so this will never cause a deadlock
1275 // on a custom class loader lock.
1276
1277 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1278 {
1279 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1280 check_loader_lock_contention(lockObject, THREAD);
1281 ObjectLocker ol(lockObject, THREAD, true);
1282 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1283 }
1284
1285 if (TraceClassLoading) {
1286 ResourceMark rm;
1287 tty->print("[Loaded %s", ik->external_name());
1288 tty->print(" from shared objects file");
1289 if (class_loader.not_null()) {
1290 tty->print(" by %s", loader_data->loader_name());
1291 }
1292 tty->print_cr("]");
1293 }
1294
1295 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1296 // Only dump the classes that can be stored into CDS archive
1297 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1298 ResourceMark rm(THREAD);
1299 classlist_file->print_cr("%s", ik->name()->as_C_string());
1300 classlist_file->flush();
1301 }
1302 }
1303
1304 // notify a class loaded from shared object
1305 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1306 true /* shared class */);
1307 }
1308 return ik;
1309 }
1310 #endif // INCLUDE_CDS
1311
1312 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1313 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1314 if (class_loader.is_null()) {
1315
1316 // Search the shared system dictionary for classes preloaded into the
1317 // shared spaces.
1318 instanceKlassHandle k;
1319 {
1320 #if INCLUDE_CDS
1321 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1322 k = load_shared_class(class_name, class_loader, THREAD);
1323 #endif
1324 }
1325
1326 if (k.is_null()) {
1327 // Use VM class loader
1328 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1329 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1330 }
1331
1332 // find_or_define_instance_class may return a different InstanceKlass
1333 if (!k.is_null()) {
1334 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1335 }
1336 return k;
1337 } else {
1338 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1339 ResourceMark rm(THREAD);
1340
1341 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1342 JavaThread* jt = (JavaThread*) THREAD;
1343
1344 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1345 ClassLoader::perf_app_classload_selftime(),
1346 ClassLoader::perf_app_classload_count(),
1347 jt->get_thread_stat()->perf_recursion_counts_addr(),
1348 jt->get_thread_stat()->perf_timers_addr(),
1349 PerfClassTraceTime::CLASS_LOAD);
1350
1351 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1352 // Translate to external class name format, i.e., convert '/' chars to '.'
1353 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1354
1355 JavaValue result(T_OBJECT);
1356
1357 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1358
1359 // Call public unsynchronized loadClass(String) directly for all class loaders
1360 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1361 // acquire a class-name based lock rather than the class loader object lock.
1362 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1363 // so the call to loadClassInternal() was not required.
1364 //
1365 // UnsyncloadClass flag means both call loadClass(String) and do
1366 // not acquire the class loader lock even for class loaders that are
1367 // not parallelCapable. This was a risky transitional
1368 // flag for diagnostic purposes only. It is risky to call
1369 // custom class loaders without synchronization.
1370 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1371 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1372 // Do NOT assume this will be supported in future releases.
1373 //
1374 // Added MustCallLoadClassInternal in case we discover in the field
1375 // a customer that counts on this call
1376 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1377 JavaCalls::call_special(&result,
1378 class_loader,
1379 spec_klass,
1380 vmSymbols::loadClassInternal_name(),
1381 vmSymbols::string_class_signature(),
1382 string,
1383 CHECK_(nh));
1384 } else {
1385 JavaCalls::call_virtual(&result,
1386 class_loader,
1387 spec_klass,
1388 vmSymbols::loadClass_name(),
1389 vmSymbols::string_class_signature(),
1390 string,
1391 CHECK_(nh));
1392 }
1393
1394 assert(result.get_type() == T_OBJECT, "just checking");
1395 oop obj = (oop) result.get_jobject();
1396
1397 // Primitive classes return null since forName() can not be
1398 // used to obtain any of the Class objects representing primitives or void
1399 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1400 instanceKlassHandle k =
1401 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1402 // For user defined Java class loaders, check that the name returned is
1403 // the same as that requested. This check is done for the bootstrap
1404 // loader when parsing the class file.
1405 if (class_name == k->name()) {
1406 return k;
1407 }
1408 }
1409 // Class is not found or has the wrong name, return NULL
1410 return nh;
1411 }
1412 }
1413
1414 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1415 EventClassDefine event;
1416 if (event.should_commit()) {
1417 event.set_definedClass(k);
1418 event.set_definingClassLoader(def_cld);
1419 event.commit();
1420 }
1421 }
1422
1423 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1424
1425 ClassLoaderData* loader_data = k->class_loader_data();
1426 Handle class_loader_h(THREAD, loader_data->class_loader());
1427
1428 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1429
1430 // for bootstrap and other parallel classloaders don't acquire lock,
1431 // use placeholder token
1432 // If a parallelCapable class loader calls define_instance_class instead of
1433 // find_or_define_instance_class to get here, we have a timing
1434 // hole with systemDictionary updates and check_constraints
1435 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1436 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1437 compute_loader_lock_object(class_loader_h, THREAD)),
1438 "define called without lock");
1439 }
1440
1441 // Check class-loading constraints. Throw exception if violation is detected.
1442 // Grabs and releases SystemDictionary_lock
1443 // The check_constraints/find_class call and update_dictionary sequence
1444 // must be "atomic" for a specific class/classloader pair so we never
1445 // define two different instanceKlasses for that class/classloader pair.
1446 // Existing classloaders will call define_instance_class with the
1447 // classloader lock held
1448 // Parallel classloaders will call find_or_define_instance_class
1449 // which will require a token to perform the define class
1450 Symbol* name_h = k->name();
1451 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1452 int d_index = dictionary()->hash_to_index(d_hash);
1453 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1454
1455 // Register class just loaded with class loader (placed in Vector)
1456 // Note we do this before updating the dictionary, as this can
1457 // fail with an OutOfMemoryError (if it does, we will *not* put this
1458 // class in the dictionary and will not update the class hierarchy).
1459 // JVMTI FollowReferences needs to find the classes this way.
1460 if (k->class_loader() != NULL) {
1461 methodHandle m(THREAD, Universe::loader_addClass_method());
1462 JavaValue result(T_VOID);
1463 JavaCallArguments args(class_loader_h);
1464 args.push_oop(Handle(THREAD, k->java_mirror()));
1465 JavaCalls::call(&result, m, &args, CHECK);
1466 }
1467
1468 // Add the new class. We need recompile lock during update of CHA.
1469 {
1470 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1471 int p_index = placeholders()->hash_to_index(p_hash);
1472
1473 MutexLocker mu_r(Compile_lock, THREAD);
1474
1475 // Add to class hierarchy, initialize vtables, and do possible
1476 // deoptimizations.
