1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #if INCLUDE_CDS
34 #include "classfile/sharedClassUtil.hpp"
35 #include "classfile/systemDictionaryShared.hpp"
36 #endif
37 #include "classfile/vmSymbols.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/bytecodeStream.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "memory/filemap.hpp"
42 #include "memory/gcLocker.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "oops/instanceKlass.hpp"
45 #include "oops/instanceRefKlass.hpp"
46 #include "oops/klass.inline.hpp"
47 #include "oops/methodData.hpp"
48 #include "oops/objArrayKlass.hpp"
49 #include "oops/oop.inline.hpp"
50 #include "oops/oop.inline2.hpp"
51 #include "oops/typeArrayKlass.hpp"
52 #include "prims/jvmtiEnvBase.hpp"
53 #include "prims/methodHandles.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/biasedLocking.hpp"
56 #include "runtime/fieldType.hpp"
57 #include "runtime/handles.inline.hpp"
58 #include "runtime/java.hpp"
59 #include "runtime/javaCalls.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/signature.hpp"
63 #include "services/classLoadingService.hpp"
64 #include "services/threadService.hpp"
65 #include "utilities/macros.hpp"
66 #include "utilities/ticks.hpp"
67 #if INCLUDE_TRACE
68 #include "trace/tracing.hpp"
69 #endif
70
71 Dictionary* SystemDictionary::_dictionary = NULL;
72 PlaceholderTable* SystemDictionary::_placeholders = NULL;
73 Dictionary* SystemDictionary::_shared_dictionary = NULL;
74 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
75 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
76 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
77
78
79 int SystemDictionary::_number_of_modifications = 0;
80 int SystemDictionary::_sdgeneration = 0;
81 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
82 20201,40423,99991};
83
84 oop SystemDictionary::_system_loader_lock_obj = NULL;
85
86 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
87 = { NULL /*, NULL...*/ };
88
89 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
90
91 oop SystemDictionary::_java_system_loader = NULL;
92
93 bool SystemDictionary::_has_loadClassInternal = false;
94 bool SystemDictionary::_has_checkPackageAccess = false;
95
96 // lazily initialized klass variables
97 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
98
99
100 // ----------------------------------------------------------------------------
101 // Java-level SystemLoader
102
103 oop SystemDictionary::java_system_loader() {
104 return _java_system_loader;
105 }
106
107 void SystemDictionary::compute_java_system_loader(TRAPS) {
108 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
109 JavaValue result(T_OBJECT);
110 JavaCalls::call_static(&result,
111 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
112 vmSymbols::getSystemClassLoader_name(),
113 vmSymbols::void_classloader_signature(),
114 CHECK);
115
116 _java_system_loader = (oop)result.get_jobject();
117
118 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
119 }
120
121
122 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
123 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
124 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
125 }
126
127 // ----------------------------------------------------------------------------
128 // debugging
129
130 #ifdef ASSERT
131
132 // return true if class_name contains no '.' (internal format is '/')
133 bool SystemDictionary::is_internal_format(Symbol* class_name) {
134 if (class_name != NULL) {
135 ResourceMark rm;
136 char* name = class_name->as_C_string();
137 return strchr(name, '.') == NULL;
138 } else {
139 return true;
140 }
141 }
142
143 #endif
144
145 // ----------------------------------------------------------------------------
146 // Parallel class loading check
147
148 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
149 if (UnsyncloadClass || class_loader.is_null()) return true;
150 if (AlwaysLockClassLoader) return false;
151 return java_lang_ClassLoader::parallelCapable(class_loader());
152 }
153 // ----------------------------------------------------------------------------
154 // ParallelDefineClass flag does not apply to bootclass loader
155 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
156 if (class_loader.is_null()) return false;
157 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
158 return true;
159 }
160 return false;
161 }
162
163 /**
164 * Returns true if the passed class loader is the extension class loader.
165 */
166 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
167 if (class_loader.is_null()) {
168 return false;
169 }
170 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
171 }
172
173 // ----------------------------------------------------------------------------
174 // Resolving of classes
175
176 // Forwards to resolve_or_null
177
178 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
179 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
180 if (HAS_PENDING_EXCEPTION || klass == NULL) {
181 KlassHandle k_h(THREAD, klass);
182 // can return a null klass
183 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
184 }
185 return klass;
186 }
187
188 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
189 if (HAS_PENDING_EXCEPTION) {
190 // If we have a pending exception we forward it to the caller, unless throw_error is true,
191 // in which case we have to check whether the pending exception is a ClassNotFoundException,
192 // and if so convert it to a NoClassDefFoundError
193 // And chain the original ClassNotFoundException
194 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
195 ResourceMark rm(THREAD);
196 assert(klass_h() == NULL, "Should not have result with exception pending");
197 Handle e(THREAD, PENDING_EXCEPTION);
198 CLEAR_PENDING_EXCEPTION;
199 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
200 } else {
201 return NULL;
202 }
203 }
204 // Class not found, throw appropriate error or exception depending on value of throw_error
205 if (klass_h() == NULL) {
206 ResourceMark rm(THREAD);
207 if (throw_error) {
208 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
209 } else {
210 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
211 }
212 }
213 return (Klass*)klass_h();
214 }
215
216
217 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
218 bool throw_error, TRAPS)
219 {
220 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
221 }
222
223
224 // Forwards to resolve_instance_class_or_null
225
226 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
227 assert(!THREAD->is_Compiler_thread(),
228 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
229 class_name->as_C_string(),
230 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
231 if (FieldType::is_array(class_name)) {
232 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
233 } else if (FieldType::is_obj(class_name)) {
234 ResourceMark rm(THREAD);
235 // Ignore wrapping L and ;.
236 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
237 class_name->utf8_length() - 2, CHECK_NULL);
238 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
239 } else {
240 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
241 }
242 }
243
244 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
245 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
246 }
247
248 // Forwards to resolve_instance_class_or_null
249
250 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
251 Handle class_loader,
252 Handle protection_domain,
253 TRAPS) {
254 assert(FieldType::is_array(class_name), "must be array");
255 Klass* k = NULL;
256 FieldArrayInfo fd;
257 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
258 // of this call
259 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
260 if (t == T_OBJECT) {
261 // naked oop "k" is OK here -- we assign back into it
262 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
263 class_loader,
264 protection_domain,
265 CHECK_NULL);
266 if (k != NULL) {
267 k = k->array_klass(fd.dimension(), CHECK_NULL);
268 }
269 } else {
270 k = Universe::typeArrayKlassObj(t);
271 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
272 }
273 return k;
274 }
275
276
277 // Must be called for any super-class or super-interface resolution
278 // during class definition to allow class circularity checking
279 // super-interface callers:
280 // parse_interfaces - for defineClass & jvmtiRedefineClasses
281 // super-class callers:
282 // ClassFileParser - for defineClass & jvmtiRedefineClasses
283 // load_shared_class - while loading a class from shared archive
284 // resolve_instance_class_or_null:
285 // via: handle_parallel_super_load
286 // when resolving a class that has an existing placeholder with
287 // a saved superclass [i.e. a defineClass is currently in progress]
288 // if another thread is trying to resolve the class, it must do
289 // super-class checks on its own thread to catch class circularity
290 // This last call is critical in class circularity checking for cases
291 // where classloading is delegated to different threads and the
292 // classloader lock is released.
293 // Take the case: Base->Super->Base
294 // 1. If thread T1 tries to do a defineClass of class Base
295 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
296 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
297 // so it tries to load Super
298 // 3. If we load the class internally, or user classloader uses same thread
299 // loadClassFromxxx or defineClass via parseClassFile Super ...
300 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
301 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
302 // 3.4 calls resolve_super_or_fail Base
303 // 3.5 finds T1,Base -> throws class circularity
304 //OR 4. If T2 tries to resolve Super via defineClass Super ...
305 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
306 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
307 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
308 // 4.4 finds T2, Super -> throws class circularity
309 // Must be called, even if superclass is null, since this is
310 // where the placeholder entry is created which claims this
311 // thread is loading this class/classloader.
312 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
313 Symbol* class_name,
314 Handle class_loader,
315 Handle protection_domain,
316 bool is_superclass,
317 TRAPS) {
318 // Double-check, if child class is already loaded, just return super-class,interface
319 // Don't add a placedholder if already loaded, i.e. already in system dictionary
320 // Make sure there's a placeholder for the *child* before resolving.
321 // Used as a claim that this thread is currently loading superclass/classloader
322 // Used here for ClassCircularity checks and also for heap verification
323 // (every InstanceKlass in the heap needs to be in the system dictionary
324 // or have a placeholder).
325 // Must check ClassCircularity before checking if super class is already loaded
326 //
327 // We might not already have a placeholder if this child_name was
328 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
329 // the name of the class might not be known until the stream is actually
330 // parsed.
331 // Bugs 4643874, 4715493
332 // compute_hash can have a safepoint
333
334 ClassLoaderData* loader_data = class_loader_data(class_loader);
335 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
336 int d_index = dictionary()->hash_to_index(d_hash);
337 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
338 int p_index = placeholders()->hash_to_index(p_hash);
339 // can't throw error holding a lock
340 bool child_already_loaded = false;
341 bool throw_circularity_error = false;
342 {
343 MutexLocker mu(SystemDictionary_lock, THREAD);
344 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
345 Klass* quicksuperk;
346 // to support // loading: if child done loading, just return superclass
347 // if class_name, & class_loader don't match:
348 // if initial define, SD update will give LinkageError
349 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
350 // so we don't throw an exception here.
351 // see: nsk redefclass014 & java.lang.instrument Instrument032
352 if ((childk != NULL ) && (is_superclass) &&
353 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
354
355 ((quicksuperk->name() == class_name) &&
356 (quicksuperk->class_loader() == class_loader()))) {
357 return quicksuperk;
358 } else {
359 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
360 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
361 throw_circularity_error = true;
362 }
363 }
364 if (!throw_circularity_error) {
365 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
366 }
367 }
368 if (throw_circularity_error) {
369 ResourceMark rm(THREAD);
370 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
371 }
372
373 // java.lang.Object should have been found above
374 assert(class_name != NULL, "null super class for resolving");
375 // Resolve the super class or interface, check results on return
376 Klass* superk = SystemDictionary::resolve_or_null(class_name,
377 class_loader,
378 protection_domain,
379 THREAD);
380
381 KlassHandle superk_h(THREAD, superk);
382
383 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
384 // It is no longer necessary to keep the placeholder table alive until update_dictionary
385 // or error. GC used to walk the placeholder table as strong roots.
386 // The instanceKlass is kept alive because the class loader is on the stack,
387 // which keeps the loader_data alive, as well as all instanceKlasses in
388 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
389 {
390 MutexLocker mu(SystemDictionary_lock, THREAD);
391 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
392 SystemDictionary_lock->notify_all();
393 }
394 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
395 // can null superk
396 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
397 }
398
399 return superk_h();
400 }
401
402 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
403 Handle class_loader,
404 Handle protection_domain,
405 TRAPS) {
406 if(!has_checkPackageAccess()) return;
407
408 // Now we have to call back to java to check if the initating class has access
409 JavaValue result(T_VOID);
410 if (TraceProtectionDomainVerification) {
411 // Print out trace information
412 tty->print_cr("Checking package access");
413 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
414 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
415 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
416 }
417
418 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
419 JavaCalls::call_special(&result,
420 class_loader,
421 system_loader,
422 vmSymbols::checkPackageAccess_name(),
423 vmSymbols::class_protectiondomain_signature(),
424 Handle(THREAD, klass->java_mirror()),
425 protection_domain,
426 THREAD);
427
428 if (TraceProtectionDomainVerification) {
429 if (HAS_PENDING_EXCEPTION) {
430 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
431 } else {
432 tty->print_cr(" -> granted");
433 }
434 tty->cr();
435 }
436
437 if (HAS_PENDING_EXCEPTION) return;
438
439 // If no exception has been thrown, we have validated the protection domain
440 // Insert the protection domain of the initiating class into the set.
