1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
58
59
60 Dictionary* SystemDictionary::_dictionary = NULL;
61 PlaceholderTable* SystemDictionary::_placeholders = NULL;
62 Dictionary* SystemDictionary::_shared_dictionary = NULL;
63 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
64 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
65 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
66
67
68 int SystemDictionary::_number_of_modifications = 0;
69 int SystemDictionary::_sdgeneration = 0;
70 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
71 20201,40423,99991};
72
73 oop SystemDictionary::_system_loader_lock_obj = NULL;
74
75 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
76 = { NULL /*, NULL...*/ };
77
78 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
79
80 oop SystemDictionary::_java_system_loader = NULL;
81
82 bool SystemDictionary::_has_loadClassInternal = false;
83 bool SystemDictionary::_has_checkPackageAccess = false;
84
85 // lazily initialized klass variables
86 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
87
88
89 // ----------------------------------------------------------------------------
90 // Java-level SystemLoader
91
92 oop SystemDictionary::java_system_loader() {
93 return _java_system_loader;
94 }
95
96 void SystemDictionary::compute_java_system_loader(TRAPS) {
97 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
98 JavaValue result(T_OBJECT);
99 JavaCalls::call_static(&result,
100 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
101 vmSymbols::getSystemClassLoader_name(),
102 vmSymbols::void_classloader_signature(),
103 CHECK);
104
105 _java_system_loader = (oop)result.get_jobject();
106 }
107
108
109 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
110 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
111 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
112 }
113
114 // ----------------------------------------------------------------------------
115 // debugging
116
117 #ifdef ASSERT
118
119 // return true if class_name contains no '.' (internal format is '/')
120 bool SystemDictionary::is_internal_format(Symbol* class_name) {
121 if (class_name != NULL) {
122 ResourceMark rm;
123 char* name = class_name->as_C_string();
124 return strchr(name, '.') == NULL;
125 } else {
126 return true;
127 }
128 }
129
130 #endif
131
132 // ----------------------------------------------------------------------------
133 // Parallel class loading check
134
135 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
136 if (UnsyncloadClass || class_loader.is_null()) return true;
137 if (AlwaysLockClassLoader) return false;
138 return java_lang_ClassLoader::parallelCapable(class_loader());
139 }
140 // ----------------------------------------------------------------------------
141 // ParallelDefineClass flag does not apply to bootclass loader
142 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
143 if (class_loader.is_null()) return false;
144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
145 return true;
146 }
147 return false;
148 }
149 // ----------------------------------------------------------------------------
150 // Resolving of classes
151
152 // Forwards to resolve_or_null
153
154 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
155 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
156 if (HAS_PENDING_EXCEPTION || klass == NULL) {
157 KlassHandle k_h(THREAD, klass);
158 // can return a null klass
159 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
160 }
161 return klass;
162 }
163
164 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
165 if (HAS_PENDING_EXCEPTION) {
166 // If we have a pending exception we forward it to the caller, unless throw_error is true,
167 // in which case we have to check whether the pending exception is a ClassNotFoundException,
168 // and if so convert it to a NoClassDefFoundError
169 // And chain the original ClassNotFoundException
170 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
171 ResourceMark rm(THREAD);
172 assert(klass_h() == NULL, "Should not have result with exception pending");
173 Handle e(THREAD, PENDING_EXCEPTION);
174 CLEAR_PENDING_EXCEPTION;
175 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
176 } else {
177 return NULL;
178 }
179 }
180 // Class not found, throw appropriate error or exception depending on value of throw_error
181 if (klass_h() == NULL) {
182 ResourceMark rm(THREAD);
183 if (throw_error) {
184 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
185 } else {
186 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
187 }
188 }
189 return (Klass*)klass_h();
190 }
191
192
193 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
194 bool throw_error, TRAPS)
195 {
196 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
197 }
198
199
200 // Forwards to resolve_instance_class_or_null
201
202 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
203 assert(!THREAD->is_Compiler_thread(),
204 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
205 class_name->as_C_string(),
206 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
207 if (FieldType::is_array(class_name)) {
208 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
209 } else if (FieldType::is_obj(class_name)) {
210 ResourceMark rm(THREAD);
211 // Ignore wrapping L and ;.
212 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
213 class_name->utf8_length() - 2, CHECK_NULL);
214 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
215 } else {
216 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
217 }
218 }
219
220 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
221 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
222 }
223
224 // Forwards to resolve_instance_class_or_null
225
226 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
227 Handle class_loader,
228 Handle protection_domain,
229 TRAPS) {
230 assert(FieldType::is_array(class_name), "must be array");
231 Klass* k = NULL;
232 FieldArrayInfo fd;
233 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
234 // of this call
235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
236 if (t == T_OBJECT) {
237 // naked oop "k" is OK here -- we assign back into it
238 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
239 class_loader,
240 protection_domain,
241 CHECK_NULL);
242 if (k != NULL) {
243 k = k->array_klass(fd.dimension(), CHECK_NULL);
244 }
245 } else {
246 k = Universe::typeArrayKlassObj(t);
247 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
248 }
249 return k;
250 }
251
252
253 // Must be called for any super-class or super-interface resolution
254 // during class definition to allow class circularity checking
255 // super-interface callers:
256 // parse_interfaces - for defineClass & jvmtiRedefineClasses
257 // super-class callers:
258 // ClassFileParser - for defineClass & jvmtiRedefineClasses
259 // load_shared_class - while loading a class from shared archive
260 // resolve_instance_class_or_null:
261 // via: handle_parallel_super_load
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
289 Symbol* class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every InstanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
309
310 ClassLoaderData* loader_data = class_loader_data(class_loader);
311 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
312 int d_index = dictionary()->hash_to_index(d_hash);
313 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
314 int p_index = placeholders()->hash_to_index(p_hash);
315 // can't throw error holding a lock
316 bool child_already_loaded = false;
317 bool throw_circularity_error = false;
318 {
319 MutexLocker mu(SystemDictionary_lock, THREAD);
320 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
321 Klass* quicksuperk;
322 // to support // loading: if child done loading, just return superclass
323 // if class_name, & class_loader don't match:
324 // if initial define, SD update will give LinkageError
325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
326 // so we don't throw an exception here.
327 // see: nsk redefclass014 & java.lang.instrument Instrument032
328 if ((childk != NULL ) && (is_superclass) &&
329 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
330
331 ((quicksuperk->name() == class_name) &&
332 (quicksuperk->class_loader() == class_loader()))) {
333 return quicksuperk;
334 } else {
335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
337 throw_circularity_error = true;
338 }
339 }
340 if (!throw_circularity_error) {
341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
342 }
343 }
344 if (throw_circularity_error) {
345 ResourceMark rm(THREAD);
346 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
347 }
348
349 // java.lang.Object should have been found above
350 assert(class_name != NULL, "null super class for resolving");
351 // Resolve the super class or interface, check results on return
352 Klass* superk = NULL;
353 superk = SystemDictionary::resolve_or_null(class_name,
354 class_loader,
355 protection_domain,
356 THREAD);
357
358 KlassHandle superk_h(THREAD, superk);
359
360 // Note: clean up of placeholders currently in callers of
361 // resolve_super_or_fail - either at update_dictionary time
362 // or on error
363 {
364 MutexLocker mu(SystemDictionary_lock, THREAD);
365 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
366 if (probe != NULL) {
367 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
368 }
369 }
370 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
371 // can null superk
372 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
373 }
374
375 return superk_h();
376 }
377
378 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
379 Handle class_loader,
380 Handle protection_domain,
381 TRAPS) {
382 if(!has_checkPackageAccess()) return;
383
384 // Now we have to call back to java to check if the initating class has access
385 JavaValue result(T_VOID);
386 if (TraceProtectionDomainVerification) {
387 // Print out trace information
388 tty->print_cr("Checking package access");
389 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
390 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
391 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
392 }
393
394 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
395 JavaCalls::call_special(&result,
396 class_loader,
397 system_loader,
398 vmSymbols::checkPackageAccess_name(),
399 vmSymbols::class_protectiondomain_signature(),
400 Handle(THREAD, klass->java_mirror()),
401 protection_domain,
402 THREAD);
403
404 if (TraceProtectionDomainVerification) {
405 if (HAS_PENDING_EXCEPTION) {
406 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
407 } else {
408 tty->print_cr(" -> granted");
409 }
410 tty->cr();
411 }
412
413 if (HAS_PENDING_EXCEPTION) return;
414
415 // If no exception has been thrown, we have validated the protection domain
416 // Insert the protection domain of the initiating class into the set.
417 {
418 // We recalculate the entry here -- we've called out to java since
419 // the last time it was calculated.
420 ClassLoaderData* loader_data = class_loader_data(class_loader);
421
422 Symbol* kn = klass->name();
423 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
424 int d_index = dictionary()->hash_to_index(d_hash);
425
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 {
428 // Note that we have an entry, and entries can be deleted only during GC,
429 // so we cannot allow GC to occur while we're holding this entry.
430
431 // We're using a No_Safepoint_Verifier to catch any place where we
432 // might potentially do a GC at all.
433 // SystemDictionary::do_unloading() asserts that classes are only
434 // unloaded at a safepoint.
435 No_Safepoint_Verifier nosafepoint;
436 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
437 protection_domain, THREAD);
438 }
439 }
440 }
441
442 // We only get here if this thread finds that another thread
443 // has already claimed the placeholder token for the current operation,
444 // but that other thread either never owned or gave up the
445 // object lock
446 // Waits on SystemDictionary_lock to indicate placeholder table updated
447 // On return, caller must recheck placeholder table state
448 //
449 // We only get here if
450 // 1) custom classLoader, i.e. not bootstrap classloader
451 // 2) UnsyncloadClass not set
452 // 3) custom classLoader has broken the class loader objectLock
453 // so another thread got here in parallel
454 //
455 // lockObject must be held.
456 // Complicated dance due to lock ordering:
457 // Must first release the classloader object lock to
458 // allow initial definer to complete the class definition
459 // and to avoid deadlock
460 // Reclaim classloader lock object with same original recursion count
461 // Must release SystemDictionary_lock after notify, since
462 // class loader lock must be claimed before SystemDictionary_lock
463 // to prevent deadlocks
464 //
465 // The notify allows applications that did an untimed wait() on
466 // the classloader object lock to not hang.
467 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
468 assert_lock_strong(SystemDictionary_lock);
469
470 bool calledholdinglock
471 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
472 assert(calledholdinglock,"must hold lock for notify");
473 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
474 ObjectSynchronizer::notifyall(lockObject, THREAD);
475 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
476 SystemDictionary_lock->wait();
477 SystemDictionary_lock->unlock();
478 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
479 SystemDictionary_lock->lock();
480 }
481
482 // If the class in is in the placeholder table, class loading is in progress
483 // For cases where the application changes threads to load classes, it
484 // is critical to ClassCircularity detection that we try loading
485 // the superclass on the same thread internally, so we do parallel
486 // super class loading here.
487 // This also is critical in cases where the original thread gets stalled
488 // even in non-circularity situations.