1477 add_to_hierarchy(k, CHECK); // No exception, but can block
1478
1479 // Add to systemDictionary - so other classes can see it.
1480 // Grabs and releases SystemDictionary_lock
1481 update_dictionary(d_index, d_hash, p_index, p_hash,
1482 k, class_loader_h, THREAD);
1483 }
1484 k->eager_initialize(THREAD);
1485
1486 // notify jvmti
1487 if (JvmtiExport::should_post_class_load()) {
1488 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1489 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1490
1491 }
1492
1493 post_class_define_event(k(), loader_data);
1494 }
1495
1496 // Support parallel classloading
1497 // All parallel class loaders, including bootstrap classloader
1498 // lock a placeholder entry for this class/class_loader pair
1499 // to allow parallel defines of different classes for this class loader
1500 // With AllowParallelDefine flag==true, in case they do not synchronize around
1501 // FindLoadedClass/DefineClass, calls, we check for parallel
1502 // loading for them, wait if a defineClass is in progress
1503 // and return the initial requestor's results
1504 // This flag does not apply to the bootstrap classloader.
1505 // With AllowParallelDefine flag==false, call through to define_instance_class
1506 // which will throw LinkageError: duplicate class definition.
1507 // False is the requested default.
1508 // For better performance, the class loaders should synchronize
1509 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1510 // potentially waste time reading and parsing the bytestream.
1511 // Note: VM callers should ensure consistency of k/class_name,class_loader
1512 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1513
1514 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1515 Symbol* name_h = k->name(); // passed in class_name may be null
1516 ClassLoaderData* loader_data = class_loader_data(class_loader);
1517
1518 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1519 int d_index = dictionary()->hash_to_index(d_hash);
1520
1521 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1522 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1523 int p_index = placeholders()->hash_to_index(p_hash);
1524 PlaceholderEntry* probe;
1525
1526 {
1527 MutexLocker mu(SystemDictionary_lock, THREAD);
1528 // First check if class already defined
1529 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1530 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1531 if (check != NULL) {
1532 return(instanceKlassHandle(THREAD, check));
1533 }
1534 }
1535
1536 // Acquire define token for this class/classloader
1537 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1538 // Wait if another thread defining in parallel
1539 // All threads wait - even those that will throw duplicate class: otherwise
1540 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1541 // if other thread has not finished updating dictionary
1542 while (probe->definer() != NULL) {
1543 SystemDictionary_lock->wait();
1544 }
1545 // Only special cases allow parallel defines and can use other thread's results
1546 // Other cases fall through, and may run into duplicate defines
1547 // caught by finding an entry in the SystemDictionary
1548 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1549 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1550 SystemDictionary_lock->notify_all();
1551 #ifdef ASSERT
1552 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1553 assert(check != NULL, "definer missed recording success");
1554 #endif
1555 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1556 } else {
1557 // This thread will define the class (even if earlier thread tried and had an error)
1558 probe->set_definer(THREAD);
1559 }
1560 }
1561
1562 define_instance_class(k, THREAD);
1563
1564 Handle linkage_exception = Handle(); // null handle
1565
1566 // definer must notify any waiting threads
1567 {
1568 MutexLocker mu(SystemDictionary_lock, THREAD);
1569 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1570 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1571 if (probe != NULL) {
1572 if (HAS_PENDING_EXCEPTION) {
1573 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1574 CLEAR_PENDING_EXCEPTION;
1575 } else {
1576 probe->set_instance_klass(k());
1577 }
1578 probe->set_definer(NULL);
1579 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1580 SystemDictionary_lock->notify_all();
1581 }
1582 }
1583
1584 // Can't throw exception while holding lock due to rank ordering
1585 if (linkage_exception() != NULL) {
1586 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1587 }
1588
1589 return k;
1590 }
1591 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1592 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1593 if (class_loader.is_null()) {
1594 return Handle(THREAD, _system_loader_lock_obj);
1595 } else {
1596 return class_loader;
1597 }
1598 }
1599
1600 // This method is added to check how often we have to wait to grab loader
1601 // lock. The results are being recorded in the performance counters defined in
1602 // ClassLoader::_sync_systemLoaderLockContentionRate and
1603 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1604 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1605 if (!UsePerfData) {
1606 return;
1607 }
1608
1609 assert(!loader_lock.is_null(), "NULL lock object");
1610
1611 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1612 == ObjectSynchronizer::owner_other) {
1613 // contention will likely happen, so increment the corresponding
1614 // contention counter.
1615 if (loader_lock() == _system_loader_lock_obj) {
1616 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1617 } else {
1618 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1619 }
1620 }
1621 }
1622
1623 // ----------------------------------------------------------------------------
1624 // Lookup
1625
1626 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1627 Symbol* class_name,
1628 ClassLoaderData* loader_data) {
1629 assert_locked_or_safepoint(SystemDictionary_lock);
1630 assert (index == dictionary()->index_for(class_name, loader_data),
1631 "incorrect index?");
1632
1633 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1634 return k;
1635 }
1636
1637
1638 // Basic find on classes in the midst of being loaded
1639 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1640 ClassLoaderData* loader_data) {
1641 assert_locked_or_safepoint(SystemDictionary_lock);
1642 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1643 int p_index = placeholders()->hash_to_index(p_hash);
1644 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1645 }
1646
1647
1648 // Used for assertions and verification only
1649 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1650 #ifndef ASSERT
1651 guarantee(VerifyBeforeGC ||
1652 VerifyDuringGC ||
1653 VerifyBeforeExit ||
1654 VerifyDuringStartup ||
1655 VerifyAfterGC, "too expensive");
1656 #endif
1657 assert_locked_or_safepoint(SystemDictionary_lock);
1658
1659 // First look in the loaded class array
1660 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1661 int d_index = dictionary()->hash_to_index(d_hash);
1662 return find_class(d_index, d_hash, class_name, loader_data);
1663 }
1664
1665
1666 // Get the next class in the diictionary.
1667 Klass* SystemDictionary::try_get_next_class() {
1668 return dictionary()->try_get_next_class();
1669 }
1670
1671
1672 // ----------------------------------------------------------------------------
1673 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1674 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1675 // before a new class is used.
1676
1677 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1678 assert(k.not_null(), "just checking");
1679 assert_locked_or_safepoint(Compile_lock);
1680
1681 // Link into hierachy. Make sure the vtables are initialized before linking into
1682 k->append_to_sibling_list(); // add to superklass/sibling list
1683 k->process_interfaces(THREAD); // handle all "implements" declarations
1684 k->set_init_state(InstanceKlass::loaded);
1685 // Now flush all code that depended on old class hierarchy.
