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 "jfr/jfrEvents.hpp"
42 #include "memory/filemap.hpp"
43 #include "memory/gcLocker.hpp"
44 #include "memory/oopFactory.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/instanceRefKlass.hpp"
47 #include "oops/klass.inline.hpp"
48 #include "oops/methodData.hpp"
49 #include "oops/objArrayKlass.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "oops/oop.inline2.hpp"
52 #include "oops/typeArrayKlass.hpp"
53 #include "prims/jvmtiEnvBase.hpp"
54 #include "prims/methodHandles.hpp"
55 #include "runtime/arguments.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/fieldType.hpp"
58 #include "runtime/handles.inline.hpp"
59 #include "runtime/java.hpp"
60 #include "runtime/javaCalls.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/signature.hpp"
64 #include "services/classLoadingService.hpp"
65 #include "services/threadService.hpp"
66 #include "utilities/macros.hpp"
67 #include "utilities/ticks.hpp"
68
69 Dictionary* SystemDictionary::_dictionary = NULL;
70 PlaceholderTable* SystemDictionary::_placeholders = NULL;
71 Dictionary* SystemDictionary::_shared_dictionary = NULL;
72 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
73 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
74 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
75
76
77 int SystemDictionary::_number_of_modifications = 0;
78 int SystemDictionary::_sdgeneration = 0;
79 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
80 20201,40423,99991};
81
82 oop SystemDictionary::_system_loader_lock_obj = NULL;
83
84 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
85 = { NULL /*, NULL...*/ };
86
87 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
88
89 oop SystemDictionary::_java_system_loader = NULL;
90
91 bool SystemDictionary::_has_loadClassInternal = false;
92 bool SystemDictionary::_has_checkPackageAccess = false;
93
94 // lazily initialized klass variables
95 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
96
97
98 // ----------------------------------------------------------------------------
99 // Java-level SystemLoader
100
101 oop SystemDictionary::java_system_loader() {
102 return _java_system_loader;
103 }
104
105 void SystemDictionary::compute_java_system_loader(TRAPS) {
106 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
107 JavaValue result(T_OBJECT);
108 JavaCalls::call_static(&result,
109 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
110 vmSymbols::getSystemClassLoader_name(),
111 vmSymbols::void_classloader_signature(),
112 CHECK);
113
114 _java_system_loader = (oop)result.get_jobject();
115
116 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
117 }
118
119
120 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
121 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
122 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
123 }
124
125 // ----------------------------------------------------------------------------
126 // debugging
127
128 #ifdef ASSERT
129
130 // return true if class_name contains no '.' (internal format is '/')
131 bool SystemDictionary::is_internal_format(Symbol* class_name) {
132 if (class_name != NULL) {
133 ResourceMark rm;
134 char* name = class_name->as_C_string();
135 return strchr(name, '.') == NULL;
136 } else {
137 return true;
138 }
139 }
140
141 #endif
142
143 // ----------------------------------------------------------------------------
144 // Parallel class loading check
145
146 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
147 if (UnsyncloadClass || class_loader.is_null()) return true;
148 if (AlwaysLockClassLoader) return false;
149 return java_lang_ClassLoader::parallelCapable(class_loader());
150 }
151 // ----------------------------------------------------------------------------
152 // ParallelDefineClass flag does not apply to bootclass loader
153 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
154 if (class_loader.is_null()) return false;
155 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
156 return true;
157 }
158 return false;
159 }
160
161 /**
162 * Returns true if the passed class loader is the extension class loader.
163 */
164 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
165 if (class_loader.is_null()) {
166 return false;
167 }
168 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
169 }
170
171 // ----------------------------------------------------------------------------
172 // Resolving of classes
173
174 // Forwards to resolve_or_null
175
176 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
177 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
178 if (HAS_PENDING_EXCEPTION || klass == NULL) {
179 KlassHandle k_h(THREAD, klass);
180 // can return a null klass
181 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
182 }
183 return klass;
184 }
185
186 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
187 if (HAS_PENDING_EXCEPTION) {
188 // If we have a pending exception we forward it to the caller, unless throw_error is true,
189 // in which case we have to check whether the pending exception is a ClassNotFoundException,
190 // and if so convert it to a NoClassDefFoundError
191 // And chain the original ClassNotFoundException
192 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
193 ResourceMark rm(THREAD);
194 assert(klass_h() == NULL, "Should not have result with exception pending");
195 Handle e(THREAD, PENDING_EXCEPTION);
196 CLEAR_PENDING_EXCEPTION;
197 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
198 } else {
199 return NULL;
200 }
201 }
202 // Class not found, throw appropriate error or exception depending on value of throw_error
203 if (klass_h() == NULL) {
204 ResourceMark rm(THREAD);
205 if (throw_error) {
206 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
207 } else {
208 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
209 }
210 }
211 return (Klass*)klass_h();
212 }
213
214
215 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
216 bool throw_error, TRAPS)
217 {
218 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
219 }
220
221
222 // Forwards to resolve_instance_class_or_null
223
224 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
225 assert(!THREAD->is_Compiler_thread(),
226 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
227 class_name->as_C_string(),
228 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
229 if (FieldType::is_array(class_name)) {
230 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
231 } else if (FieldType::is_obj(class_name)) {
232 ResourceMark rm(THREAD);
233 // Ignore wrapping L and ;.
234 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
235 class_name->utf8_length() - 2, CHECK_NULL);
236 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
237 } else {
238 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
239 }
240 }
241
242 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
243 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
244 }
245
246 // Forwards to resolve_instance_class_or_null
247
248 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
249 Handle class_loader,
250 Handle protection_domain,
251 TRAPS) {
252 assert(FieldType::is_array(class_name), "must be array");
253 Klass* k = NULL;
254 FieldArrayInfo fd;
255 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
256 // of this call
257 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
258 if (t == T_OBJECT) {
259 // naked oop "k" is OK here -- we assign back into it
260 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
261 class_loader,
262 protection_domain,
263 CHECK_NULL);
264 if (k != NULL) {
265 k = k->array_klass(fd.dimension(), CHECK_NULL);
266 }
267 } else {
268 k = Universe::typeArrayKlassObj(t);
269 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
270 }
271 return k;
272 }
273
274
275 // Must be called for any super-class or super-interface resolution
276 // during class definition to allow class circularity checking
277 // super-interface callers:
278 // parse_interfaces - for defineClass & jvmtiRedefineClasses
279 // super-class callers:
280 // ClassFileParser - for defineClass & jvmtiRedefineClasses
281 // load_shared_class - while loading a class from shared archive
282 // resolve_instance_class_or_null:
283 // via: handle_parallel_super_load
284 // when resolving a class that has an existing placeholder with
285 // a saved superclass [i.e. a defineClass is currently in progress]
286 // if another thread is trying to resolve the class, it must do
287 // super-class checks on its own thread to catch class circularity
288 // This last call is critical in class circularity checking for cases
289 // where classloading is delegated to different threads and the
290 // classloader lock is released.
291 // Take the case: Base->Super->Base
292 // 1. If thread T1 tries to do a defineClass of class Base
293 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
294 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
295 // so it tries to load Super
296 // 3. If we load the class internally, or user classloader uses same thread
297 // loadClassFromxxx or defineClass via parseClassFile Super ...
298 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
299 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
300 // 3.4 calls resolve_super_or_fail Base
301 // 3.5 finds T1,Base -> throws class circularity
302 //OR 4. If T2 tries to resolve Super via defineClass Super ...
303 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
304 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
305 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
306 // 4.4 finds T2, Super -> throws class circularity
307 // Must be called, even if superclass is null, since this is
308 // where the placeholder entry is created which claims this
309 // thread is loading this class/classloader.
310 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
311 Symbol* class_name,
312 Handle class_loader,
313 Handle protection_domain,
314 bool is_superclass,
315 TRAPS) {
316 // Double-check, if child class is already loaded, just return super-class,interface
317 // Don't add a placedholder if already loaded, i.e. already in system dictionary
318 // Make sure there's a placeholder for the *child* before resolving.
319 // Used as a claim that this thread is currently loading superclass/classloader
320 // Used here for ClassCircularity checks and also for heap verification
321 // (every InstanceKlass in the heap needs to be in the system dictionary
322 // or have a placeholder).
323 // Must check ClassCircularity before checking if super class is already loaded
324 //
325 // We might not already have a placeholder if this child_name was
326 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
327 // the name of the class might not be known until the stream is actually
328 // parsed.
329 // Bugs 4643874, 4715493
330 // compute_hash can have a safepoint
331
332 ClassLoaderData* loader_data = class_loader_data(class_loader);
333 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
334 int d_index = dictionary()->hash_to_index(d_hash);
335 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
336 int p_index = placeholders()->hash_to_index(p_hash);
337 // can't throw error holding a lock
338 bool child_already_loaded = false;
339 bool throw_circularity_error = false;
340 {
341 MutexLocker mu(SystemDictionary_lock, THREAD);
342 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
343 Klass* quicksuperk;
344 // to support // loading: if child done loading, just return superclass
345 // if class_name, & class_loader don't match:
346 // if initial define, SD update will give LinkageError
347 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
348 // so we don't throw an exception here.
349 // see: nsk redefclass014 & java.lang.instrument Instrument032
350 if ((childk != NULL ) && (is_superclass) &&
351 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
352
353 ((quicksuperk->name() == class_name) &&
354 (quicksuperk->class_loader() == class_loader()))) {
355 return quicksuperk;
356 } else {
357 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
358 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
359 throw_circularity_error = true;
360 }
361 }
362 if (!throw_circularity_error) {
363 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
364 }
365 }
366 if (throw_circularity_error) {
367 ResourceMark rm(THREAD);
368 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
369 }
370
371 // java.lang.Object should have been found above
372 assert(class_name != NULL, "null super class for resolving");
373 // Resolve the super class or interface, check results on return
374 Klass* superk = SystemDictionary::resolve_or_null(class_name,
375 class_loader,
376 protection_domain,
377 THREAD);
378
379 KlassHandle superk_h(THREAD, superk);
380
381 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
382 // It is no longer necessary to keep the placeholder table alive until update_dictionary
383 // or error. GC used to walk the placeholder table as strong roots.
384 // The instanceKlass is kept alive because the class loader is on the stack,
385 // which keeps the loader_data alive, as well as all instanceKlasses in
386 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
387 {
388 MutexLocker mu(SystemDictionary_lock, THREAD);
389 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
390 SystemDictionary_lock->notify_all();
391 }
392 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
393 // can null superk
394 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
395 }
396
397 return superk_h();
398 }
399
400 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
401 Handle class_loader,
402 Handle protection_domain,
403 TRAPS) {
404 if(!has_checkPackageAccess()) return;
405
406 // Now we have to call back to java to check if the initating class has access
407 JavaValue result(T_VOID);
408 if (TraceProtectionDomainVerification) {
409 // Print out trace information
410 tty->print_cr("Checking package access");
411 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
412 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
413 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
414 }
415
416 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
417 JavaCalls::call_special(&result,
418 class_loader,
419 system_loader,
420 vmSymbols::checkPackageAccess_name(),
421 vmSymbols::class_protectiondomain_signature(),
422 Handle(THREAD, klass->java_mirror()),
423 protection_domain,
424 THREAD);
425
426 if (TraceProtectionDomainVerification) {
427 if (HAS_PENDING_EXCEPTION) {
428 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
429 } else {
430 tty->print_cr(" -> granted");
431 }
432 tty->cr();
433 }
434
435 if (HAS_PENDING_EXCEPTION) return;
436
437 // If no exception has been thrown, we have validated the protection domain
438 // Insert the protection domain of the initiating class into the set.