489 // Note: only one thread can define the class, but multiple can resolve
490 // Note: must call resolve_super_or_fail even if null super -
491 // to force placeholder entry creation for this class for circularity detection
492 // Caller must check for pending exception
493 // Returns non-null Klass* if other thread has completed load
494 // and we are done,
495 // If return null Klass* and no pending exception, the caller must load the class
496 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
497 Symbol* name, Symbol* superclassname, Handle class_loader,
498 Handle protection_domain, Handle lockObject, TRAPS) {
499
500 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
501 ClassLoaderData* loader_data = class_loader_data(class_loader);
502 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
503 int d_index = dictionary()->hash_to_index(d_hash);
504 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
505 int p_index = placeholders()->hash_to_index(p_hash);
506
507 // superk is not used, resolve_super called for circularity check only
508 // This code is reached in two situations. One if this thread
509 // is loading the same class twice (e.g. ClassCircularity, or
510 // java.lang.instrument).
511 // The second is if another thread started the resolve_super first
512 // and has not yet finished.
513 // In both cases the original caller will clean up the placeholder
514 // entry on error.
515 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
516 superclassname,
517 class_loader,
518 protection_domain,
519 true,
520 CHECK_(nh));
521 // We don't redefine the class, so we just need to clean up if there
522 // was not an error (don't want to modify any system dictionary
523 // data structures).
524 {
525 MutexLocker mu(SystemDictionary_lock, THREAD);
526 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
527 SystemDictionary_lock->notify_all();
528 }
529
530 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
531 // Serial class loaders and bootstrap classloader do wait for superclass loads
532 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
533 MutexLocker mu(SystemDictionary_lock, THREAD);
534 // Check if classloading completed while we were loading superclass or waiting
535 Klass* check = find_class(d_index, d_hash, name, loader_data);
536 if (check != NULL) {
537 // Klass is already loaded, so just return it
538 return(instanceKlassHandle(THREAD, check));
539 } else {
540 return nh;
541 }
542 }
543
544 // must loop to both handle other placeholder updates
545 // and spurious notifications
546 bool super_load_in_progress = true;
547 PlaceholderEntry* placeholder;
548 while (super_load_in_progress) {
549 MutexLocker mu(SystemDictionary_lock, THREAD);
550 // Check if classloading completed while we were loading superclass or waiting
551 Klass* check = find_class(d_index, d_hash, name, loader_data);
552 if (check != NULL) {
553 // Klass is already loaded, so just return it
554 return(instanceKlassHandle(THREAD, check));
555 } else {
556 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
557 if (placeholder && placeholder->super_load_in_progress() ){
558 // Before UnsyncloadClass:
559 // We only get here if the application has released the
560 // classloader lock when another thread was in the middle of loading a
561 // superclass/superinterface for this class, and now
562 // this thread is also trying to load this class.
563 // To minimize surprises, the first thread that started to
564 // load a class should be the one to complete the loading
565 // with the classfile it initially expected.
566 // This logic has the current thread wait once it has done
567 // all the superclass/superinterface loading it can, until
568 // the original thread completes the class loading or fails
569 // If it completes we will use the resulting InstanceKlass
570 // which we will find below in the systemDictionary.
571 // We also get here for parallel bootstrap classloader
572 if (class_loader.is_null()) {
573 SystemDictionary_lock->wait();
574 } else {
575 double_lock_wait(lockObject, THREAD);
576 }
577 } else {
578 // If not in SD and not in PH, other thread's load must have failed
579 super_load_in_progress = false;
580 }
581 }
582 }
583 return (nh);
584 }
585
586
587 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
588 assert(name != NULL && !FieldType::is_array(name) &&
589 !FieldType::is_obj(name), "invalid class name");
590
591 // UseNewReflection
592 // Fix for 4474172; see evaluation for more details
593 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
594 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
595
596 // Do lookup to see if class already exist and the protection domain
597 // has the right access
598 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
599 int d_index = dictionary()->hash_to_index(d_hash);
600 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
601 protection_domain, THREAD);
602 if (probe != NULL) return probe;
603
604
605 // Non-bootstrap class loaders will call out to class loader and
606 // define via jvm/jni_DefineClass which will acquire the
607 // class loader object lock to protect against multiple threads
608 // defining the class in parallel by accident.
609 // This lock must be acquired here so the waiter will find
610 // any successful result in the SystemDictionary and not attempt
611 // the define
612 // ParallelCapable Classloaders and the bootstrap classloader,
613 // or all classloaders with UnsyncloadClass do not acquire lock here
614 bool DoObjectLock = true;
615 if (is_parallelCapable(class_loader)) {
616 DoObjectLock = false;
617 }
618
619 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
620 int p_index = placeholders()->hash_to_index(p_hash);
621
622 // Class is not in SystemDictionary so we have to do loading.
623 // Make sure we are synchronized on the class loader before we proceed
624 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
625 check_loader_lock_contention(lockObject, THREAD);
626 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
627
628 // Check again (after locking) if class already exist in SystemDictionary
629 bool class_has_been_loaded = false;
630 bool super_load_in_progress = false;
631 bool havesupername = false;
632 instanceKlassHandle k;
633 PlaceholderEntry* placeholder;
634 Symbol* superclassname = NULL;
635
636 {
637 MutexLocker mu(SystemDictionary_lock, THREAD);
638 Klass* check = find_class(d_index, d_hash, name, loader_data);
639 if (check != NULL) {
640 // Klass is already loaded, so just return it
641 class_has_been_loaded = true;
642 k = instanceKlassHandle(THREAD, check);
643 } else {
644 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
645 if (placeholder && placeholder->super_load_in_progress()) {
646 super_load_in_progress = true;
647 if (placeholder->havesupername() == true) {
648 superclassname = placeholder->supername();
649 havesupername = true;
650 }
651 }
652 }
653 }
654
655 // If the class in is in the placeholder table, class loading is in progress
656 if (super_load_in_progress && havesupername==true) {
657 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
658 class_loader, protection_domain, lockObject, THREAD);
659 if (HAS_PENDING_EXCEPTION) {
660 return NULL;
661 }
662 if (!k.is_null()) {
663 class_has_been_loaded = true;
664 }
665 }
666
667 if (!class_has_been_loaded) {
668
669 // add placeholder entry to record loading instance class
670 // Five cases:
671 // All cases need to prevent modifying bootclasssearchpath
672 // in parallel with a classload of same classname
673 // Redefineclasses uses existence of the placeholder for the duration
674 // of the class load to prevent concurrent redefinition of not completely
675 // defined classes.
676 // case 1. traditional classloaders that rely on the classloader object lock
677 // - no other need for LOAD_INSTANCE
678 // case 2. traditional classloaders that break the classloader object lock
679 // as a deadlock workaround. Detection of this case requires that
680 // this check is done while holding the classloader object lock,
681 // and that lock is still held when calling classloader's loadClass.
682 // For these classloaders, we ensure that the first requestor
683 // completes the load and other requestors wait for completion.
684 // case 3. UnsyncloadClass - don't use objectLocker
685 // With this flag, we allow parallel classloading of a
686 // class/classloader pair
687 // case4. Bootstrap classloader - don't own objectLocker
688 // This classloader supports parallelism at the classloader level,
689 // but only allows a single load of a class/classloader pair.
690 // No performance benefit and no deadlock issues.
691 // case 5. parallelCapable user level classloaders - without objectLocker
692 // Allow parallel classloading of a class/classloader pair
693 bool throw_circularity_error = false;
694 {
695 MutexLocker mu(SystemDictionary_lock, THREAD);
696 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
697 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
698 if (oldprobe) {
699 // only need check_seen_thread once, not on each loop
700 // 6341374 java/lang/Instrument with -Xcomp
701 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
702 throw_circularity_error = true;
703 } else {
704 // case 1: traditional: should never see load_in_progress.
705 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
706
707 // case 4: bootstrap classloader: prevent futile classloading,
708 // wait on first requestor
709 if (class_loader.is_null()) {
710 SystemDictionary_lock->wait();
711 } else {
712 // case 2: traditional with broken classloader lock. wait on first
713 // requestor.
714 double_lock_wait(lockObject, THREAD);
715 }
716 // Check if classloading completed while we were waiting
717 Klass* check = find_class(d_index, d_hash, name, loader_data);
718 if (check != NULL) {
719 // Klass is already loaded, so just return it
720 k = instanceKlassHandle(THREAD, check);
721 class_has_been_loaded = true;
722 }
723 // check if other thread failed to load and cleaned up
724 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
725 }
726 }
727 }
728 }
729 // All cases: add LOAD_INSTANCE
730 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
731 // LOAD_INSTANCE in parallel
732 // add placeholder entry even if error - callers will remove on error
733 if (!throw_circularity_error && !class_has_been_loaded) {
734 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
735 // For class loaders that do not acquire the classloader object lock,
736 // if they did not catch another thread holding LOAD_INSTANCE,
737 // need a check analogous to the acquire ObjectLocker/find_class
738 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
739 // one final check if the load has already completed
740 // class loaders holding the ObjectLock shouldn't find the class here
741 Klass* check = find_class(d_index, d_hash, name, loader_data);
742 if (check != NULL) {
743 // Klass is already loaded, so just return it
744 k = instanceKlassHandle(THREAD, check);
745 class_has_been_loaded = true;
746 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
747 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
748 SystemDictionary_lock->notify_all();
749 }
750 }
751 }
752 // must throw error outside of owning lock
753 if (throw_circularity_error) {
754 ResourceMark rm(THREAD);
755 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
756 }
757
758 if (!class_has_been_loaded) {
759
760 // Do actual loading
761 k = load_instance_class(name, class_loader, THREAD);
762
763 // For UnsyncloadClass only
764 // If they got a linkageError, check if a parallel class load succeeded.
765 // If it did, then for bytecode resolution the specification requires
766 // that we return the same result we did for the other thread, i.e. the
767 // successfully loaded InstanceKlass
768 // Should not get here for classloaders that support parallelism
769 // with the new cleaner mechanism, even with AllowParallelDefineClass
770 // Bootstrap goes through here to allow for an extra guarantee check
771 if (UnsyncloadClass || (class_loader.is_null())) {
772 if (k.is_null() && HAS_PENDING_EXCEPTION
773 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
774 MutexLocker mu(SystemDictionary_lock, THREAD);
775 Klass* check = find_class(d_index, d_hash, name, loader_data);
776 if (check != NULL) {
777 // Klass is already loaded, so just use it
778 k = instanceKlassHandle(THREAD, check);
779 CLEAR_PENDING_EXCEPTION;
780 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
781 }
782 }
783 }
784
785 // clean up placeholder entries for success or error
786 // This cleans up LOAD_INSTANCE entries
787 // It also cleans up LOAD_SUPER entries on errors from
788 // calling load_instance_class
789 {
790 MutexLocker mu(SystemDictionary_lock, THREAD);
791 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
792 if (probe != NULL) {
793 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
794 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
795 SystemDictionary_lock->notify_all();
796 }
797 }
798
799 // If everything was OK (no exceptions, no null return value), and
800 // class_loader is NOT the defining loader, do a little more bookkeeping.
801 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
802 k->class_loader() != class_loader()) {
803
804 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
805
806 // Need to check for a PENDING_EXCEPTION again; check_constraints
807 // can throw and doesn't use the CHECK macro.
808 if (!HAS_PENDING_EXCEPTION) {
809 { // Grabbing the Compile_lock prevents systemDictionary updates
810 // during compilations.