1686 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1687 // Also, first reinitialize vtable because it may have gotten out of synch
1688 // while the new class wasn't connected to the class hierarchy.
1689 Universe::flush_dependents_on(k);
1690 }
1691
1692 // ----------------------------------------------------------------------------
1693 // GC support
1694
1695 // Following roots during mark-sweep is separated in two phases.
1696 //
1697 // The first phase follows preloaded classes and all other system
1698 // classes, since these will never get unloaded anyway.
1699 //
1700 // The second phase removes (unloads) unreachable classes from the
1701 // system dictionary and follows the remaining classes' contents.
1702
1703 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1704 roots_oops_do(blk, NULL);
1705 }
1706
1707 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1708 // Follow all system classes and temporary placeholders in dictionary
1709 dictionary()->always_strong_classes_do(closure);
1710
1711 // Placeholders. These represent classes we're actively loading.
1712 placeholders()->classes_do(closure);
1713 }
1714
1715 // Calculate a "good" systemdictionary size based
1716 // on predicted or current loaded classes count
1717 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1718 int newsize = _old_default_sdsize;
1719 if ((classcount > 0) && !DumpSharedSpaces) {
1720 int desiredsize = classcount/_average_depth_goal;
1721 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1722 newsize = _primelist[++_sdgeneration]) {
1723 if (desiredsize <= newsize) {
1724 break;
1725 }
1726 }
1727 }
1728 return newsize;
1729 }
1730
1731 #ifdef ASSERT
1732 class VerifySDReachableAndLiveClosure : public OopClosure {
1733 private:
1734 BoolObjectClosure* _is_alive;
1735
1736 template <class T> void do_oop_work(T* p) {
1737 oop obj = oopDesc::load_decode_heap_oop(p);
1738 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1739 }
1740
1741 public:
1742 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1743
1744 virtual void do_oop(oop* p) { do_oop_work(p); }
1745 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1746 };
1747 #endif
1748
1749 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1750 // Note: anonymous classes are not in the SD.
1751 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1752 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1753 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1754 if (unloading_occurred) {
1755 JFR_ONLY(Jfr::on_unloading_classes();)
1756 dictionary()->do_unloading();
1757 constraints()->purge_loader_constraints();
1758 resolution_errors()->purge_resolution_errors();
1759 }
1760 // Oops referenced by the system dictionary may get unreachable independently
1761 // of the class loader (eg. cached protection domain oops). So we need to
1762 // explicitly unlink them here instead of in Dictionary::do_unloading.
1763 dictionary()->unlink(is_alive);
1764 #ifdef ASSERT
1765 VerifySDReachableAndLiveClosure cl(is_alive);
1766 dictionary()->oops_do(&cl);
1767 #endif
1768 return unloading_occurred;
1769 }
1770
1771 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1772 strong->do_oop(&_java_system_loader);
1773 strong->do_oop(&_system_loader_lock_obj);
1774 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1775
1776 // Adjust dictionary
1777 dictionary()->roots_oops_do(strong, weak);
1778
1779 // Visit extra methods
1780 invoke_method_table()->oops_do(strong);
1781 }
1782
1783 void SystemDictionary::oops_do(OopClosure* f) {
1784 f->do_oop(&_java_system_loader);
1785 f->do_oop(&_system_loader_lock_obj);
1786 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1787
1788 // Adjust dictionary
1789 dictionary()->oops_do(f);
1790
1791 // Visit extra methods
1792 invoke_method_table()->oops_do(f);
1793 }
1794
1795 // Extended Class redefinition support.
1796 // If one of these classes is replaced, we need to replace it in these places.
1797 // KlassClosure::do_klass should take the address of a class but we can
1798 // change that later.
1799 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1800 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1801 f->do_klass(_well_known_klasses[k]);
1802 }
1803
1804 {
1805 for (int i = 0; i < T_VOID+1; i++) {
1806 if (_box_klasses[i] != NULL) {
1807 assert(i >= T_BOOLEAN, "checking");
1808 f->do_klass(_box_klasses[i]);
1809 }
1810 }
1811 }
1812
1813 FilteredFieldsMap::classes_do(f);
1814 }
1815
1816 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1817 f->do_klass(_abstract_ownable_synchronizer_klass);
1818 }
1819
1820 // Just the classes from defining class loaders
1821 // Don't iterate over placeholders
1822 void SystemDictionary::classes_do(void f(Klass*)) {
1823 dictionary()->classes_do(f);
1824 }
1825
1826 // Added for initialize_itable_for_klass
1827 // Just the classes from defining class loaders
1828 // Don't iterate over placeholders
1829 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1830 dictionary()->classes_do(f, CHECK);
1831 }
1832
1833 // All classes, and their class loaders
1834 // Don't iterate over placeholders
1835 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1836 dictionary()->classes_do(f);
1837 }
1838
1839 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1840 placeholders()->entries_do(f);
1841 }
1842
1843 void SystemDictionary::methods_do(void f(Method*)) {
1844 dictionary()->methods_do(f);
1845 invoke_method_table()->methods_do(f);
1846 }
1847
1848 void SystemDictionary::remove_classes_in_error_state() {
1849 dictionary()->remove_classes_in_error_state();
1850 }
1851
1852 // ----------------------------------------------------------------------------
1853 // Lazily load klasses
1854
1855 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1856 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1857
1858 // if multiple threads calling this function, only one thread will load
1859 // the class. The other threads will find the loaded version once the
1860 // class is loaded.
