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