811 MutexLocker mu(Compile_lock, THREAD);
812 update_dictionary(d_index, d_hash, p_index, p_hash,
813 k, class_loader, THREAD);
814 }
815 if (JvmtiExport::should_post_class_load()) {
816 Thread *thread = THREAD;
817 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
818 JvmtiExport::post_class_load((JavaThread *) thread, k());
819 }
820 }
821 }
822 if (HAS_PENDING_EXCEPTION || k.is_null()) {
823 // On error, clean up placeholders
824 {
825 MutexLocker mu(SystemDictionary_lock, THREAD);
826 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
827 SystemDictionary_lock->notify_all();
828 }
829 return NULL;
830 }
831 }
832 }
833
834 #ifdef ASSERT
835 {
836 ClassLoaderData* loader_data = k->class_loader_data();
837 MutexLocker mu(SystemDictionary_lock, THREAD);
838 Klass* kk = find_class(name, loader_data);
839 assert(kk == k(), "should be present in dictionary");
840 }
841 #endif
842
843 // return if the protection domain in NULL
844 if (protection_domain() == NULL) return k();
845
846 // Check the protection domain has the right access
847 {
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 // Note that we have an entry, and entries can be deleted only during GC,
850 // so we cannot allow GC to occur while we're holding this entry.
851 // We're using a No_Safepoint_Verifier to catch any place where we
852 // might potentially do a GC at all.
853 // SystemDictionary::do_unloading() asserts that classes are only
854 // unloaded at a safepoint.
855 No_Safepoint_Verifier nosafepoint;
856 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
857 loader_data,
858 protection_domain)) {
859 return k();
860 }
861 }
862
863 // Verify protection domain. If it fails an exception is thrown
864 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
865
866 return k();
867 }
868
869
870 // This routine does not lock the system dictionary.
871 //
872 // Since readers don't hold a lock, we must make sure that system
873 // dictionary entries are only removed at a safepoint (when only one
874 // thread is running), and are added to in a safe way (all links must
875 // be updated in an MT-safe manner).
876 //
877 // Callers should be aware that an entry could be added just after
878 // _dictionary->bucket(index) is read here, so the caller will not see
879 // the new entry.
880
881 Klass* SystemDictionary::find(Symbol* class_name,
882 Handle class_loader,
883 Handle protection_domain,
884 TRAPS) {
885
886 // UseNewReflection
887 // The result of this call should be consistent with the result
888 // of the call to resolve_instance_class_or_null().
889 // See evaluation 6790209 and 4474172 for more details.
890 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
891 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
892
893 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
894 int d_index = dictionary()->hash_to_index(d_hash);
895
896 {
897 // Note that we have an entry, and entries can be deleted only during GC,
898 // so we cannot allow GC to occur while we're holding this entry.
899 // We're using a No_Safepoint_Verifier to catch any place where we
900 // might potentially do a GC at all.
901 // SystemDictionary::do_unloading() asserts that classes are only
902 // unloaded at a safepoint.
903 No_Safepoint_Verifier nosafepoint;
904 return dictionary()->find(d_index, d_hash, class_name, loader_data,
905 protection_domain, THREAD);
906 }
907 }
908
909
910 // Look for a loaded instance or array klass by name. Do not do any loading.
911 // return NULL in case of error.
912 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
913 Handle class_loader,
914 Handle protection_domain,
915 TRAPS) {
916 Klass* k = NULL;
917 assert(class_name != NULL, "class name must be non NULL");
918
919 if (FieldType::is_array(class_name)) {
920 // The name refers to an array. Parse the name.
921 // dimension and object_key in FieldArrayInfo are assigned as a
922 // side-effect of this call
923 FieldArrayInfo fd;
924 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
925 if (t != T_OBJECT) {
926 k = Universe::typeArrayKlassObj(t);
927 } else {
928 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
929 }
930 if (k != NULL) {
931 k = k->array_klass_or_null(fd.dimension());
932 }
933 } else {
934 k = find(class_name, class_loader, protection_domain, THREAD);
935 }
936 return k;
937 }
938
939 // Note: this method is much like resolve_from_stream, but
940 // updates no supplemental data structures.
941 // TODO consolidate the two methods with a helper routine?
942 Klass* SystemDictionary::parse_stream(Symbol* class_name,
943 Handle class_loader,
944 Handle protection_domain,
945 ClassFileStream* st,
946 KlassHandle host_klass,
947 GrowableArray<Handle>* cp_patches,
948 TRAPS) {
949 TempNewSymbol parsed_name = NULL;
950
951 ClassLoaderData* loader_data;
952 if (host_klass.not_null()) {
953 // Create a new CLD for anonymous class, that uses the same class loader
954 // as the host_klass
955 assert(EnableInvokeDynamic, "");
956 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
957 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
958 loader_data->record_dependency(host_klass(), CHECK_NULL);
959 } else {
960 loader_data = ClassLoaderData::class_loader_data(class_loader());
961 }
962
963 // Parse the stream. Note that we do this even though this klass might
964 // already be present in the SystemDictionary, otherwise we would not
965 // throw potential ClassFormatErrors.
966 //
967 // Note: "name" is updated.
968 // Further note: a placeholder will be added for this class when
969 // super classes are loaded (resolve_super_or_fail). We expect this
970 // to be called for all classes but java.lang.Object; and we preload
971 // java.lang.Object through resolve_or_fail, not this path.
972
973 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
974 loader_data,
975 protection_domain,
976 host_klass,
977 cp_patches,
978 parsed_name,
979 true,
980 THREAD);
981
982 // We don't redefine the class, so we just need to clean up whether there
983 // was an error or not (don't want to modify any system dictionary
984 // data structures).
985 // Parsed name could be null if we threw an error before we got far
986 // enough along to parse it -- in that case, there is nothing to clean up.
987 if (parsed_name != NULL) {
988 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
989 loader_data);
990 int p_index = placeholders()->hash_to_index(p_hash);
991 {
992 MutexLocker mu(SystemDictionary_lock, THREAD);
993 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
994 SystemDictionary_lock->notify_all();
995 }
996 }
997
998 if (host_klass.not_null() && k.not_null()) {
999 assert(EnableInvokeDynamic, "");
1000 k->set_host_klass(host_klass());
1001 // If it's anonymous, initialize it now, since nobody else will.
1002
1003 {
1004 MutexLocker mu_r(Compile_lock, THREAD);
1005
1006 // Add to class hierarchy, initialize vtables, and do possible
1007 // deoptimizations.
1008 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1009
1010 // But, do not add to system dictionary.
1011 }
1012
1013 // Rewrite and patch constant pool here.
1014 k->link_class(CHECK_NULL);
1015 if (cp_patches != NULL) {
1016 k->constants()->patch_resolved_references(cp_patches);
1017 }
1018 k->eager_initialize(CHECK_NULL);
1019
1020 // notify jvmti
1021 if (JvmtiExport::should_post_class_load()) {
1022 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1023 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1024 }
1025 }
1026 assert(host_klass.not_null() || cp_patches == NULL,
1027 "cp_patches only found with host_klass");
1028
1029 return k();
1030 }
1031
1032 // Add a klass to the system from a stream (called by jni_DefineClass and
1033 // JVM_DefineClass).
1034 // Note: class_name can be NULL. In that case we do not know the name of
1035 // the class until we have parsed the stream.
1036
1037 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1038 Handle class_loader,
1039 Handle protection_domain,
1040 ClassFileStream* st,
1041 bool verify,
1042 TRAPS) {
1043
1044 // Classloaders that support parallelism, e.g. bootstrap classloader,
1045 // or all classloaders with UnsyncloadClass do not acquire lock here
1046 bool DoObjectLock = true;
1047 if (is_parallelCapable(class_loader)) {
1048 DoObjectLock = false;
1049 }
1050
1051 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1052
1053 // Make sure we are synchronized on the class loader before we proceed
1054 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1055 check_loader_lock_contention(lockObject, THREAD);
1056 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1057
1058 TempNewSymbol parsed_name = NULL;
1059
1060 // Parse the stream. Note that we do this even though this klass might
1061 // already be present in the SystemDictionary, otherwise we would not
1062 // throw potential ClassFormatErrors.
1063 //
1064 // Note: "name" is updated.
1065 // Further note: a placeholder will be added for this class when
1066 // super classes are loaded (resolve_super_or_fail). We expect this
1067 // to be called for all classes but java.lang.Object; and we preload
1068 // java.lang.Object through resolve_or_fail, not this path.
1069
1070 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1071 loader_data,
1072 protection_domain,
1073 parsed_name,
1074 verify,
1075 THREAD);
1076
1077 const char* pkg = "java/";
1078 if (!HAS_PENDING_EXCEPTION &&
1079 !class_loader.is_null() &&
1080 parsed_name != NULL &&
1081 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1082 // It is illegal to define classes in the "java." package from
1083 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1084 ResourceMark rm(THREAD);
1085 char* name = parsed_name->as_C_string();
1086 char* index = strrchr(name, '/');
1087 *index = '\0'; // chop to just the package name
1088 while ((index = strchr(name, '/')) != NULL) {
1089 *index = '.'; // replace '/' with '.' in package name
1090 }
1091 const char* fmt = "Prohibited package name: %s";
1092 size_t len = strlen(fmt) + strlen(name);
1093 char* message = NEW_RESOURCE_ARRAY(char, len);
1094 jio_snprintf(message, len, fmt, name);
1095 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1096 vmSymbols::java_lang_SecurityException(), message);
1097 }
1098
1099 if (!HAS_PENDING_EXCEPTION) {
1100 assert(parsed_name != NULL, "Sanity");
1101 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1102 // Verification prevents us from creating names with dots in them, this
1103 // asserts that that's the case.
1104 assert(is_internal_format(parsed_name),
1105 "external class name format used internally");
1106
1107 // Add class just loaded
1108 // If a class loader supports parallel classloading handle parallel define requests
1109 // find_or_define_instance_class may return a different InstanceKlass
1110 if (is_parallelCapable(class_loader)) {
1111 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1112 } else {
1113 define_instance_class(k, THREAD);
1114 }
1115 }
1116
1117 // If parsing the class file or define_instance_class failed, we
1118 // need to remove the placeholder added on our behalf. But we
1119 // must make sure parsed_name is valid first (it won't be if we had
1120 // a format error before the class was parsed far enough to
1121 // find the name).
1122 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1123 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1124 loader_data);
1125 int p_index = placeholders()->hash_to_index(p_hash);
1126 {
1127 MutexLocker mu(SystemDictionary_lock, THREAD);
1128 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
1129 SystemDictionary_lock->notify_all();
1130 }
1131 return NULL;
1132 }
1133
1134 // Make sure that we didn't leave a place holder in the
1135 // SystemDictionary; this is only done on success
1136 debug_only( {
1137 if (!HAS_PENDING_EXCEPTION) {
1138 assert(parsed_name != NULL, "parsed_name is still null?");
1139 Symbol* h_name = k->name();
1140 ClassLoaderData *defining_loader_data = k->class_loader_data();
1141
1142 MutexLocker mu(SystemDictionary_lock, THREAD);
1143
1144 Klass* check = find_class(parsed_name, loader_data);
1145 assert(check == k(), "should be present in the dictionary");
1146
1147 Klass* check2 = find_class(h_name, defining_loader_data);
1148 assert(check == check2, "name inconsistancy in SystemDictionary");
1149 }
1150 } );
1151
1152 return k();
1153 }
1154
1155
1156 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1157 int number_of_entries) {
1158 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1159 "bad shared dictionary size.");
1160 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1161 }
1162
1163
1164 // If there is a shared dictionary, then find the entry for the
1165 // given shared system class, if any.
