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 // fullyConcurrent subsumes the parallelCapable test but
139 // maybe this should be inside java_lang_ClassLoader::parallelCapable?
140 return java_lang_ClassLoader::fullyConcurrent(class_loader()) ||
141 java_lang_ClassLoader::parallelCapable(class_loader());
142 }
143 // ----------------------------------------------------------------------------
144 // ParallelDefineClass flag does not apply to bootclass loader
145 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
146 if (class_loader.is_null()) return false;
147 if (java_lang_ClassLoader::fullyConcurrent(class_loader()) ||
148 AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
149 if (TraceClassLoading)
150 tty->print_cr("Parallel define permitted for loader: %p", class_loader());
151 return true;
152 }
153 return false;
154 }
155 // ----------------------------------------------------------------------------
156 // Resolving of classes
157
158 // Forwards to resolve_or_null
159
160 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
161 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
162 if (HAS_PENDING_EXCEPTION || klass == NULL) {
163 KlassHandle k_h(THREAD, klass);
164 // can return a null klass
165 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
166 }
167 return klass;
168 }
169
170 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
171 if (HAS_PENDING_EXCEPTION) {
172 // If we have a pending exception we forward it to the caller, unless throw_error is true,
173 // in which case we have to check whether the pending exception is a ClassNotFoundException,
174 // and if so convert it to a NoClassDefFoundError
175 // And chain the original ClassNotFoundException
176 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
177 ResourceMark rm(THREAD);
178 assert(klass_h() == NULL, "Should not have result with exception pending");
179 Handle e(THREAD, PENDING_EXCEPTION);
180 CLEAR_PENDING_EXCEPTION;
181 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
182 } else {
183 return NULL;
184 }
185 }
186 // Class not found, throw appropriate error or exception depending on value of throw_error
187 if (klass_h() == NULL) {
188 ResourceMark rm(THREAD);
189 if (throw_error) {
190 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
191 } else {
192 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
193 }
194 }
195 return (Klass*)klass_h();
196 }
197
198
199 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
200 bool throw_error, TRAPS)
201 {
202 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
203 }
204
205
206 // Forwards to resolve_instance_class_or_null
207
208 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
209 assert(!THREAD->is_Compiler_thread(),
210 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
211 class_name->as_C_string(),
212 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
213 if (FieldType::is_array(class_name)) {
214 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
215 } else if (FieldType::is_obj(class_name)) {
216 ResourceMark rm(THREAD);
217 // Ignore wrapping L and ;.
218 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
219 class_name->utf8_length() - 2, CHECK_NULL);
220 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
221 } else {
222 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
223 }
224 }
225
226 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
227 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
228 }
229
230 // Forwards to resolve_instance_class_or_null
231
232 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
233 Handle class_loader,
234 Handle protection_domain,
235 TRAPS) {
236 assert(FieldType::is_array(class_name), "must be array");
237 Klass* k = NULL;
238 FieldArrayInfo fd;
239 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
240 // of this call
241 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
242 if (t == T_OBJECT) {
243 // naked oop "k" is OK here -- we assign back into it
244 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
245 class_loader,
246 protection_domain,
247 CHECK_NULL);
248 if (k != NULL) {
249 k = k->array_klass(fd.dimension(), CHECK_NULL);
250 }
251 } else {
252 k = Universe::typeArrayKlassObj(t);
253 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
254 }
255 return k;
256 }
257
258
259 // Must be called for any super-class or super-interface resolution
260 // during class definition to allow class circularity checking
261 // super-interface callers:
262 // parse_interfaces - for defineClass & jvmtiRedefineClasses
263 // super-class callers:
264 // ClassFileParser - for defineClass & jvmtiRedefineClasses
265 // load_shared_class - while loading a class from shared archive
266 // resolve_instance_class_or_null:
267 // via: handle_parallel_super_load
268 // when resolving a class that has an existing placeholder with
269 // a saved superclass [i.e. a defineClass is currently in progress]
270 // if another thread is trying to resolve the class, it must do
271 // super-class checks on its own thread to catch class circularity
272 // This last call is critical in class circularity checking for cases
273 // where classloading is delegated to different threads and the
274 // classloader lock is released.
275 // Take the case: Base->Super->Base
276 // 1. If thread T1 tries to do a defineClass of class Base
277 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
278 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
279 // so it tries to load Super
280 // 3. If we load the class internally, or user classloader uses same thread
281 // loadClassFromxxx or defineClass via parseClassFile Super ...
282 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
283 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
284 // 3.4 calls resolve_super_or_fail Base
285 // 3.5 finds T1,Base -> throws class circularity
286 //OR 4. If T2 tries to resolve Super via defineClass Super ...
287 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
288 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
289 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
290 // 4.4 finds T2, Super -> throws class circularity
291 // Must be called, even if superclass is null, since this is
292 // where the placeholder entry is created which claims this
293 // thread is loading this class/classloader.
294 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
295 Symbol* class_name,
296 Handle class_loader,
297 Handle protection_domain,
298 bool is_superclass,
299 TRAPS) {
300 // Double-check, if child class is already loaded, just return super-class,interface
301 // Don't add a placedholder if already loaded, i.e. already in system dictionary
302 // Make sure there's a placeholder for the *child* before resolving.
303 // Used as a claim that this thread is currently loading superclass/classloader
304 // Used here for ClassCircularity checks and also for heap verification
305 // (every InstanceKlass in the heap needs to be in the system dictionary
306 // or have a placeholder).
307 // Must check ClassCircularity before checking if super class is already loaded
308 //
309 // We might not already have a placeholder if this child_name was
310 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
311 // the name of the class might not be known until the stream is actually
312 // parsed.
313 // Bugs 4643874, 4715493
314 // compute_hash can have a safepoint
315
316 ClassLoaderData* loader_data = class_loader_data(class_loader);
317 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
318 int d_index = dictionary()->hash_to_index(d_hash);
319 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
320 int p_index = placeholders()->hash_to_index(p_hash);
321 // can't throw error holding a lock
322 bool child_already_loaded = false;
323 bool throw_circularity_error = false;
324 {
325 MutexLocker mu(SystemDictionary_lock, THREAD);
326 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
327 Klass* quicksuperk;
328 // to support // loading: if child done loading, just return superclass
329 // if class_name, & class_loader don't match:
330 // if initial define, SD update will give LinkageError
331 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
332 // so we don't throw an exception here.
333 // see: nsk redefclass014 & java.lang.instrument Instrument032
334 if ((childk != NULL ) && (is_superclass) &&
335 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
336
337 ((quicksuperk->name() == class_name) &&
338 (quicksuperk->class_loader() == class_loader()))) {
339 return quicksuperk;
340 } else {
341 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
342 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
343 throw_circularity_error = true;
344 }
345 }
346 if (!throw_circularity_error) {
347 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
348 }
349 }
350 if (throw_circularity_error) {
351 ResourceMark rm(THREAD);
352 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
353 }
354
355 // java.lang.Object should have been found above
356 assert(class_name != NULL, "null super class for resolving");
357 // Resolve the super class or interface, check results on return
358 Klass* superk = NULL;
359 superk = SystemDictionary::resolve_or_null(class_name,
360 class_loader,
361 protection_domain,
362 THREAD);
363
364 KlassHandle superk_h(THREAD, superk);
365
366 // Note: clean up of placeholders currently in callers of
367 // resolve_super_or_fail - either at update_dictionary time
368 // or on error
369 {
370 MutexLocker mu(SystemDictionary_lock, THREAD);
371 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
372 if (probe != NULL) {
373 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
374 }
375 }
376 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
377 // can null superk
378 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
379 }
380
381 return superk_h();
382 }
383
384 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
385 Handle class_loader,
386 Handle protection_domain,
387 TRAPS) {
388 if(!has_checkPackageAccess()) return;
389
390 // Now we have to call back to java to check if the initating class has access
391 JavaValue result(T_VOID);
392 if (TraceProtectionDomainVerification) {
393 // Print out trace information
394 tty->print_cr("Checking package access");
395 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
396 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
397 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
398 }
399
400 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
401 JavaCalls::call_special(&result,
402 class_loader,
403 system_loader,
404 vmSymbols::checkPackageAccess_name(),
405 vmSymbols::class_protectiondomain_signature(),
406 Handle(THREAD, klass->java_mirror()),
407 protection_domain,
408 THREAD);
409
410 if (TraceProtectionDomainVerification) {
411 if (HAS_PENDING_EXCEPTION) {
412 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
413 } else {
414 tty->print_cr(" -> granted");
415 }
416 tty->cr();
417 }
418
419 if (HAS_PENDING_EXCEPTION) return;
420
421 // If no exception has been thrown, we have validated the protection domain
422 // Insert the protection domain of the initiating class into the set.
423 {
424 // We recalculate the entry here -- we've called out to java since
425 // the last time it was calculated.
426 ClassLoaderData* loader_data = class_loader_data(class_loader);
427
428 Symbol* kn = klass->name();
429 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
430 int d_index = dictionary()->hash_to_index(d_hash);
431
432 MutexLocker mu(SystemDictionary_lock, THREAD);
433 {
434 // Note that we have an entry, and entries can be deleted only during GC,
435 // so we cannot allow GC to occur while we're holding this entry.
436
437 // We're using a No_Safepoint_Verifier to catch any place where we
438 // might potentially do a GC at all.
439 // SystemDictionary::do_unloading() asserts that classes are only
440 // unloaded at a safepoint.
441 No_Safepoint_Verifier nosafepoint;
442 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
443 protection_domain, THREAD);
444 }
445 }
446 }
447
448 // We only get here if this thread finds that another thread
449 // has already claimed the placeholder token for the current operation,
450 // but that other thread either never owned or gave up the
451 // object lock
452 // Waits on SystemDictionary_lock to indicate placeholder table updated
453 // On return, caller must recheck placeholder table state
454 //
455 // We only get here if
456 // 1) custom classLoader, i.e. not bootstrap classloader
457 // 2) UnsyncloadClass not set
458 // 3) custom classLoader has broken the class loader objectLock
459 // so another thread got here in parallel
460 //
461 // lockObject must be held.
462 // Complicated dance due to lock ordering:
463 // Must first release the classloader object lock to
464 // allow initial definer to complete the class definition
465 // and to avoid deadlock
466 // Reclaim classloader lock object with same original recursion count
467 // Must release SystemDictionary_lock after notify, since
468 // class loader lock must be claimed before SystemDictionary_lock
469 // to prevent deadlocks
470 //
471 // The notify allows applications that did an untimed wait() on
472 // the classloader object lock to not hang.
473 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
474 assert_lock_strong(SystemDictionary_lock);
475
476 bool calledholdinglock
477 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
478 assert(calledholdinglock,"must hold lock for notify");
479 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
480 ObjectSynchronizer::notifyall(lockObject, THREAD);
481 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
482 SystemDictionary_lock->wait();
483 SystemDictionary_lock->unlock();
484 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
485 SystemDictionary_lock->lock();
486 }
487
488 // If the class in is in the placeholder table, class loading is in progress
489 // For cases where the application changes threads to load classes, it
490 // is critical to ClassCircularity detection that we try loading
491 // the superclass on the same thread internally, so we do parallel
492 // super class loading here.
493 // This also is critical in cases where the original thread gets stalled
494 // even in non-circularity situations.
