1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #if INCLUDE_CDS
34 #include "classfile/sharedClassUtil.hpp"
35 #include "classfile/systemDictionaryShared.hpp"
36 #endif
37 #include "classfile/vmSymbols.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/bytecodeStream.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "memory/filemap.hpp"
42 #include "memory/gcLocker.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "oops/instanceKlass.hpp"
45 #include "oops/instanceRefKlass.hpp"
46 #include "oops/klass.inline.hpp"
47 #include "oops/methodData.hpp"
48 #include "oops/objArrayKlass.hpp"
49 #include "oops/oop.inline.hpp"
50 #include "oops/oop.inline2.hpp"
51 #include "oops/typeArrayKlass.hpp"
52 #include "prims/jvmtiEnvBase.hpp"
53 #include "prims/methodHandles.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/biasedLocking.hpp"
56 #include "runtime/fieldType.hpp"
57 #include "runtime/handles.inline.hpp"
58 #include "runtime/java.hpp"
59 #include "runtime/javaCalls.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/orderAccess.inline.hpp"
62 #include "runtime/signature.hpp"
63 #include "services/classLoadingService.hpp"
64 #include "services/threadService.hpp"
65 #include "utilities/macros.hpp"
66 #include "utilities/ticks.hpp"
67 #if INCLUDE_TRACE
68 #include "trace/tracing.hpp"
69 #endif
70
71 Dictionary* SystemDictionary::_dictionary = NULL;
72 PlaceholderTable* SystemDictionary::_placeholders = NULL;
73 Dictionary* SystemDictionary::_shared_dictionary = NULL;
74 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
75 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
76 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
77
78
79 int SystemDictionary::_number_of_modifications = 0;
80 int SystemDictionary::_sdgeneration = 0;
81 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
82 20201,40423,99991};
83
84 oop SystemDictionary::_system_loader_lock_obj = NULL;
85
86 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
87 = { NULL /*, NULL...*/ };
88
89 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
90
91 oop SystemDictionary::_java_system_loader = NULL;
92
93 bool SystemDictionary::_has_loadClassInternal = false;
94 bool SystemDictionary::_has_checkPackageAccess = false;
95
96 // lazily initialized klass variables
97 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
98
99
100 // ----------------------------------------------------------------------------
101 // Java-level SystemLoader
102
103 oop SystemDictionary::java_system_loader() {
104 return _java_system_loader;
105 }
106
107 void SystemDictionary::compute_java_system_loader(TRAPS) {
108 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
109 JavaValue result(T_OBJECT);
110 JavaCalls::call_static(&result,
111 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
112 vmSymbols::getSystemClassLoader_name(),
113 vmSymbols::void_classloader_signature(),
114 CHECK);
115
116 _java_system_loader = (oop)result.get_jobject();
117
118 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
119 }
120
121
122 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
123 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
124 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
125 }
126
127 // ----------------------------------------------------------------------------
128 // debugging
129
130 #ifdef ASSERT
131
132 // return true if class_name contains no '.' (internal format is '/')
133 bool SystemDictionary::is_internal_format(Symbol* class_name) {
134 if (class_name != NULL) {
135 ResourceMark rm;
136 char* name = class_name->as_C_string();
137 return strchr(name, '.') == NULL;
138 } else {
139 return true;
140 }
141 }
142
143 #endif
144
145 // ----------------------------------------------------------------------------
146 // Parallel class loading check
147
148 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
149 if (UnsyncloadClass || class_loader.is_null()) return true;
150 if (AlwaysLockClassLoader) return false;
151 return java_lang_ClassLoader::parallelCapable(class_loader());
152 }
153 // ----------------------------------------------------------------------------
154 // ParallelDefineClass flag does not apply to bootclass loader
155 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
156 if (class_loader.is_null()) return false;
157 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
158 return true;
159 }
160 return false;
161 }
162
163 /**
164 * Returns true if the passed class loader is the extension class loader.