1166
1167 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1168 if (shared_dictionary() != NULL) {
1169 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1170 int d_index = shared_dictionary()->hash_to_index(d_hash);
1171
1172 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1173 } else {
1174 return NULL;
1175 }
1176 }
1177
1178
1179 // Load a class from the shared spaces (found through the shared system
1180 // dictionary). Force the superclass and all interfaces to be loaded.
1181 // Update the class definition to include sibling classes and no
1182 // subclasses (yet). [Classes in the shared space are not part of the
1183 // object hierarchy until loaded.]
1184
1185 instanceKlassHandle SystemDictionary::load_shared_class(
1186 Symbol* class_name, Handle class_loader, TRAPS) {
1187 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1188 return load_shared_class(ik, class_loader, THREAD);
1189 }
1190
1191 // Note well! Changes to this method may affect oop access order
1192 // in the shared archive. Please take care to not make changes that
1193 // adversely affect cold start time by changing the oop access order
1194 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1195 // MarkAndMoveOrderedReadWrite closures.
1196 instanceKlassHandle SystemDictionary::load_shared_class(
1197 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1198 assert(class_loader.is_null(), "non-null classloader for shared class?");
1199 if (ik.not_null()) {
1200 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1201 Symbol* class_name = ik->name();
1202
1203 // Found the class, now load the superclass and interfaces. If they
1204 // are shared, add them to the main system dictionary and reset
1205 // their hierarchy references (supers, subs, and interfaces).
1206
1207 if (ik->super() != NULL) {
1208 Symbol* cn = ik->super()->name();
1209 resolve_super_or_fail(class_name, cn,
1210 class_loader, Handle(), true, CHECK_(nh));
1211 }
1212
1213 Array<Klass*>* interfaces = ik->local_interfaces();
1214 int num_interfaces = interfaces->length();
1215 for (int index = 0; index < num_interfaces; index++) {
1216 Klass* k = interfaces->at(index);
1217
1218 // Note: can not use InstanceKlass::cast here because
1219 // interfaces' InstanceKlass's C++ vtbls haven't been
1220 // reinitialized yet (they will be once the interface classes
1221 // are loaded)
1222 Symbol* name = k->name();
1223 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1224 }
1225
1226 // Adjust methods to recover missing data. They need addresses for
1227 // interpreter entry points and their default native method address
1228 // must be reset.
1229
1230 // Updating methods must be done under a lock so multiple
1231 // threads don't update these in parallel
1232 // Shared classes are all currently loaded by the bootstrap
1233 // classloader, so this will never cause a deadlock on
1234 // a custom class loader lock.
1235
1236 {
1237 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1238 check_loader_lock_contention(lockObject, THREAD);
1239 ObjectLocker ol(lockObject, THREAD, true);
1240 ik->restore_unshareable_info(CHECK_(nh));
1241 }
1242
1243 if (TraceClassLoading) {
1244 ResourceMark rm;
1245 tty->print("[Loaded %s", ik->external_name());
1246 tty->print(" from shared objects file");
1247 tty->print_cr("]");
1248 }
1249 // notify a class loaded from shared object
1250 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1251 true /* shared class */);
1252 }
1253 return ik;
1254 }
1255
1256 #ifdef KERNEL
1257 // Some classes on the bootstrap class path haven't been installed on the
1258 // system yet. Call the DownloadManager method to make them appear in the
1259 // bootstrap class path and try again to load the named class.
1260 // Note that with delegation class loaders all classes in another loader will
1261 // first try to call this so it'd better be fast!!
1262 static instanceKlassHandle download_and_retry_class_load(
1263 Symbol* class_name,
1264 TRAPS) {
1265
1266 Klass* dlm = SystemDictionary::DownloadManager_klass();
1267 instanceKlassHandle nk;
1268
1269 // If download manager class isn't loaded just return.
1270 if (dlm == NULL) return nk;
1271
1272 { HandleMark hm(THREAD);
1273 ResourceMark rm(THREAD);
1274 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1275 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1276
1277 // return value
1278 JavaValue result(T_OBJECT);
1279
1280 // Call the DownloadManager. We assume that it has a lock because
1281 // multiple classes could be not found and downloaded at the same time.
1282 // class sun.misc.DownloadManager;
1283 // public static String getBootClassPathEntryForClass(String className);
1284 JavaCalls::call_static(&result,
1285 KlassHandle(THREAD, dlm),
1286 vmSymbols::getBootClassPathEntryForClass_name(),
1287 vmSymbols::string_string_signature(),
1288 class_string,
1289 CHECK_(nk));
1290
1291 // Get result.string and add to bootclasspath
1292 assert(result.get_type() == T_OBJECT, "just checking");
1293 oop obj = (oop) result.get_jobject();
1294 if (obj == NULL) { return nk; }
1295
1296 Handle h_obj(THREAD, obj);
1297 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1298 CHECK_(nk));
1299
1300 // lock the loader
1301 // we use this lock because JVMTI does.
1302 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1303
1304 ObjectLocker ol(loader_lock, THREAD);
1305 // add the file to the bootclasspath
1306 ClassLoader::update_class_path_entry_list(new_class_name, true);
1307 } // end HandleMark
1308
1309 if (TraceClassLoading) {
1310 ClassLoader::print_bootclasspath();
1311 }
1312 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1313 }
1314 #endif // KERNEL
1315
1316
1317 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1318 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1319 if (class_loader.is_null()) {
1320
1321 // Search the shared system dictionary for classes preloaded into the
1322 // shared spaces.
1323 instanceKlassHandle k;
1324 {
1325 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1326 k = load_shared_class(class_name, class_loader, THREAD);
1327 }
1328
1329 if (k.is_null()) {
1330 // Use VM class loader
1331 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1332 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1333 }
1334
1335 #ifdef KERNEL
1336 // If the VM class loader has failed to load the class, call the
1337 // DownloadManager class to make it magically appear on the classpath
1338 // and try again. This is only configured with the Kernel VM.
1339 if (k.is_null()) {
1340 k = download_and_retry_class_load(class_name, CHECK_(nh));
1341 }
1342 #endif // KERNEL
1343
1344 // find_or_define_instance_class may return a different InstanceKlass
1345 if (!k.is_null()) {
1346 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1347 }
1348 return k;
1349 } else {
1350 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1351 ResourceMark rm(THREAD);
1352
1353 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1354 JavaThread* jt = (JavaThread*) THREAD;
1355
1356 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1357 ClassLoader::perf_app_classload_selftime(),
1358 ClassLoader::perf_app_classload_count(),
1359 jt->get_thread_stat()->perf_recursion_counts_addr(),
1360 jt->get_thread_stat()->perf_timers_addr(),
1361 PerfClassTraceTime::CLASS_LOAD);
1362
1363 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1364 // Translate to external class name format, i.e., convert '/' chars to '.'
1365 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1366
1367 JavaValue result(T_OBJECT);
1368
1369 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1370
1371 // Call public unsynchronized loadClass(String) directly for all class loaders
1372 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1373 // acquire a class-name based lock rather than the class loader object lock.
1374 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1375 // so the call to loadClassInternal() was not required.
1376 //
1377 // UnsyncloadClass flag means both call loadClass(String) and do
1378 // not acquire the class loader lock even for class loaders that are
1379 // not parallelCapable. This was a risky transitional
1380 // flag for diagnostic purposes only. It is risky to call
1381 // custom class loaders without synchronization.
1382 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1383 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1384 // Do NOT assume this will be supported in future releases.
1385 //
1386 // Added MustCallLoadClassInternal in case we discover in the field
1387 // a customer that counts on this call
1388 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1389 JavaCalls::call_special(&result,
1390 class_loader,
1391 spec_klass,
1392 vmSymbols::loadClassInternal_name(),
1393 vmSymbols::string_class_signature(),
1394 string,
1395 CHECK_(nh));
1396 } else {
1397 JavaCalls::call_virtual(&result,
1398 class_loader,
1399 spec_klass,
1400 vmSymbols::loadClass_name(),
1401 vmSymbols::string_class_signature(),
1402 string,
1403 CHECK_(nh));
1404 }
1405
1406 assert(result.get_type() == T_OBJECT, "just checking");
1407 oop obj = (oop) result.get_jobject();
1408
1409 // Primitive classes return null since forName() can not be
1410 // used to obtain any of the Class objects representing primitives or void
1411 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1412 instanceKlassHandle k =
1413 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1414 // For user defined Java class loaders, check that the name returned is
1415 // the same as that requested. This check is done for the bootstrap
1416 // loader when parsing the class file.
1417 if (class_name == k->name()) {
1418 return k;
1419 }
1420 }
1421 // Class is not found or has the wrong name, return NULL
1422 return nh;
1423 }
1424 }
1425
1426 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1427
1428 ClassLoaderData* loader_data = k->class_loader_data();
1429 Handle class_loader_h(THREAD, loader_data->class_loader());
1430
1431 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1432
1433 // for bootstrap and other parallel classloaders don't acquire lock,
1434 // use placeholder token
1435 // If a parallelCapable class loader calls define_instance_class instead of
1436 // find_or_define_instance_class to get here, we have a timing
1437 // hole with systemDictionary updates and check_constraints
1438 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1439 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1440 compute_loader_lock_object(class_loader_h, THREAD)),
1441 "define called without lock");
1442 }
1443
1444 // Check class-loading constraints. Throw exception if violation is detected.
1445 // Grabs and releases SystemDictionary_lock
1446 // The check_constraints/find_class call and update_dictionary sequence
1447 // must be "atomic" for a specific class/classloader pair so we never
1448 // define two different instanceKlasses for that class/classloader pair.
1449 // Existing classloaders will call define_instance_class with the
1450 // classloader lock held
1451 // Parallel classloaders will call find_or_define_instance_class
1452 // which will require a token to perform the define class
1453 Symbol* name_h = k->name();
1454 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1455 int d_index = dictionary()->hash_to_index(d_hash);
1456 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1457
1458 // Register class just loaded with class loader (placed in Vector)
1459 // Note we do this before updating the dictionary, as this can
1460 // fail with an OutOfMemoryError (if it does, we will *not* put this
1461 // class in the dictionary and will not update the class hierarchy).
1462 // JVMTI FollowReferences needs to find the classes this way.
1463 if (k->class_loader() != NULL) {
1464 methodHandle m(THREAD, Universe::loader_addClass_method());
1465 JavaValue result(T_VOID);
1466 JavaCallArguments args(class_loader_h);
1467 args.push_oop(Handle(THREAD, k->java_mirror()));
1468 JavaCalls::call(&result, m, &args, CHECK);
1469 }
1470
1471 // Add the new class. We need recompile lock during update of CHA.