1861 Klass* aos = _abstract_ownable_synchronizer_klass;
1862 if (aos == NULL) {
1863 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1864 // Force a fence to prevent any read before the write completes
1865 OrderAccess::fence();
1866 _abstract_ownable_synchronizer_klass = k;
1867 }
1868 }
1869
1870 // ----------------------------------------------------------------------------
1871 // Initialization
1872
1873 void SystemDictionary::initialize(TRAPS) {
1874 // Allocate arrays
1875 assert(dictionary() == NULL,
1876 "SystemDictionary should only be initialized once");
1877 _sdgeneration = 0;
1878 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1879 _placeholders = new PlaceholderTable(_nof_buckets);
1880 _number_of_modifications = 0;
1881 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1882 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1883 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1884
1885 // Allocate private object used as system class loader lock
1886 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1887 // Initialize basic classes
1888 initialize_preloaded_classes(CHECK);
1889 }
1890
1891 // Compact table of directions on the initialization of klasses:
1892 static const short wk_init_info[] = {
1893 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1894 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1895 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1896 | (int)SystemDictionary::option ),
1897 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1898 #undef WK_KLASS_INIT_INFO
1899 0
1900 };
1901
1902 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1903 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1904 int info = wk_init_info[id - FIRST_WKID];
1905 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1906 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1907 Klass** klassp = &_well_known_klasses[id];
1908 bool must_load = (init_opt < SystemDictionary::Opt);
1909 if ((*klassp) == NULL) {
1910 if (must_load) {
1911 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1912 } else {
1913 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1914 }
1915 }
1916 return ((*klassp) != NULL);
1917 }
1918
1919 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1920 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1921 for (int id = (int)start_id; id < (int)limit_id; id++) {
1922 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1923 int info = wk_init_info[id - FIRST_WKID];
1924 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1925 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1926
1927 initialize_wk_klass((WKID)id, opt, CHECK);
1928 }
1929
1930 // move the starting value forward to the limit:
1931 start_id = limit_id;
1932 }
1933
1934 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1935 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1936 // Preload commonly used klasses
1937 WKID scan = FIRST_WKID;
1938 // first do Object, then String, Class
1939 if (UseSharedSpaces) {
1940 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1941 // Initialize the constant pool for the Object_class
1942 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1943 ik->constants()->restore_unshareable_info(CHECK);
1944 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1945 } else {
1946 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1947 }
1948
1949 // Calculate offsets for String and Class classes since they are loaded and
1950 // can be used after this point.
1951 java_lang_String::compute_offsets();
1952 java_lang_Class::compute_offsets();
1953
1954 // Fixup mirrors for classes loaded before java.lang.Class.
1955 // These calls iterate over the objects currently in the perm gen
1956 // so calling them at this point is matters (not before when there
1957 // are fewer objects and not later after there are more objects
1958 // in the perm gen.
1959 Universe::initialize_basic_type_mirrors(CHECK);
1960 Universe::fixup_mirrors(CHECK);
1961
1962 // do a bunch more:
1963 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1964
1965 // Preload ref klasses and set reference types
1966 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1967 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1968
1969 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1970 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1971 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1972 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1973 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1974 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1975
1976 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
1977
1978 // JSR 292 classes
1979 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1980 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1981 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1982 if (EnableInvokeDynamic) {
1983 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1984 } else {
1985 // Skip the JSR 292 classes, if not enabled.
1986 scan = WKID(jsr292_group_end + 1);
1987 }
1988
1989 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1990
1991 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1992 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1993 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1994 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1995 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1996 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1997 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1998 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1999 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2000 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2001
2002 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2003 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2004 _has_loadClassInternal = (method != NULL);
2005 }
2006 { // Compute whether we should use checkPackageAccess or NOT
2007 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2008 _has_checkPackageAccess = (method != NULL);
2009 }
2010 }
2011
2012 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2013 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2014 BasicType SystemDictionary::box_klass_type(Klass* k) {
2015 assert(k != NULL, "");
2016 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2017 if (_box_klasses[i] == k)
2018 return (BasicType)i;
2019 }
2020 return T_OBJECT;
2021 }
2022
2023 // Constraints on class loaders. The details of the algorithm can be
2024 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2025 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2026 // that the system dictionary needs to maintain a set of contraints that
2027 // must be satisfied by all classes in the dictionary.
2028 // if defining is true, then LinkageError if already in systemDictionary
2029 // if initiating loader, then ok if InstanceKlass matches existing entry
2030
2031 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2032 instanceKlassHandle k,
2033 Handle class_loader, bool defining,
2034 TRAPS) {
2035 const char *linkage_error = NULL;
2036 {
2037 Symbol* name = k->name();
2038 ClassLoaderData *loader_data = class_loader_data(class_loader);
2039
2040 MutexLocker mu(SystemDictionary_lock, THREAD);
2041
2042 Klass* check = find_class(d_index, d_hash, name, loader_data);
2043 if (check != (Klass*)NULL) {
2044 // if different InstanceKlass - duplicate class definition,
2045 // else - ok, class loaded by a different thread in parallel,
2046 // we should only have found it if it was done loading and ok to use
2047 // system dictionary only holds instance classes, placeholders
2048 // also holds array classes
2049
2050 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2051 if ((defining == true) || (k() != check)) {
2052 linkage_error = "loader (instance of %s): attempted duplicate class "
2053 "definition for name: \"%s\"";
2054 } else {
2055 return;
2056 }
2057 }
2058
2059 #ifdef ASSERT
2060 Symbol* ph_check = find_placeholder(name, loader_data);
2061 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2062 #endif
2063
2064 if (linkage_error == NULL) {
2065 if (constraints()->check_or_update(k, class_loader, name) == false) {
2066 linkage_error = "loader constraint violation: loader (instance of %s)"
2067 " previously initiated loading for a different type with name \"%s\"";
2068 }
2069 }
2070 }
2071
2072 // Throw error now if needed (cannot throw while holding
2073 // SystemDictionary_lock because of rank ordering)
2074
2075 if (linkage_error) {
2076 ResourceMark rm(THREAD);
2077 const char* class_loader_name = loader_name(class_loader());
2078 char* type_name = k->name()->as_C_string();
2079 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2080 strlen(type_name);
2081 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2082 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2083 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2084 }
2085 }
2086
2087
2088 // Update system dictionary - done after check_constraint and add_to_hierachy
2089 // have been called.
2090 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2091 int p_index, unsigned int p_hash,
2092 instanceKlassHandle k,
2093 Handle class_loader,
2094 TRAPS) {
2095 // Compile_lock prevents systemDictionary updates during compilations
2096 assert_locked_or_safepoint(Compile_lock);
2097 Symbol* name = k->name();
2098 ClassLoaderData *loader_data = class_loader_data(class_loader);
2099
2100 {
2101 MutexLocker mu1(SystemDictionary_lock, THREAD);
2102
2103 // See whether biased locking is enabled and if so set it for this
2104 // klass.
2105 // Note that this must be done past the last potential blocking
2106 // point / safepoint. We enable biased locking lazily using a
2107 // VM_Operation to iterate the SystemDictionary and installing the
2108 // biasable mark word into each InstanceKlass's prototype header.
2109 // To avoid race conditions where we accidentally miss enabling the
2110 // optimization for one class in the process of being added to the
2111 // dictionary, we must not safepoint after the test of
2112 // BiasedLocking::enabled().