495 // Note: only one thread can define the class, but multiple can resolve
496 // Note: must call resolve_super_or_fail even if null super -
497 // to force placeholder entry creation for this class for circularity detection
498 // Caller must check for pending exception
499 // Returns non-null Klass* if other thread has completed load
500 // and we are done,
501 // If return null Klass* and no pending exception, the caller must load the class
502 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
503 Symbol* name, Symbol* superclassname, Handle class_loader,
504 Handle protection_domain, Handle lockObject, TRAPS) {
505
506 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
507 ClassLoaderData* loader_data = class_loader_data(class_loader);
508 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
509 int d_index = dictionary()->hash_to_index(d_hash);
510 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
511 int p_index = placeholders()->hash_to_index(p_hash);
512
513 // superk is not used, resolve_super called for circularity check only
514 // This code is reached in two situations. One if this thread
515 // is loading the same class twice (e.g. ClassCircularity, or
516 // java.lang.instrument).
517 // The second is if another thread started the resolve_super first
518 // and has not yet finished.
519 // In both cases the original caller will clean up the placeholder
520 // entry on error.
521 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
522 superclassname,
523 class_loader,
524 protection_domain,
525 true,
526 CHECK_(nh));
527 // We don't redefine the class, so we just need to clean up if there
528 // was not an error (don't want to modify any system dictionary
529 // data structures).
530 {
531 MutexLocker mu(SystemDictionary_lock, THREAD);
532 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
533 SystemDictionary_lock->notify_all();
534 }
535
536 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
537 // Serial class loaders and bootstrap classloader do wait for superclass loads
538 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
539 MutexLocker mu(SystemDictionary_lock, THREAD);
540 // Check if classloading completed while we were loading superclass or waiting
541 Klass* check = find_class(d_index, d_hash, name, loader_data);
542 if (check != NULL) {
543 // Klass is already loaded, so just return it
544 return(instanceKlassHandle(THREAD, check));
545 } else {
546 return nh;
547 }
548 }
549
550 // must loop to both handle other placeholder updates
551 // and spurious notifications
552 bool super_load_in_progress = true;
553 PlaceholderEntry* placeholder;
554 while (super_load_in_progress) {
555 MutexLocker mu(SystemDictionary_lock, THREAD);
556 // Check if classloading completed while we were loading superclass or waiting
557 Klass* check = find_class(d_index, d_hash, name, loader_data);
558 if (check != NULL) {
559 // Klass is already loaded, so just return it
560 return(instanceKlassHandle(THREAD, check));
561 } else {
562 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
563 if (placeholder && placeholder->super_load_in_progress() ){
564 // Before UnsyncloadClass:
565 // We only get here if the application has released the
566 // classloader lock when another thread was in the middle of loading a
567 // superclass/superinterface for this class, and now
568 // this thread is also trying to load this class.
569 // To minimize surprises, the first thread that started to
570 // load a class should be the one to complete the loading
571 // with the classfile it initially expected.
572 // This logic has the current thread wait once it has done
573 // all the superclass/superinterface loading it can, until
574 // the original thread completes the class loading or fails
575 // If it completes we will use the resulting InstanceKlass
576 // which we will find below in the systemDictionary.
577 // We also get here for parallel bootstrap classloader
578 if (class_loader.is_null()) {
579 SystemDictionary_lock->wait();
580 } else {
581 double_lock_wait(lockObject, THREAD);
582 }
583 } else {
584 // If not in SD and not in PH, other thread's load must have failed
585 super_load_in_progress = false;
586 }
587 }
588 }
589 return (nh);
590 }
591
592
593 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
594 assert(name != NULL && !FieldType::is_array(name) &&
595 !FieldType::is_obj(name), "invalid class name");
596
597 // UseNewReflection
598 // Fix for 4474172; see evaluation for more details
599 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
600 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
601
602 // Do lookup to see if class already exist and the protection domain
603 // has the right access
604 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
605 int d_index = dictionary()->hash_to_index(d_hash);
606 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
607 protection_domain, THREAD);
608 if (probe != NULL) return probe;
609
610
611 // Non-bootstrap class loaders will call out to class loader and
612 // define via jvm/jni_DefineClass which will acquire the
613 // class loader object lock to protect against multiple threads
614 // defining the class in parallel by accident.
615 // This lock must be acquired here so the waiter will find
616 // any successful result in the SystemDictionary and not attempt
617 // the define
618 // ParallelCapable Classloaders and the bootstrap classloader,
619 // or all classloaders with UnsyncloadClass do not acquire lock here
620 bool DoObjectLock = true;
621 if (is_parallelCapable(class_loader)) {
622 DoObjectLock = false;
623 }
624
625 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
626 int p_index = placeholders()->hash_to_index(p_hash);
627
628 // Class is not in SystemDictionary so we have to do loading.
629 // Make sure we are synchronized on the class loader before we proceed
630 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
631 check_loader_lock_contention(lockObject, THREAD);
632 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
633
634 // Check again (after locking) if class already exist in SystemDictionary
635 bool class_has_been_loaded = false;
636 bool super_load_in_progress = false;
637 bool havesupername = false;
638 instanceKlassHandle k;
639 PlaceholderEntry* placeholder;
640 Symbol* superclassname = NULL;
641
642 {
643 MutexLocker mu(SystemDictionary_lock, THREAD);
644 Klass* check = find_class(d_index, d_hash, name, loader_data);
645 if (check != NULL) {
646 // Klass is already loaded, so just return it
647 class_has_been_loaded = true;
648 k = instanceKlassHandle(THREAD, check);
649 } else {
650 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
651 if (placeholder && placeholder->super_load_in_progress()) {
652 super_load_in_progress = true;
653 if (placeholder->havesupername() == true) {
654 superclassname = placeholder->supername();
655 havesupername = true;
656 }
657 }
658 }
659 }
660
661 // If the class in is in the placeholder table, class loading is in progress
662 if (super_load_in_progress && havesupername==true) {
663 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
664 class_loader, protection_domain, lockObject, THREAD);
665 if (HAS_PENDING_EXCEPTION) {
666 return NULL;
667 }
668 if (!k.is_null()) {
669 class_has_been_loaded = true;
670 }
671 }
672
673 if (!class_has_been_loaded) {
674
675 // add placeholder entry to record loading instance class
676 // Five cases:
677 // All cases need to prevent modifying bootclasssearchpath
678 // in parallel with a classload of same classname
679 // Redefineclasses uses existence of the placeholder for the duration
680 // of the class load to prevent concurrent redefinition of not completely
681 // defined classes.
682 // case 1. traditional classloaders that rely on the classloader object lock
683 // - no other need for LOAD_INSTANCE
684 // case 2. traditional classloaders that break the classloader object lock
685 // as a deadlock workaround. Detection of this case requires that
686 // this check is done while holding the classloader object lock,
687 // and that lock is still held when calling classloader's loadClass.
688 // For these classloaders, we ensure that the first requestor
689 // completes the load and other requestors wait for completion.
690 // case 3. UnsyncloadClass - don't use objectLocker
691 // With this flag, we allow parallel classloading of a
692 // class/classloader pair
693 // case4. Bootstrap classloader - don't own objectLocker
694 // This classloader supports parallelism at the classloader level,
695 // but only allows a single load of a class/classloader pair.
696 // No performance benefit and no deadlock issues.
697 // case 5. parallelCapable user level classloaders - without objectLocker
698 // Allow parallel classloading of a class/classloader pair
699 bool throw_circularity_error = false;
700 {
701 MutexLocker mu(SystemDictionary_lock, THREAD);
702 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
703 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
704 if (oldprobe) {
705 // only need check_seen_thread once, not on each loop
706 // 6341374 java/lang/Instrument with -Xcomp
707 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
708 throw_circularity_error = true;
709 } else {
710 // case 1: traditional: should never see load_in_progress.
711 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
712
713 // case 4: bootstrap classloader: prevent futile classloading,
714 // wait on first requestor
715 if (class_loader.is_null()) {
716 SystemDictionary_lock->wait();
717 } else {
718 // case 2: traditional with broken classloader lock. wait on first
719 // requestor.
720 double_lock_wait(lockObject, THREAD);
721 }
722 // Check if classloading completed while we were waiting
723 Klass* check = find_class(d_index, d_hash, name, loader_data);
724 if (check != NULL) {
725 // Klass is already loaded, so just return it
726 k = instanceKlassHandle(THREAD, check);
727 class_has_been_loaded = true;
728 }
729 // check if other thread failed to load and cleaned up
730 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
731 }
732 }
733 }
734 }
735 // All cases: add LOAD_INSTANCE
736 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
737 // LOAD_INSTANCE in parallel
738 // add placeholder entry even if error - callers will remove on error
739 if (!throw_circularity_error && !class_has_been_loaded) {
740 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
741 // For class loaders that do not acquire the classloader object lock,
742 // if they did not catch another thread holding LOAD_INSTANCE,
743 // need a check analogous to the acquire ObjectLocker/find_class
744 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
745 // one final check if the load has already completed
746 // class loaders holding the ObjectLock shouldn't find the class here
747 Klass* check = find_class(d_index, d_hash, name, loader_data);
748 if (check != NULL) {
749 // Klass is already loaded, so just return it
750 k = instanceKlassHandle(THREAD, check);
751 class_has_been_loaded = true;
752 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
753 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
754 SystemDictionary_lock->notify_all();
755 }
756 }
757 }
758 // must throw error outside of owning lock
759 if (throw_circularity_error) {
760 ResourceMark rm(THREAD);
761 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
762 }
763
764 if (!class_has_been_loaded) {
765
766 // Do actual loading
767 k = load_instance_class(name, class_loader, THREAD);
768
769 // For UnsyncloadClass only
770 // If they got a linkageError, check if a parallel class load succeeded.
771 // If it did, then for bytecode resolution the specification requires
772 // that we return the same result we did for the other thread, i.e. the
773 // successfully loaded InstanceKlass
774 // Should not get here for classloaders that support parallelism
775 // with the new cleaner mechanism, even with AllowParallelDefineClass
776 // Bootstrap goes through here to allow for an extra guarantee check
777 if (UnsyncloadClass || (class_loader.is_null())) {
778 if (k.is_null() && HAS_PENDING_EXCEPTION
779 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
780 MutexLocker mu(SystemDictionary_lock, THREAD);
781 Klass* check = find_class(d_index, d_hash, name, loader_data);
782 if (check != NULL) {
783 // Klass is already loaded, so just use it
784 k = instanceKlassHandle(THREAD, check);
785 CLEAR_PENDING_EXCEPTION;
786 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
787 }
788 }
789 }
790
791 // clean up placeholder entries for success or error
792 // This cleans up LOAD_INSTANCE entries
793 // It also cleans up LOAD_SUPER entries on errors from
794 // calling load_instance_class
795 {
796 MutexLocker mu(SystemDictionary_lock, THREAD);
797 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
798 if (probe != NULL) {
799 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
800 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
801 SystemDictionary_lock->notify_all();
802 }
803 }
804
805 // If everything was OK (no exceptions, no null return value), and
806 // class_loader is NOT the defining loader, do a little more bookkeeping.
807 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
808 k->class_loader() != class_loader()) {
809
810 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
811
812 // Need to check for a PENDING_EXCEPTION again; check_constraints
813 // can throw and doesn't use the CHECK macro.