1472 {
1473 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1474 int p_index = placeholders()->hash_to_index(p_hash);
1475
1476 MutexLocker mu_r(Compile_lock, THREAD);
1477
1478 // Add to class hierarchy, initialize vtables, and do possible
1479 // deoptimizations.
1480 add_to_hierarchy(k, CHECK); // No exception, but can block
1481
1482 // Add to systemDictionary - so other classes can see it.
1483 // Grabs and releases SystemDictionary_lock
1484 update_dictionary(d_index, d_hash, p_index, p_hash,
1485 k, class_loader_h, THREAD);
1486 }
1487 k->eager_initialize(THREAD);
1488
1489 // notify jvmti
1490 if (JvmtiExport::should_post_class_load()) {
1491 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1492 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1493
1494 }
1495 }
1496
1497 // Support parallel classloading
1498 // All parallel class loaders, including bootstrap classloader
1499 // lock a placeholder entry for this class/class_loader pair
1500 // to allow parallel defines of different classes for this class loader
1501 // With AllowParallelDefine flag==true, in case they do not synchronize around
1502 // FindLoadedClass/DefineClass, calls, we check for parallel
1503 // loading for them, wait if a defineClass is in progress
1504 // and return the initial requestor's results
1505 // This flag does not apply to the bootstrap classloader.
1506 // With AllowParallelDefine flag==false, call through to define_instance_class
1507 // which will throw LinkageError: duplicate class definition.
1508 // False is the requested default.
1509 // For better performance, the class loaders should synchronize
1510 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1511 // potentially waste time reading and parsing the bytestream.
1512 // Note: VM callers should ensure consistency of k/class_name,class_loader
1513 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1514
1515 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1516 Symbol* name_h = k->name(); // passed in class_name may be null
1517 ClassLoaderData* loader_data = class_loader_data(class_loader);
1518
1519 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1520 int d_index = dictionary()->hash_to_index(d_hash);
1521
1522 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1523 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1524 int p_index = placeholders()->hash_to_index(p_hash);
1525 PlaceholderEntry* probe;
1526
1527 {
1528 MutexLocker mu(SystemDictionary_lock, THREAD);
1529 // First check if class already defined
1530 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1531 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1532 if (check != NULL) {
1533 return(instanceKlassHandle(THREAD, check));
1534 }
1535 }
1536
1537 // Acquire define token for this class/classloader
1538 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1539 // Wait if another thread defining in parallel
1540 // All threads wait - even those that will throw duplicate class: otherwise
1541 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1542 // if other thread has not finished updating dictionary
1543 while (probe->definer() != NULL) {
1544 SystemDictionary_lock->wait();
1545 }
1546 // Only special cases allow parallel defines and can use other thread's results
1547 // Other cases fall through, and may run into duplicate defines
1548 // caught by finding an entry in the SystemDictionary
1549 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1550 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1551 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1552 SystemDictionary_lock->notify_all();
1553 #ifdef ASSERT
1554 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1555 assert(check != NULL, "definer missed recording success");
1556 #endif
1557 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1558 } else {
1559 // This thread will define the class (even if earlier thread tried and had an error)
1560 probe->set_definer(THREAD);
1561 }
1562 }
1563
1564 define_instance_class(k, THREAD);
1565
1566 Handle linkage_exception = Handle(); // null handle
1567
1568 // definer must notify any waiting threads
1569 {
1570 MutexLocker mu(SystemDictionary_lock, THREAD);
1571 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1572 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1573 if (probe != NULL) {
1574 if (HAS_PENDING_EXCEPTION) {
1575 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1576 CLEAR_PENDING_EXCEPTION;
1577 } else {
1578 probe->set_instance_klass(k());
1579 }
1580 probe->set_definer(NULL);
1581 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1582 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1583 SystemDictionary_lock->notify_all();
1584 }
1585 }
1586
1587 // Can't throw exception while holding lock due to rank ordering
1588 if (linkage_exception() != NULL) {
1589 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1590 }
1591
1592 return k;
1593 }
1594 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1595 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1596 if (class_loader.is_null()) {
1597 return Handle(THREAD, _system_loader_lock_obj);
1598 } else {
1599 return class_loader;
1600 }
1601 }
1602
1603 // This method is added to check how often we have to wait to grab loader
1604 // lock. The results are being recorded in the performance counters defined in
1605 // ClassLoader::_sync_systemLoaderLockContentionRate and
1606 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1607 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1608 if (!UsePerfData) {
1609 return;
1610 }
1611
1612 assert(!loader_lock.is_null(), "NULL lock object");
1613
1614 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1615 == ObjectSynchronizer::owner_other) {
1616 // contention will likely happen, so increment the corresponding
1617 // contention counter.
1618 if (loader_lock() == _system_loader_lock_obj) {
1619 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1620 } else {
1621 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1622 }
1623 }
1624 }
1625
1626 // ----------------------------------------------------------------------------
1627 // Lookup
1628
1629 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1630 Symbol* class_name,
1631 ClassLoaderData* loader_data) {
1632 assert_locked_or_safepoint(SystemDictionary_lock);
1633 assert (index == dictionary()->index_for(class_name, loader_data),
1634 "incorrect index?");
1635
1636 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1637 return k;
1638 }
1639
1640
1641 // Basic find on classes in the midst of being loaded
1642 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1643 ClassLoaderData* loader_data) {
1644 assert_locked_or_safepoint(SystemDictionary_lock);
1645 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1646 int p_index = placeholders()->hash_to_index(p_hash);
1647 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1648 }
1649
1650
1651 // Used for assertions and verification only
1652 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1653 #ifndef ASSERT
1654 guarantee(VerifyBeforeGC ||
1655 VerifyDuringGC ||
1656 VerifyBeforeExit ||
1657 VerifyAfterGC, "too expensive");
1658 #endif
1659 assert_locked_or_safepoint(SystemDictionary_lock);
1660
1661 // First look in the loaded class array
1662 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1663 int d_index = dictionary()->hash_to_index(d_hash);
1664 return find_class(d_index, d_hash, class_name, loader_data);
1665 }
1666
1667
1668 // Get the next class in the diictionary.
1669 Klass* SystemDictionary::try_get_next_class() {
1670 return dictionary()->try_get_next_class();
1671 }
1672
1673
1674 // ----------------------------------------------------------------------------
1675 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1676 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1677 // before a new class is used.
1678
1679 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1680 assert(k.not_null(), "just checking");
1681 assert_locked_or_safepoint(Compile_lock);
1682
1683 // Link into hierachy. Make sure the vtables are initialized before linking into
1684 k->append_to_sibling_list(); // add to superklass/sibling list
1685 k->process_interfaces(THREAD); // handle all "implements" declarations
1686 k->set_init_state(InstanceKlass::loaded);
1687 // Now flush all code that depended on old class hierarchy.
1688 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1689 // Also, first reinitialize vtable because it may have gotten out of synch
1690 // while the new class wasn't connected to the class hierarchy.
1691 Universe::flush_dependents_on(k);
1692 }
1693
1694
1695 // ----------------------------------------------------------------------------
1696 // GC support
1697
1698 // Following roots during mark-sweep is separated in two phases.
1699 //
1700 // The first phase follows preloaded classes and all other system
1701 // classes, since these will never get unloaded anyway.
1702 //
1703 // The second phase removes (unloads) unreachable classes from the
1704 // system dictionary and follows the remaining classes' contents.
1705
1706 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1707 blk->do_oop(&_java_system_loader);
1708 blk->do_oop(&_system_loader_lock_obj);
1709
1710 dictionary()->always_strong_oops_do(blk);
1711
1712 // Visit extra methods
1713 invoke_method_table()->oops_do(blk);
1714 }
1715
1716 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1717 // Follow all system classes and temporary placeholders in dictionary
1718 dictionary()->always_strong_classes_do(closure);
1719
1720 // Placeholders. These represent classes we're actively loading.
1721 placeholders()->classes_do(closure);
1722 }
1723
1724 // Calculate a "good" systemdictionary size based
1725 // on predicted or current loaded classes count
1726 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1727 int newsize = _old_default_sdsize;
1728 if ((classcount > 0) && !DumpSharedSpaces) {
1729 int desiredsize = classcount/_average_depth_goal;
1730 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1731 newsize = _primelist[++_sdgeneration]) {
1732 if (desiredsize <= newsize) {
1733 break;
1734 }
1735 }
1736 }
1737 return newsize;
1738 }
1739 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1740 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1741 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1742 bool unloading_occurred = false;
1743 if (has_dead_loaders) {
1744 unloading_occurred = dictionary()->do_unloading();
1745 constraints()->purge_loader_constraints();
1746 resolution_errors()->purge_resolution_errors();
1747 }
1748 return unloading_occurred;
1749 }
1750
1751 void SystemDictionary::oops_do(OopClosure* f) {
1752 f->do_oop(&_java_system_loader);
1753 f->do_oop(&_system_loader_lock_obj);
1754
1755 // Adjust dictionary
1756 dictionary()->oops_do(f);
1757
1758 // Visit extra methods
1759 invoke_method_table()->oops_do(f);
1760 }
1761
1762 // Extended Class redefinition support.
1763 // If one of these classes is replaced, we need to replace it in these places.
1764 // KlassClosure::do_klass should take the address of a class but we can
1765 // change that later.
1766 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1767 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1768 f->do_klass(_well_known_klasses[k]);
1769 }
1770
1771 {
1772 for (int i = 0; i < T_VOID+1; i++) {
1773 if (_box_klasses[i] != NULL) {
1774 assert(i >= T_BOOLEAN, "checking");
1775 f->do_klass(_box_klasses[i]);
1776 }
1777 }
1778 }
1779
1780 FilteredFieldsMap::classes_do(f);
1781 }
1782
1783 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1784 f->do_klass(_abstract_ownable_synchronizer_klass);
1785 }
1786
1787 // Just the classes from defining class loaders
1788 // Don't iterate over placeholders
1789 void SystemDictionary::classes_do(void f(Klass*)) {
1790 dictionary()->classes_do(f);
1791 }
1792
1793 // Added for initialize_itable_for_klass
1794 // Just the classes from defining class loaders
1795 // Don't iterate over placeholders
1796 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1797 dictionary()->classes_do(f, CHECK);
1798 }
1799
1800 // All classes, and their class loaders
1801 // Don't iterate over placeholders
1802 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1803 dictionary()->classes_do(f);
1804 }
1805
1806 // All classes, and their class loaders
1807 // (added for helpers that use HandleMarks and ResourceMarks)
1808 // Don't iterate over placeholders
1809 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
1810 dictionary()->classes_do(f, CHECK);
1811 }
1812
1813 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1814 placeholders()->entries_do(f);
1815 }
1816
1817 void SystemDictionary::methods_do(void f(Method*)) {
1818 dictionary()->methods_do(f);
1819 invoke_method_table()->methods_do(f);
1820 }
1821
1822 // ----------------------------------------------------------------------------
1823 // Lazily load klasses
1824
1825 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1826 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1827
1828 // if multiple threads calling this function, only one thread will load
1829 // the class. The other threads will find the loaded version once the
1830 // class is loaded.