165 */
166 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
167 if (class_loader.is_null()) {
168 return false;
169 }
170 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
171 }
172
173 // ----------------------------------------------------------------------------
174 // Resolving of classes
175
176 // Forwards to resolve_or_null
177
178 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
179 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
180 if (HAS_PENDING_EXCEPTION || klass == NULL) {
181 KlassHandle k_h(THREAD, klass);
182 // can return a null klass
183 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
184 }
185 return klass;
186 }
187
188 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
189 if (HAS_PENDING_EXCEPTION) {
190 // If we have a pending exception we forward it to the caller, unless throw_error is true,
191 // in which case we have to check whether the pending exception is a ClassNotFoundException,
192 // and if so convert it to a NoClassDefFoundError
193 // And chain the original ClassNotFoundException
194 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
195 ResourceMark rm(THREAD);
196 assert(klass_h() == NULL, "Should not have result with exception pending");
197 Handle e(THREAD, PENDING_EXCEPTION);
198 CLEAR_PENDING_EXCEPTION;
199 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
200 } else {
201 return NULL;
202 }
203 }
204 // Class not found, throw appropriate error or exception depending on value of throw_error
205 if (klass_h() == NULL) {
206 ResourceMark rm(THREAD);
207 if (throw_error) {
208 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
209 } else {
210 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
211 }
212 }
213 return (Klass*)klass_h();
214 }
215
216
217 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
218 bool throw_error, TRAPS)
219 {
220 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
221 }
222
223
224 // Forwards to resolve_instance_class_or_null
225
226 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
227 assert(!THREAD->is_Compiler_thread(),
228 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
229 class_name->as_C_string(),
230 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
231 if (FieldType::is_array(class_name)) {
232 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
233 } else if (FieldType::is_obj(class_name)) {
234 ResourceMark rm(THREAD);
235 // Ignore wrapping L and ;.
236 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
237 class_name->utf8_length() - 2, CHECK_NULL);
238 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
239 } else {
240 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
241 }
242 }
243
244 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
245 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
246 }
247
248 // Forwards to resolve_instance_class_or_null
249
250 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
251 Handle class_loader,
252 Handle protection_domain,
253 TRAPS) {
254 assert(FieldType::is_array(class_name), "must be array");
255 Klass* k = NULL;
256 FieldArrayInfo fd;
257 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
258 // of this call
259 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
260 if (t == T_OBJECT) {
261 // naked oop "k" is OK here -- we assign back into it
262 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
263 class_loader,
264 protection_domain,
265 CHECK_NULL);
266 if (k != NULL) {
267 k = k->array_klass(fd.dimension(), CHECK_NULL);
268 }
269 } else {
270 k = Universe::typeArrayKlassObj(t);
271 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
272 }
273 return k;
274 }
275
276
277 // Must be called for any super-class or super-interface resolution
278 // during class definition to allow class circularity checking
279 // super-interface callers:
280 // parse_interfaces - for defineClass & jvmtiRedefineClasses
281 // super-class callers:
282 // ClassFileParser - for defineClass & jvmtiRedefineClasses
283 // load_shared_class - while loading a class from shared archive
284 // resolve_instance_class_or_null:
285 // via: handle_parallel_super_load
286 // when resolving a class that has an existing placeholder with
287 // a saved superclass [i.e. a defineClass is currently in progress]
288 // if another thread is trying to resolve the class, it must do
289 // super-class checks on its own thread to catch class circularity
290 // This last call is critical in class circularity checking for cases
291 // where classloading is delegated to different threads and the
292 // classloader lock is released.
293 // Take the case: Base->Super->Base
294 // 1. If thread T1 tries to do a defineClass of class Base
295 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
296 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
297 // so it tries to load Super
298 // 3. If we load the class internally, or user classloader uses same thread
299 // loadClassFromxxx or defineClass via parseClassFile Super ...
300 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
301 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
302 // 3.4 calls resolve_super_or_fail Base
303 // 3.5 finds T1,Base -> throws class circularity
304 //OR 4. If T2 tries to resolve Super via defineClass Super ...
305 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
306 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
307 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
308 // 4.4 finds T2, Super -> throws class circularity
309 // Must be called, even if superclass is null, since this is
310 // where the placeholder entry is created which claims this
311 // thread is loading this class/classloader.
312 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
313 Symbol* class_name,
314 Handle class_loader,
315 Handle protection_domain,
316 bool is_superclass,
317 TRAPS) {
318 // Double-check, if child class is already loaded, just return super-class,interface
319 // Don't add a placedholder if already loaded, i.e. already in system dictionary
320 // Make sure there's a placeholder for the *child* before resolving.
321 // Used as a claim that this thread is currently loading superclass/classloader
322 // Used here for ClassCircularity checks and also for heap verification
323 // (every InstanceKlass in the heap needs to be in the system dictionary
324 // or have a placeholder).
325 // Must check ClassCircularity before checking if super class is already loaded
326 //
327 // We might not already have a placeholder if this child_name was
328 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
329 // the name of the class might not be known until the stream is actually
330 // parsed.
331 // Bugs 4643874, 4715493
332 // compute_hash can have a safepoint
333
334 ClassLoaderData* loader_data = class_loader_data(class_loader);
335 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
336 int d_index = dictionary()->hash_to_index(d_hash);
337 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
338 int p_index = placeholders()->hash_to_index(p_hash);
339 // can't throw error holding a lock
340 bool child_already_loaded = false;
341 bool throw_circularity_error = false;
342 {
343 MutexLocker mu(SystemDictionary_lock, THREAD);
344 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
345 Klass* quicksuperk;
346 // to support // loading: if child done loading, just return superclass
347 // if class_name, & class_loader don't match:
348 // if initial define, SD update will give LinkageError
349 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
350 // so we don't throw an exception here.