2113 if (UseBiasedLocking && BiasedLocking::enabled()) {
2114 // Set biased locking bit for all loaded classes; it will be
2115 // cleared if revocation occurs too often for this type
2116 // NOTE that we must only do this when the class is initally
2117 // defined, not each time it is referenced from a new class loader
2118 if (k->class_loader() == class_loader()) {
2119 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2120 }
2121 }
2122
2123 // Make a new system dictionary entry.
2124 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2125 if (sd_check == NULL) {
2126 dictionary()->add_klass(name, loader_data, k);
2127 notice_modification();
2128 }
2129 #ifdef ASSERT
2130 sd_check = find_class(d_index, d_hash, name, loader_data);
2131 assert (sd_check != NULL, "should have entry in system dictionary");
2132 // Note: there may be a placeholder entry: for circularity testing
2133 // or for parallel defines
2134 #endif
2135 SystemDictionary_lock->notify_all();
2136 }
2137 }
2138
2139
2140 // Try to find a class name using the loader constraints. The
2141 // loader constraints might know about a class that isn't fully loaded
2142 // yet and these will be ignored.
2143 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2144 Symbol* class_name, Handle class_loader, TRAPS) {
2145
2146 // First see if it has been loaded directly.
2147 // Force the protection domain to be null. (This removes protection checks.)
2148 Handle no_protection_domain;
2149 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2150 no_protection_domain, CHECK_NULL);
2151 if (klass != NULL)
2152 return klass;
2153
2154 // Now look to see if it has been loaded elsewhere, and is subject to
2155 // a loader constraint that would require this loader to return the
2156 // klass that is already loaded.
2157 if (FieldType::is_array(class_name)) {
2158 // For array classes, their Klass*s are not kept in the
2159 // constraint table. The element Klass*s are.
2160 FieldArrayInfo fd;
2161 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2162 if (t != T_OBJECT) {
2163 klass = Universe::typeArrayKlassObj(t);
2164 } else {
2165 MutexLocker mu(SystemDictionary_lock, THREAD);
2166 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2167 }
2168 // If element class already loaded, allocate array klass
2169 if (klass != NULL) {
2170 klass = klass->array_klass_or_null(fd.dimension());
2171 }
2172 } else {
2173 MutexLocker mu(SystemDictionary_lock, THREAD);
2174 // Non-array classes are easy: simply check the constraint table.
2175 klass = constraints()->find_constrained_klass(class_name, class_loader);
2176 }
2177
2178 return klass;
2179 }
2180
2181
2182 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2183 Handle class_loader1,
2184 Handle class_loader2,
2185 Thread* THREAD) {
2186 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2187 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2188
2189 Symbol* constraint_name = NULL;
2190 if (!FieldType::is_array(class_name)) {
2191 constraint_name = class_name;
2192 } else {
2193 // For array classes, their Klass*s are not kept in the
2194 // constraint table. The element classes are.
2195 FieldArrayInfo fd;
2196 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2197 // primitive types always pass
2198 if (t != T_OBJECT) {
2199 return true;
2200 } else {
2201 constraint_name = fd.object_key();
2202 }
2203 }
2204 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2205 int d_index1 = dictionary()->hash_to_index(d_hash1);
2206
2207 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2208 int d_index2 = dictionary()->hash_to_index(d_hash2);
2209 {
2210 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2211
2212 // Better never do a GC while we're holding these oops
2213 No_Safepoint_Verifier nosafepoint;
2214
2215 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2216 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2217 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2218 klass2, class_loader2);
2219 }
2220 }
2221
2222 // Add entry to resolution error table to record the error when the first
2223 // attempt to resolve a reference to a class has failed.
2224 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2225 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2226 int index = resolution_errors()->hash_to_index(hash);
2227 {
2228 MutexLocker ml(SystemDictionary_lock, Thread::current());
2229 resolution_errors()->add_entry(index, hash, pool, which, error);
2230 }
2231 }
2232
2233 // Delete a resolution error for RedefineClasses for a constant pool is going away
2234 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2235 resolution_errors()->delete_entry(pool);
2236 }
2237
2238 // Lookup resolution error table. Returns error if found, otherwise NULL.
2239 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2240 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2241 int index = resolution_errors()->hash_to_index(hash);
2242 {
2243 MutexLocker ml(SystemDictionary_lock, Thread::current());
2244 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2245 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2246 }
2247 }
2248
2249
2250 // Signature constraints ensure that callers and callees agree about
2251 // the meaning of type names in their signatures. This routine is the
2252 // intake for constraints. It collects them from several places:
2253 //
2254 // * LinkResolver::resolve_method (if check_access is true) requires
2255 // that the resolving class (the caller) and the defining class of
2256 // the resolved method (the callee) agree on each type in the
2257 // method's signature.
2258 //
2259 // * LinkResolver::resolve_interface_method performs exactly the same
2260 // checks.
2261 //
2262 // * LinkResolver::resolve_field requires that the constant pool
2263 // attempting to link to a field agree with the field's defining
2264 // class about the type of the field signature.
2265 //
2266 // * klassVtable::initialize_vtable requires that, when a class
2267 // overrides a vtable entry allocated by a superclass, that the
2268 // overriding method (i.e., the callee) agree with the superclass
2269 // on each type in the method's signature.
2270 //
2271 // * klassItable::initialize_itable requires that, when a class fills
2272 // in its itables, for each non-abstract method installed in an
2273 // itable, the method (i.e., the callee) agree with the interface
2274 // on each type in the method's signature.
2275 //
2276 // All those methods have a boolean (check_access, checkconstraints)
2277 // which turns off the checks. This is used from specialized contexts
2278 // such as bootstrapping, dumping, and debugging.
2279 //
2280 // No direct constraint is placed between the class and its
2281 // supertypes. Constraints are only placed along linked relations
2282 // between callers and callees. When a method overrides or implements
2283 // an abstract method in a supertype (superclass or interface), the
2284 // constraints are placed as if the supertype were the caller to the
2285 // overriding method. (This works well, since callers to the
2286 // supertype have already established agreement between themselves and
2287 // the supertype.) As a result of all this, a class can disagree with
2288 // its supertype about the meaning of a type name, as long as that
2289 // class neither calls a relevant method of the supertype, nor is
2290 // called (perhaps via an override) from the supertype.
2291 //
2292 //
2293 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2294 //
2295 // Make sure all class components (including arrays) in the given
2296 // signature will be resolved to the same class in both loaders.
2297 // Returns the name of the type that failed a loader constraint check, or
2298 // NULL if no constraint failed. No exception except OOME is thrown.
2299 // Arrays are not added to the loader constraint table, their elements are.
2300 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2301 Handle loader1, Handle loader2,
2302 bool is_method, TRAPS) {
2303 // Nothing to do if loaders are the same.
