1 /*
2 * Copyright (c) 1997, 2010, 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/dictionary.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/loaderConstraints.hpp"
29 #include "classfile/placeholders.hpp"
30 #include "classfile/resolutionErrors.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "interpreter/bytecodeStream.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "memory/gcLocker.hpp"
36 #include "memory/oopFactory.hpp"
37 #include "oops/instanceKlass.hpp"
38 #include "oops/instanceRefKlass.hpp"
39 #include "oops/klass.inline.hpp"
40 #include "oops/methodDataOop.hpp"
41 #include "oops/objArrayKlass.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/oop.inline2.hpp"
44 #include "oops/typeArrayKlass.hpp"
45 #include "prims/jvmtiEnvBase.hpp"
46 #include "prims/methodHandles.hpp"
47 #include "runtime/biasedLocking.hpp"
48 #include "runtime/fieldType.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/java.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/mutexLocker.hpp"
53 #include "runtime/signature.hpp"
54 #include "services/classLoadingService.hpp"
55 #include "services/threadService.hpp"
56
57
58 Dictionary* SystemDictionary::_dictionary = NULL;
59 PlaceholderTable* SystemDictionary::_placeholders = NULL;
60 Dictionary* SystemDictionary::_shared_dictionary = NULL;
61 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
62 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
63 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
64
65
66 int SystemDictionary::_number_of_modifications = 0;
67
68 oop SystemDictionary::_system_loader_lock_obj = NULL;
69
70 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
71 = { NULL /*, NULL...*/ };
72
73 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
74
75 oop SystemDictionary::_java_system_loader = NULL;
76
77 bool SystemDictionary::_has_loadClassInternal = false;
78 bool SystemDictionary::_has_checkPackageAccess = false;
79
80 // lazily initialized klass variables
81 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
82
83
84 // ----------------------------------------------------------------------------
85 // Java-level SystemLoader
86
87 oop SystemDictionary::java_system_loader() {
88 return _java_system_loader;
89 }
90
91 void SystemDictionary::compute_java_system_loader(TRAPS) {
92 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
93 JavaValue result(T_OBJECT);
94 JavaCalls::call_static(&result,
95 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
96 vmSymbolHandles::getSystemClassLoader_name(),
97 vmSymbolHandles::void_classloader_signature(),
98 CHECK);
99
100 _java_system_loader = (oop)result.get_jobject();
101 }
102
103
104 // ----------------------------------------------------------------------------
105 // debugging
106
107 #ifdef ASSERT
108
109 // return true if class_name contains no '.' (internal format is '/')
110 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
111 if (class_name.not_null()) {
112 ResourceMark rm;
113 char* name = class_name->as_C_string();
114 return strchr(name, '.') == NULL;
115 } else {
116 return true;
117 }
118 }
119
120 #endif
121
122 // ----------------------------------------------------------------------------
123 // Parallel class loading check
124
125 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
126 if (UnsyncloadClass || class_loader.is_null()) return true;
127 if (AlwaysLockClassLoader) return false;
128 return java_lang_Class::parallelCapable(class_loader());
129 }
130 // ----------------------------------------------------------------------------
131 // ParallelDefineClass flag does not apply to bootclass loader
132 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
133 if (class_loader.is_null()) return false;
134 if (AllowParallelDefineClass && java_lang_Class::parallelCapable(class_loader())) {
135 return true;
136 }
137 return false;
138 }
139 // ----------------------------------------------------------------------------
140 // Resolving of classes
141
142 // Forwards to resolve_or_null
143
144 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
145 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
146 if (HAS_PENDING_EXCEPTION || klass == NULL) {
147 KlassHandle k_h(THREAD, klass);
148 // can return a null klass
149 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
150 }
151 return klass;
152 }
153
154 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
155 if (HAS_PENDING_EXCEPTION) {
156 // If we have a pending exception we forward it to the caller, unless throw_error is true,
157 // in which case we have to check whether the pending exception is a ClassNotFoundException,
158 // and if so convert it to a NoClassDefFoundError
159 // And chain the original ClassNotFoundException
160 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
161 ResourceMark rm(THREAD);
162 assert(klass_h() == NULL, "Should not have result with exception pending");
163 Handle e(THREAD, PENDING_EXCEPTION);
164 CLEAR_PENDING_EXCEPTION;
165 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
166 } else {
167 return NULL;
168 }
169 }
170 // Class not found, throw appropriate error or exception depending on value of throw_error
171 if (klass_h() == NULL) {
172 ResourceMark rm(THREAD);
173 if (throw_error) {
174 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
175 } else {
176 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
177 }
178 }
179 return (klassOop)klass_h();
180 }
181
182
183 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
184 bool throw_error, TRAPS)
185 {
186 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
187 }
188
189
190 // Forwards to resolve_instance_class_or_null
191
192 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
193 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
194 if (FieldType::is_array(class_name())) {
195 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
196 } else {
197 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
198 }
199 }
200
201 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
202 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
203 }
204
205 // Forwards to resolve_instance_class_or_null
206
207 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
208 Handle class_loader,
209 Handle protection_domain,
210 TRAPS) {
211 assert(FieldType::is_array(class_name()), "must be array");
212 jint dimension;
213 symbolOop object_key;
214 klassOop k = NULL;
215 // dimension and object_key are assigned as a side-effect of this call
216 BasicType t = FieldType::get_array_info(class_name(),
217 &dimension,
218 &object_key,
219 CHECK_NULL);
220
221 if (t == T_OBJECT) {
222 symbolHandle h_key(THREAD, object_key);
223 // naked oop "k" is OK here -- we assign back into it
224 k = SystemDictionary::resolve_instance_class_or_null(h_key,
225 class_loader,
226 protection_domain,
227 CHECK_NULL);
228 if (k != NULL) {
229 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
230 }
231 } else {
232 k = Universe::typeArrayKlassObj(t);
233 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
234 }
235 return k;
236 }
237
238
239 // Must be called for any super-class or super-interface resolution
240 // during class definition to allow class circularity checking
241 // super-interface callers:
242 // parse_interfaces - for defineClass & jvmtiRedefineClasses
243 // super-class callers:
244 // ClassFileParser - for defineClass & jvmtiRedefineClasses
245 // load_shared_class - while loading a class from shared archive
246 // resolve_instance_class_or_null:
247 // via: handle_parallel_super_load
248 // when resolving a class that has an existing placeholder with
249 // a saved superclass [i.e. a defineClass is currently in progress]
250 // if another thread is trying to resolve the class, it must do
251 // super-class checks on its own thread to catch class circularity
252 // This last call is critical in class circularity checking for cases
253 // where classloading is delegated to different threads and the
254 // classloader lock is released.
255 // Take the case: Base->Super->Base
256 // 1. If thread T1 tries to do a defineClass of class Base
257 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
258 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
259 // so it tries to load Super
260 // 3. If we load the class internally, or user classloader uses same thread
261 // loadClassFromxxx or defineClass via parseClassFile Super ...
262 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
263 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
264 // 3.4 calls resolve_super_or_fail Base
265 // 3.5 finds T1,Base -> throws class circularity
266 //OR 4. If T2 tries to resolve Super via defineClass Super ...
267 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
268 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
269 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
270 // 4.4 finds T2, Super -> throws class circularity
271 // Must be called, even if superclass is null, since this is
272 // where the placeholder entry is created which claims this
273 // thread is loading this class/classloader.
274 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
275 symbolHandle class_name,
276 Handle class_loader,
277 Handle protection_domain,
278 bool is_superclass,
279 TRAPS) {
280
281 // Try to get one of the well-known klasses.
282 // They are trusted, and do not participate in circularities.
283 if (LinkWellKnownClasses) {
284 klassOop k = find_well_known_klass(class_name());
285 if (k != NULL) {
286 return k;
287 }
288 }
289
290 // Double-check, if child class is already loaded, just return super-class,interface
291 // Don't add a placedholder if already loaded, i.e. already in system dictionary
292 // Make sure there's a placeholder for the *child* before resolving.
293 // Used as a claim that this thread is currently loading superclass/classloader
294 // Used here for ClassCircularity checks and also for heap verification
295 // (every instanceKlass in the heap needs to be in the system dictionary
296 // or have a placeholder).
297 // Must check ClassCircularity before checking if super class is already loaded
298 //
299 // We might not already have a placeholder if this child_name was
300 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
301 // the name of the class might not be known until the stream is actually
302 // parsed.
303 // Bugs 4643874, 4715493
304 // compute_hash can have a safepoint
305
306 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
307 int d_index = dictionary()->hash_to_index(d_hash);
308 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
309 int p_index = placeholders()->hash_to_index(p_hash);
310 // can't throw error holding a lock
311 bool child_already_loaded = false;
312 bool throw_circularity_error = false;
313 {
314 MutexLocker mu(SystemDictionary_lock, THREAD);
315 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
316 klassOop quicksuperk;
317 // to support // loading: if child done loading, just return superclass
318 // if class_name, & class_loader don't match:
319 // if initial define, SD update will give LinkageError
320 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
321 // so we don't throw an exception here.
322 // see: nsk redefclass014 & java.lang.instrument Instrument032
323 if ((childk != NULL ) && (is_superclass) &&
324 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
325
326 ((Klass::cast(quicksuperk)->name() == class_name()) &&
327 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
328 return quicksuperk;
329 } else {
330 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
331 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
332 throw_circularity_error = true;
333 }
334 }
335 if (!throw_circularity_error) {
336 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
337 }
338 }
339 if (throw_circularity_error) {
340 ResourceMark rm(THREAD);
341 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
342 }
343
344 // java.lang.Object should have been found above
345 assert(class_name() != NULL, "null super class for resolving");
346 // Resolve the super class or interface, check results on return
347 klassOop superk = NULL;
348 superk = SystemDictionary::resolve_or_null(class_name,
349 class_loader,
350 protection_domain,
351 THREAD);
352
353 KlassHandle superk_h(THREAD, superk);
354
355 // Note: clean up of placeholders currently in callers of
356 // resolve_super_or_fail - either at update_dictionary time
357 // or on error
358 {
359 MutexLocker mu(SystemDictionary_lock, THREAD);
360 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
361 if (probe != NULL) {
362 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
363 }
364 }
365 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
366 // can null superk
367 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
368 }
369
370 return superk_h();
371 }
372
373 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
374 Handle class_loader,
375 Handle protection_domain,
376 TRAPS) {
377 if(!has_checkPackageAccess()) return;
378
379 // Now we have to call back to java to check if the initating class has access
380 JavaValue result(T_VOID);
381 if (TraceProtectionDomainVerification) {
382 // Print out trace information
383 tty->print_cr("Checking package access");
384 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
385 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
386 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
387 }
388
389 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
390
391 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
392 JavaCalls::call_special(&result,
393 class_loader,
394 system_loader,
395 vmSymbolHandles::checkPackageAccess_name(),
396 vmSymbolHandles::class_protectiondomain_signature(),
397 Handle(THREAD, klass->java_mirror()),
398 protection_domain,
399 THREAD);
400
401 if (TraceProtectionDomainVerification) {
402 if (HAS_PENDING_EXCEPTION) {
403 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
404 } else {
405 tty->print_cr(" -> granted");
406 }
407 tty->cr();
408 }
409
410 if (HAS_PENDING_EXCEPTION) return;
411
412 // If no exception has been thrown, we have validated the protection domain
413 // Insert the protection domain of the initiating class into the set.
414 {
415 // We recalculate the entry here -- we've called out to java since
416 // the last time it was calculated.
417 symbolHandle kn(THREAD, klass->name());
418 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
419 int d_index = dictionary()->hash_to_index(d_hash);
420
421 MutexLocker mu(SystemDictionary_lock, THREAD);
422 {
423 // Note that we have an entry, and entries can be deleted only during GC,
424 // so we cannot allow GC to occur while we're holding this entry.
425
426 // We're using a No_Safepoint_Verifier to catch any place where we
427 // might potentially do a GC at all.
428 // SystemDictionary::do_unloading() asserts that classes are only
429 // unloaded at a safepoint.