814 if (!HAS_PENDING_EXCEPTION) {
815 { // Grabbing the Compile_lock prevents systemDictionary updates
816 // during compilations.
817 MutexLocker mu(Compile_lock, THREAD);
818 update_dictionary(d_index, d_hash, p_index, p_hash,
819 k, class_loader, THREAD);
820 }
821 if (JvmtiExport::should_post_class_load()) {
822 Thread *thread = THREAD;
823 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
824 JvmtiExport::post_class_load((JavaThread *) thread, k());
825 }
826 }
827 }
828 if (HAS_PENDING_EXCEPTION || k.is_null()) {
829 // On error, clean up placeholders
830 {
831 MutexLocker mu(SystemDictionary_lock, THREAD);
832 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
833 SystemDictionary_lock->notify_all();
834 }
835 return NULL;
836 }
837 }
838 }
839
840 #ifdef ASSERT
841 {
842 ClassLoaderData* loader_data = k->class_loader_data();
843 MutexLocker mu(SystemDictionary_lock, THREAD);
844 Klass* kk = find_class(name, loader_data);
845 assert(kk == k(), "should be present in dictionary");
846 }
847 #endif
848
849 // return if the protection domain in NULL
850 if (protection_domain() == NULL) return k();
851
852 // Check the protection domain has the right access
853 {
854 MutexLocker mu(SystemDictionary_lock, THREAD);
855 // Note that we have an entry, and entries can be deleted only during GC,
856 // so we cannot allow GC to occur while we're holding this entry.
857 // We're using a No_Safepoint_Verifier to catch any place where we
858 // might potentially do a GC at all.
859 // SystemDictionary::do_unloading() asserts that classes are only
860 // unloaded at a safepoint.
861 No_Safepoint_Verifier nosafepoint;
862 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
863 loader_data,
864 protection_domain)) {
865 return k();
866 }
867 }
868
869 // Verify protection domain. If it fails an exception is thrown
870 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
871
872 return k();
873 }
874
875
876 // This routine does not lock the system dictionary.
877 //
878 // Since readers don't hold a lock, we must make sure that system
879 // dictionary entries are only removed at a safepoint (when only one
880 // thread is running), and are added to in a safe way (all links must
881 // be updated in an MT-safe manner).
882 //
883 // Callers should be aware that an entry could be added just after
884 // _dictionary->bucket(index) is read here, so the caller will not see
885 // the new entry.
886
887 Klass* SystemDictionary::find(Symbol* class_name,
888 Handle class_loader,
889 Handle protection_domain,
890 TRAPS) {
891
892 // UseNewReflection
893 // The result of this call should be consistent with the result
894 // of the call to resolve_instance_class_or_null().
895 // See evaluation 6790209 and 4474172 for more details.
896 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
897 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
898
899 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
900 int d_index = dictionary()->hash_to_index(d_hash);
901
902 {
903 // Note that we have an entry, and entries can be deleted only during GC,
904 // so we cannot allow GC to occur while we're holding this entry.
905 // We're using a No_Safepoint_Verifier to catch any place where we
906 // might potentially do a GC at all.
907 // SystemDictionary::do_unloading() asserts that classes are only
908 // unloaded at a safepoint.
909 No_Safepoint_Verifier nosafepoint;
910 return dictionary()->find(d_index, d_hash, class_name, loader_data,
911 protection_domain, THREAD);
912 }
913 }
914
915
916 // Look for a loaded instance or array klass by name. Do not do any loading.
917 // return NULL in case of error.
918 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
919 Handle class_loader,
920 Handle protection_domain,
921 TRAPS) {
922 Klass* k = NULL;
923 assert(class_name != NULL, "class name must be non NULL");
924
925 if (FieldType::is_array(class_name)) {
926 // The name refers to an array. Parse the name.
927 // dimension and object_key in FieldArrayInfo are assigned as a
928 // side-effect of this call
929 FieldArrayInfo fd;
930 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
931 if (t != T_OBJECT) {
932 k = Universe::typeArrayKlassObj(t);
933 } else {
934 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
935 }
936 if (k != NULL) {
937 k = k->array_klass_or_null(fd.dimension());
938 }
939 } else {
940 k = find(class_name, class_loader, protection_domain, THREAD);
941 }
942 return k;
943 }
944
945 // Note: this method is much like resolve_from_stream, but
946 // updates no supplemental data structures.
947 // TODO consolidate the two methods with a helper routine?
948 Klass* SystemDictionary::parse_stream(Symbol* class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 ClassFileStream* st,
952 KlassHandle host_klass,
953 GrowableArray<Handle>* cp_patches,
954 TRAPS) {
955 TempNewSymbol parsed_name = NULL;
956
957 ClassLoaderData* loader_data;
958 if (host_klass.not_null()) {
959 // Create a new CLD for anonymous class, that uses the same class loader
960 // as the host_klass
961 assert(EnableInvokeDynamic, "");
962 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
963 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
964 loader_data->record_dependency(host_klass(), CHECK_NULL);
965 } else {
966 loader_data = ClassLoaderData::class_loader_data(class_loader());
967 }
968
969 // Parse the stream. Note that we do this even though this klass might
970 // already be present in the SystemDictionary, otherwise we would not
971 // throw potential ClassFormatErrors.
972 //
973 // Note: "name" is updated.
974 // Further note: a placeholder will be added for this class when
975 // super classes are loaded (resolve_super_or_fail). We expect this
976 // to be called for all classes but java.lang.Object; and we preload
977 // java.lang.Object through resolve_or_fail, not this path.
978
979 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
980 loader_data,
981 protection_domain,
982 host_klass,
983 cp_patches,
984 parsed_name,
985 true,
986 THREAD);
987
988 // We don't redefine the class, so we just need to clean up whether there
989 // was an error or not (don't want to modify any system dictionary
990 // data structures).
991 // Parsed name could be null if we threw an error before we got far
992 // enough along to parse it -- in that case, there is nothing to clean up.
993 if (parsed_name != NULL) {
994 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
995 loader_data);
996 int p_index = placeholders()->hash_to_index(p_hash);
997 {
998 MutexLocker mu(SystemDictionary_lock, THREAD);
999 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
1000 SystemDictionary_lock->notify_all();
1001 }
1002 }
1003
1004 if (host_klass.not_null() && k.not_null()) {
1005 assert(EnableInvokeDynamic, "");
1006 k->set_host_klass(host_klass());
1007 // If it's anonymous, initialize it now, since nobody else will.
1008
1009 {
1010 MutexLocker mu_r(Compile_lock, THREAD);
1011
1012 // Add to class hierarchy, initialize vtables, and do possible
1013 // deoptimizations.
1014 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1015
1016 // But, do not add to system dictionary.
1017 }
1018
1019 // Rewrite and patch constant pool here.
1020 k->link_class(CHECK_NULL);
1021 if (cp_patches != NULL) {
1022 k->constants()->patch_resolved_references(cp_patches);
1023 }
1024 k->eager_initialize(CHECK_NULL);
1025
1026 // notify jvmti
1027 if (JvmtiExport::should_post_class_load()) {
1028 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1029 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1030 }
1031 }
1032 assert(host_klass.not_null() || cp_patches == NULL,
1033 "cp_patches only found with host_klass");
1034
1035 return k();
1036 }
1037
1038 // Add a klass to the system from a stream (called by jni_DefineClass and
1039 // JVM_DefineClass).
1040 // Note: class_name can be NULL. In that case we do not know the name of
1041 // the class until we have parsed the stream.
1042
1043 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1044 Handle class_loader,
1045 Handle protection_domain,
1046 ClassFileStream* st,
1047 bool verify,
1048 TRAPS) {
1049
1050 // Classloaders that support parallelism, e.g. bootstrap classloader,
1051 // or all classloaders with UnsyncloadClass do not acquire lock here
1052 bool DoObjectLock = true;
1053 if (is_parallelCapable(class_loader)) {
1054 DoObjectLock = false;
1055 }
1056
1057 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1058
1059 // Make sure we are synchronized on the class loader before we proceed
1060 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1061 check_loader_lock_contention(lockObject, THREAD);
1062 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1063
1064 TempNewSymbol parsed_name = NULL;
1065
1066 // Parse the stream. Note that we do this even though this klass might
1067 // already be present in the SystemDictionary, otherwise we would not
1068 // throw potential ClassFormatErrors.
1069 //
1070 // Note: "name" is updated.
1071 // Further note: a placeholder will be added for this class when
1072 // super classes are loaded (resolve_super_or_fail). We expect this
1073 // to be called for all classes but java.lang.Object; and we preload
1074 // java.lang.Object through resolve_or_fail, not this path.
1075
1076 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1077 loader_data,
1078 protection_domain,
1079 parsed_name,
1080 verify,
1081 THREAD);
1082
1083 const char* pkg = "java/";
1084 if (!HAS_PENDING_EXCEPTION &&
1085 !class_loader.is_null() &&
1086 parsed_name != NULL &&
1087 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1088 // It is illegal to define classes in the "java." package from
1089 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1090 ResourceMark rm(THREAD);
1091 char* name = parsed_name->as_C_string();
1092 char* index = strrchr(name, '/');
1093 *index = '\0'; // chop to just the package name
1094 while ((index = strchr(name, '/')) != NULL) {
1095 *index = '.'; // replace '/' with '.' in package name
1096 }
1097 const char* fmt = "Prohibited package name: %s";
1098 size_t len = strlen(fmt) + strlen(name);
1099 char* message = NEW_RESOURCE_ARRAY(char, len);
1100 jio_snprintf(message, len, fmt, name);
1101 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1102 vmSymbols::java_lang_SecurityException(), message);
1103 }
1104
1105 if (!HAS_PENDING_EXCEPTION) {
1106 assert(parsed_name != NULL, "Sanity");
1107 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1108 // Verification prevents us from creating names with dots in them, this
1109 // asserts that that's the case.
1110 assert(is_internal_format(parsed_name),
1111 "external class name format used internally");
1112
1113 // Add class just loaded
1114 // If a class loader supports parallel classloading handle parallel define requests
1115 // find_or_define_instance_class may return a different InstanceKlass
1116 if (is_parallelCapable(class_loader)) {
1117 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1118 } else {
1119 define_instance_class(k, THREAD);
1120 }
1121 }
1122
1123 // If parsing the class file or define_instance_class failed, we
1124 // need to remove the placeholder added on our behalf. But we
1125 // must make sure parsed_name is valid first (it won't be if we had
1126 // a format error before the class was parsed far enough to
1127 // find the name).