439 {
440 // We recalculate the entry here -- we've called out to java since
441 // the last time it was calculated.
442 ClassLoaderData* loader_data = class_loader_data(class_loader);
443
444 Symbol* kn = klass->name();
445 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
446 int d_index = dictionary()->hash_to_index(d_hash);
447
448 MutexLocker mu(SystemDictionary_lock, THREAD);
449 {
450 // Note that we have an entry, and entries can be deleted only during GC,
451 // so we cannot allow GC to occur while we're holding this entry.
452
453 // We're using a No_Safepoint_Verifier to catch any place where we
454 // might potentially do a GC at all.
455 // Dictionary::do_unloading() asserts that classes in SD are only
456 // unloaded at a safepoint. Anonymous classes are not in SD.
457 No_Safepoint_Verifier nosafepoint;
458 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
459 protection_domain, THREAD);
460 }
461 }
462 }
463
464 // We only get here if this thread finds that another thread
465 // has already claimed the placeholder token for the current operation,
466 // but that other thread either never owned or gave up the
467 // object lock
468 // Waits on SystemDictionary_lock to indicate placeholder table updated
469 // On return, caller must recheck placeholder table state
470 //
471 // We only get here if
472 // 1) custom classLoader, i.e. not bootstrap classloader
473 // 2) UnsyncloadClass not set
474 // 3) custom classLoader has broken the class loader objectLock
475 // so another thread got here in parallel
476 //
477 // lockObject must be held.
478 // Complicated dance due to lock ordering:
479 // Must first release the classloader object lock to
480 // allow initial definer to complete the class definition
481 // and to avoid deadlock
482 // Reclaim classloader lock object with same original recursion count
483 // Must release SystemDictionary_lock after notify, since
484 // class loader lock must be claimed before SystemDictionary_lock
485 // to prevent deadlocks
486 //
487 // The notify allows applications that did an untimed wait() on
488 // the classloader object lock to not hang.
489 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
490 assert_lock_strong(SystemDictionary_lock);
491
492 bool calledholdinglock
493 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
494 assert(calledholdinglock,"must hold lock for notify");
495 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
496 ObjectSynchronizer::notifyall(lockObject, THREAD);
497 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
498 SystemDictionary_lock->wait();
499 SystemDictionary_lock->unlock();
500 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
501 SystemDictionary_lock->lock();
502 }
503
504 // If the class in is in the placeholder table, class loading is in progress
505 // For cases where the application changes threads to load classes, it
506 // is critical to ClassCircularity detection that we try loading
507 // the superclass on the same thread internally, so we do parallel
508 // super class loading here.
509 // This also is critical in cases where the original thread gets stalled
510 // even in non-circularity situations.
511 // Note: must call resolve_super_or_fail even if null super -
512 // to force placeholder entry creation for this class for circularity detection
513 // Caller must check for pending exception
514 // Returns non-null Klass* if other thread has completed load
515 // and we are done,
516 // If return null Klass* and no pending exception, the caller must load the class
517 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
518 Symbol* name, Symbol* superclassname, Handle class_loader,
519 Handle protection_domain, Handle lockObject, TRAPS) {
520
521 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
522 ClassLoaderData* loader_data = class_loader_data(class_loader);
523 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
524 int d_index = dictionary()->hash_to_index(d_hash);
525 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
526 int p_index = placeholders()->hash_to_index(p_hash);
527
528 // superk is not used, resolve_super called for circularity check only
529 // This code is reached in two situations. One if this thread
530 // is loading the same class twice (e.g. ClassCircularity, or
531 // java.lang.instrument).
532 // The second is if another thread started the resolve_super first
533 // and has not yet finished.
534 // In both cases the original caller will clean up the placeholder
535 // entry on error.
536 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
537 superclassname,
538 class_loader,
539 protection_domain,
540 true,
541 CHECK_(nh));
542
543 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
544 // Serial class loaders and bootstrap classloader do wait for superclass loads
545 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
546 MutexLocker mu(SystemDictionary_lock, THREAD);
547 // Check if classloading completed while we were loading superclass or waiting
548 Klass* check = find_class(d_index, d_hash, name, loader_data);
549 if (check != NULL) {
550 // Klass is already loaded, so just return it
551 return(instanceKlassHandle(THREAD, check));
552 } else {
553 return nh;
554 }
555 }
556
557 // must loop to both handle other placeholder updates
558 // and spurious notifications
559 bool super_load_in_progress = true;
560 PlaceholderEntry* placeholder;
561 while (super_load_in_progress) {
562 MutexLocker mu(SystemDictionary_lock, THREAD);
563 // Check if classloading completed while we were loading superclass or waiting
564 Klass* check = find_class(d_index, d_hash, name, loader_data);
565 if (check != NULL) {
566 // Klass is already loaded, so just return it
567 return(instanceKlassHandle(THREAD, check));
568 } else {
569 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
570 if (placeholder && placeholder->super_load_in_progress() ){
571 // Before UnsyncloadClass:
572 // We only get here if the application has released the
573 // classloader lock when another thread was in the middle of loading a
574 // superclass/superinterface for this class, and now
575 // this thread is also trying to load this class.
576 // To minimize surprises, the first thread that started to
577 // load a class should be the one to complete the loading
578 // with the classfile it initially expected.
579 // This logic has the current thread wait once it has done
580 // all the superclass/superinterface loading it can, until
581 // the original thread completes the class loading or fails
582 // If it completes we will use the resulting InstanceKlass
583 // which we will find below in the systemDictionary.
584 // We also get here for parallel bootstrap classloader
585 if (class_loader.is_null()) {
586 SystemDictionary_lock->wait();
587 } else {
588 double_lock_wait(lockObject, THREAD);
589 }
590 } else {
591 // If not in SD and not in PH, other thread's load must have failed
592 super_load_in_progress = false;
593 }
594 }
595 }
596 return (nh);
597 }
598
599 // utility function for class load event
600 static void post_class_load_event(EventClassLoad &event,
601 instanceKlassHandle k,
602 Handle initiating_loader) {
603 #if INCLUDE_JFR
604 if (event.should_commit()) {
605 event.set_loadedClass(k());
606 event.set_definingClassLoader(k->class_loader_data());
607 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
608 event.set_initiatingClassLoader(class_loader != NULL ?
609 ClassLoaderData::class_loader_data_or_null(class_loader) :
610 (ClassLoaderData*)NULL);
611 event.commit();
612 }
613 #endif // INCLUDE_JFR
614 }
615
616 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
617 Handle class_loader,
618 Handle protection_domain,
619 TRAPS) {
620 assert(name != NULL && !FieldType::is_array(name) &&
621 !FieldType::is_obj(name), "invalid class name");
622
623 EventClassLoad class_load_start_event;
624
625 // UseNewReflection
626 // Fix for 4474172; see evaluation for more details
627 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
628 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
629
630 // Do lookup to see if class already exist and the protection domain
631 // has the right access
632 // This call uses find which checks protection domain already matches
633 // All subsequent calls use find_class, and set has_loaded_class so that
634 // before we return a result we call out to java to check for valid protection domain
635 // to allow returning the Klass* and add it to the pd_set if it is valid
636 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
637 int d_index = dictionary()->hash_to_index(d_hash);
638 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
639 protection_domain, THREAD);
640 if (probe != NULL) return probe;
641
642
643 // Non-bootstrap class loaders will call out to class loader and
644 // define via jvm/jni_DefineClass which will acquire the
645 // class loader object lock to protect against multiple threads
646 // defining the class in parallel by accident.
647 // This lock must be acquired here so the waiter will find
648 // any successful result in the SystemDictionary and not attempt
649 // the define
650 // ParallelCapable Classloaders and the bootstrap classloader,
651 // or all classloaders with UnsyncloadClass do not acquire lock here
652 bool DoObjectLock = true;
653 if (is_parallelCapable(class_loader)) {
654 DoObjectLock = false;
655 }
656
657 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
658 int p_index = placeholders()->hash_to_index(p_hash);
659
660 // Class is not in SystemDictionary so we have to do loading.
661 // Make sure we are synchronized on the class loader before we proceed
662 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
663 check_loader_lock_contention(lockObject, THREAD);
664 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
665
666 // Check again (after locking) if class already exist in SystemDictionary
667 bool class_has_been_loaded = false;
668 bool super_load_in_progress = false;
669 bool havesupername = false;
670 instanceKlassHandle k;
671 PlaceholderEntry* placeholder;
672 Symbol* superclassname = NULL;
673
674 {
675 MutexLocker mu(SystemDictionary_lock, THREAD);
676 Klass* check = find_class(d_index, d_hash, name, loader_data);
677 if (check != NULL) {
678 // Klass is already loaded, so just return it
679 class_has_been_loaded = true;
680 k = instanceKlassHandle(THREAD, check);
681 } else {
682 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
683 if (placeholder && placeholder->super_load_in_progress()) {
684 super_load_in_progress = true;
685 if (placeholder->havesupername() == true) {
686 superclassname = placeholder->supername();
687 havesupername = true;
688 }
689 }
690 }
691 }
692
693 // If the class is in the placeholder table, class loading is in progress
694 if (super_load_in_progress && havesupername==true) {
695 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
696 class_loader, protection_domain, lockObject, THREAD);
697 if (HAS_PENDING_EXCEPTION) {
698 return NULL;
699 }
700 if (!k.is_null()) {
701 class_has_been_loaded = true;
702 }
703 }
704
705 bool throw_circularity_error = false;
706 if (!class_has_been_loaded) {
707 bool load_instance_added = false;
708
709 // add placeholder entry to record loading instance class
710 // Five cases:
711 // All cases need to prevent modifying bootclasssearchpath
712 // in parallel with a classload of same classname
713 // Redefineclasses uses existence of the placeholder for the duration
714 // of the class load to prevent concurrent redefinition of not completely
715 // defined classes.
716 // case 1. traditional classloaders that rely on the classloader object lock
717 // - no other need for LOAD_INSTANCE
718 // case 2. traditional classloaders that break the classloader object lock
719 // as a deadlock workaround. Detection of this case requires that
720 // this check is done while holding the classloader object lock,
721 // and that lock is still held when calling classloader's loadClass.
722 // For these classloaders, we ensure that the first requestor
723 // completes the load and other requestors wait for completion.
724 // case 3. UnsyncloadClass - don't use objectLocker
725 // With this flag, we allow parallel classloading of a
726 // class/classloader pair
727 // case4. Bootstrap classloader - don't own objectLocker
728 // This classloader supports parallelism at the classloader level,
729 // but only allows a single load of a class/classloader pair.
730 // No performance benefit and no deadlock issues.
731 // case 5. parallelCapable user level classloaders - without objectLocker
732 // Allow parallel classloading of a class/classloader pair
733
734 {
735 MutexLocker mu(SystemDictionary_lock, THREAD);
736 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
737 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
738 if (oldprobe) {
739 // only need check_seen_thread once, not on each loop
740 // 6341374 java/lang/Instrument with -Xcomp
741 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
742 throw_circularity_error = true;
743 } else {
744 // case 1: traditional: should never see load_in_progress.
745 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
746
747 // case 4: bootstrap classloader: prevent futile classloading,
748 // wait on first requestor
749 if (class_loader.is_null()) {
750 SystemDictionary_lock->wait();
751 } else {
752 // case 2: traditional with broken classloader lock. wait on first
753 // requestor.