430 No_Safepoint_Verifier nosafepoint;
431 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
432 protection_domain, THREAD);
433 }
434 }
435 }
436
437 // We only get here if this thread finds that another thread
438 // has already claimed the placeholder token for the current operation,
439 // but that other thread either never owned or gave up the
440 // object lock
441 // Waits on SystemDictionary_lock to indicate placeholder table updated
442 // On return, caller must recheck placeholder table state
443 //
444 // We only get here if
445 // 1) custom classLoader, i.e. not bootstrap classloader
446 // 2) UnsyncloadClass not set
447 // 3) custom classLoader has broken the class loader objectLock
448 // so another thread got here in parallel
449 //
450 // lockObject must be held.
451 // Complicated dance due to lock ordering:
452 // Must first release the classloader object lock to
453 // allow initial definer to complete the class definition
454 // and to avoid deadlock
455 // Reclaim classloader lock object with same original recursion count
456 // Must release SystemDictionary_lock after notify, since
457 // class loader lock must be claimed before SystemDictionary_lock
458 // to prevent deadlocks
459 //
460 // The notify allows applications that did an untimed wait() on
461 // the classloader object lock to not hang.
462 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
463 assert_lock_strong(SystemDictionary_lock);
464
465 bool calledholdinglock
466 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
467 assert(calledholdinglock,"must hold lock for notify");
468 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
469 ObjectSynchronizer::notifyall(lockObject, THREAD);
470 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
471 SystemDictionary_lock->wait();
472 SystemDictionary_lock->unlock();
473 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
474 SystemDictionary_lock->lock();
475 }
476
477 // If the class in is in the placeholder table, class loading is in progress
478 // For cases where the application changes threads to load classes, it
479 // is critical to ClassCircularity detection that we try loading
480 // the superclass on the same thread internally, so we do parallel
481 // super class loading here.
482 // This also is critical in cases where the original thread gets stalled
483 // even in non-circularity situations.
484 // Note: only one thread can define the class, but multiple can resolve
485 // Note: must call resolve_super_or_fail even if null super -
486 // to force placeholder entry creation for this class for circularity detection
487 // Caller must check for pending exception
488 // Returns non-null klassOop if other thread has completed load
489 // and we are done,
490 // If return null klassOop and no pending exception, the caller must load the class
491 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
492 symbolHandle name, symbolHandle superclassname, Handle class_loader,
493 Handle protection_domain, Handle lockObject, TRAPS) {
494
495 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
496 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
497 int d_index = dictionary()->hash_to_index(d_hash);
498 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
499 int p_index = placeholders()->hash_to_index(p_hash);
500
501 // superk is not used, resolve_super called for circularity check only
502 // This code is reached in two situations. One if this thread
503 // is loading the same class twice (e.g. ClassCircularity, or
504 // java.lang.instrument).
505 // The second is if another thread started the resolve_super first
506 // and has not yet finished.
507 // In both cases the original caller will clean up the placeholder
508 // entry on error.
509 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
510 superclassname,
511 class_loader,
512 protection_domain,
513 true,
514 CHECK_(nh));
515 // We don't redefine the class, so we just need to clean up if there
516 // was not an error (don't want to modify any system dictionary
517 // data structures).
518 {
519 MutexLocker mu(SystemDictionary_lock, THREAD);
520 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
521 SystemDictionary_lock->notify_all();
522 }
523
524 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
525 // Serial class loaders and bootstrap classloader do wait for superclass loads
526 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
527 MutexLocker mu(SystemDictionary_lock, THREAD);
528 // Check if classloading completed while we were loading superclass or waiting
529 klassOop check = find_class(d_index, d_hash, name, class_loader);
530 if (check != NULL) {
531 // Klass is already loaded, so just return it
532 return(instanceKlassHandle(THREAD, check));
533 } else {
534 return nh;
535 }
536 }
537
538 // must loop to both handle other placeholder updates
539 // and spurious notifications
540 bool super_load_in_progress = true;
541 PlaceholderEntry* placeholder;
542 while (super_load_in_progress) {
543 MutexLocker mu(SystemDictionary_lock, THREAD);
544 // Check if classloading completed while we were loading superclass or waiting
545 klassOop check = find_class(d_index, d_hash, name, class_loader);
546 if (check != NULL) {
547 // Klass is already loaded, so just return it
548 return(instanceKlassHandle(THREAD, check));
549 } else {
550 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
551 if (placeholder && placeholder->super_load_in_progress() ){
552 // Before UnsyncloadClass:
553 // We only get here if the application has released the
554 // classloader lock when another thread was in the middle of loading a
555 // superclass/superinterface for this class, and now
556 // this thread is also trying to load this class.
557 // To minimize surprises, the first thread that started to
558 // load a class should be the one to complete the loading
559 // with the classfile it initially expected.
560 // This logic has the current thread wait once it has done
561 // all the superclass/superinterface loading it can, until
562 // the original thread completes the class loading or fails
563 // If it completes we will use the resulting instanceKlass
564 // which we will find below in the systemDictionary.
565 // We also get here for parallel bootstrap classloader
566 if (class_loader.is_null()) {
567 SystemDictionary_lock->wait();
568 } else {
569 double_lock_wait(lockObject, THREAD);
570 }
571 } else {
572 // If not in SD and not in PH, other thread's load must have failed
573 super_load_in_progress = false;
574 }
575 }
576 }
577 return (nh);
578 }
579
580
581 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
582 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
583 // First check to see if we should remove wrapping L and ;
584 symbolHandle name;
585 if (FieldType::is_obj(class_name())) {
586 ResourceMark rm(THREAD);
587 // Ignore wrapping L and ;.
588 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
589 } else {
590 name = class_name;
591 }
592
593 // UseNewReflection
594 // Fix for 4474172; see evaluation for more details
595 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
596
597 // Do lookup to see if class already exist and the protection domain
598 // has the right access
599 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
600 int d_index = dictionary()->hash_to_index(d_hash);
601 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
602 protection_domain, THREAD);
603 if (probe != NULL) return probe;
604
605
606 // Non-bootstrap class loaders will call out to class loader and
607 // define via jvm/jni_DefineClass which will acquire the
608 // class loader object lock to protect against multiple threads
609 // defining the class in parallel by accident.
610 // This lock must be acquired here so the waiter will find
611 // any successful result in the SystemDictionary and not attempt
612 // the define
613 // ParallelCapable Classloaders and the bootstrap classloader,
614 // or all classloaders with UnsyncloadClass do not acquire lock here
615 bool DoObjectLock = true;
616 if (is_parallelCapable(class_loader)) {
617 DoObjectLock = false;
618 }
619
620 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
621 int p_index = placeholders()->hash_to_index(p_hash);
622
623 // Class is not in SystemDictionary so we have to do loading.
624 // Make sure we are synchronized on the class loader before we proceed
625 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
626 check_loader_lock_contention(lockObject, THREAD);
627 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
628
629 // Check again (after locking) if class already exist in SystemDictionary
630 bool class_has_been_loaded = false;
631 bool super_load_in_progress = false;
632 bool havesupername = false;
633 instanceKlassHandle k;
634 PlaceholderEntry* placeholder;
635 symbolHandle superclassname;
636
637 {
638 MutexLocker mu(SystemDictionary_lock, THREAD);
639 klassOop check = find_class(d_index, d_hash, name, class_loader);
640 if (check != NULL) {
641 // Klass is already loaded, so just return it
642 class_has_been_loaded = true;
643 k = instanceKlassHandle(THREAD, check);
644 } else {
645 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
646 if (placeholder && placeholder->super_load_in_progress()) {
647 super_load_in_progress = true;
648 if (placeholder->havesupername() == true) {
649 superclassname = symbolHandle(THREAD, placeholder->supername());
650 havesupername = true;
651 }
652 }
653 }
654 }
655
656 // If the class in is in the placeholder table, class loading is in progress
657 if (super_load_in_progress && havesupername==true) {
658 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
659 class_loader, protection_domain, lockObject, THREAD);
660 if (HAS_PENDING_EXCEPTION) {
661 return NULL;
662 }
663 if (!k.is_null()) {
664 class_has_been_loaded = true;
665 }
666 }
667
668 if (!class_has_been_loaded) {
669
670 // add placeholder entry to record loading instance class
671 // Five cases:
672 // All cases need to prevent modifying bootclasssearchpath
673 // in parallel with a classload of same classname
674 // Redefineclasses uses existence of the placeholder for the duration
675 // of the class load to prevent concurrent redefinition of not completely
676 // defined classes.
677 // case 1. traditional classloaders that rely on the classloader object lock
678 // - no other need for LOAD_INSTANCE
679 // case 2. traditional classloaders that break the classloader object lock
680 // as a deadlock workaround. Detection of this case requires that
681 // this check is done while holding the classloader object lock,
682 // and that lock is still held when calling classloader's loadClass.
683 // For these classloaders, we ensure that the first requestor
684 // completes the load and other requestors wait for completion.
685 // case 3. UnsyncloadClass - don't use objectLocker
686 // With this flag, we allow parallel classloading of a
687 // class/classloader pair
688 // case4. Bootstrap classloader - don't own objectLocker
689 // This classloader supports parallelism at the classloader level,
690 // but only allows a single load of a class/classloader pair.
691 // No performance benefit and no deadlock issues.
692 // case 5. parallelCapable user level classloaders - without objectLocker
693 // Allow parallel classloading of a class/classloader pair
694 symbolHandle nullsymbolHandle;
695 bool throw_circularity_error = false;
696 {
697 MutexLocker mu(SystemDictionary_lock, THREAD);
698 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
699 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
700 if (oldprobe) {
701 // only need check_seen_thread once, not on each loop
702 // 6341374 java/lang/Instrument with -Xcomp
703 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
704 throw_circularity_error = true;
705 } else {
706 // case 1: traditional: should never see load_in_progress.
707 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
708
709 // case 4: bootstrap classloader: prevent futile classloading,
710 // wait on first requestor
711 if (class_loader.is_null()) {
712 SystemDictionary_lock->wait();
713 } else {
714 // case 2: traditional with broken classloader lock. wait on first
715 // requestor.
716 double_lock_wait(lockObject, THREAD);
717 }
718 // Check if classloading completed while we were waiting
719 klassOop check = find_class(d_index, d_hash, name, class_loader);
720 if (check != NULL) {
721 // Klass is already loaded, so just return it
722 k = instanceKlassHandle(THREAD, check);
723 class_has_been_loaded = true;
724 }
725 // check if other thread failed to load and cleaned up
726 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
727 }
728 }
729 }
730 }
731 // All cases: add LOAD_INSTANCE
732 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
733 // LOAD_INSTANCE in parallel
734 // add placeholder entry even if error - callers will remove on error
735 if (!throw_circularity_error && !class_has_been_loaded) {
736 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
737 // For class loaders that do not acquire the classloader object lock,
738 // if they did not catch another thread holding LOAD_INSTANCE,
739 // need a check analogous to the acquire ObjectLocker/find_class
740 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
741 // one final check if the load has already completed
742 // class loaders holding the ObjectLock shouldn't find the class here
743 klassOop check = find_class(d_index, d_hash, name, class_loader);
744 if (check != NULL) {
745 // Klass is already loaded, so just return it
746 k = instanceKlassHandle(THREAD, check);
747 class_has_been_loaded = true;
748 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
749 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
750 SystemDictionary_lock->notify_all();
751 }
752 }
753 }
754 // must throw error outside of owning lock
755 if (throw_circularity_error) {
756 ResourceMark rm(THREAD);
757 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
758 }
759
760 if (!class_has_been_loaded) {
761
762 // Do actual loading
763 k = load_instance_class(name, class_loader, THREAD);
764
765 // For UnsyncloadClass only
766 // If they got a linkageError, check if a parallel class load succeeded.
767 // If it did, then for bytecode resolution the specification requires
768 // that we return the same result we did for the other thread, i.e. the
769 // successfully loaded instanceKlass
770 // Should not get here for classloaders that support parallelism
771 // with the new cleaner mechanism, even with AllowParallelDefineClass
772 // Bootstrap goes through here to allow for an extra guarantee check
773 if (UnsyncloadClass || (class_loader.is_null())) {
774 if (k.is_null() && HAS_PENDING_EXCEPTION
775 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
776 MutexLocker mu(SystemDictionary_lock, THREAD);
777 klassOop check = find_class(d_index, d_hash, name, class_loader);
778 if (check != NULL) {
779 // Klass is already loaded, so just use it
780 k = instanceKlassHandle(THREAD, check);
781 CLEAR_PENDING_EXCEPTION;
782 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
783 }
784 }
785 }
786
787 // clean up placeholder entries for success or error
788 // This cleans up LOAD_INSTANCE entries
789 // It also cleans up LOAD_SUPER entries on errors from
790 // calling load_instance_class
791 {
792 MutexLocker mu(SystemDictionary_lock, THREAD);
793 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
794 if (probe != NULL) {
795 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
796 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
797 SystemDictionary_lock->notify_all();
798 }
799 }
800
801 // If everything was OK (no exceptions, no null return value), and
802 // class_loader is NOT the defining loader, do a little more bookkeeping.