1128 if (HAS_PENDING_EXCEPTION && parsed_name != NULL) {
1129 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1130 loader_data);
1131 int p_index = placeholders()->hash_to_index(p_hash);
1132 {
1133 MutexLocker mu(SystemDictionary_lock, THREAD);
1134 placeholders()->find_and_remove(p_index, p_hash, parsed_name, loader_data, THREAD);
1135 SystemDictionary_lock->notify_all();
1136 }
1137 return NULL;
1138 }
1139
1140 // Make sure that we didn't leave a place holder in the
1141 // SystemDictionary; this is only done on success
1142 debug_only( {
1143 if (!HAS_PENDING_EXCEPTION) {
1144 assert(parsed_name != NULL, "parsed_name is still null?");
1145 Symbol* h_name = k->name();
1146 ClassLoaderData *defining_loader_data = k->class_loader_data();
1147
1148 MutexLocker mu(SystemDictionary_lock, THREAD);
1149
1150 Klass* check = find_class(parsed_name, loader_data);
1151 assert(check == k(), "should be present in the dictionary");
1152
1153 Klass* check2 = find_class(h_name, defining_loader_data);
1154 assert(check == check2, "name inconsistancy in SystemDictionary");
1155 }
1156 } );
1157
1158 return k();
1159 }
1160
1161
1162 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1163 int number_of_entries) {
1164 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1165 "bad shared dictionary size.");
1166 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1167 }
1168
1169
1170 // If there is a shared dictionary, then find the entry for the
1171 // given shared system class, if any.
1172
1173 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1174 if (shared_dictionary() != NULL) {
1175 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1176 int d_index = shared_dictionary()->hash_to_index(d_hash);
1177
1178 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1179 } else {
1180 return NULL;
1181 }
1182 }
1183
1184
1185 // Load a class from the shared spaces (found through the shared system
1186 // dictionary). Force the superclass and all interfaces to be loaded.
1187 // Update the class definition to include sibling classes and no
1188 // subclasses (yet). [Classes in the shared space are not part of the
1189 // object hierarchy until loaded.]
1190
1191 instanceKlassHandle SystemDictionary::load_shared_class(
1192 Symbol* class_name, Handle class_loader, TRAPS) {
1193 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1194 return load_shared_class(ik, class_loader, THREAD);
1195 }
1196
1197 // Note well! Changes to this method may affect oop access order
1198 // in the shared archive. Please take care to not make changes that
1199 // adversely affect cold start time by changing the oop access order
1200 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1201 // MarkAndMoveOrderedReadWrite closures.
1202 instanceKlassHandle SystemDictionary::load_shared_class(
1203 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1204 assert(class_loader.is_null(), "non-null classloader for shared class?");
1205 if (ik.not_null()) {
1206 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1207 Symbol* class_name = ik->name();
1208
1209 // Found the class, now load the superclass and interfaces. If they
1210 // are shared, add them to the main system dictionary and reset
1211 // their hierarchy references (supers, subs, and interfaces).
1212
1213 if (ik->super() != NULL) {
1214 Symbol* cn = ik->super()->name();
1215 resolve_super_or_fail(class_name, cn,
1216 class_loader, Handle(), true, CHECK_(nh));
1217 }
1218
1219 Array<Klass*>* interfaces = ik->local_interfaces();
1220 int num_interfaces = interfaces->length();
1221 for (int index = 0; index < num_interfaces; index++) {
1222 Klass* k = interfaces->at(index);
1223
1224 // Note: can not use InstanceKlass::cast here because
1225 // interfaces' InstanceKlass's C++ vtbls haven't been
1226 // reinitialized yet (they will be once the interface classes
1227 // are loaded)
1228 Symbol* name = k->name();
1229 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1230 }
1231
1232 // Adjust methods to recover missing data. They need addresses for
1233 // interpreter entry points and their default native method address
1234 // must be reset.
1235
1236 // Updating methods must be done under a lock so multiple
1237 // threads don't update these in parallel
1238 // Shared classes are all currently loaded by the bootstrap
1239 // classloader, so this will never cause a deadlock on
1240 // a custom class loader lock.
1241
1242 {
1243 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1244 check_loader_lock_contention(lockObject, THREAD);
1245 ObjectLocker ol(lockObject, THREAD, true);
1246 ik->restore_unshareable_info(CHECK_(nh));
1247 }
1248
1249 if (TraceClassLoading) {
1250 ResourceMark rm;
1251 tty->print("[Loaded %s", ik->external_name());
1252 tty->print(" from shared objects file");
1253 tty->print_cr("]");
1254 }
1255 // notify a class loaded from shared object
1256 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1257 true /* shared class */);
1258 }
1259 return ik;
1260 }
1261
1262 #ifdef KERNEL
1263 // Some classes on the bootstrap class path haven't been installed on the
1264 // system yet. Call the DownloadManager method to make them appear in the
1265 // bootstrap class path and try again to load the named class.
1266 // Note that with delegation class loaders all classes in another loader will
1267 // first try to call this so it'd better be fast!!
1268 static instanceKlassHandle download_and_retry_class_load(
1269 Symbol* class_name,
1270 TRAPS) {
1271
1272 Klass* dlm = SystemDictionary::DownloadManager_klass();
1273 instanceKlassHandle nk;
1274
1275 // If download manager class isn't loaded just return.
1276 if (dlm == NULL) return nk;
1277
1278 { HandleMark hm(THREAD);
1279 ResourceMark rm(THREAD);
1280 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1281 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1282
1283 // return value
1284 JavaValue result(T_OBJECT);
1285
1286 // Call the DownloadManager. We assume that it has a lock because
1287 // multiple classes could be not found and downloaded at the same time.
1288 // class sun.misc.DownloadManager;
1289 // public static String getBootClassPathEntryForClass(String className);
1290 JavaCalls::call_static(&result,
1291 KlassHandle(THREAD, dlm),
1292 vmSymbols::getBootClassPathEntryForClass_name(),
1293 vmSymbols::string_string_signature(),
1294 class_string,
1295 CHECK_(nk));
1296
1297 // Get result.string and add to bootclasspath
1298 assert(result.get_type() == T_OBJECT, "just checking");
1299 oop obj = (oop) result.get_jobject();
1300 if (obj == NULL) { return nk; }
1301
1302 Handle h_obj(THREAD, obj);
1303 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1304 CHECK_(nk));
1305
1306 // lock the loader
1307 // we use this lock because JVMTI does.
1308 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1309
1310 ObjectLocker ol(loader_lock, THREAD);
1311 // add the file to the bootclasspath
1312 ClassLoader::update_class_path_entry_list(new_class_name, true);
1313 } // end HandleMark
1314
1315 if (TraceClassLoading) {
1316 ClassLoader::print_bootclasspath();
1317 }
1318 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1319 }
1320 #endif // KERNEL
1321
1322
1323 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1324 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1325 if (class_loader.is_null()) {
1326
1327 // Search the shared system dictionary for classes preloaded into the
1328 // shared spaces.
1329 instanceKlassHandle k;
1330 {
1331 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1332 k = load_shared_class(class_name, class_loader, THREAD);
1333 }
1334
1335 if (k.is_null()) {
1336 // Use VM class loader
1337 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1338 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1339 }
1340
1341 #ifdef KERNEL
1342 // If the VM class loader has failed to load the class, call the
1343 // DownloadManager class to make it magically appear on the classpath
1344 // and try again. This is only configured with the Kernel VM.
1345 if (k.is_null()) {
1346 k = download_and_retry_class_load(class_name, CHECK_(nh));
1347 }
1348 #endif // KERNEL
1349
1350 // find_or_define_instance_class may return a different InstanceKlass
1351 if (!k.is_null()) {
1352 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1353 }
1354 return k;
1355 } else {
1356 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1357 ResourceMark rm(THREAD);
1358
1359 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1360 JavaThread* jt = (JavaThread*) THREAD;
1361
1362 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1363 ClassLoader::perf_app_classload_selftime(),
1364 ClassLoader::perf_app_classload_count(),
1365 jt->get_thread_stat()->perf_recursion_counts_addr(),
1366 jt->get_thread_stat()->perf_timers_addr(),
1367 PerfClassTraceTime::CLASS_LOAD);
1368
1369 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1370 // Translate to external class name format, i.e., convert '/' chars to '.'
1371 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1372
1373 JavaValue result(T_OBJECT);
1374
1375 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1376
1377 // Call public unsynchronized loadClass(String) directly for all class loaders
1378 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1379 // acquire a class-name based lock rather than the class loader object lock.
1380 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1381 // so the call to loadClassInternal() was not required.
1382 //
1383 // UnsyncloadClass flag means both call loadClass(String) and do
1384 // not acquire the class loader lock even for class loaders that are
1385 // not parallelCapable. This was a risky transitional
1386 // flag for diagnostic purposes only. It is risky to call
1387 // custom class loaders without synchronization.
1388 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1389 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1390 // Do NOT assume this will be supported in future releases.
1391 //
1392 // Added MustCallLoadClassInternal in case we discover in the field
1393 // a customer that counts on this call
1394 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1395 JavaCalls::call_special(&result,
1396 class_loader,
1397 spec_klass,
1398 vmSymbols::loadClassInternal_name(),
1399 vmSymbols::string_class_signature(),
1400 string,
1401 CHECK_(nh));
1402 } else {
1403 JavaCalls::call_virtual(&result,
1404 class_loader,
1405 spec_klass,
1406 vmSymbols::loadClass_name(),
1407 vmSymbols::string_class_signature(),
1408 string,
1409 CHECK_(nh));
1410 }
1411
1412 assert(result.get_type() == T_OBJECT, "just checking");
1413 oop obj = (oop) result.get_jobject();
1414
1415 // Primitive classes return null since forName() can not be
1416 // used to obtain any of the Class objects representing primitives or void
1417 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1418 instanceKlassHandle k =
1419 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1420 // For user defined Java class loaders, check that the name returned is
1421 // the same as that requested. This check is done for the bootstrap
1422 // loader when parsing the class file.
1423 if (class_name == k->name()) {
1424 return k;
1425 }
1426 }
1427 // Class is not found or has the wrong name, return NULL
1428 return nh;
1429 }
1430 }
1431
1432 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1433
1434 ClassLoaderData* loader_data = k->class_loader_data();
1435 Handle class_loader_h(THREAD, loader_data->class_loader());
1436
1437 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1438
1439 // for bootstrap and other parallel classloaders don't acquire lock,
1440 // use placeholder token
1441 // If a parallelCapable class loader calls define_instance_class instead of
1442 // find_or_define_instance_class to get here, we have a timing
1443 // hole with systemDictionary updates and check_constraints
1444 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1445 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1446 compute_loader_lock_object(class_loader_h, THREAD)),
1447 "define called without lock");
1448 }
1449
1450 // Check class-loading constraints. Throw exception if violation is detected.
1451 // Grabs and releases SystemDictionary_lock
1452 // The check_constraints/find_class call and update_dictionary sequence
1453 // must be "atomic" for a specific class/classloader pair so we never
1454 // define two different instanceKlasses for that class/classloader pair.
1455 // Existing classloaders will call define_instance_class with the
1456 // classloader lock held
1457 // Parallel classloaders will call find_or_define_instance_class
1458 // which will require a token to perform the define class
1459 Symbol* name_h = k->name();
1460 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1461 int d_index = dictionary()->hash_to_index(d_hash);
1462 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1463
1464 // Register class just loaded with class loader (placed in Vector)
1465 // Note we do this before updating the dictionary, as this can
1466 // fail with an OutOfMemoryError (if it does, we will *not* put this
1467 // class in the dictionary and will not update the class hierarchy).
1468 // JVMTI FollowReferences needs to find the classes this way.
1469 if (k->class_loader() != NULL) {
1470 methodHandle m(THREAD, Universe::loader_addClass_method());
1471 JavaValue result(T_VOID);
1472 JavaCallArguments args(class_loader_h);
1473 args.push_oop(Handle(THREAD, k->java_mirror()));
1474 JavaCalls::call(&result, m, &args, CHECK);
1475 }
1476
1477 // Add the new class. We need recompile lock during update of CHA.