351 // see: nsk redefclass014 & java.lang.instrument Instrument032
352 if ((childk != NULL ) && (is_superclass) &&
353 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
354
355 ((quicksuperk->name() == class_name) &&
356 (quicksuperk->class_loader() == class_loader()))) {
357 return quicksuperk;
358 } else {
359 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
360 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
361 throw_circularity_error = true;
362 }
363 }
364 if (!throw_circularity_error) {
365 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
366 }
367 }
368 if (throw_circularity_error) {
369 ResourceMark rm(THREAD);
370 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
371 }
372
373 // java.lang.Object should have been found above
374 assert(class_name != NULL, "null super class for resolving");
375 // Resolve the super class or interface, check results on return
376 Klass* superk = SystemDictionary::resolve_or_null(class_name,
377 class_loader,
378 protection_domain,
379 THREAD);
380
381 KlassHandle superk_h(THREAD, superk);
382
383 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
384 // It is no longer necessary to keep the placeholder table alive until update_dictionary
385 // or error. GC used to walk the placeholder table as strong roots.
386 // The instanceKlass is kept alive because the class loader is on the stack,
387 // which keeps the loader_data alive, as well as all instanceKlasses in
388 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
389 {
390 MutexLocker mu(SystemDictionary_lock, THREAD);
391 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
392 SystemDictionary_lock->notify_all();
393 }
394 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
395 // can null superk
396 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
397 }
398
399 return superk_h();
400 }
401
402 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
403 Handle class_loader,
404 Handle protection_domain,
405 TRAPS) {
406 if(!has_checkPackageAccess()) return;
407
408 // Now we have to call back to java to check if the initating class has access
409 JavaValue result(T_VOID);
410 if (TraceProtectionDomainVerification) {
411 // Print out trace information
412 tty->print_cr("Checking package access");
413 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
414 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
415 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
416 }
417
418 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
419 JavaCalls::call_special(&result,
420 class_loader,
421 system_loader,
422 vmSymbols::checkPackageAccess_name(),
423 vmSymbols::class_protectiondomain_signature(),
424 Handle(THREAD, klass->java_mirror()),
425 protection_domain,
426 THREAD);
427
428 if (TraceProtectionDomainVerification) {
429 if (HAS_PENDING_EXCEPTION) {
430 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
431 } else {
432 tty->print_cr(" -> granted");
433 }
434 tty->cr();
435 }
436
437 if (HAS_PENDING_EXCEPTION) return;
438
439 // If no exception has been thrown, we have validated the protection domain
440 // Insert the protection domain of the initiating class into the set.
441 {
442 // We recalculate the entry here -- we've called out to java since
443 // the last time it was calculated.
444 ClassLoaderData* loader_data = class_loader_data(class_loader);
445
446 Symbol* kn = klass->name();
447 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
448 int d_index = dictionary()->hash_to_index(d_hash);
449
450 MutexLocker mu(SystemDictionary_lock, THREAD);
451 {
452 // Note that we have an entry, and entries can be deleted only during GC,
453 // so we cannot allow GC to occur while we're holding this entry.
454
455 // We're using a No_Safepoint_Verifier to catch any place where we
456 // might potentially do a GC at all.
457 // Dictionary::do_unloading() asserts that classes in SD are only
458 // unloaded at a safepoint. Anonymous classes are not in SD.
459 No_Safepoint_Verifier nosafepoint;
460 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
461 protection_domain, THREAD);
462 }
463 }
464 }
465
466 // We only get here if this thread finds that another thread
467 // has already claimed the placeholder token for the current operation,
468 // but that other thread either never owned or gave up the
469 // object lock
470 // Waits on SystemDictionary_lock to indicate placeholder table updated
471 // On return, caller must recheck placeholder table state
472 //
473 // We only get here if
474 // 1) custom classLoader, i.e. not bootstrap classloader
475 // 2) UnsyncloadClass not set
476 // 3) custom classLoader has broken the class loader objectLock
477 // so another thread got here in parallel
478 //
479 // lockObject must be held.
480 // Complicated dance due to lock ordering:
481 // Must first release the classloader object lock to
482 // allow initial definer to complete the class definition
483 // and to avoid deadlock
484 // Reclaim classloader lock object with same original recursion count
485 // Must release SystemDictionary_lock after notify, since
486 // class loader lock must be claimed before SystemDictionary_lock
487 // to prevent deadlocks
488 //
489 // The notify allows applications that did an untimed wait() on
490 // the classloader object lock to not hang.