803 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
804 k->class_loader() != class_loader()) {
805
806 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
807
808 // Need to check for a PENDING_EXCEPTION again; check_constraints
809 // can throw and doesn't use the CHECK macro.
810 if (!HAS_PENDING_EXCEPTION) {
811 { // Grabbing the Compile_lock prevents systemDictionary updates
812 // during compilations.
813 MutexLocker mu(Compile_lock, THREAD);
814 update_dictionary(d_index, d_hash, p_index, p_hash,
815 k, class_loader, THREAD);
816 }
817 if (JvmtiExport::should_post_class_load()) {
818 Thread *thread = THREAD;
819 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
820 JvmtiExport::post_class_load((JavaThread *) thread, k());
821 }
822 }
823 }
824 if (HAS_PENDING_EXCEPTION || k.is_null()) {
825 // On error, clean up placeholders
826 {
827 MutexLocker mu(SystemDictionary_lock, THREAD);
828 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
829 SystemDictionary_lock->notify_all();
830 }
831 return NULL;
832 }
833 }
834 }
835
836 #ifdef ASSERT
837 {
838 Handle loader (THREAD, k->class_loader());
839 MutexLocker mu(SystemDictionary_lock, THREAD);
840 oop kk = find_class_or_placeholder(name, loader);
841 assert(kk == k(), "should be present in dictionary");
842 }
843 #endif
844
845 // return if the protection domain in NULL
846 if (protection_domain() == NULL) return k();
847
848 // Check the protection domain has the right access
849 {
850 MutexLocker mu(SystemDictionary_lock, THREAD);
851 // Note that we have an entry, and entries can be deleted only during GC,
852 // so we cannot allow GC to occur while we're holding this entry.
853 // We're using a No_Safepoint_Verifier to catch any place where we
854 // might potentially do a GC at all.
855 // SystemDictionary::do_unloading() asserts that classes are only
856 // unloaded at a safepoint.
857 No_Safepoint_Verifier nosafepoint;
858 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
859 class_loader,
860 protection_domain)) {
861 return k();
862 }
863 }
864
865 // Verify protection domain. If it fails an exception is thrown
866 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
867
868 return k();
869 }
870
871
872 // This routine does not lock the system dictionary.
873 //
874 // Since readers don't hold a lock, we must make sure that system
875 // dictionary entries are only removed at a safepoint (when only one
876 // thread is running), and are added to in a safe way (all links must
877 // be updated in an MT-safe manner).
878 //
879 // Callers should be aware that an entry could be added just after
880 // _dictionary->bucket(index) is read here, so the caller will not see
881 // the new entry.
882
883 klassOop SystemDictionary::find(symbolHandle class_name,
884 Handle class_loader,
885 Handle protection_domain,
886 TRAPS) {
887
888 // UseNewReflection
889 // The result of this call should be consistent with the result
890 // of the call to resolve_instance_class_or_null().
891 // See evaluation 6790209 and 4474172 for more details.
892 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
893
894 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
895 int d_index = dictionary()->hash_to_index(d_hash);
896
897 {
898 // Note that we have an entry, and entries can be deleted only during GC,
899 // so we cannot allow GC to occur while we're holding this entry.
900 // We're using a No_Safepoint_Verifier to catch any place where we
901 // might potentially do a GC at all.
902 // SystemDictionary::do_unloading() asserts that classes are only
903 // unloaded at a safepoint.
904 No_Safepoint_Verifier nosafepoint;
905 return dictionary()->find(d_index, d_hash, class_name, class_loader,
906 protection_domain, THREAD);
907 }
908 }
909
910
911 // Look for a loaded instance or array klass by name. Do not do any loading.
912 // return NULL in case of error.
913 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
914 Handle class_loader,
915 Handle protection_domain,
916 TRAPS) {
917 klassOop k = NULL;
918 assert(class_name() != NULL, "class name must be non NULL");
919
920 // Try to get one of the well-known klasses.
921 if (LinkWellKnownClasses) {
922 k = find_well_known_klass(class_name());
923 if (k != NULL) {
924 return k;
925 }
926 }
927
928 if (FieldType::is_array(class_name())) {
929 // The name refers to an array. Parse the name.
930 jint dimension;
931 symbolOop object_key;
932
933 // dimension and object_key are assigned as a side-effect of this call
934 BasicType t = FieldType::get_array_info(class_name(), &dimension,
935 &object_key, CHECK_(NULL));
936 if (t != T_OBJECT) {
937 k = Universe::typeArrayKlassObj(t);
938 } else {
939 symbolHandle h_key(THREAD, object_key);
940 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
941 }
942 if (k != NULL) {
943 k = Klass::cast(k)->array_klass_or_null(dimension);
944 }
945 } else {
946 k = find(class_name, class_loader, protection_domain, THREAD);
947 }
948 return k;
949 }
950
951 // Quick range check for names of well-known classes:
952 static symbolOop wk_klass_name_limits[2] = {NULL, NULL};
953
954 #ifndef PRODUCT
955 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
956 // counts for "hello world": 3983, 1616, 1075
957 // => 60% hit after limit guard, 25% total win rate
958 #endif
959
960 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) {
961 // A bounds-check on class_name will quickly get a negative result.
962 NOT_PRODUCT(find_wkk_calls++);
963 if (class_name >= wk_klass_name_limits[0] &&
964 class_name <= wk_klass_name_limits[1]) {
965 NOT_PRODUCT(find_wkk_probes++);
966 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
967 if (sid != vmSymbols::NO_SID) {
968 klassOop k = NULL;
969 switch (sid) {
970 #define WK_KLASS_CASE(name, symbol, ignore_option) \
971 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
972 k = WK_KLASS(name); break;
973 WK_KLASSES_DO(WK_KLASS_CASE)
974 #undef WK_KLASS_CASE
975 }
976 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
977 return k;
978 }
979 }
980 return NULL;
981 }
982
983 // Note: this method is much like resolve_from_stream, but
984 // updates no supplemental data structures.
985 // TODO consolidate the two methods with a helper routine?
986 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
987 Handle class_loader,
988 Handle protection_domain,
989 ClassFileStream* st,
990 KlassHandle host_klass,
991 GrowableArray<Handle>* cp_patches,
992 TRAPS) {
993 symbolHandle parsed_name;
994
995 // Parse the stream. Note that we do this even though this klass might
996 // already be present in the SystemDictionary, otherwise we would not
997 // throw potential ClassFormatErrors.
998 //
999 // Note: "name" is updated.
1000 // Further note: a placeholder will be added for this class when
1001 // super classes are loaded (resolve_super_or_fail). We expect this
1002 // to be called for all classes but java.lang.Object; and we preload
1003 // java.lang.Object through resolve_or_fail, not this path.
1004
1005 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1006 class_loader,
1007 protection_domain,
1008 host_klass,
1009 cp_patches,
1010 parsed_name,
1011 true,
1012 THREAD);
1013
1014
1015 // We don't redefine the class, so we just need to clean up whether there
1016 // was an error or not (don't want to modify any system dictionary
1017 // data structures).
1018 // Parsed name could be null if we threw an error before we got far
1019 // enough along to parse it -- in that case, there is nothing to clean up.
1020 if (!parsed_name.is_null()) {
1021 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1022 class_loader);
1023 int p_index = placeholders()->hash_to_index(p_hash);
1024 {
1025 MutexLocker mu(SystemDictionary_lock, THREAD);
1026 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1027 SystemDictionary_lock->notify_all();
1028 }
1029 }
1030
1031 if (host_klass.not_null() && k.not_null()) {
1032 assert(AnonymousClasses, "");
1033 // If it's anonymous, initialize it now, since nobody else will.
1034 k->set_host_klass(host_klass());
1035
1036 {
1037 MutexLocker mu_r(Compile_lock, THREAD);
1038
1039 // Add to class hierarchy, initialize vtables, and do possible
1040 // deoptimizations.
1041 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1042
1043 // But, do not add to system dictionary.
1044 }
1045
1046 k->eager_initialize(THREAD);
1047
1048 // notify jvmti
1049 if (JvmtiExport::should_post_class_load()) {
1050 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1051 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1052 }
1053 }
1054
1055 return k();
1056 }
1057
1058 // Add a klass to the system from a stream (called by jni_DefineClass and
1059 // JVM_DefineClass).
1060 // Note: class_name can be NULL. In that case we do not know the name of
1061 // the class until we have parsed the stream.
1062
1063 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
1064 Handle class_loader,
1065 Handle protection_domain,
1066 ClassFileStream* st,
1067 bool verify,
1068 TRAPS) {
1069
1070 // Classloaders that support parallelism, e.g. bootstrap classloader,
1071 // or all classloaders with UnsyncloadClass do not acquire lock here
1072 bool DoObjectLock = true;
1073 if (is_parallelCapable(class_loader)) {
1074 DoObjectLock = false;
1075 }
1076
1077 // Make sure we are synchronized on the class loader before we proceed
1078 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1079 check_loader_lock_contention(lockObject, THREAD);
1080 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1081
1082 symbolHandle parsed_name;
1083
1084 // Parse the stream. Note that we do this even though this klass might
1085 // already be present in the SystemDictionary, otherwise we would not
1086 // throw potential ClassFormatErrors.
1087 //
1088 // Note: "name" is updated.
1089 // Further note: a placeholder will be added for this class when
1090 // super classes are loaded (resolve_super_or_fail). We expect this
1091 // to be called for all classes but java.lang.Object; and we preload
1092 // java.lang.Object through resolve_or_fail, not this path.
1093
1094 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1095 class_loader,
1096 protection_domain,
1097 parsed_name,
1098 verify,
1099 THREAD);
1100
1101 const char* pkg = "java/";
1102 if (!HAS_PENDING_EXCEPTION &&
1103 !class_loader.is_null() &&
1104 !parsed_name.is_null() &&
1105 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1106 // It is illegal to define classes in the "java." package from
1107 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1108 ResourceMark rm(THREAD);
1109 char* name = parsed_name->as_C_string();
1110 char* index = strrchr(name, '/');
1111 *index = '\0'; // chop to just the package name
1112 while ((index = strchr(name, '/')) != NULL) {
1113 *index = '.'; // replace '/' with '.' in package name
1114 }
1115 const char* fmt = "Prohibited package name: %s";
1116 size_t len = strlen(fmt) + strlen(name);
1117 char* message = NEW_RESOURCE_ARRAY(char, len);
1118 jio_snprintf(message, len, fmt, name);
1119 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1120 vmSymbols::java_lang_SecurityException(), message);
1121 }
1122
1123 if (!HAS_PENDING_EXCEPTION) {
1124 assert(!parsed_name.is_null(), "Sanity");
1125 assert(class_name.is_null() || class_name() == parsed_name(),
1126 "name mismatch");
1127 // Verification prevents us from creating names with dots in them, this
1128 // asserts that that's the case.
1129 assert(is_internal_format(parsed_name),
1130 "external class name format used internally");
1131
1132 // Add class just loaded
1133 // If a class loader supports parallel classloading handle parallel define requests
1134 // find_or_define_instance_class may return a different instanceKlass
1135 if (is_parallelCapable(class_loader)) {
1136 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1137 } else {
1138 define_instance_class(k, THREAD);
1139 }
1140 }
1141
1142 // If parsing the class file or define_instance_class failed, we
1143 // need to remove the placeholder added on our behalf. But we
1144 // must make sure parsed_name is valid first (it won't be if we had
1145 // a format error before the class was parsed far enough to
1146 // find the name).