1831 Klass* aos = _abstract_ownable_synchronizer_klass;
1832 if (aos == NULL) {
1833 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1834 // Force a fence to prevent any read before the write completes
1835 OrderAccess::fence();
1836 _abstract_ownable_synchronizer_klass = k;
1837 }
1838 }
1839
1840 // ----------------------------------------------------------------------------
1841 // Initialization
1842
1843 void SystemDictionary::initialize(TRAPS) {
1844 // Allocate arrays
1845 assert(dictionary() == NULL,
1846 "SystemDictionary should only be initialized once");
1847 _sdgeneration = 0;
1848 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1849 _placeholders = new PlaceholderTable(_nof_buckets);
1850 _number_of_modifications = 0;
1851 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1852 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1853 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1854
1855 // Allocate private object used as system class loader lock
1856 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1857 // Initialize basic classes
1858 initialize_preloaded_classes(CHECK);
1859 }
1860
1861 // Compact table of directions on the initialization of klasses:
1862 static const short wk_init_info[] = {
1863 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1864 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1865 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1866 | (int)SystemDictionary::option ),
1867 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1868 #undef WK_KLASS_INIT_INFO
1869 0
1870 };
1871
1872 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1873 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1874 int info = wk_init_info[id - FIRST_WKID];
1875 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1876 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1877 Klass** klassp = &_well_known_klasses[id];
1878 bool must_load = (init_opt < SystemDictionary::Opt);
1879 bool try_load = true;
1880 if (init_opt == SystemDictionary::Opt_Kernel) {
1881 #ifndef KERNEL
1882 try_load = false;
1883 #endif //KERNEL
1884 }
1885 if ((*klassp) == NULL && try_load) {
1886 if (must_load) {
1887 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1888 } else {
1889 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1890 }
1891 }
1892 return ((*klassp) != NULL);
1893 }
1894
1895 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1896 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1897 for (int id = (int)start_id; id < (int)limit_id; id++) {
1898 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1899 int info = wk_init_info[id - FIRST_WKID];
1900 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1901 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1902
1903 initialize_wk_klass((WKID)id, opt, CHECK);
1904 }
1905
1906 // move the starting value forward to the limit:
1907 start_id = limit_id;
1908 }
1909
1910 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1911 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1912 // Preload commonly used klasses
1913 WKID scan = FIRST_WKID;
1914 // first do Object, then String, Class
1915 if (UseSharedSpaces) {
1916 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1917 // Initialize the constant pool for the Object_class
1918 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1919 ik->constants()->restore_unshareable_info(CHECK);
1920 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1921 } else {
1922 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1923 }
1924
1925 // Calculate offsets for String and Class classes since they are loaded and
1926 // can be used after this point.
1927 java_lang_String::compute_offsets();
1928 java_lang_Class::compute_offsets();
1929
1930 // Fixup mirrors for classes loaded before java.lang.Class.
1931 // These calls iterate over the objects currently in the perm gen
1932 // so calling them at this point is matters (not before when there
1933 // are fewer objects and not later after there are more objects
1934 // in the perm gen.
1935 Universe::initialize_basic_type_mirrors(CHECK);
1936 Universe::fixup_mirrors(CHECK);
1937
1938 // do a bunch more:
1939 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1940
1941 // Preload ref klasses and set reference types
1942 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1943 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1944
1945 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1946 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1947 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1948 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1949 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1950
1951 // JSR 292 classes
1952 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1953 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1954 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1955 if (EnableInvokeDynamic) {
1956 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1957 } else {
1958 // Skip the JSR 292 classes, if not enabled.
1959 scan = WKID(jsr292_group_end + 1);
1960 }
1961
1962 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1963
1964 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1965 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1966 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1967 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1968 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1969 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1970 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1971 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1972 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1973 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1974
1975 #ifdef KERNEL
1976 if (DownloadManager_klass() == NULL) {
1977 warning("Cannot find sun/jkernel/DownloadManager");
1978 }
1979 #endif // KERNEL
1980
1981 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1982 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1983 _has_loadClassInternal = (method != NULL);
1984 }
1985 { // Compute whether we should use checkPackageAccess or NOT
1986 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1987 _has_checkPackageAccess = (method != NULL);
1988 }
1989 }
1990
1991 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1992 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1993 BasicType SystemDictionary::box_klass_type(Klass* k) {
1994 assert(k != NULL, "");
1995 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1996 if (_box_klasses[i] == k)
1997 return (BasicType)i;
1998 }
1999 return T_OBJECT;
2000 }
2001
2002 // Constraints on class loaders. The details of the algorithm can be
2003 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2004 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2005 // that the system dictionary needs to maintain a set of contraints that
2006 // must be satisfied by all classes in the dictionary.
2007 // if defining is true, then LinkageError if already in systemDictionary
2008 // if initiating loader, then ok if InstanceKlass matches existing entry
2009
2010 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2011 instanceKlassHandle k,
2012 Handle class_loader, bool defining,
2013 TRAPS) {
2014 const char *linkage_error = NULL;
2015 {
2016 Symbol* name = k->name();
2017 ClassLoaderData *loader_data = class_loader_data(class_loader);
2018
2019 MutexLocker mu(SystemDictionary_lock, THREAD);
2020
2021 Klass* check = find_class(d_index, d_hash, name, loader_data);
2022 if (check != (Klass*)NULL) {
2023 // if different InstanceKlass - duplicate class definition,
2024 // else - ok, class loaded by a different thread in parallel,
2025 // we should only have found it if it was done loading and ok to use
2026 // system dictionary only holds instance classes, placeholders
2027 // also holds array classes
2028
2029 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2030 if ((defining == true) || (k() != check)) {
2031 linkage_error = "loader (instance of %s): attempted duplicate class "
2032 "definition for name: \"%s\"";
2033 } else {
2034 return;
2035 }
2036 }
2037
2038 #ifdef ASSERT
2039 Symbol* ph_check = find_placeholder(name, loader_data);
2040 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2041 #endif
2042
2043 if (linkage_error == NULL) {
2044 if (constraints()->check_or_update(k, class_loader, name) == false) {
2045 linkage_error = "loader constraint violation: loader (instance of %s)"
2046 " previously initiated loading for a different type with name \"%s\"";
2047 }
2048 }
2049 }
2050
2051 // Throw error now if needed (cannot throw while holding
2052 // SystemDictionary_lock because of rank ordering)
2053
2054 if (linkage_error) {
2055 ResourceMark rm(THREAD);
2056 const char* class_loader_name = loader_name(class_loader());
2057 char* type_name = k->name()->as_C_string();
2058 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2059 strlen(type_name);
2060 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2061 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2062 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2063 }
2064 }
2065
2066
2067 // Update system dictionary - done after check_constraint and add_to_hierachy
2068 // have been called.
2069 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2070 int p_index, unsigned int p_hash,
2071 instanceKlassHandle k,
2072 Handle class_loader,
2073 TRAPS) {
2074 // Compile_lock prevents systemDictionary updates during compilations
2075 assert_locked_or_safepoint(Compile_lock);
2076 Symbol* name = k->name();
2077 ClassLoaderData *loader_data = class_loader_data(class_loader);
2078
2079 {
2080 MutexLocker mu1(SystemDictionary_lock, THREAD);
2081
2082 // See whether biased locking is enabled and if so set it for this
2083 // klass.
2084 // Note that this must be done past the last potential blocking
2085 // point / safepoint. We enable biased locking lazily using a
2086 // VM_Operation to iterate the SystemDictionary and installing the
2087 // biasable mark word into each InstanceKlass's prototype header.
2088 // To avoid race conditions where we accidentally miss enabling the
2089 // optimization for one class in the process of being added to the
2090 // dictionary, we must not safepoint after the test of
2091 // BiasedLocking::enabled().
2092 if (UseBiasedLocking && BiasedLocking::enabled()) {
2093 // Set biased locking bit for all loaded classes; it will be
2094 // cleared if revocation occurs too often for this type
2095 // NOTE that we must only do this when the class is initally
2096 // defined, not each time it is referenced from a new class loader
2097 if (k->class_loader() == class_loader()) {
2098 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2099 }
2100 }
2101
2102 // Assign a classid if one has not already been assigned. The
2103 // counter does not need to be atomically incremented since this
2104 // is only done while holding the SystemDictionary_lock.
2105 // All loaded classes get a unique ID.
2106 TRACE_INIT_ID(k);
2107
2108 // Check for a placeholder. If there, remove it and make a
2109 // new system dictionary entry.
2110 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
2111 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2112 if (sd_check == NULL) {
2113 dictionary()->add_klass(name, loader_data, k);
2114 notice_modification();
2115 }
2116 #ifdef ASSERT
2117 sd_check = find_class(d_index, d_hash, name, loader_data);
2118 assert (sd_check != NULL, "should have entry in system dictionary");
2119 // Changed to allow PH to remain to complete class circularity checking
2120 // while only one thread can define a class at one time, multiple
2121 // classes can resolve the superclass for a class at one time,
2122 // and the placeholder is used to track that
2123 // Symbol* ph_check = find_placeholder(name, class_loader);
2124 // assert (ph_check == NULL, "should not have a placeholder entry");
2125 #endif
2126 SystemDictionary_lock->notify_all();
2127 }
2128 }
2129
2130
2131 // Try to find a class name using the loader constraints. The
2132 // loader constraints might know about a class that isn't fully loaded
2133 // yet and these will be ignored.
2134 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2135 Symbol* class_name, Handle class_loader, TRAPS) {
2136
2137 // First see if it has been loaded directly.
2138 // Force the protection domain to be null. (This removes protection checks.)
2139 Handle no_protection_domain;
2140 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2141 no_protection_domain, CHECK_NULL);
2142 if (klass != NULL)
2143 return klass;
2144
2145 // Now look to see if it has been loaded elsewhere, and is subject to
2146 // a loader constraint that would require this loader to return the
2147 // klass that is already loaded.
2148 if (FieldType::is_array(class_name)) {
2149 // For array classes, their Klass*s are not kept in the
2150 // constraint table. The element Klass*s are.
2151 FieldArrayInfo fd;
2152 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2153 if (t != T_OBJECT) {
2154 klass = Universe::typeArrayKlassObj(t);
2155 } else {
2156 MutexLocker mu(SystemDictionary_lock, THREAD);
2157 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2158 }
2159 // If element class already loaded, allocate array klass
2160 if (klass != NULL) {
2161 klass = klass->array_klass_or_null(fd.dimension());
2162 }
2163 } else {
2164 MutexLocker mu(SystemDictionary_lock, THREAD);
2165 // Non-array classes are easy: simply check the constraint table.
2166 klass = constraints()->find_constrained_klass(class_name, class_loader);
2167 }
2168
2169 return klass;
2170 }
2171
2172
2173 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2174 Handle class_loader1,
2175 Handle class_loader2,
2176 Thread* THREAD) {
2177 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2178 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2179
2180 Symbol* constraint_name = NULL;
2181 if (!FieldType::is_array(class_name)) {
2182 constraint_name = class_name;
2183 } else {
2184 // For array classes, their Klass*s are not kept in the
2185 // constraint table. The element classes are.