2304 if (loader1() == loader2()) {
2305 return NULL;
2306 }
2307
2308 SignatureStream sig_strm(signature, is_method);
2309 while (!sig_strm.is_done()) {
2310 if (sig_strm.is_object()) {
2311 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2312 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2313 return sig;
2314 }
2315 }
2316 sig_strm.next();
2317 }
2318 return NULL;
2319 }
2320
2321
2322 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2323 Symbol* signature,
2324 TRAPS) {
2325 methodHandle empty;
2326 assert(EnableInvokeDynamic, "");
2327 assert(MethodHandles::is_signature_polymorphic(iid) &&
2328 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2329 iid != vmIntrinsics::_invokeGeneric,
2330 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2331
2332 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2333 int index = invoke_method_table()->hash_to_index(hash);
2334 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2335 methodHandle m;
2336 if (spe == NULL || spe->method() == NULL) {
2337 spe = NULL;
2338 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2339 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2340 if (!Arguments::is_interpreter_only()) {
2341 // Generate a compiled form of the MH intrinsic.
2342 AdapterHandlerLibrary::create_native_wrapper(m);
2343 // Check if have the compiled code.
2344 if (!m->has_compiled_code()) {
2345 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2346 "out of space in CodeCache for method handle intrinsic", empty);
2347 }
2348 }
2349 // Now grab the lock. We might have to throw away the new method,
2350 // if a racing thread has managed to install one at the same time.
2351 {
2352 MutexLocker ml(SystemDictionary_lock, THREAD);
2353 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2354 if (spe == NULL)
2355 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2356 if (spe->method() == NULL)
2357 spe->set_method(m());
2358 }
2359 }
2360
2361 assert(spe != NULL && spe->method() != NULL, "");
2362 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2363 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2364 "MH intrinsic invariant");
2365 return spe->method();
2366 }
2367
2368 // Helper for unpacking the return value from linkMethod and linkCallSite.
2369 static methodHandle unpack_method_and_appendix(Handle mname,
2370 KlassHandle accessing_klass,
2371 objArrayHandle appendix_box,
2372 Handle* appendix_result,
2373 TRAPS) {
2374 methodHandle empty;
2375 if (mname.not_null()) {
2376 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2377 if (vmtarget != NULL && vmtarget->is_method()) {
2378 Method* m = (Method*)vmtarget;
2379 oop appendix = appendix_box->obj_at(0);
2380 if (TraceMethodHandles) {
2381 #ifndef PRODUCT
2382 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2383 m->print();
2384 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2385 tty->cr();
2386 #endif //PRODUCT
2387 }
2388 (*appendix_result) = Handle(THREAD, appendix);
2389 // the target is stored in the cpCache and if a reference to this
2390 // MethodName is dropped we need a way to make sure the
2391 // class_loader containing this method is kept alive.
2392 // FIXME: the appendix might also preserve this dependency.
2393 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2394 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2395 return methodHandle(THREAD, m);
2396 }
2397 }
2398 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2399 return empty;
2400 }
2401
2402 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2403 Symbol* signature,
2404 KlassHandle accessing_klass,
2405 Handle *appendix_result,
2406 Handle *method_type_result,
2407 TRAPS) {
2408 methodHandle empty;
2409 assert(EnableInvokeDynamic, "");
2410 assert(!THREAD->is_Compiler_thread(), "");
2411 Handle method_type =
2412 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2413
2414 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2415 int ref_kind = JVM_REF_invokeVirtual;
2416 Handle name_str = StringTable::intern(name, CHECK_(empty));
2417 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2418 assert(appendix_box->obj_at(0) == NULL, "");
2419
2420 // This should not happen. JDK code should take care of that.
2421 if (accessing_klass.is_null() || method_type.is_null()) {
2422 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2423 }
2424
2425 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2426 JavaCallArguments args;
2427 args.push_oop(accessing_klass()->java_mirror());
2428 args.push_int(ref_kind);
2429 args.push_oop(mh_klass()->java_mirror());
2430 args.push_oop(name_str());
2431 args.push_oop(method_type());
2432 args.push_oop(appendix_box());
2433 JavaValue result(T_OBJECT);
2434 JavaCalls::call_static(&result,
2435 SystemDictionary::MethodHandleNatives_klass(),
2436 vmSymbols::linkMethod_name(),
2437 vmSymbols::linkMethod_signature(),
2438 &args, CHECK_(empty));
2439 Handle mname(THREAD, (oop) result.get_jobject());
2440 (*method_type_result) = method_type;
2441 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2442 }
2443
2444 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2445 // We must ensure that all class loaders everywhere will reach this class, for any client.
2446 // This is a safe bet for public classes in java.lang, such as Object and String.
2447 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2448 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2449 static bool is_always_visible_class(oop mirror) {
2450 Klass* klass = java_lang_Class::as_Klass(mirror);
2451 if (klass->oop_is_objArray()) {
2452 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2453 }
2454 if (klass->oop_is_typeArray()) {
2455 return true; // primitive array
2456 }
2457 assert(klass->oop_is_instance(), klass->external_name());
2458 return klass->is_public() &&
2459 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2460 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2461 }
2462
2463 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2464 // signature, as interpreted relative to the given class loader.
2465 // Because of class loader constraints, all method handle usage must be
2466 // consistent with this loader.
2467 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2468 KlassHandle accessing_klass,
2469 TRAPS) {
2470 Handle empty;
2471 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2472 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2473 int index = invoke_method_table()->hash_to_index(hash);
2474 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2475 if (spe != NULL && spe->method_type() != NULL) {
2476 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2477 return Handle(THREAD, spe->method_type());
2478 } else if (THREAD->is_Compiler_thread()) {
2479 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2480 return Handle(); // do not attempt from within compiler, unless it was cached
2481 }
2482
2483 Handle class_loader, protection_domain;
2484 if (accessing_klass.not_null()) {
2485 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2486 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2487 }
2488 bool can_be_cached = true;
2489 int npts = ArgumentCount(signature).size();
2490 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2491 int arg = 0;
2492 Handle rt; // the return type from the signature
2493 ResourceMark rm(THREAD);
2494 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2495 oop mirror = NULL;
2496 if (can_be_cached) {
2497 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2498 mirror = ss.as_java_mirror(Handle(), Handle(),
2499 SignatureStream::ReturnNull, CHECK_(empty));
2500 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2501 // Fall back to accessing_klass context.
2502 can_be_cached = false;
2503 }
2504 }
2505 if (!can_be_cached) {
2506 // Resolve, throwing a real error if it doesn't work.