754 double_lock_wait(lockObject, THREAD);
755 }
756 // Check if classloading completed while we were waiting
757 Klass* check = find_class(d_index, d_hash, name, loader_data);
758 if (check != NULL) {
759 // Klass is already loaded, so just return it
760 k = instanceKlassHandle(THREAD, check);
761 class_has_been_loaded = true;
762 }
763 // check if other thread failed to load and cleaned up
764 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
765 }
766 }
767 }
768 }
769 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
770 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
771 // LOAD_INSTANCE in parallel
772
773 if (!throw_circularity_error && !class_has_been_loaded) {
774 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
775 load_instance_added = true;
776 // For class loaders that do not acquire the classloader object lock,
777 // if they did not catch another thread holding LOAD_INSTANCE,
778 // need a check analogous to the acquire ObjectLocker/find_class
779 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
780 // one final check if the load has already completed
781 // class loaders holding the ObjectLock shouldn't find the class here
782 Klass* check = find_class(d_index, d_hash, name, loader_data);
783 if (check != NULL) {
784 // Klass is already loaded, so return it after checking/adding protection domain
785 k = instanceKlassHandle(THREAD, check);
786 class_has_been_loaded = true;
787 }
788 }
789 }
790
791 // must throw error outside of owning lock
792 if (throw_circularity_error) {
793 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
794 ResourceMark rm(THREAD);
795 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
796 }
797
798 if (!class_has_been_loaded) {
799
800 // Do actual loading
801 k = load_instance_class(name, class_loader, THREAD);
802
803 // For UnsyncloadClass only
804 // If they got a linkageError, check if a parallel class load succeeded.
805 // If it did, then for bytecode resolution the specification requires
806 // that we return the same result we did for the other thread, i.e. the
807 // successfully loaded InstanceKlass
808 // Should not get here for classloaders that support parallelism
809 // with the new cleaner mechanism, even with AllowParallelDefineClass
810 // Bootstrap goes through here to allow for an extra guarantee check
811 if (UnsyncloadClass || (class_loader.is_null())) {
812 if (k.is_null() && HAS_PENDING_EXCEPTION
813 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
814 MutexLocker mu(SystemDictionary_lock, THREAD);
815 Klass* check = find_class(d_index, d_hash, name, loader_data);
816 if (check != NULL) {
817 // Klass is already loaded, so just use it
818 k = instanceKlassHandle(THREAD, check);
819 CLEAR_PENDING_EXCEPTION;
820 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
821 }
822 }
823 }
824
825 // If everything was OK (no exceptions, no null return value), and
826 // class_loader is NOT the defining loader, do a little more bookkeeping.
827 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
828 k->class_loader() != class_loader()) {
829
830 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
831
832 // Need to check for a PENDING_EXCEPTION again; check_constraints
833 // can throw and doesn't use the CHECK macro.
834 if (!HAS_PENDING_EXCEPTION) {
835 { // Grabbing the Compile_lock prevents systemDictionary updates
836 // during compilations.
837 MutexLocker mu(Compile_lock, THREAD);
838 update_dictionary(d_index, d_hash, p_index, p_hash,
839 k, class_loader, THREAD);
840 }
841
842 if (JvmtiExport::should_post_class_load()) {
843 Thread *thread = THREAD;
844 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
845 JvmtiExport::post_class_load((JavaThread *) thread, k());
846 }
847 }
848 }
849 } // load_instance_class loop
850
851 if (load_instance_added == true) {
852 // clean up placeholder entries for LOAD_INSTANCE success or error
853 // This brackets the SystemDictionary updates for both defining
854 // and initiating loaders
855 MutexLocker mu(SystemDictionary_lock, THREAD);
856 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
857 SystemDictionary_lock->notify_all();
858 }
859 }
860
861 if (HAS_PENDING_EXCEPTION || k.is_null()) {
862 return NULL;
863 }
864
865 post_class_load_event(class_load_start_event, k, class_loader);
866
867 #ifdef ASSERT
868 {
869 ClassLoaderData* loader_data = k->class_loader_data();
870 MutexLocker mu(SystemDictionary_lock, THREAD);
871 Klass* kk = find_class(name, loader_data);
872 assert(kk == k(), "should be present in dictionary");
873 }
874 #endif
875
876 // return if the protection domain in NULL
877 if (protection_domain() == NULL) return k();
878
879 // Check the protection domain has the right access
880 {
881 MutexLocker mu(SystemDictionary_lock, THREAD);
882 // Note that we have an entry, and entries can be deleted only during GC,
883 // so we cannot allow GC to occur while we're holding this entry.
884 // We're using a No_Safepoint_Verifier to catch any place where we
885 // might potentially do a GC at all.
886 // Dictionary::do_unloading() asserts that classes in SD are only
887 // unloaded at a safepoint. Anonymous classes are not in SD.
888 No_Safepoint_Verifier nosafepoint;
889 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
890 loader_data,
891 protection_domain)) {
892 return k();
893 }
894 }
895
896 // Verify protection domain. If it fails an exception is thrown
897 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
898
899 return k();
900 }
901
902
903 // This routine does not lock the system dictionary.
904 //
905 // Since readers don't hold a lock, we must make sure that system
906 // dictionary entries are only removed at a safepoint (when only one
907 // thread is running), and are added to in a safe way (all links must
908 // be updated in an MT-safe manner).
909 //
910 // Callers should be aware that an entry could be added just after
911 // _dictionary->bucket(index) is read here, so the caller will not see
912 // the new entry.
913
914 Klass* SystemDictionary::find(Symbol* class_name,
915 Handle class_loader,
916 Handle protection_domain,
917 TRAPS) {
918
919 // UseNewReflection
920 // The result of this call should be consistent with the result
921 // of the call to resolve_instance_class_or_null().
922 // See evaluation 6790209 and 4474172 for more details.
923 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
924 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
925
926 if (loader_data == NULL) {
927 // If the ClassLoaderData has not been setup,
928 // then the class loader has no entries in the dictionary.
929 return NULL;
930 }
931
932 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
933 int d_index = dictionary()->hash_to_index(d_hash);
934
935 {
936 // Note that we have an entry, and entries can be deleted only during GC,
937 // so we cannot allow GC to occur while we're holding this entry.
938 // We're using a No_Safepoint_Verifier to catch any place where we
939 // might potentially do a GC at all.
940 // Dictionary::do_unloading() asserts that classes in SD are only
941 // unloaded at a safepoint. Anonymous classes are not in SD.
942 No_Safepoint_Verifier nosafepoint;
943 return dictionary()->find(d_index, d_hash, class_name, loader_data,
944 protection_domain, THREAD);
945 }
946 }
947
948
949 // Look for a loaded instance or array klass by name. Do not do any loading.
950 // return NULL in case of error.
951 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
952 Handle class_loader,
953 Handle protection_domain,
954 TRAPS) {
955 Klass* k = NULL;
956 assert(class_name != NULL, "class name must be non NULL");
957
958 if (FieldType::is_array(class_name)) {
959 // The name refers to an array. Parse the name.
960 // dimension and object_key in FieldArrayInfo are assigned as a
961 // side-effect of this call
962 FieldArrayInfo fd;
963 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
964 if (t != T_OBJECT) {
965 k = Universe::typeArrayKlassObj(t);
966 } else {
967 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
968 }
969 if (k != NULL) {
970 k = k->array_klass_or_null(fd.dimension());
971 }
972 } else {
973 k = find(class_name, class_loader, protection_domain, THREAD);
974 }
975 return k;
976 }
977
978 // Note: this method is much like resolve_from_stream, but
979 // updates no supplemental data structures.
980 // TODO consolidate the two methods with a helper routine?
981 Klass* SystemDictionary::parse_stream(Symbol* class_name,
982 Handle class_loader,
983 Handle protection_domain,
984 ClassFileStream* st,
985 KlassHandle host_klass,
986 GrowableArray<Handle>* cp_patches,
987 TRAPS) {
988 TempNewSymbol parsed_name = NULL;
989
990 EventClassLoad class_load_start_event;
991
992 ClassLoaderData* loader_data;
993 if (host_klass.not_null()) {
994 // Create a new CLD for anonymous class, that uses the same class loader
995 // as the host_klass
996 assert(EnableInvokeDynamic, "");
997 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
998 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
999 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1000 loader_data->record_dependency(host_klass(), CHECK_NULL);
1001 } else {
1002 loader_data = ClassLoaderData::class_loader_data(class_loader());
1003 }
1004
1005 // Parse the stream. Note that we do this even though this klass might
1006 // already be present in the SystemDictionary, otherwise we would not
1007 // throw potential ClassFormatErrors.
1008 //
1009 // Note: "name" is updated.
1010
1011 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1012 loader_data,
1013 protection_domain,
1014 host_klass,
1015 cp_patches,
1016 parsed_name,
1017 true,
1018 THREAD);
1019
1020
1021 if (host_klass.not_null() && k.not_null()) {
1022 assert(EnableInvokeDynamic, "");
1023 // If it's anonymous, initialize it now, since nobody else will.
1024
1025 {
1026 MutexLocker mu_r(Compile_lock, THREAD);
1027
1028 // Add to class hierarchy, initialize vtables, and do possible
1029 // deoptimizations.
1030 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1031
1032 // But, do not add to system dictionary.
1033
1034 // compiled code dependencies need to be validated anyway
1035 notice_modification();
1036 }
1037
1038 // Rewrite and patch constant pool here.
1039 k->link_class(CHECK_NULL);
1040 if (cp_patches != NULL) {
1041 k->constants()->patch_resolved_references(cp_patches);
1042 }
1043 k->eager_initialize(CHECK_NULL);
1044
1045 // notify jvmti
1046 if (JvmtiExport::should_post_class_load()) {
1047 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1048 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1049 }
1050
1051 post_class_load_event(class_load_start_event, k, class_loader);
1052 }
1053 assert(host_klass.not_null() || cp_patches == NULL,
1054 "cp_patches only found with host_klass");
1055
1056 return k();
1057 }
1058
1059 // Add a klass to the system from a stream (called by jni_DefineClass and
1060 // JVM_DefineClass).
1061 // Note: class_name can be NULL. In that case we do not know the name of
1062 // the class until we have parsed the stream.
1063
1064 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1065 Handle class_loader,
1066 Handle protection_domain,
1067 ClassFileStream* st,
1068 bool verify,
1069 TRAPS) {
1070
1071 // Classloaders that support parallelism, e.g. bootstrap classloader,
1072 // or all classloaders with UnsyncloadClass do not acquire lock here
1073 bool DoObjectLock = true;
1074 if (is_parallelCapable(class_loader)) {
1075 DoObjectLock = false;
1076 }
1077
1078 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1079
1080 // Make sure we are synchronized on the class loader before we proceed
1081 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1082 check_loader_lock_contention(lockObject, THREAD);
1083 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1084
1085 TempNewSymbol parsed_name = NULL;
1086
1087 // Parse the stream. Note that we do this even though this klass might
1088 // already be present in the SystemDictionary, otherwise we would not
1089 // throw potential ClassFormatErrors.
1090 //
1091 // Note: "name" is updated.