491 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
492 assert_lock_strong(SystemDictionary_lock);
493
494 bool calledholdinglock
495 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
496 assert(calledholdinglock,"must hold lock for notify");
497 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
498 ObjectSynchronizer::notifyall(lockObject, THREAD);
499 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
500 SystemDictionary_lock->wait();
501 SystemDictionary_lock->unlock();
502 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
503 SystemDictionary_lock->lock();
504 }
505
506 // If the class in is in the placeholder table, class loading is in progress
507 // For cases where the application changes threads to load classes, it
508 // is critical to ClassCircularity detection that we try loading
509 // the superclass on the same thread internally, so we do parallel
510 // super class loading here.
511 // This also is critical in cases where the original thread gets stalled
512 // even in non-circularity situations.
513 // Note: must call resolve_super_or_fail even if null super -
514 // to force placeholder entry creation for this class for circularity detection
515 // Caller must check for pending exception
516 // Returns non-null Klass* if other thread has completed load
517 // and we are done,
518 // If return null Klass* and no pending exception, the caller must load the class
519 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
520 Symbol* name, Symbol* superclassname, Handle class_loader,
521 Handle protection_domain, Handle lockObject, TRAPS) {
522
523 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
524 ClassLoaderData* loader_data = class_loader_data(class_loader);
525 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
526 int d_index = dictionary()->hash_to_index(d_hash);
527 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
528 int p_index = placeholders()->hash_to_index(p_hash);
529
530 // superk is not used, resolve_super called for circularity check only
531 // This code is reached in two situations. One if this thread
532 // is loading the same class twice (e.g. ClassCircularity, or
533 // java.lang.instrument).
534 // The second is if another thread started the resolve_super first
535 // and has not yet finished.
536 // In both cases the original caller will clean up the placeholder
537 // entry on error.
538 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
539 superclassname,
540 class_loader,
541 protection_domain,
542 true,
543 CHECK_(nh));
544
545 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
546 // Serial class loaders and bootstrap classloader do wait for superclass loads
547 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
548 MutexLocker mu(SystemDictionary_lock, THREAD);
549 // Check if classloading completed while we were loading superclass or waiting
550 Klass* check = find_class(d_index, d_hash, name, loader_data);
551 if (check != NULL) {
552 // Klass is already loaded, so just return it
553 return(instanceKlassHandle(THREAD, check));
554 } else {
555 return nh;
556 }
557 }
558
559 // must loop to both handle other placeholder updates
560 // and spurious notifications
561 bool super_load_in_progress = true;
562 PlaceholderEntry* placeholder;
563 while (super_load_in_progress) {
564 MutexLocker mu(SystemDictionary_lock, THREAD);
565 // Check if classloading completed while we were loading superclass or waiting
566 Klass* check = find_class(d_index, d_hash, name, loader_data);
567 if (check != NULL) {
568 // Klass is already loaded, so just return it
569 return(instanceKlassHandle(THREAD, check));
570 } else {
571 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
572 if (placeholder && placeholder->super_load_in_progress() ){
573 // Before UnsyncloadClass:
574 // We only get here if the application has released the
575 // classloader lock when another thread was in the middle of loading a
576 // superclass/superinterface for this class, and now
577 // this thread is also trying to load this class.
578 // To minimize surprises, the first thread that started to
579 // load a class should be the one to complete the loading
580 // with the classfile it initially expected.
581 // This logic has the current thread wait once it has done
582 // all the superclass/superinterface loading it can, until
583 // the original thread completes the class loading or fails
584 // If it completes we will use the resulting InstanceKlass
585 // which we will find below in the systemDictionary.
586 // We also get here for parallel bootstrap classloader
587 if (class_loader.is_null()) {
588 SystemDictionary_lock->wait();
589 } else {
590 double_lock_wait(lockObject, THREAD);
591 }
592 } else {
593 // If not in SD and not in PH, other thread's load must have failed
594 super_load_in_progress = false;
595 }
596 }
597 }
598 return (nh);
599 }
600
601
602 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
603 Handle class_loader,
604 Handle protection_domain,
605 TRAPS) {
606 assert(name != NULL && !FieldType::is_array(name) &&
607 !FieldType::is_obj(name), "invalid class name");
608
609 Ticks class_load_start_time = Ticks::now();
610
611 // UseNewReflection
612 // Fix for 4474172; see evaluation for more details
613 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
614 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
615
616 // Do lookup to see if class already exist and the protection domain
617 // has the right access
618 // This call uses find which checks protection domain already matches
619 // All subsequent calls use find_class, and set has_loaded_class so that
620 // before we return a result we call out to java to check for valid protection domain
621 // to allow returning the Klass* and add it to the pd_set if it is valid
622 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
623 int d_index = dictionary()->hash_to_index(d_hash);
624 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
625 protection_domain, THREAD);
626 if (probe != NULL) return probe;
627
628
629 // Non-bootstrap class loaders will call out to class loader and
630 // define via jvm/jni_DefineClass which will acquire the
631 // class loader object lock to protect against multiple threads
632 // defining the class in parallel by accident.