2507 mirror = ss.as_java_mirror(class_loader, protection_domain,
2508 SignatureStream::NCDFError, CHECK_(empty));
2509 }
2510 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2511 if (ss.at_return_type())
2512 rt = Handle(THREAD, mirror);
2513 else
2514 pts->obj_at_put(arg++, mirror);
2515
2516 // Check accessibility.
2517 if (ss.is_object() && accessing_klass.not_null()) {
2518 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2519 mirror = NULL; // safety
2520 // Emulate ConstantPool::verify_constant_pool_resolve.
2521 if (sel_klass->oop_is_objArray())
2522 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2523 if (sel_klass->oop_is_instance()) {
2524 KlassHandle sel_kh(THREAD, sel_klass);
2525 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2526 }
2527 }
2528 }
2529 assert(arg == npts, "");
2530
2531 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2532 JavaCallArguments args(Handle(THREAD, rt()));
2533 args.push_oop(pts());
2534 JavaValue result(T_OBJECT);
2535 JavaCalls::call_static(&result,
2536 SystemDictionary::MethodHandleNatives_klass(),
2537 vmSymbols::findMethodHandleType_name(),
2538 vmSymbols::findMethodHandleType_signature(),
2539 &args, CHECK_(empty));
2540 Handle method_type(THREAD, (oop) result.get_jobject());
2541
2542 if (can_be_cached) {
2543 // We can cache this MethodType inside the JVM.
2544 MutexLocker ml(SystemDictionary_lock, THREAD);
2545 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2546 if (spe == NULL)
2547 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2548 if (spe->method_type() == NULL) {
2549 spe->set_method_type(method_type());
2550 }
2551 }
2552
2553 // report back to the caller with the MethodType
2554 return method_type;
2555 }
2556
2557 // Ask Java code to find or construct a method handle constant.
2558 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2559 int ref_kind, //e.g., JVM_REF_invokeVirtual
2560 KlassHandle callee,
2561 Symbol* name_sym,
2562 Symbol* signature,
2563 TRAPS) {
2564 Handle empty;
2565 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2566 Handle type;
2567 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2568 type = find_method_handle_type(signature, caller, CHECK_(empty));
2569 } else if (caller.is_null()) {
2570 // This should not happen. JDK code should take care of that.
2571 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2572 } else {
2573 ResourceMark rm(THREAD);
2574 SignatureStream ss(signature, false);
2575 if (!ss.is_done()) {
2576 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2577 SignatureStream::NCDFError, CHECK_(empty));
2578 type = Handle(THREAD, mirror);
2579 ss.next();
2580 if (!ss.is_done()) type = Handle(); // error!
2581 }
2582 }
2583 if (type.is_null()) {
2584 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2585 }
2586
2587 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2588 JavaCallArguments args;
2589 args.push_oop(caller->java_mirror()); // the referring class
2590 args.push_int(ref_kind);
2591 args.push_oop(callee->java_mirror()); // the target class
2592 args.push_oop(name());
2593 args.push_oop(type());
2594 JavaValue result(T_OBJECT);
2595 JavaCalls::call_static(&result,
2596 SystemDictionary::MethodHandleNatives_klass(),
2597 vmSymbols::linkMethodHandleConstant_name(),
2598 vmSymbols::linkMethodHandleConstant_signature(),
2599 &args, CHECK_(empty));
2600 return Handle(THREAD, (oop) result.get_jobject());
2601 }
2602
2603 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2604 // name and signature, as interpreted relative to the given class loader.
2605 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2606 Handle bootstrap_specifier,
2607 Symbol* name,
2608 Symbol* type,
2609 Handle *appendix_result,
2610 Handle *method_type_result,
2611 TRAPS) {
2612 methodHandle empty;
2613 Handle bsm, info;
2614 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2615 bsm = bootstrap_specifier;
2616 } else {
2617 assert(bootstrap_specifier->is_objArray(), "");
2618 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2619 int len = args->length();
2620 assert(len >= 1, "");
2621 bsm = Handle(THREAD, args->obj_at(0));
2622 if (len > 1) {
2623 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2624 for (int i = 1; i < len; i++)
2625 args1->obj_at_put(i-1, args->obj_at(i));
2626 info = Handle(THREAD, args1);
2627 }
2628 }
2629 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2630 "caller must supply a valid BSM");
2631
2632 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2633 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2634
2635 // This should not happen. JDK code should take care of that.
2636 if (caller.is_null() || method_type.is_null()) {
2637 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2638 }
2639
2640 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2641 assert(appendix_box->obj_at(0) == NULL, "");
2642
2643 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2644 JavaCallArguments args;
2645 args.push_oop(caller->java_mirror());
2646 args.push_oop(bsm());
2647 args.push_oop(method_name());
2648 args.push_oop(method_type());
2649 args.push_oop(info());
2650 args.push_oop(appendix_box);
2651 JavaValue result(T_OBJECT);
2652 JavaCalls::call_static(&result,
2653 SystemDictionary::MethodHandleNatives_klass(),
2654 vmSymbols::linkCallSite_name(),
2655 vmSymbols::linkCallSite_signature(),
2656 &args, CHECK_(empty));
2657 Handle mname(THREAD, (oop) result.get_jobject());
2658 (*method_type_result) = method_type;
2659 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2660 }
2661
2662 // Since the identity hash code for symbols changes when the symbols are
2663 // moved from the regular perm gen (hash in the mark word) to the shared
2664 // spaces (hash is the address), the classes loaded into the dictionary
2665 // may be in the wrong buckets.