1092
1093 ClassFileParser parser(st);
1094 instanceKlassHandle k = parser.parseClassFile(class_name,
1095 loader_data,
1096 protection_domain,
1097 parsed_name,
1098 verify,
1099 THREAD);
1100
1101 const char* pkg = "java/";
1102 size_t pkglen = strlen(pkg);
1103 if (!HAS_PENDING_EXCEPTION &&
1104 !class_loader.is_null() &&
1105 parsed_name != NULL &&
1106 parsed_name->utf8_length() >= (int)pkglen &&
1107 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1108 // It is illegal to define classes in the "java." package from
1109 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1110 ResourceMark rm(THREAD);
1111 char* name = parsed_name->as_C_string();
1112 char* index = strrchr(name, '/');
1113 assert(index != NULL, "must be");
1114 *index = '\0'; // chop to just the package name
1115 while ((index = strchr(name, '/')) != NULL) {
1116 *index = '.'; // replace '/' with '.' in package name
1117 }
1118 const char* fmt = "Prohibited package name: %s";
1119 size_t len = strlen(fmt) + strlen(name);
1120 char* message = NEW_RESOURCE_ARRAY(char, len);
1121 jio_snprintf(message, len, fmt, name);
1122 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1123 vmSymbols::java_lang_SecurityException(), message);
1124 }
1125
1126 if (!HAS_PENDING_EXCEPTION) {
1127 assert(parsed_name != NULL, "Sanity");
1128 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1129 // Verification prevents us from creating names with dots in them, this
1130 // asserts that that's the case.
1131 assert(is_internal_format(parsed_name),
1132 "external class name format used internally");
1133
1134 #if INCLUDE_JFR
1135 {
1136 InstanceKlass* ik = k();
1137 ON_KLASS_CREATION(ik, parser, THREAD);
1138 k = instanceKlassHandle(ik);
1139 }
1140 #endif
1141
1142 // Add class just loaded
1143 // If a class loader supports parallel classloading handle parallel define requests
1144 // find_or_define_instance_class may return a different InstanceKlass
1145 if (is_parallelCapable(class_loader)) {
1146 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1147 } else {
1148 define_instance_class(k, THREAD);
1149 }
1150 }
1151
1152 // Make sure we have an entry in the SystemDictionary on success
1153 debug_only( {
1154 if (!HAS_PENDING_EXCEPTION) {
1155 assert(parsed_name != NULL, "parsed_name is still null?");
1156 Symbol* h_name = k->name();
1157 ClassLoaderData *defining_loader_data = k->class_loader_data();
1158
1159 MutexLocker mu(SystemDictionary_lock, THREAD);
1160
1161 Klass* check = find_class(parsed_name, loader_data);
1162 assert(check == k(), "should be present in the dictionary");
1163
1164 Klass* check2 = find_class(h_name, defining_loader_data);
1165 assert(check == check2, "name inconsistancy in SystemDictionary");
1166 }
1167 } );
1168
1169 return k();
1170 }
1171
1172 #if INCLUDE_CDS
1173 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1174 int number_of_entries) {
1175 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1176 "bad shared dictionary size.");
1177 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1178 }
1179
1180
1181 // If there is a shared dictionary, then find the entry for the
1182 // given shared system class, if any.
1183
1184 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1185 if (shared_dictionary() != NULL) {
1186 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1187 int d_index = shared_dictionary()->hash_to_index(d_hash);
1188
1189 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1190 } else {
1191 return NULL;
1192 }
1193 }
1194
1195
1196 // Load a class from the shared spaces (found through the shared system
1197 // dictionary). Force the superclass and all interfaces to be loaded.
1198 // Update the class definition to include sibling classes and no
1199 // subclasses (yet). [Classes in the shared space are not part of the
1200 // object hierarchy until loaded.]
1201
1202 instanceKlassHandle SystemDictionary::load_shared_class(
1203 Symbol* class_name, Handle class_loader, TRAPS) {
1204 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1205 // Make sure we only return the boot class for the NULL classloader.
1206 if (ik.not_null() &&
1207 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1208 Handle protection_domain;
1209 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1210 }
1211 return instanceKlassHandle();
1212 }
1213
1214 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1215 Handle class_loader,
1216 Handle protection_domain, TRAPS) {
1217 if (ik.not_null()) {
1218 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1219 Symbol* class_name = ik->name();
1220
1221 // Found the class, now load the superclass and interfaces. If they
1222 // are shared, add them to the main system dictionary and reset
1223 // their hierarchy references (supers, subs, and interfaces).
1224
1225 if (ik->super() != NULL) {
1226 Symbol* cn = ik->super()->name();
1227 Klass *s = resolve_super_or_fail(class_name, cn,
1228 class_loader, protection_domain, true, CHECK_(nh));
1229 if (s != ik->super()) {
1230 // The dynamically resolved super class is not the same as the one we used during dump time,
1231 // so we cannot use ik.
1232 return nh;
1233 }
1234 }
1235
1236 Array<Klass*>* interfaces = ik->local_interfaces();
1237 int num_interfaces = interfaces->length();
1238 for (int index = 0; index < num_interfaces; index++) {
1239 Klass* k = interfaces->at(index);
1240
1241 // Note: can not use InstanceKlass::cast here because
1242 // interfaces' InstanceKlass's C++ vtbls haven't been
1243 // reinitialized yet (they will be once the interface classes
1244 // are loaded)
1245 Symbol* name = k->name();
1246 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1247 if (k != i) {
1248 // The dynamically resolved interface class is not the same as the one we used during dump time,
1249 // so we cannot use ik.
1250 return nh;
1251 }
1252 }
1253
1254 // Adjust methods to recover missing data. They need addresses for
1255 // interpreter entry points and their default native method address
1256 // must be reset.
1257
1258 // Updating methods must be done under a lock so multiple
1259 // threads don't update these in parallel
1260 //
1261 // Shared classes are all currently loaded by either the bootstrap or
1262 // internal parallel class loaders, so this will never cause a deadlock
1263 // on a custom class loader lock.
1264
1265 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1266 {
1267 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1268 check_loader_lock_contention(lockObject, THREAD);
1269 ObjectLocker ol(lockObject, THREAD, true);
1270 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1271 }
1272
1273 if (TraceClassLoading) {
1274 ResourceMark rm;
1275 tty->print("[Loaded %s", ik->external_name());
1276 tty->print(" from shared objects file");
1277 if (class_loader.not_null()) {
1278 tty->print(" by %s", loader_data->loader_name());
1279 }
1280 tty->print_cr("]");
1281 }
1282
1283 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1284 // Only dump the classes that can be stored into CDS archive
1285 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1286 ResourceMark rm(THREAD);
1287 classlist_file->print_cr("%s", ik->name()->as_C_string());
1288 classlist_file->flush();
1289 }
1290 }
1291
1292 // notify a class loaded from shared object
1293 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1294 true /* shared class */);
1295 }
1296 return ik;
1297 }
1298 #endif // INCLUDE_CDS
1299
1300 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1301 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1302 if (class_loader.is_null()) {
1303
1304 // Search the shared system dictionary for classes preloaded into the
1305 // shared spaces.
1306 instanceKlassHandle k;
1307 {
1308 #if INCLUDE_CDS
1309 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1310 k = load_shared_class(class_name, class_loader, THREAD);
1311 #endif
1312 }
1313
1314 if (k.is_null()) {
1315 // Use VM class loader
1316 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1317 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1318 }
1319
1320 // find_or_define_instance_class may return a different InstanceKlass
1321 if (!k.is_null()) {
1322 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1323 }
1324 return k;
1325 } else {
1326 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1327 ResourceMark rm(THREAD);
1328
1329 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1330 JavaThread* jt = (JavaThread*) THREAD;
1331
1332 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1333 ClassLoader::perf_app_classload_selftime(),
1334 ClassLoader::perf_app_classload_count(),
1335 jt->get_thread_stat()->perf_recursion_counts_addr(),
1336 jt->get_thread_stat()->perf_timers_addr(),
1337 PerfClassTraceTime::CLASS_LOAD);
1338
1339 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1340 // Translate to external class name format, i.e., convert '/' chars to '.'
1341 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1342
1343 JavaValue result(T_OBJECT);
1344
1345 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1346
1347 // Call public unsynchronized loadClass(String) directly for all class loaders
1348 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1349 // acquire a class-name based lock rather than the class loader object lock.
1350 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1351 // so the call to loadClassInternal() was not required.
1352 //
1353 // UnsyncloadClass flag means both call loadClass(String) and do
1354 // not acquire the class loader lock even for class loaders that are
1355 // not parallelCapable. This was a risky transitional
1356 // flag for diagnostic purposes only. It is risky to call
1357 // custom class loaders without synchronization.
1358 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1359 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1360 // Do NOT assume this will be supported in future releases.
1361 //
1362 // Added MustCallLoadClassInternal in case we discover in the field
1363 // a customer that counts on this call
1364 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1365 JavaCalls::call_special(&result,
1366 class_loader,
1367 spec_klass,
1368 vmSymbols::loadClassInternal_name(),
1369 vmSymbols::string_class_signature(),
1370 string,
1371 CHECK_(nh));
1372 } else {
1373 JavaCalls::call_virtual(&result,
1374 class_loader,
1375 spec_klass,
1376 vmSymbols::loadClass_name(),
1377 vmSymbols::string_class_signature(),
1378 string,
1379 CHECK_(nh));
1380 }
1381
1382 assert(result.get_type() == T_OBJECT, "just checking");
1383 oop obj = (oop) result.get_jobject();
1384
1385 // Primitive classes return null since forName() can not be
1386 // used to obtain any of the Class objects representing primitives or void
1387 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1388 instanceKlassHandle k =
1389 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1390 // For user defined Java class loaders, check that the name returned is
1391 // the same as that requested. This check is done for the bootstrap
1392 // loader when parsing the class file.
1393 if (class_name == k->name()) {
1394 return k;
1395 }
1396 }
1397 // Class is not found or has the wrong name, return NULL
1398 return nh;
1399 }
1400 }
1401
1402 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1403 EventClassDefine event;
1404 if (event.should_commit()) {
1405 event.set_definedClass(k);
1406 event.set_definingClassLoader(def_cld);
1407 event.commit();
1408 }
1409 }
1410
1411 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1412
1413 ClassLoaderData* loader_data = k->class_loader_data();
1414 Handle class_loader_h(THREAD, loader_data->class_loader());
1415
1416 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1417
1418 // for bootstrap and other parallel classloaders don't acquire lock,
1419 // use placeholder token
1420 // If a parallelCapable class loader calls define_instance_class instead of
1421 // find_or_define_instance_class to get here, we have a timing
1422 // hole with systemDictionary updates and check_constraints
1423 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1424 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1425 compute_loader_lock_object(class_loader_h, THREAD)),
1426 "define called without lock");
1427 }
1428
1429 // Check class-loading constraints. Throw exception if violation is detected.
1430 // Grabs and releases SystemDictionary_lock
1431 // The check_constraints/find_class call and update_dictionary sequence
1432 // must be "atomic" for a specific class/classloader pair so we never
1433 // define two different instanceKlasses for that class/classloader pair.
1434 // Existing classloaders will call define_instance_class with the
1435 // classloader lock held
1436 // Parallel classloaders will call find_or_define_instance_class
1437 // which will require a token to perform the define class
1438 Symbol* name_h = k->name();
1439 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1440 int d_index = dictionary()->hash_to_index(d_hash);
1441 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1442
1443 // Register class just loaded with class loader (placed in Vector)
1444 // Note we do this before updating the dictionary, as this can
1445 // fail with an OutOfMemoryError (if it does, we will *not* put this
1446 // class in the dictionary and will not update the class hierarchy).
1447 // JVMTI FollowReferences needs to find the classes this way.