1147 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1148 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1149 class_loader);
1150 int p_index = placeholders()->hash_to_index(p_hash);
1151 {
1152 MutexLocker mu(SystemDictionary_lock, THREAD);
1153 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1154 SystemDictionary_lock->notify_all();
1155 }
1156 return NULL;
1157 }
1158
1159 // Make sure that we didn't leave a place holder in the
1160 // SystemDictionary; this is only done on success
1161 debug_only( {
1162 if (!HAS_PENDING_EXCEPTION) {
1163 assert(!parsed_name.is_null(), "parsed_name is still null?");
1164 symbolHandle h_name (THREAD, k->name());
1165 Handle h_loader (THREAD, k->class_loader());
1166
1167 MutexLocker mu(SystemDictionary_lock, THREAD);
1168
1169 oop check = find_class_or_placeholder(parsed_name, class_loader);
1170 assert(check == k(), "should be present in the dictionary");
1171
1172 oop check2 = find_class_or_placeholder(h_name, h_loader);
1173 assert(check == check2, "name inconsistancy in SystemDictionary");
1174 }
1175 } );
1176
1177 return k();
1178 }
1179
1180
1181 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1182 int number_of_entries) {
1183 assert(length == _nof_buckets * sizeof(HashtableBucket),
1184 "bad shared dictionary size.");
1185 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1186 }
1187
1188
1189 // If there is a shared dictionary, then find the entry for the
1190 // given shared system class, if any.
1191
1192 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1193 if (shared_dictionary() != NULL) {
1194 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1195 int d_index = dictionary()->hash_to_index(d_hash);
1196 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1197 } else {
1198 return NULL;
1199 }
1200 }
1201
1202
1203 // Load a class from the shared spaces (found through the shared system
1204 // dictionary). Force the superclass and all interfaces to be loaded.
1205 // Update the class definition to include sibling classes and no
1206 // subclasses (yet). [Classes in the shared space are not part of the
1207 // object hierarchy until loaded.]
1208
1209 instanceKlassHandle SystemDictionary::load_shared_class(
1210 symbolHandle class_name, Handle class_loader, TRAPS) {
1211 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1212 return load_shared_class(ik, class_loader, THREAD);
1213 }
1214
1215 // Note well! Changes to this method may affect oop access order
1216 // in the shared archive. Please take care to not make changes that
1217 // adversely affect cold start time by changing the oop access order
1218 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1219 // MarkAndMoveOrderedReadWrite closures.
1220 instanceKlassHandle SystemDictionary::load_shared_class(
1221 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1222 assert(class_loader.is_null(), "non-null classloader for shared class?");
1223 if (ik.not_null()) {
1224 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1225 symbolHandle class_name(THREAD, ik->name());
1226
1227 // Found the class, now load the superclass and interfaces. If they
1228 // are shared, add them to the main system dictionary and reset
1229 // their hierarchy references (supers, subs, and interfaces).
1230
1231 if (ik->super() != NULL) {
1232 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1233 resolve_super_or_fail(class_name, cn,
1234 class_loader, Handle(), true, CHECK_(nh));
1235 }
1236
1237 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1238 int num_interfaces = interfaces->length();
1239 for (int index = 0; index < num_interfaces; index++) {
1240 klassOop k = klassOop(interfaces->obj_at(index));
1241
1242 // Note: can not use instanceKlass::cast here because
1243 // interfaces' instanceKlass's C++ vtbls haven't been
1244 // reinitialized yet (they will be once the interface classes
1245 // are loaded)
1246 symbolHandle name (THREAD, k->klass_part()->name());
1247 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1248 }
1249
1250 // Adjust methods to recover missing data. They need addresses for
1251 // interpreter entry points and their default native method address
1252 // must be reset.
1253
1254 // Updating methods must be done under a lock so multiple
1255 // threads don't update these in parallel
1256 // Shared classes are all currently loaded by the bootstrap
1257 // classloader, so this will never cause a deadlock on
1258 // a custom class loader lock.
1259
1260 {
1261 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1262 check_loader_lock_contention(lockObject, THREAD);
1263 ObjectLocker ol(lockObject, THREAD, true);
1264
1265 objArrayHandle methods (THREAD, ik->methods());
1266 int num_methods = methods->length();
1267 for (int index2 = 0; index2 < num_methods; ++index2) {
1268 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1269 m()->link_method(m, CHECK_(nh));
1270 }
1271 }
1272
1273 if (TraceClassLoading) {
1274 ResourceMark rm;
1275 tty->print("[Loaded %s", ik->external_name());
1276 tty->print(" from shared objects file");
1277 tty->print_cr("]");
1278 }
1279 // notify a class loaded from shared object
1280 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1281 true /* shared class */);
1282 }
1283 return ik;
1284 }
1285
1286 #ifdef KERNEL
1287 // Some classes on the bootstrap class path haven't been installed on the
1288 // system yet. Call the DownloadManager method to make them appear in the
1289 // bootstrap class path and try again to load the named class.
1290 // Note that with delegation class loaders all classes in another loader will
1291 // first try to call this so it'd better be fast!!
1292 static instanceKlassHandle download_and_retry_class_load(
1293 symbolHandle class_name,
1294 TRAPS) {
1295
1296 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1297 instanceKlassHandle nk;
1298
1299 // If download manager class isn't loaded just return.
1300 if (dlm == NULL) return nk;
1301
1302 { HandleMark hm(THREAD);
1303 ResourceMark rm(THREAD);
1304 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1305 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1306
1307 // return value
1308 JavaValue result(T_OBJECT);
1309
1310 // Call the DownloadManager. We assume that it has a lock because
1311 // multiple classes could be not found and downloaded at the same time.
1312 // class sun.misc.DownloadManager;
1313 // public static String getBootClassPathEntryForClass(String className);
1314 JavaCalls::call_static(&result,
1315 KlassHandle(THREAD, dlm),
1316 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1317 vmSymbolHandles::string_string_signature(),
1318 class_string,
1319 CHECK_(nk));
1320
1321 // Get result.string and add to bootclasspath
1322 assert(result.get_type() == T_OBJECT, "just checking");
1323 oop obj = (oop) result.get_jobject();
1324 if (obj == NULL) { return nk; }
1325
1326 Handle h_obj(THREAD, obj);
1327 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1328 CHECK_(nk));
1329
1330 // lock the loader
1331 // we use this lock because JVMTI does.
1332 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1333
1334 ObjectLocker ol(loader_lock, THREAD);
1335 // add the file to the bootclasspath
1336 ClassLoader::update_class_path_entry_list(new_class_name, true);
1337 } // end HandleMark
1338
1339 if (TraceClassLoading) {
1340 ClassLoader::print_bootclasspath();
1341 }
1342 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1343 }
1344 #endif // KERNEL
1345
1346
1347 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1348 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1349 if (class_loader.is_null()) {
1350
1351 // Search the shared system dictionary for classes preloaded into the
1352 // shared spaces.
1353 instanceKlassHandle k;
1354 {
1355 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1356 k = load_shared_class(class_name, class_loader, THREAD);
1357 }
1358
1359 if (k.is_null()) {
1360 // Use VM class loader
1361 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1362 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1363 }
1364
1365 #ifdef KERNEL
1366 // If the VM class loader has failed to load the class, call the
1367 // DownloadManager class to make it magically appear on the classpath
1368 // and try again. This is only configured with the Kernel VM.
1369 if (k.is_null()) {
1370 k = download_and_retry_class_load(class_name, CHECK_(nh));
1371 }
1372 #endif // KERNEL
1373
1374 // find_or_define_instance_class may return a different instanceKlass
1375 if (!k.is_null()) {
1376 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1377 }
1378 return k;
1379 } else {
1380 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1381 ResourceMark rm(THREAD);
1382
1383 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1384 JavaThread* jt = (JavaThread*) THREAD;
1385
1386 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1387 ClassLoader::perf_app_classload_selftime(),
1388 ClassLoader::perf_app_classload_count(),
1389 jt->get_thread_stat()->perf_recursion_counts_addr(),
1390 jt->get_thread_stat()->perf_timers_addr(),
1391 PerfClassTraceTime::CLASS_LOAD);
1392
1393 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1394 // Translate to external class name format, i.e., convert '/' chars to '.'
1395 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1396
1397 JavaValue result(T_OBJECT);
1398
1399 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1400
1401 // Call public unsynchronized loadClass(String) directly for all class loaders
1402 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1403 // acquire a class-name based lock rather than the class loader object lock.
1404 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1405 // so the call to loadClassInternal() was not required.
1406 //
1407 // UnsyncloadClass flag means both call loadClass(String) and do
1408 // not acquire the class loader lock even for class loaders that are
1409 // not parallelCapable. This was a risky transitional
1410 // flag for diagnostic purposes only. It is risky to call
1411 // custom class loaders without synchronization.
1412 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1413 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1414 // Do NOT assume this will be supported in future releases.
1415 //
1416 // Added MustCallLoadClassInternal in case we discover in the field
1417 // a customer that counts on this call
1418 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1419 JavaCalls::call_special(&result,
1420 class_loader,
1421 spec_klass,
1422 vmSymbolHandles::loadClassInternal_name(),
1423 vmSymbolHandles::string_class_signature(),
1424 string,
1425 CHECK_(nh));
1426 } else {
1427 JavaCalls::call_virtual(&result,
1428 class_loader,
1429 spec_klass,
1430 vmSymbolHandles::loadClass_name(),
1431 vmSymbolHandles::string_class_signature(),
1432 string,
1433 CHECK_(nh));
1434 }
1435
1436 assert(result.get_type() == T_OBJECT, "just checking");
1437 oop obj = (oop) result.get_jobject();
1438
1439 // Primitive classes return null since forName() can not be
1440 // used to obtain any of the Class objects representing primitives or void
1441 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1442 instanceKlassHandle k =
1443 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1444 // For user defined Java class loaders, check that the name returned is
1445 // the same as that requested. This check is done for the bootstrap
1446 // loader when parsing the class file.
1447 if (class_name() == k->name()) {
1448 return k;
1449 }
1450 }
1451 // Class is not found or has the wrong name, return NULL
1452 return nh;
1453 }
1454 }
1455
1456 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1457
1458 Handle class_loader_h(THREAD, k->class_loader());
1459
1460 // for bootstrap and other parallel classloaders don't acquire lock,
1461 // use placeholder token
1462 // If a parallelCapable class loader calls define_instance_class instead of
1463 // find_or_define_instance_class to get here, we have a timing
1464 // hole with systemDictionary updates and check_constraints
1465 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1466 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1467 compute_loader_lock_object(class_loader_h, THREAD)),
1468 "define called without lock");
1469 }
1470
1471 // Check class-loading constraints. Throw exception if violation is detected.
1472 // Grabs and releases SystemDictionary_lock
1473 // The check_constraints/find_class call and update_dictionary sequence
1474 // must be "atomic" for a specific class/classloader pair so we never
1475 // define two different instanceKlasses for that class/classloader pair.
1476 // Existing classloaders will call define_instance_class with the
1477 // classloader lock held
1478 // Parallel classloaders will call find_or_define_instance_class
1479 // which will require a token to perform the define class
1480 symbolHandle name_h(THREAD, k->name());
1481 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1482 int d_index = dictionary()->hash_to_index(d_hash);
1483 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1484
1485 // Register class just loaded with class loader (placed in Vector)
1486 // Note we do this before updating the dictionary, as this can
1487 // fail with an OutOfMemoryError (if it does, we will *not* put this
1488 // class in the dictionary and will not update the class hierarchy).
1489 if (k->class_loader() != NULL) {
1490 methodHandle m(THREAD, Universe::loader_addClass_method());
1491 JavaValue result(T_VOID);
1492 JavaCallArguments args(class_loader_h);
1493 args.push_oop(Handle(THREAD, k->java_mirror()));
1494 JavaCalls::call(&result, m, &args, CHECK);
1495 }
1496
1497 // Add the new class. We need recompile lock during update of CHA.
1498 {
1499 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1500 int p_index = placeholders()->hash_to_index(p_hash);
1501
1502 MutexLocker mu_r(Compile_lock, THREAD);
1503
1504 // Add to class hierarchy, initialize vtables, and do possible
1505 // deoptimizations.
1506 add_to_hierarchy(k, CHECK); // No exception, but can block
1507
1508 // Add to systemDictionary - so other classes can see it.
1509 // Grabs and releases SystemDictionary_lock
1510 update_dictionary(d_index, d_hash, p_index, p_hash,
1511 k, class_loader_h, THREAD);
1512 }
1513 k->eager_initialize(THREAD);
1514
1515 // notify jvmti
1516 if (JvmtiExport::should_post_class_load()) {
1517 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1518 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1519
1520 }
1521 }
1522
1523 // Support parallel classloading
1524 // All parallel class loaders, including bootstrap classloader
1525 // lock a placeholder entry for this class/class_loader pair
1526 // to allow parallel defines of different classes for this class loader
1527 // With AllowParallelDefine flag==true, in case they do not synchronize around
1528 // FindLoadedClass/DefineClass, calls, we check for parallel
1529 // loading for them, wait if a defineClass is in progress
1530 // and return the initial requestor's results
1531 // This flag does not apply to the bootstrap classloader.