633 // This lock must be acquired here so the waiter will find
634 // any successful result in the SystemDictionary and not attempt
635 // the define
636 // ParallelCapable Classloaders and the bootstrap classloader,
637 // or all classloaders with UnsyncloadClass do not acquire lock here
638 bool DoObjectLock = true;
639 if (is_parallelCapable(class_loader)) {
640 DoObjectLock = false;
641 }
642
643 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
644 int p_index = placeholders()->hash_to_index(p_hash);
645
646 // Class is not in SystemDictionary so we have to do loading.
647 // Make sure we are synchronized on the class loader before we proceed
648 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
649 check_loader_lock_contention(lockObject, THREAD);
650 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
651
652 // Check again (after locking) if class already exist in SystemDictionary
653 bool class_has_been_loaded = false;
654 bool super_load_in_progress = false;
655 bool havesupername = false;
656 instanceKlassHandle k;
657 PlaceholderEntry* placeholder;
658 Symbol* superclassname = NULL;
659
660 {
661 MutexLocker mu(SystemDictionary_lock, THREAD);
662 Klass* check = find_class(d_index, d_hash, name, loader_data);
663 if (check != NULL) {
664 // Klass is already loaded, so just return it
665 class_has_been_loaded = true;
666 k = instanceKlassHandle(THREAD, check);
667 } else {
668 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
669 if (placeholder && placeholder->super_load_in_progress()) {
670 super_load_in_progress = true;
671 if (placeholder->havesupername() == true) {
672 superclassname = placeholder->supername();
673 havesupername = true;
674 }
675 }
676 }
677 }
678
679 // If the class is in the placeholder table, class loading is in progress
680 if (super_load_in_progress && havesupername==true) {
681 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
682 class_loader, protection_domain, lockObject, THREAD);
683 if (HAS_PENDING_EXCEPTION) {
684 return NULL;
685 }
686 if (!k.is_null()) {
687 class_has_been_loaded = true;
688 }
689 }
690
691 bool throw_circularity_error = false;
692 if (!class_has_been_loaded) {
693 bool load_instance_added = false;
694
695 // add placeholder entry to record loading instance class
696 // Five cases:
697 // All cases need to prevent modifying bootclasssearchpath
698 // in parallel with a classload of same classname
699 // Redefineclasses uses existence of the placeholder for the duration
700 // of the class load to prevent concurrent redefinition of not completely
701 // defined classes.
702 // case 1. traditional classloaders that rely on the classloader object lock
703 // - no other need for LOAD_INSTANCE
704 // case 2. traditional classloaders that break the classloader object lock
705 // as a deadlock workaround. Detection of this case requires that
706 // this check is done while holding the classloader object lock,
707 // and that lock is still held when calling classloader's loadClass.
708 // For these classloaders, we ensure that the first requestor
709 // completes the load and other requestors wait for completion.
710 // case 3. UnsyncloadClass - don't use objectLocker
711 // With this flag, we allow parallel classloading of a
712 // class/classloader pair
713 // case4. Bootstrap classloader - don't own objectLocker
714 // This classloader supports parallelism at the classloader level,
715 // but only allows a single load of a class/classloader pair.
716 // No performance benefit and no deadlock issues.
717 // case 5. parallelCapable user level classloaders - without objectLocker
718 // Allow parallel classloading of a class/classloader pair
719
720 {
721 MutexLocker mu(SystemDictionary_lock, THREAD);
722 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
723 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (oldprobe) {
725 // only need check_seen_thread once, not on each loop
726 // 6341374 java/lang/Instrument with -Xcomp
727 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
728 throw_circularity_error = true;
729 } else {
730 // case 1: traditional: should never see load_in_progress.
731 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
732
733 // case 4: bootstrap classloader: prevent futile classloading,
734 // wait on first requestor
735 if (class_loader.is_null()) {
736 SystemDictionary_lock->wait();
737 } else {
738 // case 2: traditional with broken classloader lock. wait on first
739 // requestor.