1448 if (k->class_loader() != NULL) {
1449 methodHandle m(THREAD, Universe::loader_addClass_method());
1450 JavaValue result(T_VOID);
1451 JavaCallArguments args(class_loader_h);
1452 args.push_oop(Handle(THREAD, k->java_mirror()));
1453 JavaCalls::call(&result, m, &args, CHECK);
1454 }
1455
1456 // Add the new class. We need recompile lock during update of CHA.
1457 {
1458 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1459 int p_index = placeholders()->hash_to_index(p_hash);
1460
1461 MutexLocker mu_r(Compile_lock, THREAD);
1462
1463 // Add to class hierarchy, initialize vtables, and do possible
1464 // deoptimizations.
1465 add_to_hierarchy(k, CHECK); // No exception, but can block
1466
1467 // Add to systemDictionary - so other classes can see it.
1468 // Grabs and releases SystemDictionary_lock
1469 update_dictionary(d_index, d_hash, p_index, p_hash,
1470 k, class_loader_h, THREAD);
1471 }
1472 k->eager_initialize(THREAD);
1473
1474 // notify jvmti
1475 if (JvmtiExport::should_post_class_load()) {
1476 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1477 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1478
1479 }
1480
1481 post_class_define_event(k(), loader_data);
1482 }
1483
1484 // Support parallel classloading
1485 // All parallel class loaders, including bootstrap classloader
1486 // lock a placeholder entry for this class/class_loader pair
1487 // to allow parallel defines of different classes for this class loader
1488 // With AllowParallelDefine flag==true, in case they do not synchronize around
1489 // FindLoadedClass/DefineClass, calls, we check for parallel
1490 // loading for them, wait if a defineClass is in progress
1491 // and return the initial requestor's results
1492 // This flag does not apply to the bootstrap classloader.
1493 // With AllowParallelDefine flag==false, call through to define_instance_class
1494 // which will throw LinkageError: duplicate class definition.
1495 // False is the requested default.
1496 // For better performance, the class loaders should synchronize
1497 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1498 // potentially waste time reading and parsing the bytestream.
1499 // Note: VM callers should ensure consistency of k/class_name,class_loader
1500 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1501
1502 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1503 Symbol* name_h = k->name(); // passed in class_name may be null
1504 ClassLoaderData* loader_data = class_loader_data(class_loader);
1505
1506 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1507 int d_index = dictionary()->hash_to_index(d_hash);
1508
1509 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1510 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1511 int p_index = placeholders()->hash_to_index(p_hash);
1512 PlaceholderEntry* probe;
1513
1514 {
1515 MutexLocker mu(SystemDictionary_lock, THREAD);
1516 // First check if class already defined
1517 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1518 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1519 if (check != NULL) {
1520 return(instanceKlassHandle(THREAD, check));
1521 }
1522 }
1523
1524 // Acquire define token for this class/classloader
1525 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1526 // Wait if another thread defining in parallel
1527 // All threads wait - even those that will throw duplicate class: otherwise
1528 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1529 // if other thread has not finished updating dictionary
1530 while (probe->definer() != NULL) {
1531 SystemDictionary_lock->wait();
1532 }
1533 // Only special cases allow parallel defines and can use other thread's results
1534 // Other cases fall through, and may run into duplicate defines
1535 // caught by finding an entry in the SystemDictionary
1536 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1537 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1538 SystemDictionary_lock->notify_all();
1539 #ifdef ASSERT
1540 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1541 assert(check != NULL, "definer missed recording success");
1542 #endif
1543 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1544 } else {
1545 // This thread will define the class (even if earlier thread tried and had an error)
1546 probe->set_definer(THREAD);
1547 }
1548 }
1549
1550 define_instance_class(k, THREAD);
1551
1552 Handle linkage_exception = Handle(); // null handle
1553
1554 // definer must notify any waiting threads
1555 {
1556 MutexLocker mu(SystemDictionary_lock, THREAD);
1557 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1558 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1559 if (probe != NULL) {
1560 if (HAS_PENDING_EXCEPTION) {
1561 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1562 CLEAR_PENDING_EXCEPTION;
1563 } else {
1564 probe->set_instance_klass(k());
1565 }
1566 probe->set_definer(NULL);
1567 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1568 SystemDictionary_lock->notify_all();
1569 }
1570 }
1571
1572 // Can't throw exception while holding lock due to rank ordering
1573 if (linkage_exception() != NULL) {
1574 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1575 }
1576
1577 return k;
1578 }
1579 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1580 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1581 if (class_loader.is_null()) {
1582 return Handle(THREAD, _system_loader_lock_obj);
1583 } else {
1584 return class_loader;
1585 }
1586 }
1587
1588 // This method is added to check how often we have to wait to grab loader
1589 // lock. The results are being recorded in the performance counters defined in
1590 // ClassLoader::_sync_systemLoaderLockContentionRate and
1591 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1592 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1593 if (!UsePerfData) {
1594 return;
1595 }
1596
1597 assert(!loader_lock.is_null(), "NULL lock object");
1598
1599 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1600 == ObjectSynchronizer::owner_other) {
1601 // contention will likely happen, so increment the corresponding
1602 // contention counter.
1603 if (loader_lock() == _system_loader_lock_obj) {
1604 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1605 } else {
1606 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1607 }
1608 }
1609 }
1610
1611 // ----------------------------------------------------------------------------
1612 // Lookup
1613
1614 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1615 Symbol* class_name,
1616 ClassLoaderData* loader_data) {
1617 assert_locked_or_safepoint(SystemDictionary_lock);
1618 assert (index == dictionary()->index_for(class_name, loader_data),
1619 "incorrect index?");
1620
1621 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1622 return k;
1623 }
1624
1625
1626 // Basic find on classes in the midst of being loaded
1627 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1628 ClassLoaderData* loader_data) {
1629 assert_locked_or_safepoint(SystemDictionary_lock);
1630 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1631 int p_index = placeholders()->hash_to_index(p_hash);
1632 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1633 }
1634
1635
1636 // Used for assertions and verification only
1637 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1638 #ifndef ASSERT
1639 guarantee(VerifyBeforeGC ||
1640 VerifyDuringGC ||
1641 VerifyBeforeExit ||
1642 VerifyDuringStartup ||
1643 VerifyAfterGC, "too expensive");
1644 #endif
1645 assert_locked_or_safepoint(SystemDictionary_lock);
1646
1647 // First look in the loaded class array
1648 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1649 int d_index = dictionary()->hash_to_index(d_hash);
1650 return find_class(d_index, d_hash, class_name, loader_data);
1651 }
1652
1653
1654 // Get the next class in the diictionary.
1655 Klass* SystemDictionary::try_get_next_class() {
1656 return dictionary()->try_get_next_class();
1657 }
1658
1659
1660 // ----------------------------------------------------------------------------
1661 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1662 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1663 // before a new class is used.
1664
1665 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1666 assert(k.not_null(), "just checking");
1667 assert_locked_or_safepoint(Compile_lock);
1668
1669 // Link into hierachy. Make sure the vtables are initialized before linking into
1670 k->append_to_sibling_list(); // add to superklass/sibling list
1671 k->process_interfaces(THREAD); // handle all "implements" declarations
1672 k->set_init_state(InstanceKlass::loaded);
1673 // Now flush all code that depended on old class hierarchy.
1674 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1675 // Also, first reinitialize vtable because it may have gotten out of synch
1676 // while the new class wasn't connected to the class hierarchy.
1677 Universe::flush_dependents_on(k);
1678 }
1679
1680 // ----------------------------------------------------------------------------
1681 // GC support
1682
1683 // Following roots during mark-sweep is separated in two phases.
1684 //
1685 // The first phase follows preloaded classes and all other system
1686 // classes, since these will never get unloaded anyway.
1687 //
1688 // The second phase removes (unloads) unreachable classes from the
1689 // system dictionary and follows the remaining classes' contents.
1690
1691 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1692 roots_oops_do(blk, NULL);
1693 }
1694
1695 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1696 // Follow all system classes and temporary placeholders in dictionary
1697 dictionary()->always_strong_classes_do(closure);
1698
1699 // Placeholders. These represent classes we're actively loading.
1700 placeholders()->classes_do(closure);
1701 }
1702
1703 // Calculate a "good" systemdictionary size based
1704 // on predicted or current loaded classes count
1705 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1706 int newsize = _old_default_sdsize;
1707 if ((classcount > 0) && !DumpSharedSpaces) {
1708 int desiredsize = classcount/_average_depth_goal;
1709 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1710 newsize = _primelist[++_sdgeneration]) {
1711 if (desiredsize <= newsize) {
1712 break;
1713 }
1714 }
1715 }
1716 return newsize;
1717 }
1718
1719 #ifdef ASSERT
1720 class VerifySDReachableAndLiveClosure : public OopClosure {
1721 private:
1722 BoolObjectClosure* _is_alive;
1723
1724 template <class T> void do_oop_work(T* p) {
1725 oop obj = oopDesc::load_decode_heap_oop(p);
1726 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1727 }
1728
1729 public:
1730 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1731
1732 virtual void do_oop(oop* p) { do_oop_work(p); }
1733 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1734 };
1735 #endif
1736
1737 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1738 // Note: anonymous classes are not in the SD.
1739 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1740 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1741 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1742 if (unloading_occurred) {
1743 dictionary()->do_unloading();
1744 constraints()->purge_loader_constraints();
1745 resolution_errors()->purge_resolution_errors();
1746 }
1747 // Oops referenced by the system dictionary may get unreachable independently
1748 // of the class loader (eg. cached protection domain oops). So we need to
1749 // explicitly unlink them here instead of in Dictionary::do_unloading.
1750 dictionary()->unlink(is_alive);
1751 #ifdef ASSERT
1752 VerifySDReachableAndLiveClosure cl(is_alive);
1753 dictionary()->oops_do(&cl);
1754 #endif
1755 return unloading_occurred;
1756 }
1757
1758 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1759 strong->do_oop(&_java_system_loader);
1760 strong->do_oop(&_system_loader_lock_obj);
1761 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1762
1763 // Adjust dictionary
1764 dictionary()->roots_oops_do(strong, weak);
1765
1766 // Visit extra methods
1767 invoke_method_table()->oops_do(strong);
1768 }
1769
1770 void SystemDictionary::oops_do(OopClosure* f) {
1771 f->do_oop(&_java_system_loader);
1772 f->do_oop(&_system_loader_lock_obj);
1773 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1774
1775 // Adjust dictionary
1776 dictionary()->oops_do(f);
1777
1778 // Visit extra methods
1779 invoke_method_table()->oops_do(f);
1780 }
1781
1782 // Extended Class redefinition support.
1783 // If one of these classes is replaced, we need to replace it in these places.
1784 // KlassClosure::do_klass should take the address of a class but we can
1785 // change that later.