1532 // With AllowParallelDefine flag==false, call through to define_instance_class
1533 // which will throw LinkageError: duplicate class definition.
1534 // False is the requested default.
1535 // For better performance, the class loaders should synchronize
1536 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1537 // potentially waste time reading and parsing the bytestream.
1538 // Note: VM callers should ensure consistency of k/class_name,class_loader
1539 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1540
1541 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1542 symbolHandle name_h(THREAD, k->name()); // passed in class_name may be null
1543
1544 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader);
1545 int d_index = dictionary()->hash_to_index(d_hash);
1546
1547 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1548 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader);
1549 int p_index = placeholders()->hash_to_index(p_hash);
1550 PlaceholderEntry* probe;
1551
1552 {
1553 MutexLocker mu(SystemDictionary_lock, THREAD);
1554 // First check if class already defined
1555 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1556 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1557 if (check != NULL) {
1558 return(instanceKlassHandle(THREAD, check));
1559 }
1560 }
1561
1562 // Acquire define token for this class/classloader
1563 symbolHandle nullsymbolHandle;
1564 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1565 // Wait if another thread defining in parallel
1566 // All threads wait - even those that will throw duplicate class: otherwise
1567 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1568 // if other thread has not finished updating dictionary
1569 while (probe->definer() != NULL) {
1570 SystemDictionary_lock->wait();
1571 }
1572 // Only special cases allow parallel defines and can use other thread's results
1573 // Other cases fall through, and may run into duplicate defines
1574 // caught by finding an entry in the SystemDictionary
1575 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instanceKlass() != NULL)) {
1576 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1577 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1578 SystemDictionary_lock->notify_all();
1579 #ifdef ASSERT
1580 klassOop check = find_class(d_index, d_hash, name_h, class_loader);
1581 assert(check != NULL, "definer missed recording success");
1582 #endif
1583 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1584 } else {
1585 // This thread will define the class (even if earlier thread tried and had an error)
1586 probe->set_definer(THREAD);
1587 }
1588 }
1589
1590 define_instance_class(k, THREAD);
1591
1592 Handle linkage_exception = Handle(); // null handle
1593
1594 // definer must notify any waiting threads
1595 {
1596 MutexLocker mu(SystemDictionary_lock, THREAD);
1597 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader);
1598 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1599 if (probe != NULL) {
1600 if (HAS_PENDING_EXCEPTION) {
1601 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1602 CLEAR_PENDING_EXCEPTION;
1603 } else {
1604 probe->set_instanceKlass(k());
1605 }
1606 probe->set_definer(NULL);
1607 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1608 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD);
1609 SystemDictionary_lock->notify_all();
1610 }
1611 }
1612
1613 // Can't throw exception while holding lock due to rank ordering
1614 if (linkage_exception() != NULL) {
1615 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1616 }
1617
1618 return k;
1619 }
1620 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1621 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1622 if (class_loader.is_null()) {
1623 return Handle(THREAD, _system_loader_lock_obj);
1624 } else {
1625 return class_loader;
1626 }
1627 }
1628
1629 // This method is added to check how often we have to wait to grab loader
1630 // lock. The results are being recorded in the performance counters defined in
1631 // ClassLoader::_sync_systemLoaderLockContentionRate and
1632 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1633 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1634 if (!UsePerfData) {
1635 return;
1636 }
1637
1638 assert(!loader_lock.is_null(), "NULL lock object");
1639
1640 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1641 == ObjectSynchronizer::owner_other) {
1642 // contention will likely happen, so increment the corresponding
1643 // contention counter.
1644 if (loader_lock() == _system_loader_lock_obj) {
1645 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1646 } else {
1647 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1648 }
1649 }
1650 }
1651
1652 // ----------------------------------------------------------------------------
1653 // Lookup
1654
1655 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1656 symbolHandle class_name,
1657 Handle class_loader) {
1658 assert_locked_or_safepoint(SystemDictionary_lock);
1659 assert (index == dictionary()->index_for(class_name, class_loader),
1660 "incorrect index?");
1661
1662 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1663 return k;
1664 }
1665
1666
1667 // Basic find on classes in the midst of being loaded
1668 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1669 symbolHandle class_name,
1670 Handle class_loader) {
1671 assert_locked_or_safepoint(SystemDictionary_lock);
1672
1673 return placeholders()->find_entry(index, hash, class_name, class_loader);
1674 }
1675
1676
1677 // Used for assertions and verification only
1678 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1679 Handle class_loader) {
1680 #ifndef ASSERT
1681 guarantee(VerifyBeforeGC ||
1682 VerifyDuringGC ||
1683 VerifyBeforeExit ||
1684 VerifyAfterGC, "too expensive");
1685 #endif
1686 assert_locked_or_safepoint(SystemDictionary_lock);
1687 symbolOop class_name_ = class_name();
1688 oop class_loader_ = class_loader();
1689
1690 // First look in the loaded class array
1691 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1692 int d_index = dictionary()->hash_to_index(d_hash);
1693 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1694
1695 if (lookup == NULL) {
1696 // Next try the placeholders
1697 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1698 int p_index = placeholders()->hash_to_index(p_hash);
1699 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1700 }
1701
1702 return lookup;
1703 }
1704
1705
1706 // Get the next class in the diictionary.
1707 klassOop SystemDictionary::try_get_next_class() {
1708 return dictionary()->try_get_next_class();
1709 }
1710
1711
1712 // ----------------------------------------------------------------------------
1713 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1714 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1715 // before a new class is used.
1716
1717 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1718 assert(k.not_null(), "just checking");
1719 // Link into hierachy. Make sure the vtables are initialized before linking into
1720 k->append_to_sibling_list(); // add to superklass/sibling list
1721 k->process_interfaces(THREAD); // handle all "implements" declarations
1722 k->set_init_state(instanceKlass::loaded);
1723 // Now flush all code that depended on old class hierarchy.
1724 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1725 // Also, first reinitialize vtable because it may have gotten out of synch
1726 // while the new class wasn't connected to the class hierarchy.
1727 Universe::flush_dependents_on(k);
1728 }
1729
1730
1731 // ----------------------------------------------------------------------------
1732 // GC support
1733
1734 // Following roots during mark-sweep is separated in two phases.
1735 //
1736 // The first phase follows preloaded classes and all other system
1737 // classes, since these will never get unloaded anyway.
1738 //
1739 // The second phase removes (unloads) unreachable classes from the
1740 // system dictionary and follows the remaining classes' contents.
1741
1742 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1743 // Follow preloaded classes/mirrors and system loader object
1744 blk->do_oop(&_java_system_loader);
1745 preloaded_oops_do(blk);
1746 always_strong_classes_do(blk);
1747 }
1748
1749
1750 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1751 // Follow all system classes and temporary placeholders in dictionary
1752 dictionary()->always_strong_classes_do(blk);
1753
1754 // Placeholders. These are *always* strong roots, as they
1755 // represent classes we're actively loading.
1756 placeholders_do(blk);
1757
1758 // Visit extra methods
1759 if (invoke_method_table() != NULL)
1760 invoke_method_table()->oops_do(blk);
1761
1762 // Loader constraints. We must keep the symbolOop used in the name alive.
1763 constraints()->always_strong_classes_do(blk);
1764
1765 // Resolution errors keep the symbolOop for the error alive
1766 resolution_errors()->always_strong_classes_do(blk);
1767 }
1768
1769
1770 void SystemDictionary::placeholders_do(OopClosure* blk) {
1771 placeholders()->oops_do(blk);
1772 }
1773
1774
1775 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1776 bool result = dictionary()->do_unloading(is_alive);
1777 constraints()->purge_loader_constraints(is_alive);
1778 resolution_errors()->purge_resolution_errors(is_alive);
1779 return result;
1780 }
1781
1782
1783 // The mirrors are scanned by shared_oops_do() which is
1784 // not called by oops_do(). In order to process oops in
1785 // a necessary order, shared_oops_do() is call by
1786 // Universe::oops_do().
1787 void SystemDictionary::oops_do(OopClosure* f) {
1788 // Adjust preloaded classes and system loader object
1789 f->do_oop(&_java_system_loader);
1790 preloaded_oops_do(f);
1791
1792 lazily_loaded_oops_do(f);
1793
1794 // Adjust dictionary
1795 dictionary()->oops_do(f);
1796
1797 // Visit extra methods
1798 if (invoke_method_table() != NULL)
1799 invoke_method_table()->oops_do(f);
1800
1801 // Partially loaded classes
1802 placeholders()->oops_do(f);
1803
1804 // Adjust constraint table
1805 constraints()->oops_do(f);
1806
1807 // Adjust resolution error table
1808 resolution_errors()->oops_do(f);
1809 }
1810
1811
1812 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1813 f->do_oop((oop*) &wk_klass_name_limits[0]);
1814 f->do_oop((oop*) &wk_klass_name_limits[1]);
1815
1816 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1817 f->do_oop((oop*) &_well_known_klasses[k]);
1818 }
1819
1820 {
1821 for (int i = 0; i < T_VOID+1; i++) {
1822 if (_box_klasses[i] != NULL) {
1823 assert(i >= T_BOOLEAN, "checking");
1824 f->do_oop((oop*) &_box_klasses[i]);
1825 }
1826 }
1827 }
1828
1829 // The basic type mirrors would have already been processed in
1830 // Universe::oops_do(), via a call to shared_oops_do(), so should
1831 // not be processed again.
1832
1833 f->do_oop((oop*) &_system_loader_lock_obj);
1834 FilteredFieldsMap::klasses_oops_do(f);
1835 }
1836
1837 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1838 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1839 }
1840
1841 // Just the classes from defining class loaders
1842 // Don't iterate over placeholders
1843 void SystemDictionary::classes_do(void f(klassOop)) {
1844 dictionary()->classes_do(f);
1845 }
1846
1847 // Added for initialize_itable_for_klass
1848 // Just the classes from defining class loaders
1849 // Don't iterate over placeholders
1850 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1851 dictionary()->classes_do(f, CHECK);
1852 }
1853
1854 // All classes, and their class loaders
1855 // Don't iterate over placeholders
1856 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1857 dictionary()->classes_do(f);
1858 }
1859
1860 // All classes, and their class loaders
1861 // (added for helpers that use HandleMarks and ResourceMarks)
1862 // Don't iterate over placeholders
1863 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1864 dictionary()->classes_do(f, CHECK);
1865 }
1866
1867 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1868 placeholders()->entries_do(f);
1869 }
1870
1871 void SystemDictionary::methods_do(void f(methodOop)) {
1872 dictionary()->methods_do(f);
1873 if (invoke_method_table() != NULL)
1874 invoke_method_table()->methods_do(f);
1875 }
1876
1877 // ----------------------------------------------------------------------------
1878 // Lazily load klasses
1879
1880 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1881 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1882
1883 // if multiple threads calling this function, only one thread will load
1884 // the class. The other threads will find the loaded version once the
1885 // class is loaded.