441 {
442 // We recalculate the entry here -- we've called out to java since
443 // the last time it was calculated.
444 ClassLoaderData* loader_data = class_loader_data(class_loader);
445
446 Symbol* kn = klass->name();
447 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
448 int d_index = dictionary()->hash_to_index(d_hash);
449
450 MutexLocker mu(SystemDictionary_lock, THREAD);
451 {
452 // Note that we have an entry, and entries can be deleted only during GC,
453 // so we cannot allow GC to occur while we're holding this entry.
454
455 // We're using a No_Safepoint_Verifier to catch any place where we
456 // might potentially do a GC at all.
457 // Dictionary::do_unloading() asserts that classes in SD are only
458 // unloaded at a safepoint. Anonymous classes are not in SD.
459 No_Safepoint_Verifier nosafepoint;
460 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
461 protection_domain, THREAD);
462 }
463 }
464 }
465
466 // We only get here if this thread finds that another thread
467 // has already claimed the placeholder token for the current operation,
468 // but that other thread either never owned or gave up the
469 // object lock
470 // Waits on SystemDictionary_lock to indicate placeholder table updated
471 // On return, caller must recheck placeholder table state
472 //
473 // We only get here if
474 // 1) custom classLoader, i.e. not bootstrap classloader
475 // 2) UnsyncloadClass not set
476 // 3) custom classLoader has broken the class loader objectLock
477 // so another thread got here in parallel
478 //
479 // lockObject must be held.
480 // Complicated dance due to lock ordering:
481 // Must first release the classloader object lock to
482 // allow initial definer to complete the class definition
483 // and to avoid deadlock
484 // Reclaim classloader lock object with same original recursion count
485 // Must release SystemDictionary_lock after notify, since
486 // class loader lock must be claimed before SystemDictionary_lock
487 // to prevent deadlocks
488 //
489 // The notify allows applications that did an untimed wait() on
490 // the classloader object lock to not hang.
491 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
492 assert_lock_strong(SystemDictionary_lock);
493
494 bool calledholdinglock
495 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
496 assert(calledholdinglock,"must hold lock for notify");
497 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
498 ObjectSynchronizer::notifyall(lockObject, THREAD);
499 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
500 SystemDictionary_lock->wait();
501 SystemDictionary_lock->unlock();
502 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
503 SystemDictionary_lock->lock();
504 }
505
506 // If the class in is in the placeholder table, class loading is in progress
507 // For cases where the application changes threads to load classes, it
508 // is critical to ClassCircularity detection that we try loading
509 // the superclass on the same thread internally, so we do parallel
510 // super class loading here.
511 // This also is critical in cases where the original thread gets stalled
512 // even in non-circularity situations.
513 // Note: must call resolve_super_or_fail even if null super -
514 // to force placeholder entry creation for this class for circularity detection
515 // Caller must check for pending exception
516 // Returns non-null Klass* if other thread has completed load
517 // and we are done,
518 // If return null Klass* and no pending exception, the caller must load the class
519 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
520 Symbol* name, Symbol* superclassname, Handle class_loader,
521 Handle protection_domain, Handle lockObject, TRAPS) {
522
523 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
524 ClassLoaderData* loader_data = class_loader_data(class_loader);
525 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
526 int d_index = dictionary()->hash_to_index(d_hash);
527 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
528 int p_index = placeholders()->hash_to_index(p_hash);
529
530 // superk is not used, resolve_super called for circularity check only
531 // This code is reached in two situations. One if this thread
532 // is loading the same class twice (e.g. ClassCircularity, or
533 // java.lang.instrument).
534 // The second is if another thread started the resolve_super first
535 // and has not yet finished.
536 // In both cases the original caller will clean up the placeholder
537 // entry on error.
538 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
539 superclassname,
540 class_loader,
541 protection_domain,
542 true,
543 CHECK_(nh));
544
545 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
546 // Serial class loaders and bootstrap classloader do wait for superclass loads
547 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
548 MutexLocker mu(SystemDictionary_lock, THREAD);
549 // Check if classloading completed while we were loading superclass or waiting
550 Klass* check = find_class(d_index, d_hash, name, loader_data);
551 if (check != NULL) {
552 // Klass is already loaded, so just return it
553 return(instanceKlassHandle(THREAD, check));
554 } else {
555 return nh;
556 }
557 }
558
559 // must loop to both handle other placeholder updates
560 // and spurious notifications
561 bool super_load_in_progress = true;
562 PlaceholderEntry* placeholder;
563 while (super_load_in_progress) {
564 MutexLocker mu(SystemDictionary_lock, THREAD);
565 // Check if classloading completed while we were loading superclass or waiting
566 Klass* check = find_class(d_index, d_hash, name, loader_data);
567 if (check != NULL) {
568 // Klass is already loaded, so just return it
569 return(instanceKlassHandle(THREAD, check));
570 } else {
571 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
572 if (placeholder && placeholder->super_load_in_progress() ){
573 // Before UnsyncloadClass:
574 // We only get here if the application has released the
575 // classloader lock when another thread was in the middle of loading a
576 // superclass/superinterface for this class, and now
577 // this thread is also trying to load this class.
578 // To minimize surprises, the first thread that started to
579 // load a class should be the one to complete the loading
580 // with the classfile it initially expected.
581 // This logic has the current thread wait once it has done
582 // all the superclass/superinterface loading it can, until
583 // the original thread completes the class loading or fails
584 // If it completes we will use the resulting InstanceKlass
585 // which we will find below in the systemDictionary.
586 // We also get here for parallel bootstrap classloader
587 if (class_loader.is_null()) {
588 SystemDictionary_lock->wait();
589 } else {
590 double_lock_wait(lockObject, THREAD);
591 }
592 } else {
593 // If not in SD and not in PH, other thread's load must have failed
594 super_load_in_progress = false;
595 }
596 }
597 }
598 return (nh);
599 }
600
601
602 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
603 Handle class_loader,
604 Handle protection_domain,
605 TRAPS) {
606 assert(name != NULL && !FieldType::is_array(name) &&
607 !FieldType::is_obj(name), "invalid class name");
608
609 Ticks class_load_start_time = Ticks::now();
610
611 // UseNewReflection
612 // Fix for 4474172; see evaluation for more details
613 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
614 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
615
616 // Do lookup to see if class already exist and the protection domain
617 // has the right access
618 // This call uses find which checks protection domain already matches
619 // All subsequent calls use find_class, and set has_loaded_class so that
620 // before we return a result we call out to java to check for valid protection domain
621 // to allow returning the Klass* and add it to the pd_set if it is valid
622 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
623 int d_index = dictionary()->hash_to_index(d_hash);
624 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
625 protection_domain, THREAD);
626 if (probe != NULL) return probe;
627
628
629 // Non-bootstrap class loaders will call out to class loader and
630 // define via jvm/jni_DefineClass which will acquire the
631 // class loader object lock to protect against multiple threads
632 // defining the class in parallel by accident.
633 // This lock must be acquired here so the waiter will find
634 // any successful result in the SystemDictionary and not attempt
635 // the define
636 // ParallelCapable Classloaders and the bootstrap classloader,
637 // or all classloaders with UnsyncloadClass do not acquire lock here
638 bool DoObjectLock = true;
639 if (is_parallelCapable(class_loader)) {
640 DoObjectLock = false;
641 }
642
643 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
644 int p_index = placeholders()->hash_to_index(p_hash);
645
646 // Class is not in SystemDictionary so we have to do loading.
647 // Make sure we are synchronized on the class loader before we proceed
648 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
649 check_loader_lock_contention(lockObject, THREAD);
650 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
651
652 // Check again (after locking) if class already exist in SystemDictionary
653 bool class_has_been_loaded = false;
654 bool super_load_in_progress = false;
655 bool havesupername = false;
656 instanceKlassHandle k;
657 PlaceholderEntry* placeholder;
658 Symbol* superclassname = NULL;
659
660 {
661 MutexLocker mu(SystemDictionary_lock, THREAD);
662 Klass* check = find_class(d_index, d_hash, name, loader_data);
663 if (check != NULL) {
664 // Klass is already loaded, so just return it
665 class_has_been_loaded = true;
666 k = instanceKlassHandle(THREAD, check);
667 } else {
668 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
669 if (placeholder && placeholder->super_load_in_progress()) {
670 super_load_in_progress = true;
671 if (placeholder->havesupername() == true) {
672 superclassname = placeholder->supername();
673 havesupername = true;
674 }
675 }
676 }
677 }
678
679 // If the class is in the placeholder table, class loading is in progress
680 if (super_load_in_progress && havesupername==true) {
681 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
682 class_loader, protection_domain, lockObject, THREAD);
683 if (HAS_PENDING_EXCEPTION) {
684 return NULL;
685 }
686 if (!k.is_null()) {
687 class_has_been_loaded = true;
688 }
689 }
690
691 bool throw_circularity_error = false;
692 if (!class_has_been_loaded) {
693 bool load_instance_added = false;
694
695 // add placeholder entry to record loading instance class
696 // Five cases:
697 // All cases need to prevent modifying bootclasssearchpath
698 // in parallel with a classload of same classname
699 // Redefineclasses uses existence of the placeholder for the duration
700 // of the class load to prevent concurrent redefinition of not completely
701 // defined classes.
702 // case 1. traditional classloaders that rely on the classloader object lock
703 // - no other need for LOAD_INSTANCE
704 // case 2. traditional classloaders that break the classloader object lock
705 // as a deadlock workaround. Detection of this case requires that
706 // this check is done while holding the classloader object lock,
707 // and that lock is still held when calling classloader's loadClass.
708 // For these classloaders, we ensure that the first requestor
709 // completes the load and other requestors wait for completion.
710 // case 3. UnsyncloadClass - don't use objectLocker
711 // With this flag, we allow parallel classloading of a
712 // class/classloader pair
713 // case4. Bootstrap classloader - don't own objectLocker
714 // This classloader supports parallelism at the classloader level,
715 // but only allows a single load of a class/classloader pair.
716 // No performance benefit and no deadlock issues.
717 // case 5. parallelCapable user level classloaders - without objectLocker
718 // Allow parallel classloading of a class/classloader pair
719
720 {
721 MutexLocker mu(SystemDictionary_lock, THREAD);
722 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
723 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (oldprobe) {
725 // only need check_seen_thread once, not on each loop
726 // 6341374 java/lang/Instrument with -Xcomp
727 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
728 throw_circularity_error = true;
729 } else {
730 // case 1: traditional: should never see load_in_progress.
731 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
732
733 // case 4: bootstrap classloader: prevent futile classloading,
734 // wait on first requestor
735 if (class_loader.is_null()) {
736 SystemDictionary_lock->wait();
737 } else {
738 // case 2: traditional with broken classloader lock. wait on first
739 // requestor.