740 double_lock_wait(lockObject, THREAD);
741 }
742 // Check if classloading completed while we were waiting
743 Klass* check = find_class(d_index, d_hash, name, loader_data);
744 if (check != NULL) {
745 // Klass is already loaded, so just return it
746 k = instanceKlassHandle(THREAD, check);
747 class_has_been_loaded = true;
748 }
749 // check if other thread failed to load and cleaned up
750 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
751 }
752 }
753 }
754 }
755 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
756 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
757 // LOAD_INSTANCE in parallel
758
759 if (!throw_circularity_error && !class_has_been_loaded) {
760 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
761 load_instance_added = true;
762 // For class loaders that do not acquire the classloader object lock,
763 // if they did not catch another thread holding LOAD_INSTANCE,
764 // need a check analogous to the acquire ObjectLocker/find_class
765 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
766 // one final check if the load has already completed
767 // class loaders holding the ObjectLock shouldn't find the class here
768 Klass* check = find_class(d_index, d_hash, name, loader_data);
769 if (check != NULL) {
770 // Klass is already loaded, so return it after checking/adding protection domain
771 k = instanceKlassHandle(THREAD, check);
772 class_has_been_loaded = true;
773 }
774 }
775 }
776
777 // must throw error outside of owning lock
778 if (throw_circularity_error) {
779 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
780 ResourceMark rm(THREAD);
781 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
782 }
783
784 if (!class_has_been_loaded) {
785
786 // Do actual loading
787 k = load_instance_class(name, class_loader, THREAD);
788
789 // For UnsyncloadClass only
790 // If they got a linkageError, check if a parallel class load succeeded.
791 // If it did, then for bytecode resolution the specification requires
792 // that we return the same result we did for the other thread, i.e. the
793 // successfully loaded InstanceKlass
794 // Should not get here for classloaders that support parallelism
795 // with the new cleaner mechanism, even with AllowParallelDefineClass
796 // Bootstrap goes through here to allow for an extra guarantee check
797 if (UnsyncloadClass || (class_loader.is_null())) {
798 if (k.is_null() && HAS_PENDING_EXCEPTION
799 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
800 MutexLocker mu(SystemDictionary_lock, THREAD);
801 Klass* check = find_class(d_index, d_hash, name, loader_data);
802 if (check != NULL) {
803 // Klass is already loaded, so just use it
804 k = instanceKlassHandle(THREAD, check);
805 CLEAR_PENDING_EXCEPTION;
806 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
807 }
808 }
809 }
810
811 // If everything was OK (no exceptions, no null return value), and
812 // class_loader is NOT the defining loader, do a little more bookkeeping.
813 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
814 k->class_loader() != class_loader()) {
815
816 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
817
818 // Need to check for a PENDING_EXCEPTION again; check_constraints
819 // can throw and doesn't use the CHECK macro.
820 if (!HAS_PENDING_EXCEPTION) {
821 { // Grabbing the Compile_lock prevents systemDictionary updates
822 // during compilations.
823 MutexLocker mu(Compile_lock, THREAD);
824 update_dictionary(d_index, d_hash, p_index, p_hash,
825 k, class_loader, THREAD);
826 }
827
828 if (JvmtiExport::should_post_class_load()) {
829 Thread *thread = THREAD;
830 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
831 JvmtiExport::post_class_load((JavaThread *) thread, k());
832 }
833 }
834 }
835 } // load_instance_class loop
836
837 if (load_instance_added == true) {
838 // clean up placeholder entries for LOAD_INSTANCE success or error
839 // This brackets the SystemDictionary updates for both defining
840 // and initiating loaders
841 MutexLocker mu(SystemDictionary_lock, THREAD);
842 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
843 SystemDictionary_lock->notify_all();
844 }
845 }
846
847 if (HAS_PENDING_EXCEPTION || k.is_null()) {
848 return NULL;
849 }
850
851 post_class_load_event(class_load_start_time, k, class_loader);
852
853 #ifdef ASSERT
854 {
855 ClassLoaderData* loader_data = k->class_loader_data();
856 MutexLocker mu(SystemDictionary_lock, THREAD);
857 Klass* kk = find_class(name, loader_data);
858 assert(kk == k(), "should be present in dictionary");
859 }
860 #endif
861
862 // return if the protection domain in NULL
863 if (protection_domain() == NULL) return k();
864
865 // Check the protection domain has the right access
866 {
867 MutexLocker mu(SystemDictionary_lock, THREAD);
868 // Note that we have an entry, and entries can be deleted only during GC,
869 // so we cannot allow GC to occur while we're holding this entry.
870 // We're using a No_Safepoint_Verifier to catch any place where we
871 // might potentially do a GC at all.
872 // Dictionary::do_unloading() asserts that classes in SD are only
873 // unloaded at a safepoint. Anonymous classes are not in SD.