2186 FieldArrayInfo fd;
2187 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2188 // primitive types always pass
2189 if (t != T_OBJECT) {
2190 return true;
2191 } else {
2192 constraint_name = fd.object_key();
2193 }
2194 }
2195 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2196 int d_index1 = dictionary()->hash_to_index(d_hash1);
2197
2198 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2199 int d_index2 = dictionary()->hash_to_index(d_hash2);
2200 {
2201 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2202
2203 // Better never do a GC while we're holding these oops
2204 No_Safepoint_Verifier nosafepoint;
2205
2206 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2207 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2208 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2209 klass2, class_loader2);
2210 }
2211 }
2212
2213 // Add entry to resolution error table to record the error when the first
2214 // attempt to resolve a reference to a class has failed.
2215 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2216 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2217 int index = resolution_errors()->hash_to_index(hash);
2218 {
2219 MutexLocker ml(SystemDictionary_lock, Thread::current());
2220 resolution_errors()->add_entry(index, hash, pool, which, error);
2221 }
2222 }
2223
2224 // Delete a resolution error for RedefineClasses for a constant pool is going away
2225 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2226 resolution_errors()->delete_entry(pool);
2227 }
2228
2229 // Lookup resolution error table. Returns error if found, otherwise NULL.
2230 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2231 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2232 int index = resolution_errors()->hash_to_index(hash);
2233 {
2234 MutexLocker ml(SystemDictionary_lock, Thread::current());
2235 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2236 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2237 }
2238 }
2239
2240
2241 // Signature constraints ensure that callers and callees agree about
2242 // the meaning of type names in their signatures. This routine is the
2243 // intake for constraints. It collects them from several places:
2244 //
2245 // * LinkResolver::resolve_method (if check_access is true) requires
2246 // that the resolving class (the caller) and the defining class of
2247 // the resolved method (the callee) agree on each type in the
2248 // method's signature.
2249 //
2250 // * LinkResolver::resolve_interface_method performs exactly the same
2251 // checks.
2252 //
2253 // * LinkResolver::resolve_field requires that the constant pool
2254 // attempting to link to a field agree with the field's defining
2255 // class about the type of the field signature.
2256 //
2257 // * klassVtable::initialize_vtable requires that, when a class
2258 // overrides a vtable entry allocated by a superclass, that the
2259 // overriding method (i.e., the callee) agree with the superclass
2260 // on each type in the method's signature.
2261 //
2262 // * klassItable::initialize_itable requires that, when a class fills
2263 // in its itables, for each non-abstract method installed in an
2264 // itable, the method (i.e., the callee) agree with the interface
2265 // on each type in the method's signature.
2266 //
2267 // All those methods have a boolean (check_access, checkconstraints)
2268 // which turns off the checks. This is used from specialized contexts
2269 // such as bootstrapping, dumping, and debugging.
2270 //
2271 // No direct constraint is placed between the class and its
2272 // supertypes. Constraints are only placed along linked relations
2273 // between callers and callees. When a method overrides or implements
2274 // an abstract method in a supertype (superclass or interface), the
2275 // constraints are placed as if the supertype were the caller to the
2276 // overriding method. (This works well, since callers to the
2277 // supertype have already established agreement between themselves and
2278 // the supertype.) As a result of all this, a class can disagree with
2279 // its supertype about the meaning of a type name, as long as that
2280 // class neither calls a relevant method of the supertype, nor is
2281 // called (perhaps via an override) from the supertype.
2282 //
2283 //
2284 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2285 //
2286 // Make sure all class components (including arrays) in the given
2287 // signature will be resolved to the same class in both loaders.
2288 // Returns the name of the type that failed a loader constraint check, or
2289 // NULL if no constraint failed. The returned C string needs cleaning up
2290 // with a ResourceMark in the caller. No exception except OOME is thrown.
2291 // Arrays are not added to the loader constraint table, their elements are.
2292 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2293 Handle loader1, Handle loader2,
2294 bool is_method, TRAPS) {
2295 // Nothing to do if loaders are the same.
2296 if (loader1() == loader2()) {
2297 return NULL;
2298 }
2299
2300 ResourceMark rm(THREAD);
2301 SignatureStream sig_strm(signature, is_method);
2302 while (!sig_strm.is_done()) {
2303 if (sig_strm.is_object()) {
2304 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2305 Symbol* sig = s;
2306 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2307 return sig->as_C_string();
2308 }
2309 }
2310 sig_strm.next();
2311 }
2312 return NULL;
2313 }
2314
2315
2316 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2317 Symbol* signature,
2318 TRAPS) {
2319 methodHandle empty;
2320 assert(EnableInvokeDynamic, "");
2321 assert(MethodHandles::is_signature_polymorphic(iid) &&
2322 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2323 iid != vmIntrinsics::_invokeGeneric,
2324 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2325
2326 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2327 int index = invoke_method_table()->hash_to_index(hash);
2328 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2329 methodHandle m;
2330 if (spe == NULL || spe->method() == NULL) {
2331 spe = NULL;
2332 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2333 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2334 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2335 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2336
2337 // Now grab the lock. We might have to throw away the new method,
2338 // if a racing thread has managed to install one at the same time.
2339 {
2340 MutexLocker ml(SystemDictionary_lock, THREAD);
2341 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2342 if (spe == NULL)
2343 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2344 if (spe->method() == NULL)
2345 spe->set_method(m());
2346 }
2347 }
2348
2349 assert(spe != NULL && spe->method() != NULL, "");
2350 return spe->method();
2351 }
2352
2353 // Helper for unpacking the return value from linkMethod and linkCallSite.
2354 static methodHandle unpack_method_and_appendix(Handle mname,
2355 KlassHandle accessing_klass,
2356 objArrayHandle appendix_box,
2357 Handle* appendix_result,
2358 TRAPS) {
2359 methodHandle empty;
2360 if (mname.not_null()) {
2361 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2362 if (vmtarget != NULL && vmtarget->is_method()) {
2363 Method* m = (Method*)vmtarget;
2364 oop appendix = appendix_box->obj_at(0);
2365 if (TraceMethodHandles) {
2366 #ifndef PRODUCT
2367 tty->print("Linked method="INTPTR_FORMAT": ", m);
2368 m->print();
2369 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2370 tty->cr();
2371 #endif //PRODUCT
2372 }
2373 (*appendix_result) = Handle(THREAD, appendix);
2374 // the target is stored in the cpCache and if a reference to this
2375 // MethodName is dropped we need a way to make sure the
2376 // class_loader containing this method is kept alive.
2377 // FIXME: the appendix might also preserve this dependency.
2378 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2379 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2380 return methodHandle(THREAD, m);
2381 }
2382 }
2383 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2384 return empty;
2385 }
2386
2387 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2388 Symbol* signature,
2389 KlassHandle accessing_klass,
2390 Handle *appendix_result,
2391 Handle *method_type_result,
2392 TRAPS) {
2393 methodHandle empty;
2394 assert(EnableInvokeDynamic, "");
2395 assert(!THREAD->is_Compiler_thread(), "");
2396 Handle method_type =
2397 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2398 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2399 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2400 }
2401
2402 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2403 int ref_kind = JVM_REF_invokeVirtual;
2404 Handle name_str = StringTable::intern(name, CHECK_(empty));
2405 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2406 assert(appendix_box->obj_at(0) == NULL, "");
2407
2408 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2409 JavaCallArguments args;
2410 args.push_oop(accessing_klass()->java_mirror());
2411 args.push_int(ref_kind);
2412 args.push_oop(mh_klass()->java_mirror());
2413 args.push_oop(name_str());
2414 args.push_oop(method_type());
2415 args.push_oop(appendix_box());
2416 JavaValue result(T_OBJECT);
2417 JavaCalls::call_static(&result,
2418 SystemDictionary::MethodHandleNatives_klass(),
2419 vmSymbols::linkMethod_name(),
2420 vmSymbols::linkMethod_signature(),
2421 &args, CHECK_(empty));
2422 Handle mname(THREAD, (oop) result.get_jobject());
2423 (*method_type_result) = method_type;
2424 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2425 }
2426
2427
2428 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2429 // signature, as interpreted relative to the given class loader.
2430 // Because of class loader constraints, all method handle usage must be
2431 // consistent with this loader.
2432 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2433 KlassHandle accessing_klass,
2434 TRAPS) {
2435 Handle empty;
2436 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2437 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2438 int index = invoke_method_table()->hash_to_index(hash);
2439 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2440 if (spe != NULL && spe->method_type() != NULL) {
2441 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2442 return Handle(THREAD, spe->method_type());
2443 } else if (THREAD->is_Compiler_thread()) {
2444 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2445 return Handle(); // do not attempt from within compiler, unless it was cached
2446 }
2447
2448 Handle class_loader, protection_domain;
2449 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2450 int npts = ArgumentCount(signature).size();
2451 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2452 int arg = 0;
2453 Handle rt; // the return type from the signature
2454 ResourceMark rm(THREAD);
2455 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2456 oop mirror = NULL;
2457 if (is_on_bcp) {
2458 // Note: class_loader & protection_domain are both null at this point.
2459 mirror = ss.as_java_mirror(class_loader, protection_domain,
2460 SignatureStream::ReturnNull, CHECK_(empty));
2461 if (mirror == NULL) {
2462 // fall back from BCP to accessing_klass
2463 if (accessing_klass.not_null()) {
2464 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2465 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2466 }
2467 is_on_bcp = false;
2468 }
2469 }
2470 if (!is_on_bcp) {
2471 // Resolve, throwing a real error if it doesn't work.
2472 mirror = ss.as_java_mirror(class_loader, protection_domain,
2473 SignatureStream::NCDFError, CHECK_(empty));
2474 }
2475 if (ss.at_return_type())
2476 rt = Handle(THREAD, mirror);
2477 else
2478 pts->obj_at_put(arg++, mirror);
2479
2480 // Check accessibility.
2481 if (ss.is_object() && accessing_klass.not_null()) {
2482 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2483 mirror = NULL; // safety
2484 // Emulate ConstantPool::verify_constant_pool_resolve.
2485 if (sel_klass->oop_is_objArray())
2486 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2487 if (sel_klass->oop_is_instance()) {
2488 KlassHandle sel_kh(THREAD, sel_klass);
2489 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2490 }
2491 }
2492 }
2493 assert(arg == npts, "");
2494
2495 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2496 JavaCallArguments args(Handle(THREAD, rt()));
2497 args.push_oop(pts());
2498 JavaValue result(T_OBJECT);
2499 JavaCalls::call_static(&result,
2500 SystemDictionary::MethodHandleNatives_klass(),
2501 vmSymbols::findMethodHandleType_name(),
2502 vmSymbols::findMethodHandleType_signature(),
2503 &args, CHECK_(empty));
2504 Handle method_type(THREAD, (oop) result.get_jobject());
2505
2506 if (is_on_bcp) {
2507 // We can cache this MethodType inside the JVM.
2508 MutexLocker ml(SystemDictionary_lock, THREAD);
2509 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2510 if (spe == NULL)
2511 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2512 if (spe->method_type() == NULL) {
2513 spe->set_method_type(method_type());
2514 }
2515 }
2516
2517 // report back to the caller with the MethodType
2518 return method_type;
2519 }
2520
2521 // Ask Java code to find or construct a method handle constant.