740 double_lock_wait(lockObject, THREAD);
741 }
742 // Check if classloading completed while we were waiting
743 Klass* check = find_class(d_index, d_hash, name, loader_data);
744 if (check != NULL) {
745 // Klass is already loaded, so just return it
746 k = instanceKlassHandle(THREAD, check);
747 class_has_been_loaded = true;
748 }
749 // check if other thread failed to load and cleaned up
750 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
751 }
752 }
753 }
754 }
755 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
756 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
757 // LOAD_INSTANCE in parallel
758
759 if (!throw_circularity_error && !class_has_been_loaded) {
760 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
761 load_instance_added = true;
762 // For class loaders that do not acquire the classloader object lock,
763 // if they did not catch another thread holding LOAD_INSTANCE,
764 // need a check analogous to the acquire ObjectLocker/find_class
765 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
766 // one final check if the load has already completed
767 // class loaders holding the ObjectLock shouldn't find the class here
768 Klass* check = find_class(d_index, d_hash, name, loader_data);
769 if (check != NULL) {
770 // Klass is already loaded, so return it after checking/adding protection domain
771 k = instanceKlassHandle(THREAD, check);
772 class_has_been_loaded = true;
773 }
774 }
775 }
776
777 // must throw error outside of owning lock
778 if (throw_circularity_error) {
779 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
780 ResourceMark rm(THREAD);
781 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
782 }
783
784 if (!class_has_been_loaded) {
785
786 // Do actual loading
787 k = load_instance_class(name, class_loader, THREAD);
788
789 // For UnsyncloadClass only
790 // If they got a linkageError, check if a parallel class load succeeded.
791 // If it did, then for bytecode resolution the specification requires
792 // that we return the same result we did for the other thread, i.e. the
793 // successfully loaded InstanceKlass
794 // Should not get here for classloaders that support parallelism
795 // with the new cleaner mechanism, even with AllowParallelDefineClass
796 // Bootstrap goes through here to allow for an extra guarantee check
797 if (UnsyncloadClass || (class_loader.is_null())) {
798 if (k.is_null() && HAS_PENDING_EXCEPTION
799 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
800 MutexLocker mu(SystemDictionary_lock, THREAD);
801 Klass* check = find_class(d_index, d_hash, name, loader_data);
802 if (check != NULL) {
803 // Klass is already loaded, so just use it
804 k = instanceKlassHandle(THREAD, check);
805 CLEAR_PENDING_EXCEPTION;
806 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
807 }
808 }
809 }
810
811 // If everything was OK (no exceptions, no null return value), and
812 // class_loader is NOT the defining loader, do a little more bookkeeping.
813 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
814 k->class_loader() != class_loader()) {
815
816 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
817
818 // Need to check for a PENDING_EXCEPTION again; check_constraints
819 // can throw and doesn't use the CHECK macro.
820 if (!HAS_PENDING_EXCEPTION) {
821 { // Grabbing the Compile_lock prevents systemDictionary updates
822 // during compilations.
823 MutexLocker mu(Compile_lock, THREAD);
824 update_dictionary(d_index, d_hash, p_index, p_hash,
825 k, class_loader, THREAD);
826 }
827
828 if (JvmtiExport::should_post_class_load()) {
829 Thread *thread = THREAD;
830 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
831 JvmtiExport::post_class_load((JavaThread *) thread, k());
832 }
833 }
834 }
835 } // load_instance_class loop
836
837 if (load_instance_added == true) {
838 // clean up placeholder entries for LOAD_INSTANCE success or error
839 // This brackets the SystemDictionary updates for both defining
840 // and initiating loaders
841 MutexLocker mu(SystemDictionary_lock, THREAD);
842 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
843 SystemDictionary_lock->notify_all();
844 }
845 }
846
847 if (HAS_PENDING_EXCEPTION || k.is_null()) {
848 return NULL;
849 }
850
851 post_class_load_event(class_load_start_time, k, class_loader);
852
853 #ifdef ASSERT
854 {
855 ClassLoaderData* loader_data = k->class_loader_data();
856 MutexLocker mu(SystemDictionary_lock, THREAD);
857 Klass* kk = find_class(name, loader_data);
858 assert(kk == k(), "should be present in dictionary");
859 }
860 #endif
861
862 // return if the protection domain in NULL
863 if (protection_domain() == NULL) return k();
864
865 // Check the protection domain has the right access
866 {
867 MutexLocker mu(SystemDictionary_lock, THREAD);
868 // Note that we have an entry, and entries can be deleted only during GC,
869 // so we cannot allow GC to occur while we're holding this entry.
870 // We're using a No_Safepoint_Verifier to catch any place where we
871 // might potentially do a GC at all.
872 // Dictionary::do_unloading() asserts that classes in SD are only
873 // unloaded at a safepoint. Anonymous classes are not in SD.
874 No_Safepoint_Verifier nosafepoint;
875 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
876 loader_data,
877 protection_domain)) {
878 return k();
879 }
880 }
881
882 // Verify protection domain. If it fails an exception is thrown
883 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
884
885 return k();
886 }
887
888
889 // This routine does not lock the system dictionary.
890 //
891 // Since readers don't hold a lock, we must make sure that system
892 // dictionary entries are only removed at a safepoint (when only one
893 // thread is running), and are added to in a safe way (all links must
894 // be updated in an MT-safe manner).
895 //
896 // Callers should be aware that an entry could be added just after
897 // _dictionary->bucket(index) is read here, so the caller will not see
898 // the new entry.
899
900 Klass* SystemDictionary::find(Symbol* class_name,
901 Handle class_loader,
902 Handle protection_domain,
903 TRAPS) {
904
905 // UseNewReflection
906 // The result of this call should be consistent with the result
907 // of the call to resolve_instance_class_or_null().
908 // See evaluation 6790209 and 4474172 for more details.
909 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
910 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
911
912 if (loader_data == NULL) {
913 // If the ClassLoaderData has not been setup,
914 // then the class loader has no entries in the dictionary.
915 return NULL;
916 }
917
918 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
919 int d_index = dictionary()->hash_to_index(d_hash);
920
921 {
922 // Note that we have an entry, and entries can be deleted only during GC,
923 // so we cannot allow GC to occur while we're holding this entry.
924 // We're using a No_Safepoint_Verifier to catch any place where we
925 // might potentially do a GC at all.
926 // Dictionary::do_unloading() asserts that classes in SD are only
927 // unloaded at a safepoint. Anonymous classes are not in SD.
928 No_Safepoint_Verifier nosafepoint;
929 return dictionary()->find(d_index, d_hash, class_name, loader_data,
930 protection_domain, THREAD);
931 }
932 }
933
934
935 // Look for a loaded instance or array klass by name. Do not do any loading.
936 // return NULL in case of error.
937 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
938 Handle class_loader,
939 Handle protection_domain,
940 TRAPS) {
941 Klass* k = NULL;
942 assert(class_name != NULL, "class name must be non NULL");
943
944 if (FieldType::is_array(class_name)) {
945 // The name refers to an array. Parse the name.
946 // dimension and object_key in FieldArrayInfo are assigned as a
947 // side-effect of this call
948 FieldArrayInfo fd;
949 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
950 if (t != T_OBJECT) {
951 k = Universe::typeArrayKlassObj(t);
952 } else {
953 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
954 }
955 if (k != NULL) {
956 k = k->array_klass_or_null(fd.dimension());
957 }
958 } else {
959 k = find(class_name, class_loader, protection_domain, THREAD);
960 }
961 return k;
962 }
963
964 // Note: this method is much like resolve_from_stream, but
965 // updates no supplemental data structures.
966 // TODO consolidate the two methods with a helper routine?
967 Klass* SystemDictionary::parse_stream(Symbol* class_name,
968 Handle class_loader,
969 Handle protection_domain,
970 ClassFileStream* st,
971 KlassHandle host_klass,
972 GrowableArray<Handle>* cp_patches,
973 TRAPS) {
974 TempNewSymbol parsed_name = NULL;
975
976 Ticks class_load_start_time = Ticks::now();
977
978 ClassLoaderData* loader_data;
979 if (host_klass.not_null()) {
980 // Create a new CLD for anonymous class, that uses the same class loader
981 // as the host_klass
982 assert(EnableInvokeDynamic, "");
983 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
984 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
985 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
986 loader_data->record_dependency(host_klass(), CHECK_NULL);
987 } else {
988 loader_data = ClassLoaderData::class_loader_data(class_loader());
989 }
990
991 // Parse the stream. Note that we do this even though this klass might
992 // already be present in the SystemDictionary, otherwise we would not
993 // throw potential ClassFormatErrors.
994 //
995 // Note: "name" is updated.
996
997 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
998 loader_data,
999 protection_domain,
1000 host_klass,
1001 cp_patches,
1002 parsed_name,
1003 true,
1004 THREAD);
1005
1006
1007 if (host_klass.not_null() && k.not_null()) {
1008 assert(EnableInvokeDynamic, "");
1009 // If it's anonymous, initialize it now, since nobody else will.
1010
1011 {
1012 MutexLocker mu_r(Compile_lock, THREAD);
1013
1014 // Add to class hierarchy, initialize vtables, and do possible
1015 // deoptimizations.
1016 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1017
1018 // But, do not add to system dictionary.
1019
1020 // compiled code dependencies need to be validated anyway
1021 notice_modification();
1022 }
1023
1024 // Rewrite and patch constant pool here.
1025 k->link_class(CHECK_NULL);
1026 if (cp_patches != NULL) {
1027 k->constants()->patch_resolved_references(cp_patches);
1028 }
1029 k->eager_initialize(CHECK_NULL);
1030
1031 // notify jvmti
1032 if (JvmtiExport::should_post_class_load()) {
1033 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1034 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1035 }
1036
1037 post_class_load_event(class_load_start_time, k, class_loader);
1038 }
1039 assert(host_klass.not_null() || cp_patches == NULL,
1040 "cp_patches only found with host_klass");
1041
1042 return k();
1043 }
1044
1045 // Add a klass to the system from a stream (called by jni_DefineClass and
1046 // JVM_DefineClass).
1047 // Note: class_name can be NULL. In that case we do not know the name of
1048 // the class until we have parsed the stream.
1049
1050 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1051 Handle class_loader,
1052 Handle protection_domain,
1053 ClassFileStream* st,
1054 bool verify,
1055 TRAPS) {
1056
1057 // Classloaders that support parallelism, e.g. bootstrap classloader,
1058 // or all classloaders with UnsyncloadClass do not acquire lock here
1059 bool DoObjectLock = true;
1060 if (is_parallelCapable(class_loader)) {
1061 DoObjectLock = false;
1062 }
1063
1064 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1065
1066 // Make sure we are synchronized on the class loader before we proceed
1067 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1068 check_loader_lock_contention(lockObject, THREAD);
1069 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1070
1071 TempNewSymbol parsed_name = NULL;
1072
1073 // Parse the stream. Note that we do this even though this klass might
1074 // already be present in the SystemDictionary, otherwise we would not
1075 // throw potential ClassFormatErrors.
1076 //
1077 // Note: "name" is updated.