1478 {
1479 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1480 int p_index = placeholders()->hash_to_index(p_hash);
1481
1482 MutexLocker mu_r(Compile_lock, THREAD);
1483
1484 // Add to class hierarchy, initialize vtables, and do possible
1485 // deoptimizations.
1486 add_to_hierarchy(k, CHECK); // No exception, but can block
1487
1488 // Add to systemDictionary - so other classes can see it.
1489 // Grabs and releases SystemDictionary_lock
1490 update_dictionary(d_index, d_hash, p_index, p_hash,
1491 k, class_loader_h, THREAD);
1492 }
1493 k->eager_initialize(THREAD);
1494
1495 // notify jvmti
1496 if (JvmtiExport::should_post_class_load()) {
1497 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1498 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1499
1500 }
1501 }
1502
1503 // Support parallel classloading
1504 // All parallel class loaders, including bootstrap classloader
1505 // lock a placeholder entry for this class/class_loader pair
1506 // to allow parallel defines of different classes for this class loader
1507 // With AllowParallelDefine flag==true, in case they do not synchronize around
1508 // FindLoadedClass/DefineClass, calls, we check for parallel
1509 // loading for them, wait if a defineClass is in progress
1510 // and return the initial requestor's results
1511 // This flag does not apply to the bootstrap classloader.
1512 // With AllowParallelDefine flag==false, call through to define_instance_class
1513 // which will throw LinkageError: duplicate class definition.
1514 // False is the requested default.
1515 // For better performance, the class loaders should synchronize
1516 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1517 // potentially waste time reading and parsing the bytestream.
1518 // Note: VM callers should ensure consistency of k/class_name,class_loader
1519 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1520
1521 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1522 Symbol* name_h = k->name(); // passed in class_name may be null
1523 ClassLoaderData* loader_data = class_loader_data(class_loader);
1524
1525 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1526 int d_index = dictionary()->hash_to_index(d_hash);
1527
1528 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1529 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1530 int p_index = placeholders()->hash_to_index(p_hash);
1531 PlaceholderEntry* probe;
1532
1533 {
1534 MutexLocker mu(SystemDictionary_lock, THREAD);
1535 // First check if class already defined
1536 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1537 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1538 if (check != NULL) {
1539 return(instanceKlassHandle(THREAD, check));
1540 }
1541 }
1542
1543 // Acquire define token for this class/classloader
1544 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1545 // Wait if another thread defining in parallel
1546 // All threads wait - even those that will throw duplicate class: otherwise
1547 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1548 // if other thread has not finished updating dictionary
1549 while (probe->definer() != NULL) {
1550 SystemDictionary_lock->wait();
1551 }
1552 // Only special cases allow parallel defines and can use other thread's results
1553 // Other cases fall through, and may run into duplicate defines
1554 // caught by finding an entry in the SystemDictionary
1555 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1556 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1557 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1558 SystemDictionary_lock->notify_all();
1559 #ifdef ASSERT
1560 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1561 assert(check != NULL, "definer missed recording success");
1562 #endif
1563 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1564 } else {
1565 // This thread will define the class (even if earlier thread tried and had an error)
1566 probe->set_definer(THREAD);
1567 }
1568 }
1569
1570 define_instance_class(k, THREAD);
1571
1572 Handle linkage_exception = Handle(); // null handle
1573
1574 // definer must notify any waiting threads
1575 {
1576 MutexLocker mu(SystemDictionary_lock, THREAD);
1577 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1578 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1579 if (probe != NULL) {
1580 if (HAS_PENDING_EXCEPTION) {
1581 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1582 CLEAR_PENDING_EXCEPTION;
1583 } else {
1584 probe->set_instance_klass(k());
1585 }
1586 probe->set_definer(NULL);
1587 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1588 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, THREAD);
1589 SystemDictionary_lock->notify_all();
1590 }
1591 }
1592
1593 // Can't throw exception while holding lock due to rank ordering
1594 if (linkage_exception() != NULL) {
1595 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1596 }
1597
1598 return k;
1599 }
1600 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1601 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1602 if (class_loader.is_null()) {
1603 return Handle(THREAD, _system_loader_lock_obj);
1604 } else {
1605 return class_loader;
1606 }
1607 }
1608
1609 // This method is added to check how often we have to wait to grab loader
1610 // lock. The results are being recorded in the performance counters defined in
1611 // ClassLoader::_sync_systemLoaderLockContentionRate and
1612 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1613 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1614 if (!UsePerfData) {
1615 return;
1616 }
1617
1618 assert(!loader_lock.is_null(), "NULL lock object");
1619
1620 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1621 == ObjectSynchronizer::owner_other) {
1622 // contention will likely happen, so increment the corresponding
1623 // contention counter.
1624 if (loader_lock() == _system_loader_lock_obj) {
1625 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1626 } else {
1627 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1628 }
1629 }
1630 }
1631
1632 // ----------------------------------------------------------------------------
1633 // Lookup
1634
1635 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1636 Symbol* class_name,
1637 ClassLoaderData* loader_data) {
1638 assert_locked_or_safepoint(SystemDictionary_lock);
1639 assert (index == dictionary()->index_for(class_name, loader_data),
1640 "incorrect index?");
1641
1642 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1643 return k;
1644 }
1645
1646
1647 // Basic find on classes in the midst of being loaded
1648 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1649 ClassLoaderData* loader_data) {
1650 assert_locked_or_safepoint(SystemDictionary_lock);
1651 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1652 int p_index = placeholders()->hash_to_index(p_hash);
1653 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1654 }
1655
1656
1657 // Used for assertions and verification only
1658 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1659 #ifndef ASSERT
1660 guarantee(VerifyBeforeGC ||
1661 VerifyDuringGC ||
1662 VerifyBeforeExit ||
1663 VerifyAfterGC, "too expensive");
1664 #endif
1665 assert_locked_or_safepoint(SystemDictionary_lock);
1666
1667 // First look in the loaded class array
1668 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1669 int d_index = dictionary()->hash_to_index(d_hash);
1670 return find_class(d_index, d_hash, class_name, loader_data);
1671 }
1672
1673
1674 // Get the next class in the diictionary.
1675 Klass* SystemDictionary::try_get_next_class() {
1676 return dictionary()->try_get_next_class();
1677 }
1678
1679
1680 // ----------------------------------------------------------------------------
1681 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1682 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1683 // before a new class is used.
1684
1685 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1686 assert(k.not_null(), "just checking");
1687 assert_locked_or_safepoint(Compile_lock);
1688
1689 // Link into hierachy. Make sure the vtables are initialized before linking into
1690 k->append_to_sibling_list(); // add to superklass/sibling list
1691 k->process_interfaces(THREAD); // handle all "implements" declarations
1692 k->set_init_state(InstanceKlass::loaded);
1693 // Now flush all code that depended on old class hierarchy.
1694 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1695 // Also, first reinitialize vtable because it may have gotten out of synch
1696 // while the new class wasn't connected to the class hierarchy.
1697 Universe::flush_dependents_on(k);
1698 }
1699
1700
1701 // ----------------------------------------------------------------------------
1702 // GC support
1703
1704 // Following roots during mark-sweep is separated in two phases.
1705 //
1706 // The first phase follows preloaded classes and all other system
1707 // classes, since these will never get unloaded anyway.
1708 //
1709 // The second phase removes (unloads) unreachable classes from the
1710 // system dictionary and follows the remaining classes' contents.
1711
1712 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1713 blk->do_oop(&_java_system_loader);
1714 blk->do_oop(&_system_loader_lock_obj);
1715
1716 dictionary()->always_strong_oops_do(blk);
1717
1718 // Visit extra methods
1719 invoke_method_table()->oops_do(blk);
1720 }
1721
1722 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1723 // Follow all system classes and temporary placeholders in dictionary
1724 dictionary()->always_strong_classes_do(closure);
1725
1726 // Placeholders. These represent classes we're actively loading.
1727 placeholders()->classes_do(closure);
1728 }
1729
1730 // Calculate a "good" systemdictionary size based
1731 // on predicted or current loaded classes count
1732 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1733 int newsize = _old_default_sdsize;
1734 if ((classcount > 0) && !DumpSharedSpaces) {
1735 int desiredsize = classcount/_average_depth_goal;
1736 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1737 newsize = _primelist[++_sdgeneration]) {
1738 if (desiredsize <= newsize) {
1739 break;
1740 }
1741 }
1742 }
1743 return newsize;
1744 }
1745 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1746 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1747 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1748 bool unloading_occurred = false;
1749 if (has_dead_loaders) {
1750 unloading_occurred = dictionary()->do_unloading();
1751 constraints()->purge_loader_constraints();
1752 resolution_errors()->purge_resolution_errors();
1753 }
1754 return unloading_occurred;
1755 }
1756
1757 void SystemDictionary::oops_do(OopClosure* f) {
1758 f->do_oop(&_java_system_loader);
1759 f->do_oop(&_system_loader_lock_obj);
1760
1761 // Adjust dictionary
1762 dictionary()->oops_do(f);
1763
1764 // Visit extra methods
1765 invoke_method_table()->oops_do(f);
1766 }
1767
1768 // Extended Class redefinition support.
1769 // If one of these classes is replaced, we need to replace it in these places.
1770 // KlassClosure::do_klass should take the address of a class but we can
1771 // change that later.
1772 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1773 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1774 f->do_klass(_well_known_klasses[k]);
1775 }
1776
1777 {
1778 for (int i = 0; i < T_VOID+1; i++) {
1779 if (_box_klasses[i] != NULL) {
1780 assert(i >= T_BOOLEAN, "checking");
1781 f->do_klass(_box_klasses[i]);
1782 }
1783 }
1784 }
1785
1786 FilteredFieldsMap::classes_do(f);
1787 }
1788
1789 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1790 f->do_klass(_abstract_ownable_synchronizer_klass);
1791 }
1792
1793 // Just the classes from defining class loaders
1794 // Don't iterate over placeholders
1795 void SystemDictionary::classes_do(void f(Klass*)) {
1796 dictionary()->classes_do(f);
1797 }
1798
1799 // Added for initialize_itable_for_klass
1800 // Just the classes from defining class loaders
1801 // Don't iterate over placeholders
1802 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1803 dictionary()->classes_do(f, CHECK);
1804 }
1805
1806 // All classes, and their class loaders
1807 // Don't iterate over placeholders
1808 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1809 dictionary()->classes_do(f);
1810 }
1811
1812 // All classes, and their class loaders
1813 // (added for helpers that use HandleMarks and ResourceMarks)
1814 // Don't iterate over placeholders
1815 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
1816 dictionary()->classes_do(f, CHECK);
1817 }
1818
1819 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1820 placeholders()->entries_do(f);
1821 }
1822
1823 void SystemDictionary::methods_do(void f(Method*)) {
1824 dictionary()->methods_do(f);
1825 invoke_method_table()->methods_do(f);
1826 }
1827
1828 // ----------------------------------------------------------------------------
1829 // Lazily load klasses
1830
1831 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1832 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1833
1834 // if multiple threads calling this function, only one thread will load
1835 // the class. The other threads will find the loaded version once the
1836 // class is loaded.