1786 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1787 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1788 f->do_klass(_well_known_klasses[k]);
1789 }
1790
1791 {
1792 for (int i = 0; i < T_VOID+1; i++) {
1793 if (_box_klasses[i] != NULL) {
1794 assert(i >= T_BOOLEAN, "checking");
1795 f->do_klass(_box_klasses[i]);
1796 }
1797 }
1798 }
1799
1800 FilteredFieldsMap::classes_do(f);
1801 }
1802
1803 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1804 f->do_klass(_abstract_ownable_synchronizer_klass);
1805 }
1806
1807 // Just the classes from defining class loaders
1808 // Don't iterate over placeholders
1809 void SystemDictionary::classes_do(void f(Klass*)) {
1810 dictionary()->classes_do(f);
1811 }
1812
1813 // Added for initialize_itable_for_klass
1814 // Just the classes from defining class loaders
1815 // Don't iterate over placeholders
1816 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1817 dictionary()->classes_do(f, CHECK);
1818 }
1819
1820 // All classes, and their class loaders
1821 // Don't iterate over placeholders
1822 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1823 dictionary()->classes_do(f);
1824 }
1825
1826 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1827 placeholders()->entries_do(f);
1828 }
1829
1830 void SystemDictionary::methods_do(void f(Method*)) {
1831 dictionary()->methods_do(f);
1832 invoke_method_table()->methods_do(f);
1833 }
1834
1835 void SystemDictionary::remove_classes_in_error_state() {
1836 dictionary()->remove_classes_in_error_state();
1837 }
1838
1839 // ----------------------------------------------------------------------------
1840 // Lazily load klasses
1841
1842 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1843 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1844
1845 // if multiple threads calling this function, only one thread will load
1846 // the class. The other threads will find the loaded version once the
1847 // class is loaded.
1848 Klass* aos = _abstract_ownable_synchronizer_klass;
1849 if (aos == NULL) {
1850 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1851 // Force a fence to prevent any read before the write completes
1852 OrderAccess::fence();
1853 _abstract_ownable_synchronizer_klass = k;
1854 }
1855 }
1856
1857 // ----------------------------------------------------------------------------
1858 // Initialization
1859
1860 void SystemDictionary::initialize(TRAPS) {
1861 // Allocate arrays
1862 assert(dictionary() == NULL,
1863 "SystemDictionary should only be initialized once");
1864 _sdgeneration = 0;
1865 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1866 _placeholders = new PlaceholderTable(_nof_buckets);
1867 _number_of_modifications = 0;
1868 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1869 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1870 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1871
1872 // Allocate private object used as system class loader lock
1873 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1874 // Initialize basic classes
1875 initialize_preloaded_classes(CHECK);
1876 }
1877
1878 // Compact table of directions on the initialization of klasses:
1879 static const short wk_init_info[] = {
1880 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1881 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1882 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1883 | (int)SystemDictionary::option ),
1884 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1885 #undef WK_KLASS_INIT_INFO
1886 0
1887 };
1888
1889 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1890 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1891 int info = wk_init_info[id - FIRST_WKID];
1892 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1893 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1894 Klass** klassp = &_well_known_klasses[id];
1895 bool must_load = (init_opt < SystemDictionary::Opt);
1896 if ((*klassp) == NULL) {
1897 if (must_load) {
1898 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1899 } else {
1900 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1901 }
1902 }
1903 return ((*klassp) != NULL);
1904 }
1905
1906 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1907 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1908 for (int id = (int)start_id; id < (int)limit_id; id++) {
1909 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1910 int info = wk_init_info[id - FIRST_WKID];
1911 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1912 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1913
1914 initialize_wk_klass((WKID)id, opt, CHECK);
1915 }
1916
1917 // move the starting value forward to the limit:
1918 start_id = limit_id;
1919 }
1920
1921 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1922 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1923 // Preload commonly used klasses
1924 WKID scan = FIRST_WKID;
1925 // first do Object, then String, Class
1926 if (UseSharedSpaces) {
1927 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1928 // Initialize the constant pool for the Object_class
1929 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1930 ik->constants()->restore_unshareable_info(CHECK);
1931 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1932 } else {
1933 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1934 }
1935
1936 // Calculate offsets for String and Class classes since they are loaded and
1937 // can be used after this point.
1938 java_lang_String::compute_offsets();
1939 java_lang_Class::compute_offsets();
1940
1941 // Fixup mirrors for classes loaded before java.lang.Class.
1942 // These calls iterate over the objects currently in the perm gen
1943 // so calling them at this point is matters (not before when there
1944 // are fewer objects and not later after there are more objects
1945 // in the perm gen.
1946 Universe::initialize_basic_type_mirrors(CHECK);
1947 Universe::fixup_mirrors(CHECK);
1948
1949 // do a bunch more:
1950 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1951
1952 // Preload ref klasses and set reference types
1953 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1954 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1955
1956 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1957 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1958 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1959 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1960 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1961 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1962
1963 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
1964
1965 // JSR 292 classes
1966 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1967 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1968 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1969 if (EnableInvokeDynamic) {
1970 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1971 } else {
1972 // Skip the JSR 292 classes, if not enabled.
1973 scan = WKID(jsr292_group_end + 1);
1974 }
1975
1976 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1977
1978 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1979 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1980 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1981 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1982 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1983 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1984 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1985 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1986 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1987 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1988
1989 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1990 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1991 _has_loadClassInternal = (method != NULL);
1992 }
1993 { // Compute whether we should use checkPackageAccess or NOT
1994 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1995 _has_checkPackageAccess = (method != NULL);
1996 }
1997 }
1998
1999 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2000 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2001 BasicType SystemDictionary::box_klass_type(Klass* k) {
2002 assert(k != NULL, "");
2003 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2004 if (_box_klasses[i] == k)
2005 return (BasicType)i;
2006 }
2007 return T_OBJECT;
2008 }
2009
2010 // Constraints on class loaders. The details of the algorithm can be
2011 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2012 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2013 // that the system dictionary needs to maintain a set of contraints that
2014 // must be satisfied by all classes in the dictionary.
2015 // if defining is true, then LinkageError if already in systemDictionary
2016 // if initiating loader, then ok if InstanceKlass matches existing entry
2017
2018 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2019 instanceKlassHandle k,
2020 Handle class_loader, bool defining,
2021 TRAPS) {
2022 const char *linkage_error = NULL;
2023 {
2024 Symbol* name = k->name();
2025 ClassLoaderData *loader_data = class_loader_data(class_loader);
2026
2027 MutexLocker mu(SystemDictionary_lock, THREAD);
2028
2029 Klass* check = find_class(d_index, d_hash, name, loader_data);
2030 if (check != (Klass*)NULL) {
2031 // if different InstanceKlass - duplicate class definition,
2032 // else - ok, class loaded by a different thread in parallel,
2033 // we should only have found it if it was done loading and ok to use
2034 // system dictionary only holds instance classes, placeholders
2035 // also holds array classes
2036
2037 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2038 if ((defining == true) || (k() != check)) {
2039 linkage_error = "loader (instance of %s): attempted duplicate class "
2040 "definition for name: \"%s\"";
2041 } else {
2042 return;
2043 }
2044 }
2045
2046 #ifdef ASSERT
2047 Symbol* ph_check = find_placeholder(name, loader_data);
2048 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2049 #endif
2050
2051 if (linkage_error == NULL) {
2052 if (constraints()->check_or_update(k, class_loader, name) == false) {
2053 linkage_error = "loader constraint violation: loader (instance of %s)"
2054 " previously initiated loading for a different type with name \"%s\"";
2055 }
2056 }
2057 }
2058
2059 // Throw error now if needed (cannot throw while holding
2060 // SystemDictionary_lock because of rank ordering)
2061
2062 if (linkage_error) {
2063 ResourceMark rm(THREAD);
2064 const char* class_loader_name = loader_name(class_loader());
2065 char* type_name = k->name()->as_C_string();
2066 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2067 strlen(type_name);
2068 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2069 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2070 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2071 }
2072 }
2073
2074
2075 // Update system dictionary - done after check_constraint and add_to_hierachy
2076 // have been called.
2077 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2078 int p_index, unsigned int p_hash,
2079 instanceKlassHandle k,
2080 Handle class_loader,
2081 TRAPS) {
2082 // Compile_lock prevents systemDictionary updates during compilations
2083 assert_locked_or_safepoint(Compile_lock);
2084 Symbol* name = k->name();
2085 ClassLoaderData *loader_data = class_loader_data(class_loader);
2086
2087 {
2088 MutexLocker mu1(SystemDictionary_lock, THREAD);
2089
2090 // See whether biased locking is enabled and if so set it for this
2091 // klass.
2092 // Note that this must be done past the last potential blocking
2093 // point / safepoint. We enable biased locking lazily using a
2094 // VM_Operation to iterate the SystemDictionary and installing the
2095 // biasable mark word into each InstanceKlass's prototype header.
2096 // To avoid race conditions where we accidentally miss enabling the
2097 // optimization for one class in the process of being added to the
2098 // dictionary, we must not safepoint after the test of
2099 // BiasedLocking::enabled().
2100 if (UseBiasedLocking && BiasedLocking::enabled()) {
2101 // Set biased locking bit for all loaded classes; it will be
2102 // cleared if revocation occurs too often for this type
2103 // NOTE that we must only do this when the class is initally
2104 // defined, not each time it is referenced from a new class loader
2105 if (k->class_loader() == class_loader()) {
2106 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2107 }
2108 }
2109
2110 // Make a new system dictionary entry.
2111 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2112 if (sd_check == NULL) {
2113 dictionary()->add_klass(name, loader_data, k);
2114 notice_modification();
2115 }
2116 #ifdef ASSERT
2117 sd_check = find_class(d_index, d_hash, name, loader_data);
2118 assert (sd_check != NULL, "should have entry in system dictionary");
2119 // Note: there may be a placeholder entry: for circularity testing
2120 // or for parallel defines
2121 #endif
2122 SystemDictionary_lock->notify_all();
2123 }
2124 }
2125
2126
2127 // Try to find a class name using the loader constraints. The
2128 // loader constraints might know about a class that isn't fully loaded
2129 // yet and these will be ignored.
2130 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2131 Symbol* class_name, Handle class_loader, TRAPS) {
2132
2133 // First see if it has been loaded directly.
2134 // Force the protection domain to be null. (This removes protection checks.)
2135 Handle no_protection_domain;
2136 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2137 no_protection_domain, CHECK_NULL);
2138 if (klass != NULL)
2139 return klass;
2140
2141 // Now look to see if it has been loaded elsewhere, and is subject to
2142 // a loader constraint that would require this loader to return the
2143 // klass that is already loaded.
2144 if (FieldType::is_array(class_name)) {
2145 // For array classes, their Klass*s are not kept in the
2146 // constraint table. The element Klass*s are.
2147 FieldArrayInfo fd;
2148 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2149 if (t != T_OBJECT) {
2150 klass = Universe::typeArrayKlassObj(t);
2151 } else {
2152 MutexLocker mu(SystemDictionary_lock, THREAD);
2153 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2154 }
2155 // If element class already loaded, allocate array klass
2156 if (klass != NULL) {
2157 klass = klass->array_klass_or_null(fd.dimension());
2158 }
2159 } else {
2160 MutexLocker mu(SystemDictionary_lock, THREAD);
2161 // Non-array classes are easy: simply check the constraint table.
2162 klass = constraints()->find_constrained_klass(class_name, class_loader);
2163 }
2164
2165 return klass;
2166 }
2167
2168
2169 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2170 Handle class_loader1,
2171 Handle class_loader2,
2172 Thread* THREAD) {
2173 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2174 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2175
2176 Symbol* constraint_name = NULL;
2177 if (!FieldType::is_array(class_name)) {
2178 constraint_name = class_name;
2179 } else {
2180 // For array classes, their Klass*s are not kept in the
2181 // constraint table. The element classes are.