1078
1079 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1080 loader_data,
1081 protection_domain,
1082 parsed_name,
1083 verify,
1084 THREAD);
1085
1086 const char* pkg = "java/";
1087 size_t pkglen = strlen(pkg);
1088 if (!HAS_PENDING_EXCEPTION &&
1089 !class_loader.is_null() &&
1090 parsed_name != NULL &&
1091 parsed_name->utf8_length() >= (int)pkglen &&
1092 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1093 // It is illegal to define classes in the "java." package from
1094 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1095 ResourceMark rm(THREAD);
1096 char* name = parsed_name->as_C_string();
1097 char* index = strrchr(name, '/');
1098 assert(index != NULL, "must be");
1099 *index = '\0'; // chop to just the package name
1100 while ((index = strchr(name, '/')) != NULL) {
1101 *index = '.'; // replace '/' with '.' in package name
1102 }
1103 const char* fmt = "Prohibited package name: %s";
1104 size_t len = strlen(fmt) + strlen(name);
1105 char* message = NEW_RESOURCE_ARRAY(char, len);
1106 jio_snprintf(message, len, fmt, name);
1107 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1108 vmSymbols::java_lang_SecurityException(), message);
1109 }
1110
1111 if (!HAS_PENDING_EXCEPTION) {
1112 assert(parsed_name != NULL, "Sanity");
1113 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1114 // Verification prevents us from creating names with dots in them, this
1115 // asserts that that's the case.
1116 assert(is_internal_format(parsed_name),
1117 "external class name format used internally");
1118
1119 // Add class just loaded
1120 // If a class loader supports parallel classloading handle parallel define requests
1121 // find_or_define_instance_class may return a different InstanceKlass
1122 if (is_parallelCapable(class_loader)) {
1123 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1124 } else {
1125 define_instance_class(k, THREAD);
1126 }
1127 }
1128
1129 // Make sure we have an entry in the SystemDictionary on success
1130 debug_only( {
1131 if (!HAS_PENDING_EXCEPTION) {
1132 assert(parsed_name != NULL, "parsed_name is still null?");
1133 Symbol* h_name = k->name();
1134 ClassLoaderData *defining_loader_data = k->class_loader_data();
1135
1136 MutexLocker mu(SystemDictionary_lock, THREAD);
1137
1138 Klass* check = find_class(parsed_name, loader_data);
1139 assert(check == k(), "should be present in the dictionary");
1140
1141 Klass* check2 = find_class(h_name, defining_loader_data);
1142 assert(check == check2, "name inconsistancy in SystemDictionary");
1143 }
1144 } );
1145
1146 return k();
1147 }
1148
1149 #if INCLUDE_CDS
1150 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1151 int number_of_entries) {
1152 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1153 "bad shared dictionary size.");
1154 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1155 }
1156
1157
1158 // If there is a shared dictionary, then find the entry for the
1159 // given shared system class, if any.
1160
1161 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1162 if (shared_dictionary() != NULL) {
1163 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1164 int d_index = shared_dictionary()->hash_to_index(d_hash);
1165
1166 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1167 } else {
1168 return NULL;
1169 }
1170 }
1171
1172
1173 // Load a class from the shared spaces (found through the shared system
1174 // dictionary). Force the superclass and all interfaces to be loaded.
1175 // Update the class definition to include sibling classes and no
1176 // subclasses (yet). [Classes in the shared space are not part of the
1177 // object hierarchy until loaded.]
1178
1179 instanceKlassHandle SystemDictionary::load_shared_class(
1180 Symbol* class_name, Handle class_loader, TRAPS) {
1181 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1182 // Make sure we only return the boot class for the NULL classloader.
1183 if (ik.not_null() &&
1184 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1185 Handle protection_domain;
1186 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1187 }
1188 return instanceKlassHandle();
1189 }
1190
1191 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1192 Handle class_loader,
1193 Handle protection_domain, TRAPS) {
1194 if (ik.not_null()) {
1195 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1196 Symbol* class_name = ik->name();
1197
1198 // Found the class, now load the superclass and interfaces. If they
1199 // are shared, add them to the main system dictionary and reset
1200 // their hierarchy references (supers, subs, and interfaces).
1201
1202 if (ik->super() != NULL) {
1203 Symbol* cn = ik->super()->name();
1204 Klass *s = resolve_super_or_fail(class_name, cn,
1205 class_loader, protection_domain, true, CHECK_(nh));
1206 if (s != ik->super()) {
1207 // The dynamically resolved super class is not the same as the one we used during dump time,
1208 // so we cannot use ik.
1209 return nh;
1210 }
1211 }
1212
1213 Array<Klass*>* interfaces = ik->local_interfaces();
1214 int num_interfaces = interfaces->length();
1215 for (int index = 0; index < num_interfaces; index++) {
1216 Klass* k = interfaces->at(index);
1217
1218 // Note: can not use InstanceKlass::cast here because
1219 // interfaces' InstanceKlass's C++ vtbls haven't been
1220 // reinitialized yet (they will be once the interface classes
1221 // are loaded)
1222 Symbol* name = k->name();
1223 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1224 if (k != i) {
1225 // The dynamically resolved interface class is not the same as the one we used during dump time,
1226 // so we cannot use ik.
1227 return nh;
1228 }
1229 }
1230
1231 // Adjust methods to recover missing data. They need addresses for
1232 // interpreter entry points and their default native method address
1233 // must be reset.
1234
1235 // Updating methods must be done under a lock so multiple
1236 // threads don't update these in parallel
1237 //
1238 // Shared classes are all currently loaded by either the bootstrap or
1239 // internal parallel class loaders, so this will never cause a deadlock
1240 // on a custom class loader lock.
1241
1242 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1243 {
1244 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1245 check_loader_lock_contention(lockObject, THREAD);
1246 ObjectLocker ol(lockObject, THREAD, true);
1247 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1248 }
1249
1250 if (TraceClassLoading) {
1251 ResourceMark rm;
1252 tty->print("[Loaded %s", ik->external_name());
1253 tty->print(" from shared objects file");
1254 if (class_loader.not_null()) {
1255 tty->print(" by %s", loader_data->loader_name());
1256 }
1257 tty->print_cr("]");
1258 }
1259
1260 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1261 // Only dump the classes that can be stored into CDS archive
1262 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1263 ResourceMark rm(THREAD);
1264 classlist_file->print_cr("%s", ik->name()->as_C_string());
1265 classlist_file->flush();
1266 }
1267 }
1268
1269 // notify a class loaded from shared object
1270 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1271 true /* shared class */);
1272 }
1273 return ik;
1274 }
1275 #endif // INCLUDE_CDS
1276
1277 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1278 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1279 if (class_loader.is_null()) {
1280
1281 // Search the shared system dictionary for classes preloaded into the
1282 // shared spaces.
1283 instanceKlassHandle k;
1284 {
1285 #if INCLUDE_CDS
1286 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1287 k = load_shared_class(class_name, class_loader, THREAD);
1288 #endif
1289 }
1290
1291 if (k.is_null()) {
1292 // Use VM class loader
1293 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1294 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1295 }
1296
1297 // find_or_define_instance_class may return a different InstanceKlass
1298 if (!k.is_null()) {
1299 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1300 }
1301 return k;
1302 } else {
1303 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1304 ResourceMark rm(THREAD);
1305
1306 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1307 JavaThread* jt = (JavaThread*) THREAD;
1308
1309 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1310 ClassLoader::perf_app_classload_selftime(),
1311 ClassLoader::perf_app_classload_count(),
1312 jt->get_thread_stat()->perf_recursion_counts_addr(),
1313 jt->get_thread_stat()->perf_timers_addr(),
1314 PerfClassTraceTime::CLASS_LOAD);
1315
1316 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1317 // Translate to external class name format, i.e., convert '/' chars to '.'
1318 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1319
1320 JavaValue result(T_OBJECT);
1321
1322 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1323
1324 // Call public unsynchronized loadClass(String) directly for all class loaders
1325 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1326 // acquire a class-name based lock rather than the class loader object lock.
1327 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1328 // so the call to loadClassInternal() was not required.
1329 //
1330 // UnsyncloadClass flag means both call loadClass(String) and do
1331 // not acquire the class loader lock even for class loaders that are
1332 // not parallelCapable. This was a risky transitional
1333 // flag for diagnostic purposes only. It is risky to call
1334 // custom class loaders without synchronization.
1335 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1336 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1337 // Do NOT assume this will be supported in future releases.
1338 //
1339 // Added MustCallLoadClassInternal in case we discover in the field
1340 // a customer that counts on this call
1341 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1342 JavaCalls::call_special(&result,
1343 class_loader,
1344 spec_klass,
1345 vmSymbols::loadClassInternal_name(),
1346 vmSymbols::string_class_signature(),
1347 string,
1348 CHECK_(nh));
1349 } else {
1350 JavaCalls::call_virtual(&result,
1351 class_loader,
1352 spec_klass,
1353 vmSymbols::loadClass_name(),
1354 vmSymbols::string_class_signature(),
1355 string,
1356 CHECK_(nh));
1357 }
1358
1359 assert(result.get_type() == T_OBJECT, "just checking");
1360 oop obj = (oop) result.get_jobject();
1361
1362 // Primitive classes return null since forName() can not be
1363 // used to obtain any of the Class objects representing primitives or void
1364 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1365 instanceKlassHandle k =
1366 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1367 // For user defined Java class loaders, check that the name returned is
1368 // the same as that requested. This check is done for the bootstrap
1369 // loader when parsing the class file.
1370 if (class_name == k->name()) {
1371 return k;
1372 }
1373 }
1374 // Class is not found or has the wrong name, return NULL
1375 return nh;
1376 }
1377 }
1378
1379 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1380
1381 ClassLoaderData* loader_data = k->class_loader_data();
1382 Handle class_loader_h(THREAD, loader_data->class_loader());
1383
1384 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1385
1386 // for bootstrap and other parallel classloaders don't acquire lock,
1387 // use placeholder token
1388 // If a parallelCapable class loader calls define_instance_class instead of
1389 // find_or_define_instance_class to get here, we have a timing
1390 // hole with systemDictionary updates and check_constraints
1391 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1392 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1393 compute_loader_lock_object(class_loader_h, THREAD)),
1394 "define called without lock");
1395 }
1396
1397 // Check class-loading constraints. Throw exception if violation is detected.
1398 // Grabs and releases SystemDictionary_lock
1399 // The check_constraints/find_class call and update_dictionary sequence
1400 // must be "atomic" for a specific class/classloader pair so we never
1401 // define two different instanceKlasses for that class/classloader pair.
1402 // Existing classloaders will call define_instance_class with the
1403 // classloader lock held
1404 // Parallel classloaders will call find_or_define_instance_class
1405 // which will require a token to perform the define class
1406 Symbol* name_h = k->name();
1407 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1408 int d_index = dictionary()->hash_to_index(d_hash);
1409 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1410
1411 // Register class just loaded with class loader (placed in Vector)
1412 // Note we do this before updating the dictionary, as this can
1413 // fail with an OutOfMemoryError (if it does, we will *not* put this
1414 // class in the dictionary and will not update the class hierarchy).
1415 // JVMTI FollowReferences needs to find the classes this way.
1416 if (k->class_loader() != NULL) {
1417 methodHandle m(THREAD, Universe::loader_addClass_method());
1418 JavaValue result(T_VOID);
1419 JavaCallArguments args(class_loader_h);
1420 args.push_oop(Handle(THREAD, k->java_mirror()));
1421 JavaCalls::call(&result, m, &args, CHECK);
1422 }
1423
1424 // Add the new class. We need recompile lock during update of CHA.
1425 {
1426 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1427 int p_index = placeholders()->hash_to_index(p_hash);
1428
1429 MutexLocker mu_r(Compile_lock, THREAD);
1430
1431 // Add to class hierarchy, initialize vtables, and do possible
1432 // deoptimizations.
1433 add_to_hierarchy(k, CHECK); // No exception, but can block
1434
1435 // Add to systemDictionary - so other classes can see it.