874 No_Safepoint_Verifier nosafepoint;
875 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
876 loader_data,
877 protection_domain)) {
878 return k();
879 }
880 }
881
882 // Verify protection domain. If it fails an exception is thrown
883 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
884
885 return k();
886 }
887
888
889 // This routine does not lock the system dictionary.
890 //
891 // Since readers don't hold a lock, we must make sure that system
892 // dictionary entries are only removed at a safepoint (when only one
893 // thread is running), and are added to in a safe way (all links must
894 // be updated in an MT-safe manner).
895 //
896 // Callers should be aware that an entry could be added just after
897 // _dictionary->bucket(index) is read here, so the caller will not see
898 // the new entry.
899
900 Klass* SystemDictionary::find(Symbol* class_name,
901 Handle class_loader,
902 Handle protection_domain,
903 TRAPS) {
904
905 // UseNewReflection
906 // The result of this call should be consistent with the result
907 // of the call to resolve_instance_class_or_null().
908 // See evaluation 6790209 and 4474172 for more details.
909 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
910 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
911
912 if (loader_data == NULL) {
913 // If the ClassLoaderData has not been setup,
914 // then the class loader has no entries in the dictionary.
915 return NULL;
916 }
917
918 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
919 int d_index = dictionary()->hash_to_index(d_hash);
920
921 {
922 // Note that we have an entry, and entries can be deleted only during GC,
923 // so we cannot allow GC to occur while we're holding this entry.
924 // We're using a No_Safepoint_Verifier to catch any place where we
925 // might potentially do a GC at all.
926 // Dictionary::do_unloading() asserts that classes in SD are only
927 // unloaded at a safepoint. Anonymous classes are not in SD.
928 No_Safepoint_Verifier nosafepoint;
929 return dictionary()->find(d_index, d_hash, class_name, loader_data,
930 protection_domain, THREAD);
931 }
932 }
933
934
935 // Look for a loaded instance or array klass by name. Do not do any loading.
936 // return NULL in case of error.
937 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
938 Handle class_loader,
939 Handle protection_domain,
940 TRAPS) {
941 Klass* k = NULL;
942 assert(class_name != NULL, "class name must be non NULL");
943
944 if (FieldType::is_array(class_name)) {
945 // The name refers to an array. Parse the name.
946 // dimension and object_key in FieldArrayInfo are assigned as a
947 // side-effect of this call
948 FieldArrayInfo fd;
949 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
950 if (t != T_OBJECT) {
951 k = Universe::typeArrayKlassObj(t);
952 } else {
953 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
954 }
955 if (k != NULL) {
956 k = k->array_klass_or_null(fd.dimension());
957 }
958 } else {
959 k = find(class_name, class_loader, protection_domain, THREAD);
960 }
961 return k;
962 }
963
964 // Note: this method is much like resolve_from_stream, but
965 // updates no supplemental data structures.
966 // TODO consolidate the two methods with a helper routine?
967 Klass* SystemDictionary::parse_stream(Symbol* class_name,
968 Handle class_loader,
969 Handle protection_domain,
970 ClassFileStream* st,
971 KlassHandle host_klass,
972 GrowableArray<Handle>* cp_patches,
973 TRAPS) {
974 TempNewSymbol parsed_name = NULL;
975
976 Ticks class_load_start_time = Ticks::now();
977
978 ClassLoaderData* loader_data;
979 if (host_klass.not_null()) {
980 // Create a new CLD for anonymous class, that uses the same class loader
981 // as the host_klass
982 assert(EnableInvokeDynamic, "");
983 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
984 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
985 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
986 loader_data->record_dependency(host_klass(), CHECK_NULL);
987 } else {
988 loader_data = ClassLoaderData::class_loader_data(class_loader());
989 }
990
991 // Parse the stream. Note that we do this even though this klass might
992 // already be present in the SystemDictionary, otherwise we would not
993 // throw potential ClassFormatErrors.
994 //
995 // Note: "name" is updated.
996
997 ClassFileParser parser(st);
998 instanceKlassHandle k = parser.parseClassFile(class_name,
999 loader_data,
1000 protection_domain,
1001 host_klass,
1002 cp_patches,
1003 parsed_name,
1004 true,
1005 THREAD);
1006 TRACE_KLASS_CREATION(k, parser, THREAD);
1007
1008 if (host_klass.not_null() && k.not_null()) {
1009 assert(EnableInvokeDynamic, "");
1010 // If it's anonymous, initialize it now, since nobody else will.
1011
1012 {
1013 MutexLocker mu_r(Compile_lock, THREAD);
1014
1015 // Add to class hierarchy, initialize vtables, and do possible
1016 // deoptimizations.
1017 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1018
1019 // But, do not add to system dictionary.