2182 FieldArrayInfo fd;
2183 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2184 // primitive types always pass
2185 if (t != T_OBJECT) {
2186 return true;
2187 } else {
2188 constraint_name = fd.object_key();
2189 }
2190 }
2191 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2192 int d_index1 = dictionary()->hash_to_index(d_hash1);
2193
2194 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2195 int d_index2 = dictionary()->hash_to_index(d_hash2);
2196 {
2197 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2198
2199 // Better never do a GC while we're holding these oops
2200 No_Safepoint_Verifier nosafepoint;
2201
2202 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2203 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2204 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2205 klass2, class_loader2);
2206 }
2207 }
2208
2209 // Add entry to resolution error table to record the error when the first
2210 // attempt to resolve a reference to a class has failed.
2211 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2212 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2213 int index = resolution_errors()->hash_to_index(hash);
2214 {
2215 MutexLocker ml(SystemDictionary_lock, Thread::current());
2216 resolution_errors()->add_entry(index, hash, pool, which, error);
2217 }
2218 }
2219
2220 // Delete a resolution error for RedefineClasses for a constant pool is going away
2221 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2222 resolution_errors()->delete_entry(pool);
2223 }
2224
2225 // Lookup resolution error table. Returns error if found, otherwise NULL.
2226 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2227 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2228 int index = resolution_errors()->hash_to_index(hash);
2229 {
2230 MutexLocker ml(SystemDictionary_lock, Thread::current());
2231 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2232 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2233 }
2234 }
2235
2236
2237 // Signature constraints ensure that callers and callees agree about
2238 // the meaning of type names in their signatures. This routine is the
2239 // intake for constraints. It collects them from several places:
2240 //
2241 // * LinkResolver::resolve_method (if check_access is true) requires
2242 // that the resolving class (the caller) and the defining class of
2243 // the resolved method (the callee) agree on each type in the
2244 // method's signature.
2245 //
2246 // * LinkResolver::resolve_interface_method performs exactly the same
2247 // checks.
2248 //
2249 // * LinkResolver::resolve_field requires that the constant pool
2250 // attempting to link to a field agree with the field's defining
2251 // class about the type of the field signature.
2252 //
2253 // * klassVtable::initialize_vtable requires that, when a class
2254 // overrides a vtable entry allocated by a superclass, that the
2255 // overriding method (i.e., the callee) agree with the superclass
2256 // on each type in the method's signature.
2257 //
2258 // * klassItable::initialize_itable requires that, when a class fills
2259 // in its itables, for each non-abstract method installed in an
2260 // itable, the method (i.e., the callee) agree with the interface
2261 // on each type in the method's signature.
2262 //
2263 // All those methods have a boolean (check_access, checkconstraints)
2264 // which turns off the checks. This is used from specialized contexts
2265 // such as bootstrapping, dumping, and debugging.
2266 //
2267 // No direct constraint is placed between the class and its
2268 // supertypes. Constraints are only placed along linked relations
2269 // between callers and callees. When a method overrides or implements
2270 // an abstract method in a supertype (superclass or interface), the
2271 // constraints are placed as if the supertype were the caller to the
2272 // overriding method. (This works well, since callers to the
2273 // supertype have already established agreement between themselves and
2274 // the supertype.) As a result of all this, a class can disagree with
2275 // its supertype about the meaning of a type name, as long as that
2276 // class neither calls a relevant method of the supertype, nor is
2277 // called (perhaps via an override) from the supertype.
2278 //
2279 //
2280 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2281 //
2282 // Make sure all class components (including arrays) in the given
2283 // signature will be resolved to the same class in both loaders.
2284 // Returns the name of the type that failed a loader constraint check, or
2285 // NULL if no constraint failed. No exception except OOME is thrown.
2286 // Arrays are not added to the loader constraint table, their elements are.
2287 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2288 Handle loader1, Handle loader2,
2289 bool is_method, TRAPS) {
2290 // Nothing to do if loaders are the same.
2291 if (loader1() == loader2()) {
2292 return NULL;
2293 }
2294
2295 SignatureStream sig_strm(signature, is_method);
2296 while (!sig_strm.is_done()) {
2297 if (sig_strm.is_object()) {
2298 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2299 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2300 return sig;
2301 }
2302 }
2303 sig_strm.next();
2304 }
2305 return NULL;
2306 }
2307
2308
2309 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2310 Symbol* signature,
2311 TRAPS) {
2312 methodHandle empty;
2313 assert(EnableInvokeDynamic, "");
2314 assert(MethodHandles::is_signature_polymorphic(iid) &&
2315 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2316 iid != vmIntrinsics::_invokeGeneric,
2317 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2318
2319 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2320 int index = invoke_method_table()->hash_to_index(hash);
2321 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2322 methodHandle m;
2323 if (spe == NULL || spe->method() == NULL) {
2324 spe = NULL;
2325 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2326 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2327 if (!Arguments::is_interpreter_only()) {
2328 // Generate a compiled form of the MH intrinsic.
2329 AdapterHandlerLibrary::create_native_wrapper(m);
2330 // Check if have the compiled code.
2331 if (!m->has_compiled_code()) {
2332 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2333 "out of space in CodeCache for method handle intrinsic", empty);
2334 }
2335 }
2336 // Now grab the lock. We might have to throw away the new method,
2337 // if a racing thread has managed to install one at the same time.
2338 {
2339 MutexLocker ml(SystemDictionary_lock, THREAD);
2340 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2341 if (spe == NULL)
2342 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2343 if (spe->method() == NULL)
2344 spe->set_method(m());
2345 }
2346 }
2347
2348 assert(spe != NULL && spe->method() != NULL, "");
2349 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2350 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2351 "MH intrinsic invariant");
2352 return spe->method();
2353 }
2354
2355 // Helper for unpacking the return value from linkMethod and linkCallSite.
2356 static methodHandle unpack_method_and_appendix(Handle mname,
2357 KlassHandle accessing_klass,
2358 objArrayHandle appendix_box,
2359 Handle* appendix_result,
2360 TRAPS) {
2361 methodHandle empty;
2362 if (mname.not_null()) {
2363 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2364 if (vmtarget != NULL && vmtarget->is_method()) {
2365 Method* m = (Method*)vmtarget;
2366 oop appendix = appendix_box->obj_at(0);
2367 if (TraceMethodHandles) {
2368 #ifndef PRODUCT
2369 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2370 m->print();
2371 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2372 tty->cr();
2373 #endif //PRODUCT
2374 }
2375 (*appendix_result) = Handle(THREAD, appendix);
2376 // the target is stored in the cpCache and if a reference to this
2377 // MethodName is dropped we need a way to make sure the
2378 // class_loader containing this method is kept alive.
2379 // FIXME: the appendix might also preserve this dependency.
2380 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2381 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2382 return methodHandle(THREAD, m);
2383 }
2384 }
2385 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2386 return empty;
2387 }
2388
2389 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2390 Symbol* signature,
2391 KlassHandle accessing_klass,
2392 Handle *appendix_result,
2393 Handle *method_type_result,
2394 TRAPS) {
2395 methodHandle empty;
2396 assert(EnableInvokeDynamic, "");
2397 assert(!THREAD->is_Compiler_thread(), "");
2398 Handle method_type =
2399 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2400
2401 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2402 int ref_kind = JVM_REF_invokeVirtual;
2403 Handle name_str = StringTable::intern(name, CHECK_(empty));
2404 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2405 assert(appendix_box->obj_at(0) == NULL, "");
2406
2407 // This should not happen. JDK code should take care of that.
2408 if (accessing_klass.is_null() || method_type.is_null()) {
2409 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2410 }
2411
2412 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2413 JavaCallArguments args;
2414 args.push_oop(accessing_klass()->java_mirror());
2415 args.push_int(ref_kind);
2416 args.push_oop(mh_klass()->java_mirror());
2417 args.push_oop(name_str());
2418 args.push_oop(method_type());
2419 args.push_oop(appendix_box());
2420 JavaValue result(T_OBJECT);
2421 JavaCalls::call_static(&result,
2422 SystemDictionary::MethodHandleNatives_klass(),
2423 vmSymbols::linkMethod_name(),
2424 vmSymbols::linkMethod_signature(),
2425 &args, CHECK_(empty));
2426 Handle mname(THREAD, (oop) result.get_jobject());
2427 (*method_type_result) = method_type;
2428 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2429 }
2430
2431 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2432 // We must ensure that all class loaders everywhere will reach this class, for any client.
2433 // This is a safe bet for public classes in java.lang, such as Object and String.
2434 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2435 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2436 static bool is_always_visible_class(oop mirror) {
2437 Klass* klass = java_lang_Class::as_Klass(mirror);
2438 if (klass->oop_is_objArray()) {
2439 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2440 }
2441 if (klass->oop_is_typeArray()) {
2442 return true; // primitive array
2443 }
2444 assert(klass->oop_is_instance(), klass->external_name());
2445 return klass->is_public() &&
2446 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2447 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2448 }
2449
2450 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2451 // signature, as interpreted relative to the given class loader.
2452 // Because of class loader constraints, all method handle usage must be
2453 // consistent with this loader.
2454 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2455 KlassHandle accessing_klass,
2456 TRAPS) {
2457 Handle empty;
2458 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2459 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2460 int index = invoke_method_table()->hash_to_index(hash);
2461 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2462 if (spe != NULL && spe->method_type() != NULL) {
2463 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2464 return Handle(THREAD, spe->method_type());
2465 } else if (THREAD->is_Compiler_thread()) {
2466 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2467 return Handle(); // do not attempt from within compiler, unless it was cached
2468 }
2469
2470 Handle class_loader, protection_domain;
2471 if (accessing_klass.not_null()) {
2472 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2473 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2474 }
2475 bool can_be_cached = true;
2476 int npts = ArgumentCount(signature).size();
2477 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2478 int arg = 0;
2479 Handle rt; // the return type from the signature
2480 ResourceMark rm(THREAD);
2481 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2482 oop mirror = NULL;
2483 if (can_be_cached) {
2484 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2485 mirror = ss.as_java_mirror(Handle(), Handle(),
2486 SignatureStream::ReturnNull, CHECK_(empty));
2487 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2488 // Fall back to accessing_klass context.
2489 can_be_cached = false;
2490 }
2491 }
2492 if (!can_be_cached) {
2493 // Resolve, throwing a real error if it doesn't work.
2494 mirror = ss.as_java_mirror(class_loader, protection_domain,
2495 SignatureStream::NCDFError, CHECK_(empty));
2496 }
2497 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2498 if (ss.at_return_type())
2499 rt = Handle(THREAD, mirror);
2500 else
2501 pts->obj_at_put(arg++, mirror);
2502
2503 // Check accessibility.
2504 if (ss.is_object() && accessing_klass.not_null()) {
2505 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2506 mirror = NULL; // safety
2507 // Emulate ConstantPool::verify_constant_pool_resolve.
2508 if (sel_klass->oop_is_objArray())
2509 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2510 if (sel_klass->oop_is_instance()) {
2511 KlassHandle sel_kh(THREAD, sel_klass);
2512 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2513 }
2514 }
2515 }
2516 assert(arg == npts, "");
2517
2518 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2519 JavaCallArguments args(Handle(THREAD, rt()));
2520 args.push_oop(pts());
2521 JavaValue result(T_OBJECT);
2522 JavaCalls::call_static(&result,
2523 SystemDictionary::MethodHandleNatives_klass(),
2524 vmSymbols::findMethodHandleType_name(),
2525 vmSymbols::findMethodHandleType_signature(),
2526 &args, CHECK_(empty));
2527 Handle method_type(THREAD, (oop) result.get_jobject());
2528
2529 if (can_be_cached) {
2530 // We can cache this MethodType inside the JVM.