1436 // Grabs and releases SystemDictionary_lock
1437 update_dictionary(d_index, d_hash, p_index, p_hash,
1438 k, class_loader_h, THREAD);
1439 }
1440 k->eager_initialize(THREAD);
1441
1442 // notify jvmti
1443 if (JvmtiExport::should_post_class_load()) {
1444 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1445 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1446
1447 }
1448
1449 }
1450
1451 // Support parallel classloading
1452 // All parallel class loaders, including bootstrap classloader
1453 // lock a placeholder entry for this class/class_loader pair
1454 // to allow parallel defines of different classes for this class loader
1455 // With AllowParallelDefine flag==true, in case they do not synchronize around
1456 // FindLoadedClass/DefineClass, calls, we check for parallel
1457 // loading for them, wait if a defineClass is in progress
1458 // and return the initial requestor's results
1459 // This flag does not apply to the bootstrap classloader.
1460 // With AllowParallelDefine flag==false, call through to define_instance_class
1461 // which will throw LinkageError: duplicate class definition.
1462 // False is the requested default.
1463 // For better performance, the class loaders should synchronize
1464 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1465 // potentially waste time reading and parsing the bytestream.
1466 // Note: VM callers should ensure consistency of k/class_name,class_loader
1467 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1468
1469 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1470 Symbol* name_h = k->name(); // passed in class_name may be null
1471 ClassLoaderData* loader_data = class_loader_data(class_loader);
1472
1473 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1474 int d_index = dictionary()->hash_to_index(d_hash);
1475
1476 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1477 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1478 int p_index = placeholders()->hash_to_index(p_hash);
1479 PlaceholderEntry* probe;
1480
1481 {
1482 MutexLocker mu(SystemDictionary_lock, THREAD);
1483 // First check if class already defined
1484 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1485 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1486 if (check != NULL) {
1487 return(instanceKlassHandle(THREAD, check));
1488 }
1489 }
1490
1491 // Acquire define token for this class/classloader
1492 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1493 // Wait if another thread defining in parallel
1494 // All threads wait - even those that will throw duplicate class: otherwise
1495 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1496 // if other thread has not finished updating dictionary
1497 while (probe->definer() != NULL) {
1498 SystemDictionary_lock->wait();
1499 }
1500 // Only special cases allow parallel defines and can use other thread's results
1501 // Other cases fall through, and may run into duplicate defines
1502 // caught by finding an entry in the SystemDictionary
1503 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1504 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1505 SystemDictionary_lock->notify_all();
1506 #ifdef ASSERT
1507 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1508 assert(check != NULL, "definer missed recording success");
1509 #endif
1510 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1511 } else {
1512 // This thread will define the class (even if earlier thread tried and had an error)
1513 probe->set_definer(THREAD);
1514 }
1515 }
1516
1517 define_instance_class(k, THREAD);
1518
1519 Handle linkage_exception = Handle(); // null handle
1520
1521 // definer must notify any waiting threads
1522 {
1523 MutexLocker mu(SystemDictionary_lock, THREAD);
1524 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1525 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1526 if (probe != NULL) {
1527 if (HAS_PENDING_EXCEPTION) {
1528 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1529 CLEAR_PENDING_EXCEPTION;
1530 } else {
1531 probe->set_instance_klass(k());
1532 }
1533 probe->set_definer(NULL);
1534 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1535 SystemDictionary_lock->notify_all();
1536 }
1537 }
1538
1539 // Can't throw exception while holding lock due to rank ordering
1540 if (linkage_exception() != NULL) {
1541 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1542 }
1543
1544 return k;
1545 }
1546 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1547 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1548 if (class_loader.is_null()) {
1549 return Handle(THREAD, _system_loader_lock_obj);
1550 } else {
1551 return class_loader;
1552 }
1553 }
1554
1555 // This method is added to check how often we have to wait to grab loader
1556 // lock. The results are being recorded in the performance counters defined in
1557 // ClassLoader::_sync_systemLoaderLockContentionRate and
1558 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1559 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1560 if (!UsePerfData) {
1561 return;
1562 }
1563
1564 assert(!loader_lock.is_null(), "NULL lock object");
1565
1566 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1567 == ObjectSynchronizer::owner_other) {
1568 // contention will likely happen, so increment the corresponding
1569 // contention counter.
1570 if (loader_lock() == _system_loader_lock_obj) {
1571 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1572 } else {
1573 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1574 }
1575 }
1576 }
1577
1578 // ----------------------------------------------------------------------------
1579 // Lookup
1580
1581 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1582 Symbol* class_name,
1583 ClassLoaderData* loader_data) {
1584 assert_locked_or_safepoint(SystemDictionary_lock);
1585 assert (index == dictionary()->index_for(class_name, loader_data),
1586 "incorrect index?");
1587
1588 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1589 return k;
1590 }
1591
1592
1593 // Basic find on classes in the midst of being loaded
1594 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1595 ClassLoaderData* loader_data) {
1596 assert_locked_or_safepoint(SystemDictionary_lock);
1597 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1598 int p_index = placeholders()->hash_to_index(p_hash);
1599 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1600 }
1601
1602
1603 // Used for assertions and verification only
1604 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1605 #ifndef ASSERT
1606 guarantee(VerifyBeforeGC ||
1607 VerifyDuringGC ||
1608 VerifyBeforeExit ||
1609 VerifyDuringStartup ||
1610 VerifyAfterGC, "too expensive");
1611 #endif
1612 assert_locked_or_safepoint(SystemDictionary_lock);
1613
1614 // First look in the loaded class array
1615 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1616 int d_index = dictionary()->hash_to_index(d_hash);
1617 return find_class(d_index, d_hash, class_name, loader_data);
1618 }
1619
1620
1621 // Get the next class in the diictionary.
1622 Klass* SystemDictionary::try_get_next_class() {
1623 return dictionary()->try_get_next_class();
1624 }
1625
1626
1627 // ----------------------------------------------------------------------------
1628 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1629 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1630 // before a new class is used.
1631
1632 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1633 assert(k.not_null(), "just checking");
1634 assert_locked_or_safepoint(Compile_lock);
1635
1636 // Link into hierachy. Make sure the vtables are initialized before linking into
1637 k->append_to_sibling_list(); // add to superklass/sibling list
1638 k->process_interfaces(THREAD); // handle all "implements" declarations
1639 k->set_init_state(InstanceKlass::loaded);
1640 // Now flush all code that depended on old class hierarchy.
1641 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1642 // Also, first reinitialize vtable because it may have gotten out of synch
1643 // while the new class wasn't connected to the class hierarchy.
1644 Universe::flush_dependents_on(k);
1645 }
1646
1647 // ----------------------------------------------------------------------------
1648 // GC support
1649
1650 // Following roots during mark-sweep is separated in two phases.
1651 //
1652 // The first phase follows preloaded classes and all other system
1653 // classes, since these will never get unloaded anyway.
1654 //
1655 // The second phase removes (unloads) unreachable classes from the
1656 // system dictionary and follows the remaining classes' contents.
1657
1658 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1659 roots_oops_do(blk, NULL);
1660 }
1661
1662 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1663 // Follow all system classes and temporary placeholders in dictionary
1664 dictionary()->always_strong_classes_do(closure);
1665
1666 // Placeholders. These represent classes we're actively loading.
1667 placeholders()->classes_do(closure);
1668 }
1669
1670 // Calculate a "good" systemdictionary size based
1671 // on predicted or current loaded classes count
1672 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1673 int newsize = _old_default_sdsize;
1674 if ((classcount > 0) && !DumpSharedSpaces) {
1675 int desiredsize = classcount/_average_depth_goal;
1676 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1677 newsize = _primelist[++_sdgeneration]) {
1678 if (desiredsize <= newsize) {
1679 break;
1680 }
1681 }
1682 }
1683 return newsize;
1684 }
1685
1686 #ifdef ASSERT
1687 class VerifySDReachableAndLiveClosure : public OopClosure {
1688 private:
1689 BoolObjectClosure* _is_alive;
1690
1691 template <class T> void do_oop_work(T* p) {
1692 oop obj = oopDesc::load_decode_heap_oop(p);
1693 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1694 }
1695
1696 public:
1697 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1698
1699 virtual void do_oop(oop* p) { do_oop_work(p); }
1700 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1701 };
1702 #endif
1703
1704 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1705 // Note: anonymous classes are not in the SD.
1706 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1707 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1708 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1709 if (unloading_occurred) {
1710 dictionary()->do_unloading();
1711 constraints()->purge_loader_constraints();
1712 resolution_errors()->purge_resolution_errors();
1713 }
1714 // Oops referenced by the system dictionary may get unreachable independently
1715 // of the class loader (eg. cached protection domain oops). So we need to
1716 // explicitly unlink them here instead of in Dictionary::do_unloading.
1717 dictionary()->unlink(is_alive);
1718 #ifdef ASSERT
1719 VerifySDReachableAndLiveClosure cl(is_alive);
1720 dictionary()->oops_do(&cl);
1721 #endif
1722 return unloading_occurred;
1723 }
1724
1725 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1726 strong->do_oop(&_java_system_loader);
1727 strong->do_oop(&_system_loader_lock_obj);
1728 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1729
1730 // Adjust dictionary
1731 dictionary()->roots_oops_do(strong, weak);
1732
1733 // Visit extra methods
1734 invoke_method_table()->oops_do(strong);
1735 }
1736
1737 void SystemDictionary::oops_do(OopClosure* f) {
1738 f->do_oop(&_java_system_loader);
1739 f->do_oop(&_system_loader_lock_obj);
1740 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1741
1742 // Adjust dictionary
1743 dictionary()->oops_do(f);
1744
1745 // Visit extra methods
1746 invoke_method_table()->oops_do(f);
1747 }
1748
1749 // Extended Class redefinition support.
1750 // If one of these classes is replaced, we need to replace it in these places.
1751 // KlassClosure::do_klass should take the address of a class but we can
1752 // change that later.
1753 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1754 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1755 f->do_klass(_well_known_klasses[k]);
1756 }
1757
1758 {
1759 for (int i = 0; i < T_VOID+1; i++) {
1760 if (_box_klasses[i] != NULL) {
1761 assert(i >= T_BOOLEAN, "checking");
1762 f->do_klass(_box_klasses[i]);
1763 }
1764 }
1765 }
1766
1767 FilteredFieldsMap::classes_do(f);
1768 }
1769
1770 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1771 f->do_klass(_abstract_ownable_synchronizer_klass);
1772 }
1773
1774 // Just the classes from defining class loaders
1775 // Don't iterate over placeholders
1776 void SystemDictionary::classes_do(void f(Klass*)) {
1777 dictionary()->classes_do(f);
1778 }
1779
1780 // Added for initialize_itable_for_klass
1781 // Just the classes from defining class loaders
1782 // Don't iterate over placeholders
1783 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1784 dictionary()->classes_do(f, CHECK);
1785 }
1786
1787 // All classes, and their class loaders
1788 // Don't iterate over placeholders
1789 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1790 dictionary()->classes_do(f);
1791 }
1792
1793 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1794 placeholders()->entries_do(f);
1795 }
1796
1797 void SystemDictionary::methods_do(void f(Method*)) {
1798 dictionary()->methods_do(f);
1799 invoke_method_table()->methods_do(f);
1800 }
1801
1802 void SystemDictionary::remove_classes_in_error_state() {
1803 dictionary()->remove_classes_in_error_state();
1804 }
1805
1806 // ----------------------------------------------------------------------------
1807 // Lazily load klasses
1808
1809 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1810 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1811
1812 // if multiple threads calling this function, only one thread will load
1813 // the class. The other threads will find the loaded version once the
1814 // class is loaded.