2666
2667 void SystemDictionary::reorder_dictionary() {
2668 dictionary()->reorder_dictionary();
2669 }
2670
2671
2672 void SystemDictionary::copy_buckets(char** top, char* end) {
2673 dictionary()->copy_buckets(top, end);
2674 }
2675
2676
2677 void SystemDictionary::copy_table(char** top, char* end) {
2678 dictionary()->copy_table(top, end);
2679 }
2680
2681
2682 void SystemDictionary::reverse() {
2683 dictionary()->reverse();
2684 }
2685
2686 int SystemDictionary::number_of_classes() {
2687 return dictionary()->number_of_entries();
2688 }
2689
2690
2691 // ----------------------------------------------------------------------------
2692 void SystemDictionary::print_shared(bool details) {
2693 shared_dictionary()->print(details);
2694 }
2695
2696 void SystemDictionary::print(bool details) {
2697 dictionary()->print(details);
2698
2699 // Placeholders
2700 GCMutexLocker mu(SystemDictionary_lock);
2701 placeholders()->print();
2702
2703 // loader constraints - print under SD_lock
2704 constraints()->print();
2705 }
2706
2707
2708 void SystemDictionary::verify() {
2709 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2710 guarantee(constraints() != NULL,
2711 "Verify of loader constraints failed");
2712 guarantee(dictionary()->number_of_entries() >= 0 &&
2713 placeholders()->number_of_entries() >= 0,
2714 "Verify of system dictionary failed");
2715
2716 // Verify dictionary
2717 dictionary()->verify();
2718
2719 GCMutexLocker mu(SystemDictionary_lock);
2720 placeholders()->verify();
2721
2722 // Verify constraint table
2723 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2724 constraints()->verify(dictionary(), placeholders());
2725 }
2726
2727 #ifndef PRODUCT
2728
2729 // statistics code
2730 class ClassStatistics: AllStatic {
2731 private:
2732 static int nclasses; // number of classes
2733 static int nmethods; // number of methods
2734 static int nmethoddata; // number of methodData
2735 static int class_size; // size of class objects in words
2736 static int method_size; // size of method objects in words
2737 static int debug_size; // size of debug info in methods
2738 static int methoddata_size; // size of methodData objects in words
2739
2740 static void do_class(Klass* k) {
2741 nclasses++;
2742 class_size += k->size();
2743 if (k->oop_is_instance()) {
2744 InstanceKlass* ik = (InstanceKlass*)k;
2745 class_size += ik->methods()->size();
2746 class_size += ik->constants()->size();
2747 class_size += ik->local_interfaces()->size();
2748 class_size += ik->transitive_interfaces()->size();
2749 // We do not have to count implementors, since we only store one!
2750 // SSS: How should these be accounted now that they have moved?
2751 // class_size += ik->fields()->length();
2752 }
2753 }
2754
2755 static void do_method(Method* m) {
2756 nmethods++;
2757 method_size += m->size();
2758 // class loader uses same objArray for empty vectors, so don't count these
2759 if (m->has_stackmap_table()) {
2760 method_size += m->stackmap_data()->size();
2761 }
2762
2763 MethodData* mdo = m->method_data();
2764 if (mdo != NULL) {
2765 nmethoddata++;
2766 methoddata_size += mdo->size();
2767 }
2768 }
2769
2770 public:
2771 static void print() {
2772 SystemDictionary::classes_do(do_class);
2773 SystemDictionary::methods_do(do_method);
2774 tty->print_cr("Class statistics:");
2775 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2776 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2777 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2778 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2779 }
2780 };
2781
2782
2783 int ClassStatistics::nclasses = 0;
2784 int ClassStatistics::nmethods = 0;
2785 int ClassStatistics::nmethoddata = 0;
2786 int ClassStatistics::class_size = 0;
2787 int ClassStatistics::method_size = 0;
2788 int ClassStatistics::debug_size = 0;
2789 int ClassStatistics::methoddata_size = 0;
2790
2791 void SystemDictionary::print_class_statistics() {
2792 ResourceMark rm;
2793 ClassStatistics::print();
2794 }
2795
2796
2797 class MethodStatistics: AllStatic {
2798 public:
2799 enum {
2800 max_parameter_size = 10
2801 };
2802 private:
2803
2804 static int _number_of_methods;
2805 static int _number_of_final_methods;
2806 static int _number_of_static_methods;
2807 static int _number_of_native_methods;
2808 static int _number_of_synchronized_methods;
2809 static int _number_of_profiled_methods;
2810 static int _number_of_bytecodes;
2811 static int _parameter_size_profile[max_parameter_size];
2812 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2813
2814 static void initialize() {
2815 _number_of_methods = 0;
2816 _number_of_final_methods = 0;
2817 _number_of_static_methods = 0;
2818 _number_of_native_methods = 0;
2819 _number_of_synchronized_methods = 0;
2820 _number_of_profiled_methods = 0;
2821 _number_of_bytecodes = 0;
2822 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2823 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2824 };
2825
2826 static void do_method(Method* m) {
2827 _number_of_methods++;
2828 // collect flag info
2829 if (m->is_final() ) _number_of_final_methods++;
2830 if (m->is_static() ) _number_of_static_methods++;
2831 if (m->is_native() ) _number_of_native_methods++;
2832 if (m->is_synchronized()) _number_of_synchronized_methods++;
2833 if (m->method_data() != NULL) _number_of_profiled_methods++;
2834 // collect parameter size info (add one for receiver, if any)
2835 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2836 // collect bytecodes info
2837 {
2838 Thread *thread = Thread::current();
2839 HandleMark hm(thread);
2840 BytecodeStream s(methodHandle(thread, m));
2841 Bytecodes::Code c;
2842 while ((c = s.next()) >= 0) {
2843 _number_of_bytecodes++;
2844 _bytecodes_profile[c]++;
2845 }
2846 }
2847 }
2848
2849 public:
2850 static void print() {
2851 initialize();
2852 SystemDictionary::methods_do(do_method);
2853 // generate output
2854 tty->cr();
2855 tty->print_cr("Method statistics (static):");
2856 // flag distribution
2857 tty->cr();
2858 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2859 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2860 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2861 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2862 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2863 // parameter size profile
2864 tty->cr();
2865 { int tot = 0;
2866 int avg = 0;
2867 for (int i = 0; i < max_parameter_size; i++) {
2868 int n = _parameter_size_profile[i];
2869 tot += n;
2870 avg += n*i;
2871 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2872 }
2873 assert(tot == _number_of_methods, "should be the same");
2874 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2875 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2876 }
2877 // bytecodes profile
2878 tty->cr();
2879 { int tot = 0;
2880 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2881 if (Bytecodes::is_defined(i)) {
2882 Bytecodes::Code c = Bytecodes::cast(i);
2883 int n = _bytecodes_profile[c];
2884 tot += n;
2885 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2886 }
2887 }
2888 assert(tot == _number_of_bytecodes, "should be the same");
2889 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2890 }
2891 tty->cr();
2892 }
2893 };
2894
2895 int MethodStatistics::_number_of_methods;
2896 int MethodStatistics::_number_of_final_methods;
2897 int MethodStatistics::_number_of_static_methods;
2898 int MethodStatistics::_number_of_native_methods;
2899 int MethodStatistics::_number_of_synchronized_methods;
2900 int MethodStatistics::_number_of_profiled_methods;
2901 int MethodStatistics::_number_of_bytecodes;
2902 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2903 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2904
2905
2906 void SystemDictionary::print_method_statistics() {
2907 MethodStatistics::print();
2908 }
2909
2910 #endif // PRODUCT