1886 klassOop aos = _abstract_ownable_synchronizer_klass;
1887 if (aos == NULL) {
1888 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1889 // Force a fence to prevent any read before the write completes
1890 OrderAccess::fence();
1891 _abstract_ownable_synchronizer_klass = k;
1892 }
1893 }
1894
1895 // ----------------------------------------------------------------------------
1896 // Initialization
1897
1898 void SystemDictionary::initialize(TRAPS) {
1899 // Allocate arrays
1900 assert(dictionary() == NULL,
1901 "SystemDictionary should only be initialized once");
1902 _dictionary = new Dictionary(_nof_buckets);
1903 _placeholders = new PlaceholderTable(_nof_buckets);
1904 _number_of_modifications = 0;
1905 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1906 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1907 // _invoke_method_table is allocated lazily in find_method_handle_invoke()
1908
1909 // Allocate private object used as system class loader lock
1910 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1911 // Initialize basic classes
1912 initialize_preloaded_classes(CHECK);
1913 }
1914
1915 // Compact table of directions on the initialization of klasses:
1916 static const short wk_init_info[] = {
1917 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1918 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1919 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1920 | (int)SystemDictionary::option ),
1921 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1922 #undef WK_KLASS_INIT_INFO
1923 0
1924 };
1925
1926 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1927 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1928 int info = wk_init_info[id - FIRST_WKID];
1929 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1930 symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid);
1931 klassOop* klassp = &_well_known_klasses[id];
1932 bool must_load = (init_opt < SystemDictionary::Opt);
1933 bool try_load = true;
1934 if (init_opt == SystemDictionary::Opt_Kernel) {
1935 #ifndef KERNEL
1936 try_load = false;
1937 #endif //KERNEL
1938 }
1939 if ((*klassp) == NULL && try_load) {
1940 if (must_load) {
1941 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1942 } else {
1943 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1944 }
1945 }
1946 return ((*klassp) != NULL);
1947 }
1948
1949 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1950 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1951 for (int id = (int)start_id; id < (int)limit_id; id++) {
1952 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1953 int info = wk_init_info[id - FIRST_WKID];
1954 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1955 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1956
1957 initialize_wk_klass((WKID)id, opt, CHECK);
1958
1959 // Update limits, so find_well_known_klass can be very fast:
1960 symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1961 if (wk_klass_name_limits[1] == NULL) {
1962 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1963 } else if (wk_klass_name_limits[1] < s) {
1964 wk_klass_name_limits[1] = s;
1965 } else if (wk_klass_name_limits[0] > s) {
1966 wk_klass_name_limits[0] = s;
1967 }
1968 }
1969
1970 // move the starting value forward to the limit:
1971 start_id = limit_id;
1972 }
1973
1974
1975 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1976 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1977 // Preload commonly used klasses
1978 WKID scan = FIRST_WKID;
1979 // first do Object, String, Class
1980 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1981
1982 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(Class_klass)));
1983
1984 // Fixup mirrors for classes loaded before java.lang.Class.
1985 // These calls iterate over the objects currently in the perm gen
1986 // so calling them at this point is matters (not before when there
1987 // are fewer objects and not later after there are more objects
1988 // in the perm gen.
1989 Universe::initialize_basic_type_mirrors(CHECK);
1990 Universe::fixup_mirrors(CHECK);
1991
1992 // do a bunch more:
1993 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1994
1995 // Preload ref klasses and set reference types
1996 instanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1997 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1998
1999 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2000 instanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2001 instanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2002 instanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2003 instanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2004
2005 WKID meth_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2006 WKID meth_group_end = WK_KLASS_ENUM_NAME(WrongMethodTypeException_klass);
2007 initialize_wk_klasses_until(meth_group_start, scan, CHECK);
2008 if (EnableMethodHandles) {
2009 initialize_wk_klasses_through(meth_group_end, scan, CHECK);
2010 }
2011 if (_well_known_klasses[meth_group_start] == NULL) {
2012 // Skip the rest of the method handle classes, if MethodHandle is not loaded.
2013 scan = WKID(meth_group_end+1);
2014 }
2015 WKID indy_group_start = WK_KLASS_ENUM_NAME(Linkage_klass);
2016 WKID indy_group_end = WK_KLASS_ENUM_NAME(InvokeDynamic_klass);
2017 initialize_wk_klasses_until(indy_group_start, scan, CHECK);
2018 if (EnableInvokeDynamic) {
2019 initialize_wk_klasses_through(indy_group_end, scan, CHECK);
2020 }
2021 if (_well_known_klasses[indy_group_start] == NULL) {
2022 // Skip the rest of the dynamic typing classes, if Linkage is not loaded.
2023 scan = WKID(indy_group_end+1);
2024 }
2025
2026 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2027
2028 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2029 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2030 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2031 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2032 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2033 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2034 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2035 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2036 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2037 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2038
2039 #ifdef KERNEL
2040 if (sun_jkernel_DownloadManager_klass() == NULL) {
2041 warning("Cannot find sun/jkernel/DownloadManager");
2042 }
2043 #endif // KERNEL
2044
2045 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2046 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2047 _has_loadClassInternal = (method != NULL);
2048 }
2049 { // Compute whether we should use checkPackageAccess or NOT
2050 methodOop method = instanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2051 _has_checkPackageAccess = (method != NULL);
2052 }
2053 }
2054
2055 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2056 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2057 BasicType SystemDictionary::box_klass_type(klassOop k) {
2058 assert(k != NULL, "");
2059 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2060 if (_box_klasses[i] == k)
2061 return (BasicType)i;
2062 }
2063 return T_OBJECT;
2064 }
2065
2066 KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
2067 if (t >= T_BOOLEAN && t <= T_VOID)
2068 return KlassHandle(&SystemDictionary::_box_klasses[t], true);
2069 else
2070 return KlassHandle();
2071 }
2072
2073 // Constraints on class loaders. The details of the algorithm can be
2074 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2075 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2076 // that the system dictionary needs to maintain a set of contraints that
2077 // must be satisfied by all classes in the dictionary.
2078 // if defining is true, then LinkageError if already in systemDictionary
2079 // if initiating loader, then ok if instanceKlass matches existing entry
2080
2081 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2082 instanceKlassHandle k,
2083 Handle class_loader, bool defining,
2084 TRAPS) {
2085 const char *linkage_error = NULL;
2086 {
2087 symbolHandle name (THREAD, k->name());
2088 MutexLocker mu(SystemDictionary_lock, THREAD);
2089
2090 klassOop check = find_class(d_index, d_hash, name, class_loader);
2091 if (check != (klassOop)NULL) {
2092 // if different instanceKlass - duplicate class definition,
2093 // else - ok, class loaded by a different thread in parallel,
2094 // we should only have found it if it was done loading and ok to use
2095 // system dictionary only holds instance classes, placeholders
2096 // also holds array classes
2097
2098 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2099 if ((defining == true) || (k() != check)) {
2100 linkage_error = "loader (instance of %s): attempted duplicate class "
2101 "definition for name: \"%s\"";
2102 } else {
2103 return;
2104 }
2105 }
2106
2107 #ifdef ASSERT
2108 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
2109 int p_index = placeholders()->hash_to_index(p_hash);
2110 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2111 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
2112 #endif
2113
2114 if (linkage_error == NULL) {
2115 if (constraints()->check_or_update(k, class_loader, name) == false) {
2116 linkage_error = "loader constraint violation: loader (instance of %s)"
2117 " previously initiated loading for a different type with name \"%s\"";
2118 }
2119 }
2120 }
2121
2122 // Throw error now if needed (cannot throw while holding
2123 // SystemDictionary_lock because of rank ordering)
2124
2125 if (linkage_error) {
2126 ResourceMark rm(THREAD);
2127 const char* class_loader_name = loader_name(class_loader());
2128 char* type_name = k->name()->as_C_string();
2129 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2130 strlen(type_name);
2131 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2132 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2133 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2134 }
2135 }
2136
2137
2138 // Update system dictionary - done after check_constraint and add_to_hierachy
2139 // have been called.
2140 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2141 int p_index, unsigned int p_hash,
2142 instanceKlassHandle k,
2143 Handle class_loader,
2144 TRAPS) {
2145 // Compile_lock prevents systemDictionary updates during compilations
2146 assert_locked_or_safepoint(Compile_lock);
2147 symbolHandle name (THREAD, k->name());
2148
2149 {
2150 MutexLocker mu1(SystemDictionary_lock, THREAD);
2151
2152 // See whether biased locking is enabled and if so set it for this
2153 // klass.
2154 // Note that this must be done past the last potential blocking
2155 // point / safepoint. We enable biased locking lazily using a
2156 // VM_Operation to iterate the SystemDictionary and installing the
2157 // biasable mark word into each instanceKlass's prototype header.
2158 // To avoid race conditions where we accidentally miss enabling the
2159 // optimization for one class in the process of being added to the
2160 // dictionary, we must not safepoint after the test of
2161 // BiasedLocking::enabled().
2162 if (UseBiasedLocking && BiasedLocking::enabled()) {
2163 // Set biased locking bit for all loaded classes; it will be
2164 // cleared if revocation occurs too often for this type
2165 // NOTE that we must only do this when the class is initally
2166 // defined, not each time it is referenced from a new class loader
2167 if (k->class_loader() == class_loader()) {
2168 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2169 }
2170 }
2171
2172 // Check for a placeholder. If there, remove it and make a
2173 // new system dictionary entry.
2174 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2175 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2176 if (sd_check == NULL) {
2177 dictionary()->add_klass(name, class_loader, k);
2178 notice_modification();
2179 }
2180 #ifdef ASSERT
2181 sd_check = find_class(d_index, d_hash, name, class_loader);
2182 assert (sd_check != NULL, "should have entry in system dictionary");
2183 // Changed to allow PH to remain to complete class circularity checking
2184 // while only one thread can define a class at one time, multiple
2185 // classes can resolve the superclass for a class at one time,
2186 // and the placeholder is used to track that
2187 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2188 // assert (ph_check == NULL, "should not have a placeholder entry");
2189 #endif
2190 SystemDictionary_lock->notify_all();
2191 }
2192 }
2193
2194
2195 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2196 symbolHandle class_name, Handle class_loader, TRAPS) {
2197
2198 // First see if it has been loaded directly.
2199 // Force the protection domain to be null. (This removes protection checks.)
2200 Handle no_protection_domain;
2201 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2202 no_protection_domain, CHECK_NULL);
2203 if (klass != NULL)
2204 return klass;
2205
2206 // Now look to see if it has been loaded elsewhere, and is subject to
2207 // a loader constraint that would require this loader to return the
2208 // klass that is already loaded.
2209 if (FieldType::is_array(class_name())) {
2210 // For array classes, their klassOops are not kept in the
2211 // constraint table. The element klassOops are.
2212 jint dimension;
2213 symbolOop object_key;
2214 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2215 &object_key, CHECK_(NULL));
2216 if (t != T_OBJECT) {
2217 klass = Universe::typeArrayKlassObj(t);
2218 } else {
2219 symbolHandle elem_name(THREAD, object_key);
2220 MutexLocker mu(SystemDictionary_lock, THREAD);
2221 klass = constraints()->find_constrained_klass(elem_name, class_loader);
2222 }
2223 // If element class already loaded, allocate array klass
2224 if (klass != NULL) {
2225 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2226 }
2227 } else {
2228 MutexLocker mu(SystemDictionary_lock, THREAD);
2229 // Non-array classes are easy: simply check the constraint table.
2230 klass = constraints()->find_constrained_klass(class_name, class_loader);
2231 }
2232
2233 return klass;
2234 }
2235
2236
2237 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2238 Handle class_loader1,
2239 Handle class_loader2,
2240 Thread* THREAD) {
2241 symbolHandle constraint_name;
2242 if (!FieldType::is_array(class_name())) {
2243 constraint_name = class_name;
2244 } else {
2245 // For array classes, their klassOops are not kept in the
2246 // constraint table. The element classes are.
2247 jint dimension;
2248 symbolOop object_key;
2249 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2250 &object_key, CHECK_(false));
2251 // primitive types always pass
2252 if (t != T_OBJECT) {
2253 return true;
2254 } else {
2255 constraint_name = symbolHandle(THREAD, object_key);
2256 }
2257 }
2258 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, class_loader1);
2259 int d_index1 = dictionary()->hash_to_index(d_hash1);
2260
2261 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, class_loader2);
2262 int d_index2 = dictionary()->hash_to_index(d_hash2);
2263 {
2264 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2265
2266 // Better never do a GC while we're holding these oops
2267 No_Safepoint_Verifier nosafepoint;
2268
2269 klassOop klass1 = find_class(d_index1, d_hash1, constraint_name, class_loader1);
2270 klassOop klass2 = find_class(d_index2, d_hash2, constraint_name, class_loader2);
2271 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2272 klass2, class_loader2);
2273 }
2274 }
2275
2276 // Add entry to resolution error table to record the error when the first
2277 // attempt to resolve a reference to a class has failed.
2278 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2279 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2280 int index = resolution_errors()->hash_to_index(hash);
2281 {
2282 MutexLocker ml(SystemDictionary_lock, Thread::current());
2283 resolution_errors()->add_entry(index, hash, pool, which, error);
2284 }
2285 }
2286
2287 // Lookup resolution error table. Returns error if found, otherwise NULL.