1815 Klass* aos = _abstract_ownable_synchronizer_klass;
1816 if (aos == NULL) {
1817 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1818 // Force a fence to prevent any read before the write completes
1819 OrderAccess::fence();
1820 _abstract_ownable_synchronizer_klass = k;
1821 }
1822 }
1823
1824 // ----------------------------------------------------------------------------
1825 // Initialization
1826
1827 void SystemDictionary::initialize(TRAPS) {
1828 // Allocate arrays
1829 assert(dictionary() == NULL,
1830 "SystemDictionary should only be initialized once");
1831 _sdgeneration = 0;
1832 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1833 _placeholders = new PlaceholderTable(_nof_buckets);
1834 _number_of_modifications = 0;
1835 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1836 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1837 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1838
1839 // Allocate private object used as system class loader lock
1840 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1841 // Initialize basic classes
1842 initialize_preloaded_classes(CHECK);
1843 }
1844
1845 // Compact table of directions on the initialization of klasses:
1846 static const short wk_init_info[] = {
1847 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1848 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1849 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1850 | (int)SystemDictionary::option ),
1851 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1852 #undef WK_KLASS_INIT_INFO
1853 0
1854 };
1855
1856 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1857 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1858 int info = wk_init_info[id - FIRST_WKID];
1859 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1860 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1861 Klass** klassp = &_well_known_klasses[id];
1862 bool must_load = (init_opt < SystemDictionary::Opt);
1863 if ((*klassp) == NULL) {
1864 if (must_load) {
1865 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1866 } else {
1867 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1868 }
1869 }
1870 return ((*klassp) != NULL);
1871 }
1872
1873 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1874 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1875 for (int id = (int)start_id; id < (int)limit_id; id++) {
1876 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1877 int info = wk_init_info[id - FIRST_WKID];
1878 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1879 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1880
1881 initialize_wk_klass((WKID)id, opt, CHECK);
1882 }
1883
1884 // move the starting value forward to the limit:
1885 start_id = limit_id;
1886 }
1887
1888 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1889 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1890 // Preload commonly used klasses
1891 WKID scan = FIRST_WKID;
1892 // first do Object, then String, Class
1893 if (UseSharedSpaces) {
1894 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1895 // Initialize the constant pool for the Object_class
1896 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1897 ik->constants()->restore_unshareable_info(CHECK);
1898 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1899 } else {
1900 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1901 }
1902
1903 // Calculate offsets for String and Class classes since they are loaded and
1904 // can be used after this point.
1905 java_lang_String::compute_offsets();
1906 java_lang_Class::compute_offsets();
1907
1908 // Fixup mirrors for classes loaded before java.lang.Class.
1909 // These calls iterate over the objects currently in the perm gen
1910 // so calling them at this point is matters (not before when there
1911 // are fewer objects and not later after there are more objects
1912 // in the perm gen.
1913 Universe::initialize_basic_type_mirrors(CHECK);
1914 Universe::fixup_mirrors(CHECK);
1915
1916 // do a bunch more:
1917 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1918
1919 // Preload ref klasses and set reference types
1920 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1921 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1922
1923 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1924 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1925 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1926 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1927 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1928 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1929
1930 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
1931
1932 // JSR 292 classes
1933 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1934 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1935 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1936 if (EnableInvokeDynamic) {
1937 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1938 } else {
1939 // Skip the JSR 292 classes, if not enabled.
1940 scan = WKID(jsr292_group_end + 1);
1941 }
1942
1943 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1944
1945 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1946 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1947 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1948 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1949 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1950 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1951 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1952 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1953 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1954 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1955
1956 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1957 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1958 _has_loadClassInternal = (method != NULL);
1959 }
1960 { // Compute whether we should use checkPackageAccess or NOT
1961 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1962 _has_checkPackageAccess = (method != NULL);
1963 }
1964 }
1965
1966 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1967 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1968 BasicType SystemDictionary::box_klass_type(Klass* k) {
1969 assert(k != NULL, "");
1970 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1971 if (_box_klasses[i] == k)
1972 return (BasicType)i;
1973 }
1974 return T_OBJECT;
1975 }
1976
1977 // Constraints on class loaders. The details of the algorithm can be
1978 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1979 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1980 // that the system dictionary needs to maintain a set of contraints that
1981 // must be satisfied by all classes in the dictionary.
1982 // if defining is true, then LinkageError if already in systemDictionary
1983 // if initiating loader, then ok if InstanceKlass matches existing entry
1984
1985 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1986 instanceKlassHandle k,
1987 Handle class_loader, bool defining,
1988 TRAPS) {
1989 const char *linkage_error = NULL;
1990 {
1991 Symbol* name = k->name();
1992 ClassLoaderData *loader_data = class_loader_data(class_loader);
1993
1994 MutexLocker mu(SystemDictionary_lock, THREAD);
1995
1996 Klass* check = find_class(d_index, d_hash, name, loader_data);
1997 if (check != (Klass*)NULL) {
1998 // if different InstanceKlass - duplicate class definition,
1999 // else - ok, class loaded by a different thread in parallel,
2000 // we should only have found it if it was done loading and ok to use
2001 // system dictionary only holds instance classes, placeholders
2002 // also holds array classes
2003
2004 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2005 if ((defining == true) || (k() != check)) {
2006 linkage_error = "loader (instance of %s): attempted duplicate class "
2007 "definition for name: \"%s\"";
2008 } else {
2009 return;
2010 }
2011 }
2012
2013 #ifdef ASSERT
2014 Symbol* ph_check = find_placeholder(name, loader_data);
2015 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2016 #endif
2017
2018 if (linkage_error == NULL) {
2019 if (constraints()->check_or_update(k, class_loader, name) == false) {
2020 linkage_error = "loader constraint violation: loader (instance of %s)"
2021 " previously initiated loading for a different type with name \"%s\"";
2022 }
2023 }
2024 }
2025
2026 // Throw error now if needed (cannot throw while holding
2027 // SystemDictionary_lock because of rank ordering)
2028
2029 if (linkage_error) {
2030 ResourceMark rm(THREAD);
2031 const char* class_loader_name = loader_name(class_loader());
2032 char* type_name = k->name()->as_C_string();
2033 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2034 strlen(type_name);
2035 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2036 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2037 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2038 }
2039 }
2040
2041
2042 // Update system dictionary - done after check_constraint and add_to_hierachy
2043 // have been called.
2044 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2045 int p_index, unsigned int p_hash,
2046 instanceKlassHandle k,
2047 Handle class_loader,
2048 TRAPS) {
2049 // Compile_lock prevents systemDictionary updates during compilations
2050 assert_locked_or_safepoint(Compile_lock);
2051 Symbol* name = k->name();
2052 ClassLoaderData *loader_data = class_loader_data(class_loader);
2053
2054 {
2055 MutexLocker mu1(SystemDictionary_lock, THREAD);
2056
2057 // See whether biased locking is enabled and if so set it for this
2058 // klass.
2059 // Note that this must be done past the last potential blocking
2060 // point / safepoint. We enable biased locking lazily using a
2061 // VM_Operation to iterate the SystemDictionary and installing the
2062 // biasable mark word into each InstanceKlass's prototype header.
2063 // To avoid race conditions where we accidentally miss enabling the
2064 // optimization for one class in the process of being added to the
2065 // dictionary, we must not safepoint after the test of
2066 // BiasedLocking::enabled().
2067 if (UseBiasedLocking && BiasedLocking::enabled()) {
2068 // Set biased locking bit for all loaded classes; it will be
2069 // cleared if revocation occurs too often for this type
2070 // NOTE that we must only do this when the class is initally
2071 // defined, not each time it is referenced from a new class loader
2072 if (k->class_loader() == class_loader()) {
2073 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2074 }
2075 }
2076
2077 // Make a new system dictionary entry.
2078 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2079 if (sd_check == NULL) {
2080 dictionary()->add_klass(name, loader_data, k);
2081 notice_modification();
2082 }
2083 #ifdef ASSERT
2084 sd_check = find_class(d_index, d_hash, name, loader_data);
2085 assert (sd_check != NULL, "should have entry in system dictionary");
2086 // Note: there may be a placeholder entry: for circularity testing
2087 // or for parallel defines
2088 #endif
2089 SystemDictionary_lock->notify_all();
2090 }
2091 }
2092
2093
2094 // Try to find a class name using the loader constraints. The
2095 // loader constraints might know about a class that isn't fully loaded
2096 // yet and these will be ignored.
2097 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2098 Symbol* class_name, Handle class_loader, TRAPS) {
2099
2100 // First see if it has been loaded directly.
2101 // Force the protection domain to be null. (This removes protection checks.)
2102 Handle no_protection_domain;
2103 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2104 no_protection_domain, CHECK_NULL);
2105 if (klass != NULL)
2106 return klass;
2107
2108 // Now look to see if it has been loaded elsewhere, and is subject to
2109 // a loader constraint that would require this loader to return the
2110 // klass that is already loaded.
2111 if (FieldType::is_array(class_name)) {
2112 // For array classes, their Klass*s are not kept in the
2113 // constraint table. The element Klass*s are.
2114 FieldArrayInfo fd;
2115 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2116 if (t != T_OBJECT) {
2117 klass = Universe::typeArrayKlassObj(t);
2118 } else {
2119 MutexLocker mu(SystemDictionary_lock, THREAD);
2120 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2121 }
2122 // If element class already loaded, allocate array klass
2123 if (klass != NULL) {
2124 klass = klass->array_klass_or_null(fd.dimension());
2125 }
2126 } else {
2127 MutexLocker mu(SystemDictionary_lock, THREAD);
2128 // Non-array classes are easy: simply check the constraint table.
2129 klass = constraints()->find_constrained_klass(class_name, class_loader);
2130 }
2131
2132 return klass;
2133 }
2134
2135
2136 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2137 Handle class_loader1,
2138 Handle class_loader2,
2139 Thread* THREAD) {
2140 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2141 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2142
2143 Symbol* constraint_name = NULL;
2144 if (!FieldType::is_array(class_name)) {
2145 constraint_name = class_name;
2146 } else {
2147 // For array classes, their Klass*s are not kept in the
2148 // constraint table. The element classes are.
2149 FieldArrayInfo fd;
2150 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2151 // primitive types always pass
2152 if (t != T_OBJECT) {
2153 return true;
2154 } else {
2155 constraint_name = fd.object_key();
2156 }
2157 }
2158 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2159 int d_index1 = dictionary()->hash_to_index(d_hash1);
2160
2161 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2162 int d_index2 = dictionary()->hash_to_index(d_hash2);
2163 {
2164 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2165
2166 // Better never do a GC while we're holding these oops
2167 No_Safepoint_Verifier nosafepoint;
2168
2169 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2170 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2171 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2172 klass2, class_loader2);
2173 }
2174 }
2175
2176 // Add entry to resolution error table to record the error when the first
2177 // attempt to resolve a reference to a class has failed.
2178 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2179 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2180 int index = resolution_errors()->hash_to_index(hash);
2181 {
2182 MutexLocker ml(SystemDictionary_lock, Thread::current());
2183 resolution_errors()->add_entry(index, hash, pool, which, error);
2184 }
2185 }
2186
2187 // Delete a resolution error for RedefineClasses for a constant pool is going away
2188 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2189 resolution_errors()->delete_entry(pool);
2190 }
2191
2192 // Lookup resolution error table. Returns error if found, otherwise NULL.