2531 MutexLocker ml(SystemDictionary_lock, THREAD);
2532 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2533 if (spe == NULL)
2534 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2535 if (spe->method_type() == NULL) {
2536 spe->set_method_type(method_type());
2537 }
2538 }
2539
2540 // report back to the caller with the MethodType
2541 return method_type;
2542 }
2543
2544 // Ask Java code to find or construct a method handle constant.
2545 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2546 int ref_kind, //e.g., JVM_REF_invokeVirtual
2547 KlassHandle callee,
2548 Symbol* name_sym,
2549 Symbol* signature,
2550 TRAPS) {
2551 Handle empty;
2552 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2553 Handle type;
2554 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2555 type = find_method_handle_type(signature, caller, CHECK_(empty));
2556 } else if (caller.is_null()) {
2557 // This should not happen. JDK code should take care of that.
2558 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2559 } else {
2560 ResourceMark rm(THREAD);
2561 SignatureStream ss(signature, false);
2562 if (!ss.is_done()) {
2563 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2564 SignatureStream::NCDFError, CHECK_(empty));
2565 type = Handle(THREAD, mirror);
2566 ss.next();
2567 if (!ss.is_done()) type = Handle(); // error!
2568 }
2569 }
2570 if (type.is_null()) {
2571 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2572 }
2573
2574 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2575 JavaCallArguments args;
2576 args.push_oop(caller->java_mirror()); // the referring class
2577 args.push_int(ref_kind);
2578 args.push_oop(callee->java_mirror()); // the target class
2579 args.push_oop(name());
2580 args.push_oop(type());
2581 JavaValue result(T_OBJECT);
2582 JavaCalls::call_static(&result,
2583 SystemDictionary::MethodHandleNatives_klass(),
2584 vmSymbols::linkMethodHandleConstant_name(),
2585 vmSymbols::linkMethodHandleConstant_signature(),
2586 &args, CHECK_(empty));
2587 return Handle(THREAD, (oop) result.get_jobject());
2588 }
2589
2590 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2591 // name and signature, as interpreted relative to the given class loader.
2592 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2593 Handle bootstrap_specifier,
2594 Symbol* name,
2595 Symbol* type,
2596 Handle *appendix_result,
2597 Handle *method_type_result,
2598 TRAPS) {
2599 methodHandle empty;
2600 Handle bsm, info;
2601 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2602 bsm = bootstrap_specifier;
2603 } else {
2604 assert(bootstrap_specifier->is_objArray(), "");
2605 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2606 int len = args->length();
2607 assert(len >= 1, "");
2608 bsm = Handle(THREAD, args->obj_at(0));
2609 if (len > 1) {
2610 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2611 for (int i = 1; i < len; i++)
2612 args1->obj_at_put(i-1, args->obj_at(i));
2613 info = Handle(THREAD, args1);
2614 }
2615 }
2616 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2617 "caller must supply a valid BSM");
2618
2619 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2620 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2621
2622 // This should not happen. JDK code should take care of that.
2623 if (caller.is_null() || method_type.is_null()) {
2624 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2625 }
2626
2627 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2628 assert(appendix_box->obj_at(0) == NULL, "");
2629
2630 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2631 JavaCallArguments args;
2632 args.push_oop(caller->java_mirror());
2633 args.push_oop(bsm());
2634 args.push_oop(method_name());
2635 args.push_oop(method_type());
2636 args.push_oop(info());
2637 args.push_oop(appendix_box);
2638 JavaValue result(T_OBJECT);
2639 JavaCalls::call_static(&result,
2640 SystemDictionary::MethodHandleNatives_klass(),
2641 vmSymbols::linkCallSite_name(),
2642 vmSymbols::linkCallSite_signature(),
2643 &args, CHECK_(empty));
2644 Handle mname(THREAD, (oop) result.get_jobject());
2645 (*method_type_result) = method_type;
2646 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2647 }
2648
2649 // Since the identity hash code for symbols changes when the symbols are
2650 // moved from the regular perm gen (hash in the mark word) to the shared
2651 // spaces (hash is the address), the classes loaded into the dictionary
2652 // may be in the wrong buckets.
2653
2654 void SystemDictionary::reorder_dictionary() {
2655 dictionary()->reorder_dictionary();
2656 }
2657
2658
2659 void SystemDictionary::copy_buckets(char** top, char* end) {
2660 dictionary()->copy_buckets(top, end);
2661 }
2662
2663
2664 void SystemDictionary::copy_table(char** top, char* end) {
2665 dictionary()->copy_table(top, end);
2666 }
2667
2668
2669 void SystemDictionary::reverse() {
2670 dictionary()->reverse();
2671 }
2672
2673 int SystemDictionary::number_of_classes() {
2674 return dictionary()->number_of_entries();
2675 }
2676
2677
2678 // ----------------------------------------------------------------------------
2679 void SystemDictionary::print_shared(bool details) {
2680 shared_dictionary()->print(details);
2681 }
2682
2683 void SystemDictionary::print(bool details) {
2684 dictionary()->print(details);
2685
2686 // Placeholders
2687 GCMutexLocker mu(SystemDictionary_lock);
2688 placeholders()->print();
2689
2690 // loader constraints - print under SD_lock
2691 constraints()->print();
2692 }
2693
2694
2695 void SystemDictionary::verify() {
2696 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2697 guarantee(constraints() != NULL,
2698 "Verify of loader constraints failed");
2699 guarantee(dictionary()->number_of_entries() >= 0 &&
2700 placeholders()->number_of_entries() >= 0,
2701 "Verify of system dictionary failed");
2702
2703 // Verify dictionary
2704 dictionary()->verify();
2705
2706 GCMutexLocker mu(SystemDictionary_lock);
2707 placeholders()->verify();
2708
2709 // Verify constraint table
2710 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2711 constraints()->verify(dictionary(), placeholders());
2712 }
2713
2714 #ifndef PRODUCT
2715
2716 // statistics code
2717 class ClassStatistics: AllStatic {
2718 private:
2719 static int nclasses; // number of classes
2720 static int nmethods; // number of methods
2721 static int nmethoddata; // number of methodData
2722 static int class_size; // size of class objects in words
2723 static int method_size; // size of method objects in words
2724 static int debug_size; // size of debug info in methods
2725 static int methoddata_size; // size of methodData objects in words
2726
2727 static void do_class(Klass* k) {
2728 nclasses++;
2729 class_size += k->size();
2730 if (k->oop_is_instance()) {
2731 InstanceKlass* ik = (InstanceKlass*)k;
2732 class_size += ik->methods()->size();
2733 class_size += ik->constants()->size();
2734 class_size += ik->local_interfaces()->size();
2735 class_size += ik->transitive_interfaces()->size();
2736 // We do not have to count implementors, since we only store one!
2737 // SSS: How should these be accounted now that they have moved?
2738 // class_size += ik->fields()->length();
2739 }
2740 }
2741
2742 static void do_method(Method* m) {
2743 nmethods++;
2744 method_size += m->size();
2745 // class loader uses same objArray for empty vectors, so don't count these
2746 if (m->has_stackmap_table()) {
2747 method_size += m->stackmap_data()->size();
2748 }
2749
2750 MethodData* mdo = m->method_data();
2751 if (mdo != NULL) {
2752 nmethoddata++;
2753 methoddata_size += mdo->size();
2754 }
2755 }
2756
2757 public:
2758 static void print() {
2759 SystemDictionary::classes_do(do_class);
2760 SystemDictionary::methods_do(do_method);
2761 tty->print_cr("Class statistics:");
2762 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2763 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2764 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2765 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2766 }
2767 };
2768
2769
2770 int ClassStatistics::nclasses = 0;
2771 int ClassStatistics::nmethods = 0;
2772 int ClassStatistics::nmethoddata = 0;
2773 int ClassStatistics::class_size = 0;
2774 int ClassStatistics::method_size = 0;
2775 int ClassStatistics::debug_size = 0;
2776 int ClassStatistics::methoddata_size = 0;
2777
2778 void SystemDictionary::print_class_statistics() {
2779 ResourceMark rm;
2780 ClassStatistics::print();
2781 }
2782
2783
2784 class MethodStatistics: AllStatic {
2785 public:
2786 enum {
2787 max_parameter_size = 10
2788 };
2789 private:
2790
2791 static int _number_of_methods;
2792 static int _number_of_final_methods;
2793 static int _number_of_static_methods;
2794 static int _number_of_native_methods;
2795 static int _number_of_synchronized_methods;
2796 static int _number_of_profiled_methods;
2797 static int _number_of_bytecodes;
2798 static int _parameter_size_profile[max_parameter_size];
2799 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2800
2801 static void initialize() {
2802 _number_of_methods = 0;
2803 _number_of_final_methods = 0;
2804 _number_of_static_methods = 0;
2805 _number_of_native_methods = 0;
2806 _number_of_synchronized_methods = 0;
2807 _number_of_profiled_methods = 0;
2808 _number_of_bytecodes = 0;
2809 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2810 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2811 };
2812
2813 static void do_method(Method* m) {
2814 _number_of_methods++;
2815 // collect flag info
2816 if (m->is_final() ) _number_of_final_methods++;
2817 if (m->is_static() ) _number_of_static_methods++;
2818 if (m->is_native() ) _number_of_native_methods++;
2819 if (m->is_synchronized()) _number_of_synchronized_methods++;
2820 if (m->method_data() != NULL) _number_of_profiled_methods++;
2821 // collect parameter size info (add one for receiver, if any)
2822 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2823 // collect bytecodes info
2824 {
2825 Thread *thread = Thread::current();
2826 HandleMark hm(thread);
2827 BytecodeStream s(methodHandle(thread, m));
2828 Bytecodes::Code c;
2829 while ((c = s.next()) >= 0) {
2830 _number_of_bytecodes++;
2831 _bytecodes_profile[c]++;
2832 }
2833 }
2834 }
2835
2836 public:
2837 static void print() {
2838 initialize();
2839 SystemDictionary::methods_do(do_method);
2840 // generate output
2841 tty->cr();
2842 tty->print_cr("Method statistics (static):");
2843 // flag distribution
2844 tty->cr();
2845 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2846 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2847 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2848 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2849 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2850 // parameter size profile
2851 tty->cr();
2852 { int tot = 0;
2853 int avg = 0;
2854 for (int i = 0; i < max_parameter_size; i++) {
2855 int n = _parameter_size_profile[i];
2856 tot += n;
2857 avg += n*i;
2858 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2859 }
2860 assert(tot == _number_of_methods, "should be the same");
2861 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2862 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2863 }
2864 // bytecodes profile
2865 tty->cr();
2866 { int tot = 0;
2867 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2868 if (Bytecodes::is_defined(i)) {
2869 Bytecodes::Code c = Bytecodes::cast(i);
2870 int n = _bytecodes_profile[c];
2871 tot += n;
2872 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2873 }
2874 }
2875 assert(tot == _number_of_bytecodes, "should be the same");
2876 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2877 }
2878 tty->cr();
2879 }
2880 };
2881
2882 int MethodStatistics::_number_of_methods;
2883 int MethodStatistics::_number_of_final_methods;
2884 int MethodStatistics::_number_of_static_methods;
2885 int MethodStatistics::_number_of_native_methods;
2886 int MethodStatistics::_number_of_synchronized_methods;
2887 int MethodStatistics::_number_of_profiled_methods;
2888 int MethodStatistics::_number_of_bytecodes;
2889 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2890 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2891
2892
2893 void SystemDictionary::print_method_statistics() {
2894 MethodStatistics::print();
2895 }
2896
2897 #endif // PRODUCT