2288 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2289 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2290 int index = resolution_errors()->hash_to_index(hash);
2291 {
2292 MutexLocker ml(SystemDictionary_lock, Thread::current());
2293 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2294 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2295 }
2296 }
2297
2298
2299 // Signature constraints ensure that callers and callees agree about
2300 // the meaning of type names in their signatures. This routine is the
2301 // intake for constraints. It collects them from several places:
2302 //
2303 // * LinkResolver::resolve_method (if check_access is true) requires
2304 // that the resolving class (the caller) and the defining class of
2305 // the resolved method (the callee) agree on each type in the
2306 // method's signature.
2307 //
2308 // * LinkResolver::resolve_interface_method performs exactly the same
2309 // checks.
2310 //
2311 // * LinkResolver::resolve_field requires that the constant pool
2312 // attempting to link to a field agree with the field's defining
2313 // class about the type of the field signature.
2314 //
2315 // * klassVtable::initialize_vtable requires that, when a class
2316 // overrides a vtable entry allocated by a superclass, that the
2317 // overriding method (i.e., the callee) agree with the superclass
2318 // on each type in the method's signature.
2319 //
2320 // * klassItable::initialize_itable requires that, when a class fills
2321 // in its itables, for each non-abstract method installed in an
2322 // itable, the method (i.e., the callee) agree with the interface
2323 // on each type in the method's signature.
2324 //
2325 // All those methods have a boolean (check_access, checkconstraints)
2326 // which turns off the checks. This is used from specialized contexts
2327 // such as bootstrapping, dumping, and debugging.
2328 //
2329 // No direct constraint is placed between the class and its
2330 // supertypes. Constraints are only placed along linked relations
2331 // between callers and callees. When a method overrides or implements
2332 // an abstract method in a supertype (superclass or interface), the
2333 // constraints are placed as if the supertype were the caller to the
2334 // overriding method. (This works well, since callers to the
2335 // supertype have already established agreement between themselves and
2336 // the supertype.) As a result of all this, a class can disagree with
2337 // its supertype about the meaning of a type name, as long as that
2338 // class neither calls a relevant method of the supertype, nor is
2339 // called (perhaps via an override) from the supertype.
2340 //
2341 //
2342 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2343 //
2344 // Make sure all class components (including arrays) in the given
2345 // signature will be resolved to the same class in both loaders.
2346 // Returns the name of the type that failed a loader constraint check, or
2347 // NULL if no constraint failed. The returned C string needs cleaning up
2348 // with a ResourceMark in the caller. No exception except OOME is thrown.
2349 // Arrays are not added to the loader constraint table, their elements are.
2350 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2351 Handle loader1, Handle loader2,
2352 bool is_method, TRAPS) {
2353 // Nothing to do if loaders are the same.
2354 if (loader1() == loader2()) {
2355 return NULL;
2356 }
2357
2358 SignatureStream sig_strm(signature, is_method);
2359 while (!sig_strm.is_done()) {
2360 if (sig_strm.is_object()) {
2361 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2362 symbolHandle sig (THREAD, s);
2363 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2364 return sig()->as_C_string();
2365 }
2366 }
2367 sig_strm.next();
2368 }
2369 return NULL;
2370 }
2371
2372
2373 methodOop SystemDictionary::find_method_handle_invoke(symbolHandle name,
2374 symbolHandle signature,
2375 KlassHandle accessing_klass,
2376 TRAPS) {
2377 if (!EnableMethodHandles) return NULL;
2378 if (invoke_method_table() == NULL) {
2379 // create this side table lazily
2380 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2381 }
2382 vmSymbols::SID name_id = vmSymbols::find_sid(name());
2383 assert(name_id != vmSymbols::NO_SID, "must be a known name");
2384 unsigned int hash = invoke_method_table()->compute_hash(signature, name_id);
2385 int index = invoke_method_table()->hash_to_index(hash);
2386 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2387 methodHandle non_cached_result;
2388 if (spe == NULL || spe->property_oop() == NULL) {
2389 spe = NULL;
2390 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2391 if (THREAD->is_Compiler_thread())
2392 return NULL; // do not attempt from within compiler
2393 bool for_invokeGeneric = (name_id == vmSymbols::VM_SYMBOL_ENUM_NAME(invokeGeneric_name));
2394 bool found_on_bcp = false;
2395 Handle mt = find_method_handle_type(signature(), accessing_klass,
2396 for_invokeGeneric,
2397 found_on_bcp, CHECK_NULL);
2398 KlassHandle mh_klass = SystemDictionaryHandles::MethodHandle_klass();
2399 methodHandle m = methodOopDesc::make_invoke_method(mh_klass, name, signature,
2400 mt, CHECK_NULL);
2401 // Now grab the lock. We might have to throw away the new method,
2402 // if a racing thread has managed to install one at the same time.
2403 if (found_on_bcp) {
2404 MutexLocker ml(SystemDictionary_lock, Thread::current());
2405 spe = invoke_method_table()->find_entry(index, hash, signature, name_id);
2406 if (spe == NULL)
2407 spe = invoke_method_table()->add_entry(index, hash, signature, name_id);
2408 if (spe->property_oop() == NULL)
2409 spe->set_property_oop(m());
2410 } else {
2411 non_cached_result = m;
2412 }
2413 }
2414 if (spe != NULL && spe->property_oop() != NULL) {
2415 assert(spe->property_oop()->is_method(), "");
2416 return (methodOop) spe->property_oop();
2417 } else {
2418 return non_cached_result();
2419 }
2420 }
2421
2422 // Ask Java code to find or construct a java.dyn.MethodType for the given
2423 // signature, as interpreted relative to the given class loader.
2424 // Because of class loader constraints, all method handle usage must be
2425 // consistent with this loader.
2426 Handle SystemDictionary::find_method_handle_type(symbolHandle signature,
2427 KlassHandle accessing_klass,
2428 bool for_invokeGeneric,
2429 bool& return_bcp_flag,
2430 TRAPS) {
2431 Handle class_loader, protection_domain;
2432 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2433 Handle empty;
2434 int npts = ArgumentCount(signature()).size();
2435 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2436 int arg = 0;
2437 Handle rt; // the return type from the signature
2438 for (SignatureStream ss(signature()); !ss.is_done(); ss.next()) {
2439 oop mirror = NULL;
2440 if (is_on_bcp) {
2441 mirror = ss.as_java_mirror(class_loader, protection_domain,
2442 SignatureStream::ReturnNull, CHECK_(empty));
2443 if (mirror == NULL) {
2444 // fall back from BCP to accessing_klass
2445 if (accessing_klass.not_null()) {
2446 class_loader = Handle(THREAD, instanceKlass::cast(accessing_klass())->class_loader());
2447 protection_domain = Handle(THREAD, instanceKlass::cast(accessing_klass())->protection_domain());
2448 }
2449 is_on_bcp = false;
2450 }
2451 }
2452 if (!is_on_bcp) {
2453 // Resolve, throwing a real error if it doesn't work.
2454 mirror = ss.as_java_mirror(class_loader, protection_domain,
2455 SignatureStream::NCDFError, CHECK_(empty));
2456 }
2457 if (ss.at_return_type())
2458 rt = Handle(THREAD, mirror);
2459 else
2460 pts->obj_at_put(arg++, mirror);
2461 // Check accessibility.
2462 if (ss.is_object() && accessing_klass.not_null()) {
2463 klassOop sel_klass = java_lang_Class::as_klassOop(mirror);
2464 // Emulate constantPoolOopDesc::verify_constant_pool_resolve.
2465 if (Klass::cast(sel_klass)->oop_is_objArray())
2466 sel_klass = objArrayKlass::cast(sel_klass)->bottom_klass();
2467 if (Klass::cast(sel_klass)->oop_is_instance()) {
2468 KlassHandle sel_kh(THREAD, sel_klass);
2469 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2470 }
2471 }
2472 }
2473 assert(arg == npts, "");
2474
2475 // call sun.dyn.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2476 JavaCallArguments args(Handle(THREAD, rt()));
2477 args.push_oop(pts());
2478 JavaValue result(T_OBJECT);
2479 JavaCalls::call_static(&result,
2480 SystemDictionary::MethodHandleNatives_klass(),
2481 vmSymbols::findMethodHandleType_name(),
2482 vmSymbols::findMethodHandleType_signature(),
2483 &args, CHECK_(empty));
2484 Handle method_type(THREAD, (oop) result.get_jobject());
2485
2486 if (for_invokeGeneric) {
2487 // call sun.dyn.MethodHandleNatives::notifyGenericMethodType(MethodType) -> void
2488 JavaCallArguments args(Handle(THREAD, method_type()));
2489 JavaValue no_result(T_VOID);
2490 JavaCalls::call_static(&no_result,
2491 SystemDictionary::MethodHandleNatives_klass(),
2492 vmSymbols::notifyGenericMethodType_name(),
2493 vmSymbols::notifyGenericMethodType_signature(),
2494 &args, THREAD);
2495 if (HAS_PENDING_EXCEPTION) {
2496 // If the notification fails, just kill it.
2497 CLEAR_PENDING_EXCEPTION;
2498 }
2499 }
2500
2501 // report back to the caller with the MethodType and the "on_bcp" flag
2502 return_bcp_flag = is_on_bcp;
2503 return method_type;
2504 }
2505
2506 // Ask Java code to find or construct a method handle constant.
2507 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2508 int ref_kind, //e.g., JVM_REF_invokeVirtual
2509 KlassHandle callee,
2510 symbolHandle name_sym,
2511 symbolHandle signature,
2512 TRAPS) {
2513 Handle empty;
2514 Handle name = java_lang_String::create_from_symbol(name_sym(), CHECK_(empty));
2515 Handle type;
2516 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2517 bool ignore_is_on_bcp = false;
2518 type = find_method_handle_type(signature, caller, false, ignore_is_on_bcp, CHECK_(empty));
2519 } else {
2520 SignatureStream ss(signature(), false);
2521 if (!ss.is_done()) {
2522 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2523 SignatureStream::NCDFError, CHECK_(empty));
2524 type = Handle(THREAD, mirror);
2525 ss.next();
2526 if (!ss.is_done()) type = Handle(); // error!
2527 }
2528 }
2529 if (type.is_null()) {
2530 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2531 }
2532
2533 // call sun.dyn.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2534 JavaCallArguments args;
2535 args.push_oop(caller->java_mirror()); // the referring class
2536 args.push_int(ref_kind);
2537 args.push_oop(callee->java_mirror()); // the target class
2538 args.push_oop(name());
2539 args.push_oop(type());
2540 JavaValue result(T_OBJECT);
2541 JavaCalls::call_static(&result,
2542 SystemDictionary::MethodHandleNatives_klass(),
2543 vmSymbols::linkMethodHandleConstant_name(),
2544 vmSymbols::linkMethodHandleConstant_signature(),
2545 &args, CHECK_(empty));
2546 return Handle(THREAD, (oop) result.get_jobject());
2547 }
2548
2549 // Ask Java code to find or construct a java.dyn.CallSite for the given
2550 // name and signature, as interpreted relative to the given class loader.
2551 Handle SystemDictionary::make_dynamic_call_site(Handle bootstrap_method,
2552 symbolHandle name,
2553 methodHandle signature_invoker,
2554 Handle info,
2555 methodHandle caller_method,
2556 int caller_bci,
2557 TRAPS) {
2558 Handle empty;
2559 guarantee(bootstrap_method.not_null() &&
2560 java_dyn_MethodHandle::is_instance(bootstrap_method()),
2561 "caller must supply a valid BSM");
2562
2563 Handle caller_mname = MethodHandles::new_MemberName(CHECK_(empty));
2564 MethodHandles::init_MemberName(caller_mname(), caller_method());
2565
2566 // call sun.dyn.MethodHandleNatives::makeDynamicCallSite(bootm, name, mtype, info, caller_mname, caller_pos)
2567 oop name_str_oop = StringTable::intern(name(), CHECK_(empty)); // not a handle!