2193 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2194 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2195 int index = resolution_errors()->hash_to_index(hash);
2196 {
2197 MutexLocker ml(SystemDictionary_lock, Thread::current());
2198 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2199 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2200 }
2201 }
2202
2203
2204 // Signature constraints ensure that callers and callees agree about
2205 // the meaning of type names in their signatures. This routine is the
2206 // intake for constraints. It collects them from several places:
2207 //
2208 // * LinkResolver::resolve_method (if check_access is true) requires
2209 // that the resolving class (the caller) and the defining class of
2210 // the resolved method (the callee) agree on each type in the
2211 // method's signature.
2212 //
2213 // * LinkResolver::resolve_interface_method performs exactly the same
2214 // checks.
2215 //
2216 // * LinkResolver::resolve_field requires that the constant pool
2217 // attempting to link to a field agree with the field's defining
2218 // class about the type of the field signature.
2219 //
2220 // * klassVtable::initialize_vtable requires that, when a class
2221 // overrides a vtable entry allocated by a superclass, that the
2222 // overriding method (i.e., the callee) agree with the superclass
2223 // on each type in the method's signature.
2224 //
2225 // * klassItable::initialize_itable requires that, when a class fills
2226 // in its itables, for each non-abstract method installed in an
2227 // itable, the method (i.e., the callee) agree with the interface
2228 // on each type in the method's signature.
2229 //
2230 // All those methods have a boolean (check_access, checkconstraints)
2231 // which turns off the checks. This is used from specialized contexts
2232 // such as bootstrapping, dumping, and debugging.
2233 //
2234 // No direct constraint is placed between the class and its
2235 // supertypes. Constraints are only placed along linked relations
2236 // between callers and callees. When a method overrides or implements
2237 // an abstract method in a supertype (superclass or interface), the
2238 // constraints are placed as if the supertype were the caller to the
2239 // overriding method. (This works well, since callers to the
2240 // supertype have already established agreement between themselves and
2241 // the supertype.) As a result of all this, a class can disagree with
2242 // its supertype about the meaning of a type name, as long as that
2243 // class neither calls a relevant method of the supertype, nor is
2244 // called (perhaps via an override) from the supertype.
2245 //
2246 //
2247 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2248 //
2249 // Make sure all class components (including arrays) in the given
2250 // signature will be resolved to the same class in both loaders.
2251 // Returns the name of the type that failed a loader constraint check, or
2252 // NULL if no constraint failed. No exception except OOME is thrown.
2253 // Arrays are not added to the loader constraint table, their elements are.
2254 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2255 Handle loader1, Handle loader2,
2256 bool is_method, TRAPS) {
2257 // Nothing to do if loaders are the same.
2258 if (loader1() == loader2()) {
2259 return NULL;
2260 }
2261
2262 SignatureStream sig_strm(signature, is_method);
2263 while (!sig_strm.is_done()) {
2264 if (sig_strm.is_object()) {
2265 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2266 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2267 return sig;
2268 }
2269 }
2270 sig_strm.next();
2271 }
2272 return NULL;
2273 }
2274
2275
2276 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2277 Symbol* signature,
2278 TRAPS) {
2279 methodHandle empty;
2280 assert(EnableInvokeDynamic, "");
2281 assert(MethodHandles::is_signature_polymorphic(iid) &&
2282 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2283 iid != vmIntrinsics::_invokeGeneric,
2284 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2285
2286 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2287 int index = invoke_method_table()->hash_to_index(hash);
2288 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2289 methodHandle m;
2290 if (spe == NULL || spe->method() == NULL) {
2291 spe = NULL;
2292 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2293 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2294 if (!Arguments::is_interpreter_only()) {
2295 // Generate a compiled form of the MH intrinsic.
2296 AdapterHandlerLibrary::create_native_wrapper(m);
2297 // Check if have the compiled code.
2298 if (!m->has_compiled_code()) {
2299 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2300 "out of space in CodeCache for method handle intrinsic", empty);
2301 }
2302 }
2303 // Now grab the lock. We might have to throw away the new method,
2304 // if a racing thread has managed to install one at the same time.
2305 {
2306 MutexLocker ml(SystemDictionary_lock, THREAD);
2307 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2308 if (spe == NULL)
2309 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2310 if (spe->method() == NULL)
2311 spe->set_method(m());
2312 }
2313 }
2314
2315 assert(spe != NULL && spe->method() != NULL, "");
2316 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2317 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2318 "MH intrinsic invariant");
2319 return spe->method();
2320 }
2321
2322 // Helper for unpacking the return value from linkMethod and linkCallSite.
2323 static methodHandle unpack_method_and_appendix(Handle mname,
2324 KlassHandle accessing_klass,
2325 objArrayHandle appendix_box,
2326 Handle* appendix_result,
2327 TRAPS) {
2328 methodHandle empty;
2329 if (mname.not_null()) {
2330 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2331 if (vmtarget != NULL && vmtarget->is_method()) {
2332 Method* m = (Method*)vmtarget;
2333 oop appendix = appendix_box->obj_at(0);
2334 if (TraceMethodHandles) {
2335 #ifndef PRODUCT
2336 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2337 m->print();
2338 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2339 tty->cr();
2340 #endif //PRODUCT
2341 }
2342 (*appendix_result) = Handle(THREAD, appendix);
2343 // the target is stored in the cpCache and if a reference to this
2344 // MethodName is dropped we need a way to make sure the
2345 // class_loader containing this method is kept alive.
2346 // FIXME: the appendix might also preserve this dependency.
2347 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2348 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2349 return methodHandle(THREAD, m);
2350 }
2351 }
2352 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2353 return empty;
2354 }
2355
2356 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2357 Symbol* signature,
2358 KlassHandle accessing_klass,
2359 Handle *appendix_result,
2360 Handle *method_type_result,
2361 TRAPS) {
2362 methodHandle empty;
2363 assert(EnableInvokeDynamic, "");
2364 assert(!THREAD->is_Compiler_thread(), "");
2365 Handle method_type =
2366 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2367
2368 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2369 int ref_kind = JVM_REF_invokeVirtual;
2370 Handle name_str = StringTable::intern(name, CHECK_(empty));
2371 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2372 assert(appendix_box->obj_at(0) == NULL, "");
2373
2374 // This should not happen. JDK code should take care of that.
2375 if (accessing_klass.is_null() || method_type.is_null()) {
2376 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2377 }
2378
2379 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2380 JavaCallArguments args;
2381 args.push_oop(accessing_klass()->java_mirror());
2382 args.push_int(ref_kind);
2383 args.push_oop(mh_klass()->java_mirror());
2384 args.push_oop(name_str());
2385 args.push_oop(method_type());
2386 args.push_oop(appendix_box());
2387 JavaValue result(T_OBJECT);
2388 JavaCalls::call_static(&result,
2389 SystemDictionary::MethodHandleNatives_klass(),
2390 vmSymbols::linkMethod_name(),
2391 vmSymbols::linkMethod_signature(),
2392 &args, CHECK_(empty));
2393 Handle mname(THREAD, (oop) result.get_jobject());
2394 (*method_type_result) = method_type;
2395 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2396 }
2397
2398 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2399 // We must ensure that all class loaders everywhere will reach this class, for any client.
2400 // This is a safe bet for public classes in java.lang, such as Object and String.
2401 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2402 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2403 static bool is_always_visible_class(oop mirror) {
2404 Klass* klass = java_lang_Class::as_Klass(mirror);
2405 if (klass->oop_is_objArray()) {
2406 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2407 }
2408 if (klass->oop_is_typeArray()) {
2409 return true; // primitive array
2410 }
2411 assert(klass->oop_is_instance(), klass->external_name());
2412 return klass->is_public() &&
2413 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2414 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2415 }
2416
2417 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2418 // signature, as interpreted relative to the given class loader.
2419 // Because of class loader constraints, all method handle usage must be
2420 // consistent with this loader.
2421 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2422 KlassHandle accessing_klass,
2423 TRAPS) {
2424 Handle empty;
2425 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2426 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2427 int index = invoke_method_table()->hash_to_index(hash);
2428 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2429 if (spe != NULL && spe->method_type() != NULL) {
2430 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2431 return Handle(THREAD, spe->method_type());
2432 } else if (THREAD->is_Compiler_thread()) {
2433 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2434 return Handle(); // do not attempt from within compiler, unless it was cached
2435 }
2436
2437 Handle class_loader, protection_domain;
2438 if (accessing_klass.not_null()) {
2439 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2440 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2441 }
2442 bool can_be_cached = true;
2443 int npts = ArgumentCount(signature).size();
2444 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2445 int arg = 0;
2446 Handle rt; // the return type from the signature
2447 ResourceMark rm(THREAD);
2448 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2449 oop mirror = NULL;
2450 if (can_be_cached) {
2451 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2452 mirror = ss.as_java_mirror(Handle(), Handle(),
2453 SignatureStream::ReturnNull, CHECK_(empty));
2454 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2455 // Fall back to accessing_klass context.
2456 can_be_cached = false;
2457 }
2458 }
2459 if (!can_be_cached) {
2460 // Resolve, throwing a real error if it doesn't work.
2461 mirror = ss.as_java_mirror(class_loader, protection_domain,
2462 SignatureStream::NCDFError, CHECK_(empty));
2463 }
2464 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2465 if (ss.at_return_type())
2466 rt = Handle(THREAD, mirror);
2467 else
2468 pts->obj_at_put(arg++, mirror);
2469
2470 // Check accessibility.
2471 if (ss.is_object() && accessing_klass.not_null()) {
2472 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2473 mirror = NULL; // safety
2474 // Emulate ConstantPool::verify_constant_pool_resolve.
2475 if (sel_klass->oop_is_objArray())
2476 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2477 if (sel_klass->oop_is_instance()) {
2478 KlassHandle sel_kh(THREAD, sel_klass);
2479 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2480 }
2481 }
2482 }
2483 assert(arg == npts, "");
2484
2485 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2486 JavaCallArguments args(Handle(THREAD, rt()));
2487 args.push_oop(pts());
2488 JavaValue result(T_OBJECT);
2489 JavaCalls::call_static(&result,
2490 SystemDictionary::MethodHandleNatives_klass(),
2491 vmSymbols::findMethodHandleType_name(),
2492 vmSymbols::findMethodHandleType_signature(),
2493 &args, CHECK_(empty));
2494 Handle method_type(THREAD, (oop) result.get_jobject());
2495
2496 if (can_be_cached) {
2497 // We can cache this MethodType inside the JVM.
2498 MutexLocker ml(SystemDictionary_lock, THREAD);
2499 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2500 if (spe == NULL)
2501 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2502 if (spe->method_type() == NULL) {
2503 spe->set_method_type(method_type());
2504 }
2505 }
2506
2507 // report back to the caller with the MethodType
2508 return method_type;
2509 }
2510
2511 // Ask Java code to find or construct a method handle constant.
2512 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2513 int ref_kind, //e.g., JVM_REF_invokeVirtual
2514 KlassHandle callee,
2515 Symbol* name_sym,
2516 Symbol* signature,
2517 TRAPS) {
2518 Handle empty;
2519 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2520 Handle type;
2521 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2522 type = find_method_handle_type(signature, caller, CHECK_(empty));
2523 } else if (caller.is_null()) {
2524 // This should not happen. JDK code should take care of that.