1837 Klass* aos = _abstract_ownable_synchronizer_klass;
1838 if (aos == NULL) {
1839 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1840 // Force a fence to prevent any read before the write completes
1841 OrderAccess::fence();
1842 _abstract_ownable_synchronizer_klass = k;
1843 }
1844 }
1845
1846 // ----------------------------------------------------------------------------
1847 // Initialization
1848
1849 void SystemDictionary::initialize(TRAPS) {
1850 // Allocate arrays
1851 assert(dictionary() == NULL,
1852 "SystemDictionary should only be initialized once");
1853 _sdgeneration = 0;
1854 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1855 _placeholders = new PlaceholderTable(_nof_buckets);
1856 _number_of_modifications = 0;
1857 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1858 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1859 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1860
1861 // Allocate private object used as system class loader lock
1862 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1863 // Initialize basic classes
1864 initialize_preloaded_classes(CHECK);
1865 }
1866
1867 // Compact table of directions on the initialization of klasses:
1868 static const short wk_init_info[] = {
1869 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1870 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1871 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1872 | (int)SystemDictionary::option ),
1873 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1874 #undef WK_KLASS_INIT_INFO
1875 0
1876 };
1877
1878 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1879 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1880 int info = wk_init_info[id - FIRST_WKID];
1881 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1882 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1883 Klass** klassp = &_well_known_klasses[id];
1884 bool must_load = (init_opt < SystemDictionary::Opt);
1885 bool try_load = true;
1886 if (init_opt == SystemDictionary::Opt_Kernel) {
1887 #ifndef KERNEL
1888 try_load = false;
1889 #endif //KERNEL
1890 }
1891 if ((*klassp) == NULL && try_load) {
1892 if (must_load) {
1893 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1894 } else {
1895 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1896 }
1897 }
1898 return ((*klassp) != NULL);
1899 }
1900
1901 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1902 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1903 for (int id = (int)start_id; id < (int)limit_id; id++) {
1904 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1905 int info = wk_init_info[id - FIRST_WKID];
1906 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1907 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1908
1909 initialize_wk_klass((WKID)id, opt, CHECK);
1910 }
1911
1912 // move the starting value forward to the limit:
1913 start_id = limit_id;
1914 }
1915
1916 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1917 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1918 // Preload commonly used klasses
1919 WKID scan = FIRST_WKID;
1920 // first do Object, then String, Class
1921 if (UseSharedSpaces) {
1922 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1923 // Initialize the constant pool for the Object_class
1924 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1925 ik->constants()->restore_unshareable_info(CHECK);
1926 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1927 } else {
1928 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1929 }
1930
1931 // Calculate offsets for String and Class classes since they are loaded and
1932 // can be used after this point.
1933 java_lang_String::compute_offsets();
1934 java_lang_Class::compute_offsets();
1935
1936 // Fixup mirrors for classes loaded before java.lang.Class.
1937 // These calls iterate over the objects currently in the perm gen
1938 // so calling them at this point is matters (not before when there
1939 // are fewer objects and not later after there are more objects
1940 // in the perm gen.
1941 Universe::initialize_basic_type_mirrors(CHECK);
1942 Universe::fixup_mirrors(CHECK);
1943
1944 // do a bunch more:
1945 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1946
1947 // Preload ref klasses and set reference types
1948 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1949 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1950
1951 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1952 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1953 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1954 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1955 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1956
1957 // JSR 292 classes
1958 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1959 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1960 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1961 if (EnableInvokeDynamic) {
1962 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1963 } else {
1964 // Skip the JSR 292 classes, if not enabled.
1965 scan = WKID(jsr292_group_end + 1);
1966 }
1967
1968 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1969
1970 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1971 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1972 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1973 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1974 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1975 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1976 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1977 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1978 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1979 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1980
1981 #ifdef KERNEL
1982 if (DownloadManager_klass() == NULL) {
1983 warning("Cannot find sun/jkernel/DownloadManager");
1984 }
1985 #endif // KERNEL
1986
1987 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1988 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1989 _has_loadClassInternal = (method != NULL);
1990 }
1991 { // Compute whether we should use checkPackageAccess or NOT
1992 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1993 _has_checkPackageAccess = (method != NULL);
1994 }
1995 }
1996
1997 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1998 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1999 BasicType SystemDictionary::box_klass_type(Klass* k) {
2000 assert(k != NULL, "");
2001 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2002 if (_box_klasses[i] == k)
2003 return (BasicType)i;
2004 }
2005 return T_OBJECT;
2006 }
2007
2008 // Constraints on class loaders. The details of the algorithm can be
2009 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2010 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2011 // that the system dictionary needs to maintain a set of contraints that
2012 // must be satisfied by all classes in the dictionary.
2013 // if defining is true, then LinkageError if already in systemDictionary
2014 // if initiating loader, then ok if InstanceKlass matches existing entry
2015
2016 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2017 instanceKlassHandle k,
2018 Handle class_loader, bool defining,
2019 TRAPS) {
2020 const char *linkage_error = NULL;
2021 {
2022 Symbol* name = k->name();
2023 ClassLoaderData *loader_data = class_loader_data(class_loader);
2024
2025 MutexLocker mu(SystemDictionary_lock, THREAD);
2026
2027 Klass* check = find_class(d_index, d_hash, name, loader_data);
2028 if (check != (Klass*)NULL) {
2029 // if different InstanceKlass - duplicate class definition,
2030 // else - ok, class loaded by a different thread in parallel,
2031 // we should only have found it if it was done loading and ok to use
2032 // system dictionary only holds instance classes, placeholders
2033 // also holds array classes
2034
2035 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2036 if ((defining == true) || (k() != check)) {
2037 linkage_error = "loader (instance of %s): attempted duplicate class "
2038 "definition for name: \"%s\"";
2039 } else {
2040 return;
2041 }
2042 }
2043
2044 #ifdef ASSERT
2045 Symbol* ph_check = find_placeholder(name, loader_data);
2046 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2047 #endif
2048
2049 if (linkage_error == NULL) {
2050 if (constraints()->check_or_update(k, class_loader, name) == false) {
2051 linkage_error = "loader constraint violation: loader (instance of %s)"
2052 " previously initiated loading for a different type with name \"%s\"";
2053 }
2054 }
2055 }
2056
2057 // Throw error now if needed (cannot throw while holding
2058 // SystemDictionary_lock because of rank ordering)
2059
2060 if (linkage_error) {
2061 ResourceMark rm(THREAD);
2062 const char* class_loader_name = loader_name(class_loader());
2063 char* type_name = k->name()->as_C_string();
2064 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2065 strlen(type_name);
2066 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2067 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2068 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2069 }
2070 }
2071
2072
2073 // Update system dictionary - done after check_constraint and add_to_hierachy
2074 // have been called.
2075 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2076 int p_index, unsigned int p_hash,
2077 instanceKlassHandle k,
2078 Handle class_loader,
2079 TRAPS) {
2080 // Compile_lock prevents systemDictionary updates during compilations
2081 assert_locked_or_safepoint(Compile_lock);
2082 Symbol* name = k->name();
2083 ClassLoaderData *loader_data = class_loader_data(class_loader);
2084
2085 {
2086 MutexLocker mu1(SystemDictionary_lock, THREAD);
2087
2088 // See whether biased locking is enabled and if so set it for this
2089 // klass.
2090 // Note that this must be done past the last potential blocking
2091 // point / safepoint. We enable biased locking lazily using a
2092 // VM_Operation to iterate the SystemDictionary and installing the
2093 // biasable mark word into each InstanceKlass's prototype header.
2094 // To avoid race conditions where we accidentally miss enabling the
2095 // optimization for one class in the process of being added to the
2096 // dictionary, we must not safepoint after the test of
2097 // BiasedLocking::enabled().
2098 if (UseBiasedLocking && BiasedLocking::enabled()) {
2099 // Set biased locking bit for all loaded classes; it will be
2100 // cleared if revocation occurs too often for this type
2101 // NOTE that we must only do this when the class is initally
2102 // defined, not each time it is referenced from a new class loader
2103 if (k->class_loader() == class_loader()) {
2104 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2105 }
2106 }
2107
2108 // Assign a classid if one has not already been assigned. The
2109 // counter does not need to be atomically incremented since this
2110 // is only done while holding the SystemDictionary_lock.
2111 // All loaded classes get a unique ID.
2112 TRACE_INIT_ID(k);
2113
2114 // Check for a placeholder. If there, remove it and make a
2115 // new system dictionary entry.
2116 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, THREAD);
2117 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2118 if (sd_check == NULL) {
2119 dictionary()->add_klass(name, loader_data, k);
2120 notice_modification();
2121 }
2122 #ifdef ASSERT
2123 sd_check = find_class(d_index, d_hash, name, loader_data);
2124 assert (sd_check != NULL, "should have entry in system dictionary");
2125 // Changed to allow PH to remain to complete class circularity checking
2126 // while only one thread can define a class at one time, multiple
2127 // classes can resolve the superclass for a class at one time,
2128 // and the placeholder is used to track that
2129 // Symbol* ph_check = find_placeholder(name, class_loader);
2130 // assert (ph_check == NULL, "should not have a placeholder entry");
2131 #endif
2132 SystemDictionary_lock->notify_all();
2133 }
2134 }
2135
2136
2137 // Try to find a class name using the loader constraints. The
2138 // loader constraints might know about a class that isn't fully loaded
2139 // yet and these will be ignored.
2140 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2141 Symbol* class_name, Handle class_loader, TRAPS) {
2142
2143 // First see if it has been loaded directly.
2144 // Force the protection domain to be null. (This removes protection checks.)
2145 Handle no_protection_domain;
2146 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2147 no_protection_domain, CHECK_NULL);
2148 if (klass != NULL)
2149 return klass;
2150
2151 // Now look to see if it has been loaded elsewhere, and is subject to
2152 // a loader constraint that would require this loader to return the
2153 // klass that is already loaded.
2154 if (FieldType::is_array(class_name)) {
2155 // For array classes, their Klass*s are not kept in the
2156 // constraint table. The element Klass*s are.
2157 FieldArrayInfo fd;
2158 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2159 if (t != T_OBJECT) {
2160 klass = Universe::typeArrayKlassObj(t);
2161 } else {
2162 MutexLocker mu(SystemDictionary_lock, THREAD);
2163 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2164 }
2165 // If element class already loaded, allocate array klass
2166 if (klass != NULL) {
2167 klass = klass->array_klass_or_null(fd.dimension());
2168 }
2169 } else {
2170 MutexLocker mu(SystemDictionary_lock, THREAD);
2171 // Non-array classes are easy: simply check the constraint table.
2172 klass = constraints()->find_constrained_klass(class_name, class_loader);
2173 }
2174
2175 return klass;
2176 }
2177
2178
2179 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2180 Handle class_loader1,
2181 Handle class_loader2,
2182 Thread* THREAD) {
2183 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2184 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2185
2186 Symbol* constraint_name = NULL;
2187 if (!FieldType::is_array(class_name)) {
2188 constraint_name = class_name;
2189 } else {
2190 // For array classes, their Klass*s are not kept in the
2191 // constraint table. The element classes are.