2568 JavaCallArguments args(Handle(THREAD, bootstrap_method()));
2569 args.push_oop(name_str_oop);
2570 args.push_oop(signature_invoker->method_handle_type());
2571 args.push_oop(info());
2572 args.push_oop(caller_mname());
2573 args.push_int(caller_bci);
2574 JavaValue result(T_OBJECT);
2575 JavaCalls::call_static(&result,
2576 SystemDictionary::MethodHandleNatives_klass(),
2577 vmSymbols::makeDynamicCallSite_name(),
2578 vmSymbols::makeDynamicCallSite_signature(),
2579 &args, CHECK_(empty));
2580 oop call_site_oop = (oop) result.get_jobject();
2581 assert(call_site_oop->is_oop()
2582 /*&& java_dyn_CallSite::is_instance(call_site_oop)*/, "must be sane");
2583 if (TraceMethodHandles) {
2584 #ifndef PRODUCT
2585 tty->print_cr("Linked invokedynamic bci=%d site="INTPTR_FORMAT":", caller_bci, call_site_oop);
2586 call_site_oop->print();
2587 tty->cr();
2588 #endif //PRODUCT
2589 }
2590 return call_site_oop;
2591 }
2592
2593 Handle SystemDictionary::find_bootstrap_method(methodHandle caller_method, int caller_bci,
2594 int cache_index, TRAPS) {
2595 Handle empty;
2596
2597 constantPoolHandle pool;
2598 {
2599 klassOop caller = caller_method->method_holder();
2600 if (!Klass::cast(caller)->oop_is_instance()) return empty;
2601 pool = constantPoolHandle(THREAD, instanceKlass::cast(caller)->constants());
2602 }
2603
2604 int constant_pool_index = pool->cache()->entry_at(cache_index)->constant_pool_index();
2605 constantTag tag = pool->tag_at(constant_pool_index);
2606
2607 if (tag.is_invoke_dynamic()) {
2608 // JVM_CONSTANT_InvokeDynamic is an ordered pair of [bootm, name&type]
2609 // The bootm, being a JVM_CONSTANT_MethodHandle, has its own cache entry.
2610 int bsm_index = pool->invoke_dynamic_bootstrap_method_ref_index_at(constant_pool_index);
2611 if (bsm_index != 0) {
2612 int bsm_index_in_cache = pool->cache()->entry_at(cache_index)->bootstrap_method_index_in_cache();
2613 DEBUG_ONLY(int bsm_index_2 = pool->cache()->entry_at(bsm_index_in_cache)->constant_pool_index());
2614 assert(bsm_index == bsm_index_2, "BSM constant lifted to cache");
2615 if (TraceMethodHandles) {
2616 tty->print_cr("resolving bootstrap method for "PTR_FORMAT" at %d at cache[%d]CP[%d]...",
2617 (intptr_t) caller_method(), caller_bci, cache_index, constant_pool_index);
2618 }
2619 oop bsm_oop = pool->resolve_cached_constant_at(bsm_index_in_cache, CHECK_(empty));
2620 if (TraceMethodHandles) {
2621 tty->print_cr("bootstrap method for "PTR_FORMAT" at %d retrieved as "PTR_FORMAT":",
2622 (intptr_t) caller_method(), caller_bci, (intptr_t) bsm_oop);
2623 }
2624 assert(bsm_oop->is_oop()
2625 && java_dyn_MethodHandle::is_instance(bsm_oop), "must be sane");
2626 return Handle(THREAD, bsm_oop);
2627 }
2628 // else null BSM; fall through
2629 } else if (tag.is_name_and_type()) {
2630 // JSR 292 EDR does not have JVM_CONSTANT_InvokeDynamic
2631 // a bare name&type defaults its BSM to null, so fall through...
2632 } else {
2633 ShouldNotReachHere(); // verifier does not allow this
2634 }
2635
2636 // Fall through to pick up the per-class bootstrap method.
2637 // This mechanism may go away in the PFD.
2638 assert(AllowTransitionalJSR292, "else the verifier should have stopped us already");
2639 oop bsm_oop = instanceKlass::cast(caller_method->method_holder())->bootstrap_method();
2640 if (bsm_oop != NULL) {
2641 if (TraceMethodHandles) {
2642 tty->print_cr("bootstrap method for "PTR_FORMAT" registered as "PTR_FORMAT":",
2643 (intptr_t) caller_method(), (intptr_t) bsm_oop);
2644 }
2645 assert(bsm_oop->is_oop()
2646 && java_dyn_MethodHandle::is_instance(bsm_oop), "must be sane");
2647 return Handle(THREAD, bsm_oop);
2648 }
2649
2650 return empty;
2651 }
2652
2653 // Since the identity hash code for symbols changes when the symbols are
2654 // moved from the regular perm gen (hash in the mark word) to the shared
2655 // spaces (hash is the address), the classes loaded into the dictionary
2656 // may be in the wrong buckets.
2657
2658 void SystemDictionary::reorder_dictionary() {
2659 dictionary()->reorder_dictionary();
2660 }
2661
2662
2663 void SystemDictionary::copy_buckets(char** top, char* end) {
2664 dictionary()->copy_buckets(top, end);
2665 }
2666
2667
2668 void SystemDictionary::copy_table(char** top, char* end) {
2669 dictionary()->copy_table(top, end);
2670 }
2671
2672
2673 void SystemDictionary::reverse() {
2674 dictionary()->reverse();
2675 }
2676
2677 int SystemDictionary::number_of_classes() {
2678 return dictionary()->number_of_entries();
2679 }
2680
2681
2682 // ----------------------------------------------------------------------------
2683 #ifndef PRODUCT
2684
2685 void SystemDictionary::print() {
2686 dictionary()->print();
2687
2688 // Placeholders
2689 GCMutexLocker mu(SystemDictionary_lock);
2690 placeholders()->print();
2691
2692 // loader constraints - print under SD_lock
2693 constraints()->print();
2694 }
2695
2696 #endif
2697
2698 void SystemDictionary::verify() {
2699 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2700 guarantee(constraints() != NULL,
2701 "Verify of loader constraints failed");
2702 guarantee(dictionary()->number_of_entries() >= 0 &&
2703 placeholders()->number_of_entries() >= 0,
2704 "Verify of system dictionary failed");
2705
2706 // Verify dictionary
2707 dictionary()->verify();
2708
2709 GCMutexLocker mu(SystemDictionary_lock);
2710 placeholders()->verify();
2711
2712 // Verify constraint table
2713 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2714 constraints()->verify(dictionary(), placeholders());
2715 }
2716
2717
2718 void SystemDictionary::verify_obj_klass_present(Handle obj,
2719 symbolHandle class_name,
2720 Handle class_loader) {
2721 GCMutexLocker mu(SystemDictionary_lock);
2722 oop probe = find_class_or_placeholder(class_name, class_loader);
2723 if (probe == NULL) {
2724 probe = SystemDictionary::find_shared_class(class_name);
2725 }
2726 guarantee(probe != NULL &&
2727 (!probe->is_klass() || probe == obj()),
2728 "Loaded klasses should be in SystemDictionary");
2729 }
2730
2731 #ifndef PRODUCT
2732
2733 // statistics code
2734 class ClassStatistics: AllStatic {
2735 private:
2736 static int nclasses; // number of classes
2737 static int nmethods; // number of methods
2738 static int nmethoddata; // number of methodData
2739 static int class_size; // size of class objects in words
2740 static int method_size; // size of method objects in words
2741 static int debug_size; // size of debug info in methods
2742 static int methoddata_size; // size of methodData objects in words
2743
2744 static void do_class(klassOop k) {
2745 nclasses++;
2746 class_size += k->size();
2747 if (k->klass_part()->oop_is_instance()) {
2748 instanceKlass* ik = (instanceKlass*)k->klass_part();
2749 class_size += ik->methods()->size();
2750 class_size += ik->constants()->size();
2751 class_size += ik->local_interfaces()->size();
2752 class_size += ik->transitive_interfaces()->size();
2753 // We do not have to count implementors, since we only store one!
2754 class_size += ik->fields()->size();
2755 }
2756 }
2757
2758 static void do_method(methodOop m) {
2759 nmethods++;
2760 method_size += m->size();
2761 // class loader uses same objArray for empty vectors, so don't count these
2762 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2763 if (m->has_stackmap_table()) {
2764 method_size += m->stackmap_data()->size();
2765 }
2766
2767 methodDataOop mdo = m->method_data();
2768 if (mdo != NULL) {
2769 nmethoddata++;
2770 methoddata_size += mdo->size();
2771 }
2772 }
2773
2774 public:
2775 static void print() {
2776 SystemDictionary::classes_do(do_class);
2777 SystemDictionary::methods_do(do_method);
2778 tty->print_cr("Class statistics:");
2779 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2780 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2781 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2782 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2783 }
2784 };
2785
2786
2787 int ClassStatistics::nclasses = 0;
2788 int ClassStatistics::nmethods = 0;
2789 int ClassStatistics::nmethoddata = 0;
2790 int ClassStatistics::class_size = 0;
2791 int ClassStatistics::method_size = 0;
2792 int ClassStatistics::debug_size = 0;
2793 int ClassStatistics::methoddata_size = 0;
2794
2795 void SystemDictionary::print_class_statistics() {
2796 ResourceMark rm;
2797 ClassStatistics::print();
2798 }
2799
2800
2801 class MethodStatistics: AllStatic {
2802 public:
2803 enum {
2804 max_parameter_size = 10
2805 };
2806 private:
2807
2808 static int _number_of_methods;
2809 static int _number_of_final_methods;
2810 static int _number_of_static_methods;
2811 static int _number_of_native_methods;
2812 static int _number_of_synchronized_methods;
2813 static int _number_of_profiled_methods;
2814 static int _number_of_bytecodes;
2815 static int _parameter_size_profile[max_parameter_size];
2816 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2817
2818 static void initialize() {
2819 _number_of_methods = 0;
2820 _number_of_final_methods = 0;
2821 _number_of_static_methods = 0;
2822 _number_of_native_methods = 0;
2823 _number_of_synchronized_methods = 0;
2824 _number_of_profiled_methods = 0;
2825 _number_of_bytecodes = 0;
2826 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2827 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2828 };
2829
2830 static void do_method(methodOop m) {
2831 _number_of_methods++;
2832 // collect flag info
2833 if (m->is_final() ) _number_of_final_methods++;
2834 if (m->is_static() ) _number_of_static_methods++;
2835 if (m->is_native() ) _number_of_native_methods++;
2836 if (m->is_synchronized()) _number_of_synchronized_methods++;
2837 if (m->method_data() != NULL) _number_of_profiled_methods++;
2838 // collect parameter size info (add one for receiver, if any)
2839 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2840 // collect bytecodes info
2841 {
2842 Thread *thread = Thread::current();
2843 HandleMark hm(thread);
2844 BytecodeStream s(methodHandle(thread, m));
2845 Bytecodes::Code c;
2846 while ((c = s.next()) >= 0) {
2847 _number_of_bytecodes++;
2848 _bytecodes_profile[c]++;
2849 }
2850 }
2851 }
2852
2853 public:
2854 static void print() {
2855 initialize();
2856 SystemDictionary::methods_do(do_method);
2857 // generate output
2858 tty->cr();
2859 tty->print_cr("Method statistics (static):");
2860 // flag distribution
2861 tty->cr();
2862 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2863 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2864 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2865 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2866 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2867 // parameter size profile
2868 tty->cr();
2869 { int tot = 0;
2870 int avg = 0;
2871 for (int i = 0; i < max_parameter_size; i++) {
2872 int n = _parameter_size_profile[i];
2873 tot += n;
2874 avg += n*i;
2875 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2876 }
2877 assert(tot == _number_of_methods, "should be the same");
2878 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2879 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2880 }
2881 // bytecodes profile
2882 tty->cr();
2883 { int tot = 0;
2884 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2885 if (Bytecodes::is_defined(i)) {
2886 Bytecodes::Code c = Bytecodes::cast(i);
2887 int n = _bytecodes_profile[c];
2888 tot += n;
2889 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2890 }
2891 }
2892 assert(tot == _number_of_bytecodes, "should be the same");
2893 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2894 }
2895 tty->cr();
2896 }
2897 };
2898
2899 int MethodStatistics::_number_of_methods;
2900 int MethodStatistics::_number_of_final_methods;
2901 int MethodStatistics::_number_of_static_methods;
2902 int MethodStatistics::_number_of_native_methods;
2903 int MethodStatistics::_number_of_synchronized_methods;
2904 int MethodStatistics::_number_of_profiled_methods;
2905 int MethodStatistics::_number_of_bytecodes;
2906 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2907 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2908
2909
2910 void SystemDictionary::print_method_statistics() {
2911 MethodStatistics::print();
2912 }
2913
2914 #endif // PRODUCT