2525 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2526 } else {
2527 ResourceMark rm(THREAD);
2528 SignatureStream ss(signature, false);
2529 if (!ss.is_done()) {
2530 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2531 SignatureStream::NCDFError, CHECK_(empty));
2532 type = Handle(THREAD, mirror);
2533 ss.next();
2534 if (!ss.is_done()) type = Handle(); // error!
2535 }
2536 }
2537 if (type.is_null()) {
2538 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2539 }
2540
2541 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2542 JavaCallArguments args;
2543 args.push_oop(caller->java_mirror()); // the referring class
2544 args.push_int(ref_kind);
2545 args.push_oop(callee->java_mirror()); // the target class
2546 args.push_oop(name());
2547 args.push_oop(type());
2548 JavaValue result(T_OBJECT);
2549 JavaCalls::call_static(&result,
2550 SystemDictionary::MethodHandleNatives_klass(),
2551 vmSymbols::linkMethodHandleConstant_name(),
2552 vmSymbols::linkMethodHandleConstant_signature(),
2553 &args, CHECK_(empty));
2554 return Handle(THREAD, (oop) result.get_jobject());
2555 }
2556
2557 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2558 // name and signature, as interpreted relative to the given class loader.
2559 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2560 Handle bootstrap_specifier,
2561 Symbol* name,
2562 Symbol* type,
2563 Handle *appendix_result,
2564 Handle *method_type_result,
2565 TRAPS) {
2566 methodHandle empty;
2567 Handle bsm, info;
2568 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2569 bsm = bootstrap_specifier;
2570 } else {
2571 assert(bootstrap_specifier->is_objArray(), "");
2572 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2573 int len = args->length();
2574 assert(len >= 1, "");
2575 bsm = Handle(THREAD, args->obj_at(0));
2576 if (len > 1) {
2577 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2578 for (int i = 1; i < len; i++)
2579 args1->obj_at_put(i-1, args->obj_at(i));
2580 info = Handle(THREAD, args1);
2581 }
2582 }
2583 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2584 "caller must supply a valid BSM");
2585
2586 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2587 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2588
2589 // This should not happen. JDK code should take care of that.
2590 if (caller.is_null() || method_type.is_null()) {
2591 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2592 }
2593
2594 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2595 assert(appendix_box->obj_at(0) == NULL, "");
2596
2597 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2598 JavaCallArguments args;
2599 args.push_oop(caller->java_mirror());
2600 args.push_oop(bsm());
2601 args.push_oop(method_name());
2602 args.push_oop(method_type());
2603 args.push_oop(info());
2604 args.push_oop(appendix_box);
2605 JavaValue result(T_OBJECT);
2606 JavaCalls::call_static(&result,
2607 SystemDictionary::MethodHandleNatives_klass(),
2608 vmSymbols::linkCallSite_name(),
2609 vmSymbols::linkCallSite_signature(),
2610 &args, CHECK_(empty));
2611 Handle mname(THREAD, (oop) result.get_jobject());
2612 (*method_type_result) = method_type;
2613 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2614 }
2615
2616 // Since the identity hash code for symbols changes when the symbols are
2617 // moved from the regular perm gen (hash in the mark word) to the shared
2618 // spaces (hash is the address), the classes loaded into the dictionary
2619 // may be in the wrong buckets.
2620
2621 void SystemDictionary::reorder_dictionary() {
2622 dictionary()->reorder_dictionary();
2623 }
2624
2625
2626 void SystemDictionary::copy_buckets(char** top, char* end) {
2627 dictionary()->copy_buckets(top, end);
2628 }
2629
2630
2631 void SystemDictionary::copy_table(char** top, char* end) {
2632 dictionary()->copy_table(top, end);
2633 }
2634
2635
2636 void SystemDictionary::reverse() {
2637 dictionary()->reverse();
2638 }
2639
2640 int SystemDictionary::number_of_classes() {
2641 return dictionary()->number_of_entries();
2642 }
2643
2644
2645 // ----------------------------------------------------------------------------
2646 void SystemDictionary::print_shared(bool details) {
2647 shared_dictionary()->print(details);
2648 }
2649
2650 void SystemDictionary::print(bool details) {
2651 dictionary()->print(details);
2652
2653 // Placeholders
2654 GCMutexLocker mu(SystemDictionary_lock);
2655 placeholders()->print();
2656
2657 // loader constraints - print under SD_lock
2658 constraints()->print();
2659 }
2660
2661
2662 void SystemDictionary::verify() {
2663 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2664 guarantee(constraints() != NULL,
2665 "Verify of loader constraints failed");
2666 guarantee(dictionary()->number_of_entries() >= 0 &&
2667 placeholders()->number_of_entries() >= 0,
2668 "Verify of system dictionary failed");
2669
2670 // Verify dictionary
2671 dictionary()->verify();
2672
2673 GCMutexLocker mu(SystemDictionary_lock);
2674 placeholders()->verify();
2675
2676 // Verify constraint table
2677 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2678 constraints()->verify(dictionary(), placeholders());
2679 }
2680
2681 // utility function for class load event
2682 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2683 instanceKlassHandle k,
2684 Handle initiating_loader) {
2685 #if INCLUDE_TRACE
2686 EventClassLoad event(UNTIMED);
2687 if (event.should_commit()) {
2688 event.set_starttime(start_time);
2689 event.set_loadedClass(k());
2690 oop defining_class_loader = k->class_loader();
2691 event.set_definingClassLoader(defining_class_loader != NULL ?
2692 defining_class_loader->klass() : (Klass*)NULL);
2693 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
2694 event.set_initiatingClassLoader(class_loader != NULL ?
2695 class_loader->klass() : (Klass*)NULL);
2696 event.commit();
2697 }
2698 #endif // INCLUDE_TRACE
2699 }
2700
2701 #ifndef PRODUCT
2702
2703 // statistics code
2704 class ClassStatistics: AllStatic {
2705 private:
2706 static int nclasses; // number of classes
2707 static int nmethods; // number of methods
2708 static int nmethoddata; // number of methodData
2709 static int class_size; // size of class objects in words
2710 static int method_size; // size of method objects in words
2711 static int debug_size; // size of debug info in methods
2712 static int methoddata_size; // size of methodData objects in words
2713
2714 static void do_class(Klass* k) {
2715 nclasses++;
2716 class_size += k->size();
2717 if (k->oop_is_instance()) {
2718 InstanceKlass* ik = (InstanceKlass*)k;
2719 class_size += ik->methods()->size();
2720 class_size += ik->constants()->size();
2721 class_size += ik->local_interfaces()->size();
2722 class_size += ik->transitive_interfaces()->size();
2723 // We do not have to count implementors, since we only store one!
2724 // SSS: How should these be accounted now that they have moved?
2725 // class_size += ik->fields()->length();
2726 }
2727 }
2728
2729 static void do_method(Method* m) {
2730 nmethods++;
2731 method_size += m->size();
2732 // class loader uses same objArray for empty vectors, so don't count these
2733 if (m->has_stackmap_table()) {
2734 method_size += m->stackmap_data()->size();
2735 }
2736
2737 MethodData* mdo = m->method_data();
2738 if (mdo != NULL) {
2739 nmethoddata++;
2740 methoddata_size += mdo->size();
2741 }
2742 }
2743
2744 public:
2745 static void print() {
2746 SystemDictionary::classes_do(do_class);
2747 SystemDictionary::methods_do(do_method);
2748 tty->print_cr("Class statistics:");
2749 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2750 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2751 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2752 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2753 }
2754 };
2755
2756
2757 int ClassStatistics::nclasses = 0;
2758 int ClassStatistics::nmethods = 0;
2759 int ClassStatistics::nmethoddata = 0;
2760 int ClassStatistics::class_size = 0;
2761 int ClassStatistics::method_size = 0;
2762 int ClassStatistics::debug_size = 0;
2763 int ClassStatistics::methoddata_size = 0;
2764
2765 void SystemDictionary::print_class_statistics() {
2766 ResourceMark rm;
2767 ClassStatistics::print();
2768 }
2769
2770
2771 class MethodStatistics: AllStatic {
2772 public:
2773 enum {
2774 max_parameter_size = 10
2775 };
2776 private:
2777
2778 static int _number_of_methods;
2779 static int _number_of_final_methods;
2780 static int _number_of_static_methods;
2781 static int _number_of_native_methods;
2782 static int _number_of_synchronized_methods;
2783 static int _number_of_profiled_methods;
2784 static int _number_of_bytecodes;
2785 static int _parameter_size_profile[max_parameter_size];
2786 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2787
2788 static void initialize() {
2789 _number_of_methods = 0;
2790 _number_of_final_methods = 0;
2791 _number_of_static_methods = 0;
2792 _number_of_native_methods = 0;
2793 _number_of_synchronized_methods = 0;
2794 _number_of_profiled_methods = 0;
2795 _number_of_bytecodes = 0;
2796 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2797 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2798 };
2799
2800 static void do_method(Method* m) {
2801 _number_of_methods++;
2802 // collect flag info
2803 if (m->is_final() ) _number_of_final_methods++;
2804 if (m->is_static() ) _number_of_static_methods++;
2805 if (m->is_native() ) _number_of_native_methods++;
2806 if (m->is_synchronized()) _number_of_synchronized_methods++;
2807 if (m->method_data() != NULL) _number_of_profiled_methods++;
2808 // collect parameter size info (add one for receiver, if any)
2809 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2810 // collect bytecodes info
2811 {
2812 Thread *thread = Thread::current();
2813 HandleMark hm(thread);
2814 BytecodeStream s(methodHandle(thread, m));
2815 Bytecodes::Code c;
2816 while ((c = s.next()) >= 0) {
2817 _number_of_bytecodes++;
2818 _bytecodes_profile[c]++;
2819 }
2820 }
2821 }
2822
2823 public:
2824 static void print() {
2825 initialize();
2826 SystemDictionary::methods_do(do_method);
2827 // generate output
2828 tty->cr();
2829 tty->print_cr("Method statistics (static):");
2830 // flag distribution
2831 tty->cr();
2832 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2833 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2834 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2835 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2836 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2837 // parameter size profile
2838 tty->cr();
2839 { int tot = 0;
2840 int avg = 0;
2841 for (int i = 0; i < max_parameter_size; i++) {
2842 int n = _parameter_size_profile[i];
2843 tot += n;
2844 avg += n*i;
2845 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2846 }
2847 assert(tot == _number_of_methods, "should be the same");
2848 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2849 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2850 }
2851 // bytecodes profile
2852 tty->cr();
2853 { int tot = 0;
2854 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2855 if (Bytecodes::is_defined(i)) {
2856 Bytecodes::Code c = Bytecodes::cast(i);
2857 int n = _bytecodes_profile[c];
2858 tot += n;
2859 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2860 }
2861 }
2862 assert(tot == _number_of_bytecodes, "should be the same");
2863 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2864 }
2865 tty->cr();
2866 }
2867 };
2868
2869 int MethodStatistics::_number_of_methods;
2870 int MethodStatistics::_number_of_final_methods;
2871 int MethodStatistics::_number_of_static_methods;
2872 int MethodStatistics::_number_of_native_methods;
2873 int MethodStatistics::_number_of_synchronized_methods;
2874 int MethodStatistics::_number_of_profiled_methods;
2875 int MethodStatistics::_number_of_bytecodes;
2876 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2877 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2878
2879
2880 void SystemDictionary::print_method_statistics() {
2881 MethodStatistics::print();
2882 }
2883
2884 #endif // PRODUCT