2522 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2523 int ref_kind, //e.g., JVM_REF_invokeVirtual
2524 KlassHandle callee,
2525 Symbol* name_sym,
2526 Symbol* signature,
2527 TRAPS) {
2528 Handle empty;
2529 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2530 Handle type;
2531 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2532 type = find_method_handle_type(signature, caller, CHECK_(empty));
2533 } else {
2534 ResourceMark rm(THREAD);
2535 SignatureStream ss(signature, false);
2536 if (!ss.is_done()) {
2537 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2538 SignatureStream::NCDFError, CHECK_(empty));
2539 type = Handle(THREAD, mirror);
2540 ss.next();
2541 if (!ss.is_done()) type = Handle(); // error!
2542 }
2543 }
2544 if (type.is_null()) {
2545 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2546 }
2547
2548 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2549 JavaCallArguments args;
2550 args.push_oop(caller->java_mirror()); // the referring class
2551 args.push_int(ref_kind);
2552 args.push_oop(callee->java_mirror()); // the target class
2553 args.push_oop(name());
2554 args.push_oop(type());
2555 JavaValue result(T_OBJECT);
2556 JavaCalls::call_static(&result,
2557 SystemDictionary::MethodHandleNatives_klass(),
2558 vmSymbols::linkMethodHandleConstant_name(),
2559 vmSymbols::linkMethodHandleConstant_signature(),
2560 &args, CHECK_(empty));
2561 return Handle(THREAD, (oop) result.get_jobject());
2562 }
2563
2564 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2565 // name and signature, as interpreted relative to the given class loader.
2566 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2567 Handle bootstrap_specifier,
2568 Symbol* name,
2569 Symbol* type,
2570 Handle *appendix_result,
2571 Handle *method_type_result,
2572 TRAPS) {
2573 methodHandle empty;
2574 Handle bsm, info;
2575 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2576 bsm = bootstrap_specifier;
2577 } else {
2578 assert(bootstrap_specifier->is_objArray(), "");
2579 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2580 int len = args->length();
2581 assert(len >= 1, "");
2582 bsm = Handle(THREAD, args->obj_at(0));
2583 if (len > 1) {
2584 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2585 for (int i = 1; i < len; i++)
2586 args1->obj_at_put(i-1, args->obj_at(i));
2587 info = Handle(THREAD, args1);
2588 }
2589 }
2590 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2591 "caller must supply a valid BSM");
2592
2593 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2594 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2595
2596 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2597 assert(appendix_box->obj_at(0) == NULL, "");
2598
2599 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2600 JavaCallArguments args;
2601 args.push_oop(caller->java_mirror());
2602 args.push_oop(bsm());
2603 args.push_oop(method_name());
2604 args.push_oop(method_type());
2605 args.push_oop(info());
2606 args.push_oop(appendix_box);
2607 JavaValue result(T_OBJECT);
2608 JavaCalls::call_static(&result,
2609 SystemDictionary::MethodHandleNatives_klass(),
2610 vmSymbols::linkCallSite_name(),
2611 vmSymbols::linkCallSite_signature(),
2612 &args, CHECK_(empty));
2613 Handle mname(THREAD, (oop) result.get_jobject());
2614 (*method_type_result) = method_type;
2615 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2616 }
2617
2618 // Since the identity hash code for symbols changes when the symbols are
2619 // moved from the regular perm gen (hash in the mark word) to the shared
2620 // spaces (hash is the address), the classes loaded into the dictionary
2621 // may be in the wrong buckets.
2622
2623 void SystemDictionary::reorder_dictionary() {
2624 dictionary()->reorder_dictionary();
2625 }
2626
2627
2628 void SystemDictionary::copy_buckets(char** top, char* end) {
2629 dictionary()->copy_buckets(top, end);
2630 }
2631
2632
2633 void SystemDictionary::copy_table(char** top, char* end) {
2634 dictionary()->copy_table(top, end);
2635 }
2636
2637
2638 void SystemDictionary::reverse() {
2639 dictionary()->reverse();
2640 }
2641
2642 int SystemDictionary::number_of_classes() {
2643 return dictionary()->number_of_entries();
2644 }
2645
2646
2647 // ----------------------------------------------------------------------------
2648 #ifndef PRODUCT
2649
2650 void SystemDictionary::print() {
2651 dictionary()->print();
2652
2653 // Placeholders
2654 GCMutexLocker mu(SystemDictionary_lock);
2655 placeholders()->print();
2656
2657 // loader constraints - print under SD_lock
2658 constraints()->print();
2659 }
2660
2661 #endif
2662
2663 void SystemDictionary::verify() {
2664 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2665 guarantee(constraints() != NULL,
2666 "Verify of loader constraints failed");
2667 guarantee(dictionary()->number_of_entries() >= 0 &&
2668 placeholders()->number_of_entries() >= 0,
2669 "Verify of system dictionary failed");
2670
2671 // Verify dictionary
2672 dictionary()->verify();
2673
2674 GCMutexLocker mu(SystemDictionary_lock);
2675 placeholders()->verify();
2676
2677 // Verify constraint table
2678 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2679 constraints()->verify(dictionary(), placeholders());
2680 }
2681
2682
2683 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2684 ClassLoaderData* loader_data) {
2685 GCMutexLocker mu(SystemDictionary_lock);
2686 Symbol* name;
2687
2688 Klass* probe = find_class(class_name, loader_data);
2689 if (probe == NULL) {
2690 probe = SystemDictionary::find_shared_class(class_name);
2691 if (probe == NULL) {
2692 name = find_placeholder(class_name, loader_data);
2693 }
2694 }
2695 guarantee(probe != NULL || name != NULL,
2696 "Loaded klasses should be in SystemDictionary");
2697 }
2698
2699 #ifndef PRODUCT
2700
2701 // statistics code
2702 class ClassStatistics: AllStatic {
2703 private:
2704 static int nclasses; // number of classes
2705 static int nmethods; // number of methods
2706 static int nmethoddata; // number of methodData
2707 static int class_size; // size of class objects in words
2708 static int method_size; // size of method objects in words
2709 static int debug_size; // size of debug info in methods
2710 static int methoddata_size; // size of methodData objects in words
2711
2712 static void do_class(Klass* k) {
2713 nclasses++;
2714 class_size += k->size();
2715 if (k->oop_is_instance()) {
2716 InstanceKlass* ik = (InstanceKlass*)k;
2717 class_size += ik->methods()->size();
2718 class_size += ik->constants()->size();
2719 class_size += ik->local_interfaces()->size();
2720 class_size += ik->transitive_interfaces()->size();
2721 // We do not have to count implementors, since we only store one!
2722 // SSS: How should these be accounted now that they have moved?
2723 // class_size += ik->fields()->length();
2724 }
2725 }
2726
2727 static void do_method(Method* m) {
2728 nmethods++;
2729 method_size += m->size();
2730 // class loader uses same objArray for empty vectors, so don't count these
2731 if (m->has_stackmap_table()) {
2732 method_size += m->stackmap_data()->size();
2733 }
2734
2735 MethodData* mdo = m->method_data();
2736 if (mdo != NULL) {
2737 nmethoddata++;
2738 methoddata_size += mdo->size();
2739 }
2740 }
2741
2742 public:
2743 static void print() {
2744 SystemDictionary::classes_do(do_class);
2745 SystemDictionary::methods_do(do_method);
2746 tty->print_cr("Class statistics:");
2747 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2748 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2749 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2750 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2751 }
2752 };
2753
2754
2755 int ClassStatistics::nclasses = 0;
2756 int ClassStatistics::nmethods = 0;
2757 int ClassStatistics::nmethoddata = 0;
2758 int ClassStatistics::class_size = 0;
2759 int ClassStatistics::method_size = 0;
2760 int ClassStatistics::debug_size = 0;
2761 int ClassStatistics::methoddata_size = 0;
2762
2763 void SystemDictionary::print_class_statistics() {
2764 ResourceMark rm;
2765 ClassStatistics::print();
2766 }
2767
2768
2769 class MethodStatistics: AllStatic {
2770 public:
2771 enum {
2772 max_parameter_size = 10
2773 };
2774 private:
2775
2776 static int _number_of_methods;
2777 static int _number_of_final_methods;
2778 static int _number_of_static_methods;
2779 static int _number_of_native_methods;
2780 static int _number_of_synchronized_methods;
2781 static int _number_of_profiled_methods;
2782 static int _number_of_bytecodes;
2783 static int _parameter_size_profile[max_parameter_size];
2784 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2785
2786 static void initialize() {
2787 _number_of_methods = 0;
2788 _number_of_final_methods = 0;
2789 _number_of_static_methods = 0;
2790 _number_of_native_methods = 0;
2791 _number_of_synchronized_methods = 0;
2792 _number_of_profiled_methods = 0;
2793 _number_of_bytecodes = 0;
2794 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2795 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2796 };
2797
2798 static void do_method(Method* m) {
2799 _number_of_methods++;
2800 // collect flag info
2801 if (m->is_final() ) _number_of_final_methods++;
2802 if (m->is_static() ) _number_of_static_methods++;
2803 if (m->is_native() ) _number_of_native_methods++;
2804 if (m->is_synchronized()) _number_of_synchronized_methods++;
2805 if (m->method_data() != NULL) _number_of_profiled_methods++;
2806 // collect parameter size info (add one for receiver, if any)
2807 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2808 // collect bytecodes info
2809 {
2810 Thread *thread = Thread::current();
2811 HandleMark hm(thread);
2812 BytecodeStream s(methodHandle(thread, m));
2813 Bytecodes::Code c;
2814 while ((c = s.next()) >= 0) {
2815 _number_of_bytecodes++;
2816 _bytecodes_profile[c]++;
2817 }
2818 }
2819 }
2820
2821 public:
2822 static void print() {
2823 initialize();
2824 SystemDictionary::methods_do(do_method);
2825 // generate output
2826 tty->cr();
2827 tty->print_cr("Method statistics (static):");
2828 // flag distribution
2829 tty->cr();
2830 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2831 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2832 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2833 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2834 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2835 // parameter size profile
2836 tty->cr();
2837 { int tot = 0;
2838 int avg = 0;
2839 for (int i = 0; i < max_parameter_size; i++) {
2840 int n = _parameter_size_profile[i];
2841 tot += n;
2842 avg += n*i;
2843 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2844 }
2845 assert(tot == _number_of_methods, "should be the same");
2846 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2847 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2848 }
2849 // bytecodes profile
2850 tty->cr();
2851 { int tot = 0;
2852 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2853 if (Bytecodes::is_defined(i)) {
2854 Bytecodes::Code c = Bytecodes::cast(i);
2855 int n = _bytecodes_profile[c];
2856 tot += n;
2857 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2858 }
2859 }
2860 assert(tot == _number_of_bytecodes, "should be the same");
2861 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2862 }
2863 tty->cr();
2864 }
2865 };
2866
2867 int MethodStatistics::_number_of_methods;
2868 int MethodStatistics::_number_of_final_methods;
2869 int MethodStatistics::_number_of_static_methods;
2870 int MethodStatistics::_number_of_native_methods;
2871 int MethodStatistics::_number_of_synchronized_methods;
2872 int MethodStatistics::_number_of_profiled_methods;
2873 int MethodStatistics::_number_of_bytecodes;
2874 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2875 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2876
2877
2878 void SystemDictionary::print_method_statistics() {
2879 MethodStatistics::print();
2880 }
2881
2882 #endif // PRODUCT