2192 FieldArrayInfo fd;
2193 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2194 // primitive types always pass
2195 if (t != T_OBJECT) {
2196 return true;
2197 } else {
2198 constraint_name = fd.object_key();
2199 }
2200 }
2201 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2202 int d_index1 = dictionary()->hash_to_index(d_hash1);
2203
2204 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2205 int d_index2 = dictionary()->hash_to_index(d_hash2);
2206 {
2207 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2208
2209 // Better never do a GC while we're holding these oops
2210 No_Safepoint_Verifier nosafepoint;
2211
2212 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2213 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2214 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2215 klass2, class_loader2);
2216 }
2217 }
2218
2219 // Add entry to resolution error table to record the error when the first
2220 // attempt to resolve a reference to a class has failed.
2221 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2222 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2223 int index = resolution_errors()->hash_to_index(hash);
2224 {
2225 MutexLocker ml(SystemDictionary_lock, Thread::current());
2226 resolution_errors()->add_entry(index, hash, pool, which, error);
2227 }
2228 }
2229
2230 // Delete a resolution error for RedefineClasses for a constant pool is going away
2231 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2232 resolution_errors()->delete_entry(pool);
2233 }
2234
2235 // Lookup resolution error table. Returns error if found, otherwise NULL.
2236 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2237 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2238 int index = resolution_errors()->hash_to_index(hash);
2239 {
2240 MutexLocker ml(SystemDictionary_lock, Thread::current());
2241 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2242 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2243 }
2244 }
2245
2246
2247 // Signature constraints ensure that callers and callees agree about
2248 // the meaning of type names in their signatures. This routine is the
2249 // intake for constraints. It collects them from several places:
2250 //
2251 // * LinkResolver::resolve_method (if check_access is true) requires
2252 // that the resolving class (the caller) and the defining class of
2253 // the resolved method (the callee) agree on each type in the
2254 // method's signature.
2255 //
2256 // * LinkResolver::resolve_interface_method performs exactly the same
2257 // checks.
2258 //
2259 // * LinkResolver::resolve_field requires that the constant pool
2260 // attempting to link to a field agree with the field's defining
2261 // class about the type of the field signature.
2262 //
2263 // * klassVtable::initialize_vtable requires that, when a class
2264 // overrides a vtable entry allocated by a superclass, that the
2265 // overriding method (i.e., the callee) agree with the superclass
2266 // on each type in the method's signature.
2267 //
2268 // * klassItable::initialize_itable requires that, when a class fills
2269 // in its itables, for each non-abstract method installed in an
2270 // itable, the method (i.e., the callee) agree with the interface
2271 // on each type in the method's signature.
2272 //
2273 // All those methods have a boolean (check_access, checkconstraints)
2274 // which turns off the checks. This is used from specialized contexts
2275 // such as bootstrapping, dumping, and debugging.
2276 //
2277 // No direct constraint is placed between the class and its
2278 // supertypes. Constraints are only placed along linked relations
2279 // between callers and callees. When a method overrides or implements
2280 // an abstract method in a supertype (superclass or interface), the
2281 // constraints are placed as if the supertype were the caller to the
2282 // overriding method. (This works well, since callers to the
2283 // supertype have already established agreement between themselves and
2284 // the supertype.) As a result of all this, a class can disagree with
2285 // its supertype about the meaning of a type name, as long as that
2286 // class neither calls a relevant method of the supertype, nor is
2287 // called (perhaps via an override) from the supertype.
2288 //
2289 //
2290 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2291 //
2292 // Make sure all class components (including arrays) in the given
2293 // signature will be resolved to the same class in both loaders.
2294 // Returns the name of the type that failed a loader constraint check, or
2295 // NULL if no constraint failed. The returned C string needs cleaning up
2296 // with a ResourceMark in the caller. No exception except OOME is thrown.
2297 // Arrays are not added to the loader constraint table, their elements are.
2298 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2299 Handle loader1, Handle loader2,
2300 bool is_method, TRAPS) {
2301 // Nothing to do if loaders are the same.
2302 if (loader1() == loader2()) {
2303 return NULL;
2304 }
2305
2306 ResourceMark rm(THREAD);
2307 SignatureStream sig_strm(signature, is_method);
2308 while (!sig_strm.is_done()) {
2309 if (sig_strm.is_object()) {
2310 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2311 Symbol* sig = s;
2312 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2313 return sig->as_C_string();
2314 }
2315 }
2316 sig_strm.next();
2317 }
2318 return NULL;
2319 }
2320
2321
2322 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2323 Symbol* signature,
2324 TRAPS) {
2325 methodHandle empty;
2326 assert(EnableInvokeDynamic, "");
2327 assert(MethodHandles::is_signature_polymorphic(iid) &&
2328 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2329 iid != vmIntrinsics::_invokeGeneric,
2330 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2331
2332 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2333 int index = invoke_method_table()->hash_to_index(hash);
2334 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2335 methodHandle m;
2336 if (spe == NULL || spe->method() == NULL) {
2337 spe = NULL;
2338 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2339 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2340 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2341 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2342
2343 // Now grab the lock. We might have to throw away the new method,
2344 // if a racing thread has managed to install one at the same time.
2345 {
2346 MutexLocker ml(SystemDictionary_lock, THREAD);
2347 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2348 if (spe == NULL)
2349 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2350 if (spe->method() == NULL)
2351 spe->set_method(m());
2352 }
2353 }
2354
2355 assert(spe != NULL && spe->method() != NULL, "");
2356 return spe->method();
2357 }
2358
2359 // Helper for unpacking the return value from linkMethod and linkCallSite.
2360 static methodHandle unpack_method_and_appendix(Handle mname,
2361 KlassHandle accessing_klass,
2362 objArrayHandle appendix_box,
2363 Handle* appendix_result,
2364 TRAPS) {
2365 methodHandle empty;
2366 if (mname.not_null()) {
2367 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2368 if (vmtarget != NULL && vmtarget->is_method()) {
2369 Method* m = (Method*)vmtarget;
2370 oop appendix = appendix_box->obj_at(0);
2371 if (TraceMethodHandles) {
2372 #ifndef PRODUCT
2373 tty->print("Linked method="INTPTR_FORMAT": ", m);
2374 m->print();
2375 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2376 tty->cr();
2377 #endif //PRODUCT
2378 }
2379 (*appendix_result) = Handle(THREAD, appendix);
2380 // the target is stored in the cpCache and if a reference to this
2381 // MethodName is dropped we need a way to make sure the
2382 // class_loader containing this method is kept alive.
2383 // FIXME: the appendix might also preserve this dependency.
2384 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2385 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2386 return methodHandle(THREAD, m);
2387 }
2388 }
2389 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2390 return empty;
2391 }
2392
2393 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2394 Symbol* signature,
2395 KlassHandle accessing_klass,
2396 Handle *appendix_result,
2397 Handle *method_type_result,
2398 TRAPS) {
2399 methodHandle empty;
2400 assert(EnableInvokeDynamic, "");
2401 assert(!THREAD->is_Compiler_thread(), "");
2402 Handle method_type =
2403 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2404 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2405 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2406 }
2407
2408 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2409 int ref_kind = JVM_REF_invokeVirtual;
2410 Handle name_str = StringTable::intern(name, CHECK_(empty));
2411 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2412 assert(appendix_box->obj_at(0) == NULL, "");
2413
2414 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2415 JavaCallArguments args;
2416 args.push_oop(accessing_klass()->java_mirror());
2417 args.push_int(ref_kind);
2418 args.push_oop(mh_klass()->java_mirror());
2419 args.push_oop(name_str());
2420 args.push_oop(method_type());
2421 args.push_oop(appendix_box());
2422 JavaValue result(T_OBJECT);
2423 JavaCalls::call_static(&result,
2424 SystemDictionary::MethodHandleNatives_klass(),
2425 vmSymbols::linkMethod_name(),
2426 vmSymbols::linkMethod_signature(),
2427 &args, CHECK_(empty));
2428 Handle mname(THREAD, (oop) result.get_jobject());
2429 (*method_type_result) = method_type;
2430 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2431 }
2432
2433
2434 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2435 // signature, as interpreted relative to the given class loader.
2436 // Because of class loader constraints, all method handle usage must be
2437 // consistent with this loader.
2438 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2439 KlassHandle accessing_klass,
2440 TRAPS) {
2441 Handle empty;
2442 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2443 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2444 int index = invoke_method_table()->hash_to_index(hash);
2445 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2446 if (spe != NULL && spe->method_type() != NULL) {
2447 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2448 return Handle(THREAD, spe->method_type());
2449 } else if (THREAD->is_Compiler_thread()) {
2450 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2451 return Handle(); // do not attempt from within compiler, unless it was cached
2452 }
2453
2454 Handle class_loader, protection_domain;
2455 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2456 int npts = ArgumentCount(signature).size();
2457 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2458 int arg = 0;
2459 Handle rt; // the return type from the signature
2460 ResourceMark rm(THREAD);
2461 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2462 oop mirror = NULL;
2463 if (is_on_bcp) {
2464 // Note: class_loader & protection_domain are both null at this point.
2465 mirror = ss.as_java_mirror(class_loader, protection_domain,
2466 SignatureStream::ReturnNull, CHECK_(empty));
2467 if (mirror == NULL) {
2468 // fall back from BCP to accessing_klass
2469 if (accessing_klass.not_null()) {
2470 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2471 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2472 }
2473 is_on_bcp = false;
2474 }
2475 }
2476 if (!is_on_bcp) {
2477 // Resolve, throwing a real error if it doesn't work.
2478 mirror = ss.as_java_mirror(class_loader, protection_domain,
2479 SignatureStream::NCDFError, CHECK_(empty));
2480 }
2481 if (ss.at_return_type())
2482 rt = Handle(THREAD, mirror);
2483 else
2484 pts->obj_at_put(arg++, mirror);
2485
2486 // Check accessibility.
2487 if (ss.is_object() && accessing_klass.not_null()) {
2488 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2489 mirror = NULL; // safety
2490 // Emulate ConstantPool::verify_constant_pool_resolve.
2491 if (sel_klass->oop_is_objArray())
2492 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2493 if (sel_klass->oop_is_instance()) {
2494 KlassHandle sel_kh(THREAD, sel_klass);
2495 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2496 }
2497 }
2498 }
2499 assert(arg == npts, "");
2500
2501 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2502 JavaCallArguments args(Handle(THREAD, rt()));
2503 args.push_oop(pts());
2504 JavaValue result(T_OBJECT);
2505 JavaCalls::call_static(&result,
2506 SystemDictionary::MethodHandleNatives_klass(),
2507 vmSymbols::findMethodHandleType_name(),
2508 vmSymbols::findMethodHandleType_signature(),
2509 &args, CHECK_(empty));
2510 Handle method_type(THREAD, (oop) result.get_jobject());
2511
2512 if (is_on_bcp) {
2513 // We can cache this MethodType inside the JVM.
2514 MutexLocker ml(SystemDictionary_lock, THREAD);
2515 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2516 if (spe == NULL)
2517 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2518 if (spe->method_type() == NULL) {
2519 spe->set_method_type(method_type());
2520 }
2521 }
2522
2523 // report back to the caller with the MethodType
2524 return method_type;
2525 }
2526
2527 // Ask Java code to find or construct a method handle constant.
2528 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2529 int ref_kind, //e.g., JVM_REF_invokeVirtual
2530 KlassHandle callee,
2531 Symbol* name_sym,
2532 Symbol* signature,
2533 TRAPS) {
2534 Handle empty;
2535 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2536 Handle type;
2537 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2538 type = find_method_handle_type(signature, caller, CHECK_(empty));
2539 } else {
2540 ResourceMark rm(THREAD);
2541 SignatureStream ss(signature, false);
2542 if (!ss.is_done()) {
2543 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2544 SignatureStream::NCDFError, CHECK_(empty));
2545 type = Handle(THREAD, mirror);
2546 ss.next();
2547 if (!ss.is_done()) type = Handle(); // error!
2548 }
2549 }
2550 if (type.is_null()) {
2551 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2552 }
2553
2554 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2555 JavaCallArguments args;
2556 args.push_oop(caller->java_mirror()); // the referring class
2557 args.push_int(ref_kind);
2558 args.push_oop(callee->java_mirror()); // the target class
2559 args.push_oop(name());
2560 args.push_oop(type());
2561 JavaValue result(T_OBJECT);
2562 JavaCalls::call_static(&result,
2563 SystemDictionary::MethodHandleNatives_klass(),
2564 vmSymbols::linkMethodHandleConstant_name(),
2565 vmSymbols::linkMethodHandleConstant_signature(),
2566 &args, CHECK_(empty));
2567 return Handle(THREAD, (oop) result.get_jobject());
2568 }
2569
2570 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2571 // name and signature, as interpreted relative to the given class loader.
2572 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2573 Handle bootstrap_specifier,
2574 Symbol* name,
2575 Symbol* type,
2576 Handle *appendix_result,
2577 Handle *method_type_result,
2578 TRAPS) {
2579 methodHandle empty;
2580 Handle bsm, info;
2581 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2582 bsm = bootstrap_specifier;
2583 } else {
2584 assert(bootstrap_specifier->is_objArray(), "");
2585 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2586 int len = args->length();
2587 assert(len >= 1, "");
2588 bsm = Handle(THREAD, args->obj_at(0));
2589 if (len > 1) {
2590 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2591 for (int i = 1; i < len; i++)
2592 args1->obj_at_put(i-1, args->obj_at(i));
2593 info = Handle(THREAD, args1);
2594 }
2595 }
2596 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2597 "caller must supply a valid BSM");
2598
2599 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2600 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2601
2602 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2603 assert(appendix_box->obj_at(0) == NULL, "");
2604
2605 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2606 JavaCallArguments args;
2607 args.push_oop(caller->java_mirror());
2608 args.push_oop(bsm());
2609 args.push_oop(method_name());
2610 args.push_oop(method_type());
2611 args.push_oop(info());
2612 args.push_oop(appendix_box);
2613 JavaValue result(T_OBJECT);
2614 JavaCalls::call_static(&result,
2615 SystemDictionary::MethodHandleNatives_klass(),
2616 vmSymbols::linkCallSite_name(),
2617 vmSymbols::linkCallSite_signature(),
2618 &args, CHECK_(empty));
2619 Handle mname(THREAD, (oop) result.get_jobject());
2620 (*method_type_result) = method_type;
2621 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2622 }
2623
2624 // Since the identity hash code for symbols changes when the symbols are
2625 // moved from the regular perm gen (hash in the mark word) to the shared
2626 // spaces (hash is the address), the classes loaded into the dictionary
2627 // may be in the wrong buckets.
2628
2629 void SystemDictionary::reorder_dictionary() {
2630 dictionary()->reorder_dictionary();
2631 }
2632
2633
2634 void SystemDictionary::copy_buckets(char** top, char* end) {
2635 dictionary()->copy_buckets(top, end);
2636 }
2637
2638
2639 void SystemDictionary::copy_table(char** top, char* end) {
2640 dictionary()->copy_table(top, end);
2641 }
2642
2643
2644 void SystemDictionary::reverse() {
2645 dictionary()->reverse();
2646 }
2647
2648 int SystemDictionary::number_of_classes() {
2649 return dictionary()->number_of_entries();
2650 }
2651
2652
2653 // ----------------------------------------------------------------------------
2654 #ifndef PRODUCT
2655
2656 void SystemDictionary::print() {
2657 dictionary()->print();
2658
2659 // Placeholders
2660 GCMutexLocker mu(SystemDictionary_lock);
2661 placeholders()->print();
2662
2663 // loader constraints - print under SD_lock
2664 constraints()->print();
2665 }
2666
2667 #endif
2668
2669 void SystemDictionary::verify() {
2670 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2671 guarantee(constraints() != NULL,
2672 "Verify of loader constraints failed");
2673 guarantee(dictionary()->number_of_entries() >= 0 &&
2674 placeholders()->number_of_entries() >= 0,
2675 "Verify of system dictionary failed");
2676
2677 // Verify dictionary
2678 dictionary()->verify();
2679
2680 GCMutexLocker mu(SystemDictionary_lock);
2681 placeholders()->verify();
2682
2683 // Verify constraint table
2684 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2685 constraints()->verify(dictionary(), placeholders());
2686 }
2687
2688
2689 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2690 ClassLoaderData* loader_data) {
2691 GCMutexLocker mu(SystemDictionary_lock);
2692 Symbol* name;
2693
2694 Klass* probe = find_class(class_name, loader_data);
2695 if (probe == NULL) {
2696 probe = SystemDictionary::find_shared_class(class_name);
2697 if (probe == NULL) {
2698 name = find_placeholder(class_name, loader_data);
2699 }
2700 }
2701 guarantee(probe != NULL || name != NULL,
2702 "Loaded klasses should be in SystemDictionary");
2703 }
2704
2705 #ifndef PRODUCT
2706
2707 // statistics code
2708 class ClassStatistics: AllStatic {
2709 private:
2710 static int nclasses; // number of classes
2711 static int nmethods; // number of methods
2712 static int nmethoddata; // number of methodData
2713 static int class_size; // size of class objects in words
2714 static int method_size; // size of method objects in words
2715 static int debug_size; // size of debug info in methods
2716 static int methoddata_size; // size of methodData objects in words
2717
2718 static void do_class(Klass* k) {
2719 nclasses++;
2720 class_size += k->size();
2721 if (k->oop_is_instance()) {
2722 InstanceKlass* ik = (InstanceKlass*)k;
2723 class_size += ik->methods()->size();
2724 class_size += ik->constants()->size();
2725 class_size += ik->local_interfaces()->size();
2726 class_size += ik->transitive_interfaces()->size();
2727 // We do not have to count implementors, since we only store one!
2728 // SSS: How should these be accounted now that they have moved?
2729 // class_size += ik->fields()->length();
2730 }
2731 }
2732
2733 static void do_method(Method* m) {
2734 nmethods++;
2735 method_size += m->size();
2736 // class loader uses same objArray for empty vectors, so don't count these
2737 if (m->has_stackmap_table()) {
2738 method_size += m->stackmap_data()->size();
2739 }
2740
2741 MethodData* mdo = m->method_data();
2742 if (mdo != NULL) {
2743 nmethoddata++;
2744 methoddata_size += mdo->size();
2745 }
2746 }
2747
2748 public:
2749 static void print() {
2750 SystemDictionary::classes_do(do_class);
2751 SystemDictionary::methods_do(do_method);
2752 tty->print_cr("Class statistics:");
2753 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2754 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2755 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2756 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2757 }
2758 };
2759
2760
2761 int ClassStatistics::nclasses = 0;
2762 int ClassStatistics::nmethods = 0;
2763 int ClassStatistics::nmethoddata = 0;
2764 int ClassStatistics::class_size = 0;
2765 int ClassStatistics::method_size = 0;
2766 int ClassStatistics::debug_size = 0;
2767 int ClassStatistics::methoddata_size = 0;
2768
2769 void SystemDictionary::print_class_statistics() {
2770 ResourceMark rm;
2771 ClassStatistics::print();
2772 }
2773
2774
2775 class MethodStatistics: AllStatic {
2776 public:
2777 enum {
2778 max_parameter_size = 10
2779 };
2780 private:
2781
2782 static int _number_of_methods;
2783 static int _number_of_final_methods;
2784 static int _number_of_static_methods;
2785 static int _number_of_native_methods;
2786 static int _number_of_synchronized_methods;
2787 static int _number_of_profiled_methods;
2788 static int _number_of_bytecodes;
2789 static int _parameter_size_profile[max_parameter_size];
2790 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2791
2792 static void initialize() {
2793 _number_of_methods = 0;
2794 _number_of_final_methods = 0;
2795 _number_of_static_methods = 0;
2796 _number_of_native_methods = 0;
2797 _number_of_synchronized_methods = 0;
2798 _number_of_profiled_methods = 0;
2799 _number_of_bytecodes = 0;
2800 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2801 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2802 };
2803
2804 static void do_method(Method* m) {
2805 _number_of_methods++;
2806 // collect flag info
2807 if (m->is_final() ) _number_of_final_methods++;
2808 if (m->is_static() ) _number_of_static_methods++;
2809 if (m->is_native() ) _number_of_native_methods++;
2810 if (m->is_synchronized()) _number_of_synchronized_methods++;
2811 if (m->method_data() != NULL) _number_of_profiled_methods++;
2812 // collect parameter size info (add one for receiver, if any)
2813 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2814 // collect bytecodes info
2815 {
2816 Thread *thread = Thread::current();
2817 HandleMark hm(thread);
2818 BytecodeStream s(methodHandle(thread, m));
2819 Bytecodes::Code c;
2820 while ((c = s.next()) >= 0) {
2821 _number_of_bytecodes++;
2822 _bytecodes_profile[c]++;
2823 }
2824 }
2825 }
2826
2827 public:
2828 static void print() {
2829 initialize();
2830 SystemDictionary::methods_do(do_method);
2831 // generate output
2832 tty->cr();
2833 tty->print_cr("Method statistics (static):");
2834 // flag distribution
2835 tty->cr();
2836 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2837 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2838 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2839 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2840 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2841 // parameter size profile
2842 tty->cr();
2843 { int tot = 0;
2844 int avg = 0;
2845 for (int i = 0; i < max_parameter_size; i++) {
2846 int n = _parameter_size_profile[i];
2847 tot += n;
2848 avg += n*i;
2849 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2850 }
2851 assert(tot == _number_of_methods, "should be the same");
2852 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2853 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2854 }
2855 // bytecodes profile
2856 tty->cr();
2857 { int tot = 0;
2858 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2859 if (Bytecodes::is_defined(i)) {
2860 Bytecodes::Code c = Bytecodes::cast(i);
2861 int n = _bytecodes_profile[c];
2862 tot += n;
2863 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2864 }
2865 }
2866 assert(tot == _number_of_bytecodes, "should be the same");
2867 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2868 }
2869 tty->cr();
2870 }
2871 };
2872
2873 int MethodStatistics::_number_of_methods;
2874 int MethodStatistics::_number_of_final_methods;
2875 int MethodStatistics::_number_of_static_methods;
2876 int MethodStatistics::_number_of_native_methods;
2877 int MethodStatistics::_number_of_synchronized_methods;
2878 int MethodStatistics::_number_of_profiled_methods;
2879 int MethodStatistics::_number_of_bytecodes;
2880 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2881 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2882
2883
2884 void SystemDictionary::print_method_statistics() {
2885 MethodStatistics::print();
2886 }
2887
2888 #endif // PRODUCT