1020
1021 // compiled code dependencies need to be validated anyway
1022 notice_modification();
1023 }
1024
1025 // Rewrite and patch constant pool here.
1026 k->link_class(CHECK_NULL);
1027 if (cp_patches != NULL) {
1028 k->constants()->patch_resolved_references(cp_patches);
1029 }
1030 k->eager_initialize(CHECK_NULL);
1031
1032 // notify jvmti
1033 if (JvmtiExport::should_post_class_load()) {
1034 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1035 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1036 }
1037
1038 post_class_load_event(class_load_start_time, k, class_loader);
1039 }
1040 assert(host_klass.not_null() || cp_patches == NULL,
1041 "cp_patches only found with host_klass");
1042
1043 return k();
1044 }
1045
1046 // Add a klass to the system from a stream (called by jni_DefineClass and
1047 // JVM_DefineClass).
1048 // Note: class_name can be NULL. In that case we do not know the name of
1049 // the class until we have parsed the stream.
1050
1051 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1052 Handle class_loader,
1053 Handle protection_domain,
1054 ClassFileStream* st,
1055 bool verify,
1056 TRAPS) {
1057
1058 // Classloaders that support parallelism, e.g. bootstrap classloader,
1059 // or all classloaders with UnsyncloadClass do not acquire lock here
1060 bool DoObjectLock = true;
1061 if (is_parallelCapable(class_loader)) {
1062 DoObjectLock = false;
1063 }
1064
1065 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1066
1067 // Make sure we are synchronized on the class loader before we proceed
1068 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1069 check_loader_lock_contention(lockObject, THREAD);
1070 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1071
1072 TempNewSymbol parsed_name = NULL;
1073
1074 // Parse the stream. Note that we do this even though this klass might
1075 // already be present in the SystemDictionary, otherwise we would not
1076 // throw potential ClassFormatErrors.
1077 //
1078 // Note: "name" is updated.
1079
1080 ClassFileParser parser(st);
1081 instanceKlassHandle k = parser.parseClassFile(class_name,
1082 loader_data,
1083 protection_domain,
1084 parsed_name,
1085 verify,
1086 THREAD);
1087 TRACE_KLASS_CREATION(k, parser, THREAD);
1088
1089 const char* pkg = "java/";
1090 size_t pkglen = strlen(pkg);
1091 if (!HAS_PENDING_EXCEPTION &&
1092 !class_loader.is_null() &&
1093 parsed_name != NULL &&
1094 parsed_name->utf8_length() >= (int)pkglen &&
1095 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1096 // It is illegal to define classes in the "java." package from
1097 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1098 ResourceMark rm(THREAD);
1099 char* name = parsed_name->as_C_string();
1100 char* index = strrchr(name, '/');
1101 assert(index != NULL, "must be");
1102 *index = '\0'; // chop to just the package name
1103 while ((index = strchr(name, '/')) != NULL) {
1104 *index = '.'; // replace '/' with '.' in package name
1105 }
1106 const char* fmt = "Prohibited package name: %s";
1107 size_t len = strlen(fmt) + strlen(name);
1108 char* message = NEW_RESOURCE_ARRAY(char, len);
1109 jio_snprintf(message, len, fmt, name);
1110 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1111 vmSymbols::java_lang_SecurityException(), message);
1112 }
1113
1114 if (!HAS_PENDING_EXCEPTION) {
1115 assert(parsed_name != NULL, "Sanity");
1116 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1117 // Verification prevents us from creating names with dots in them, this
1118 // asserts that that's the case.
1119 assert(is_internal_format(parsed_name),
1120 "external class name format used internally");
1121
1122 // Add class just loaded
1123 // If a class loader supports parallel classloading handle parallel define requests
1124 // find_or_define_instance_class may return a different InstanceKlass
1125 if (is_parallelCapable(class_loader)) {
1126 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1127 } else {
1128 define_instance_class(k, THREAD);
1129 }
1130 }
1131
1132 // Make sure we have an entry in the SystemDictionary on success
1133 debug_only( {
1134 if (!HAS_PENDING_EXCEPTION) {
1135 assert(parsed_name != NULL, "parsed_name is still null?");
1136 Symbol* h_name = k->name();
1137 ClassLoaderData *defining_loader_data = k->class_loader_data();
1138
1139 MutexLocker mu(SystemDictionary_lock, THREAD);
1140
1141 Klass* check = find_class(parsed_name, loader_data);
1142 assert(check == k(), "should be present in the dictionary");
1143
1144 Klass* check2 = find_class(h_name, defining_loader_data);
1145 assert(check == check2, "name inconsistancy in SystemDictionary");
1146 }
1147 } );
1148
1149 return k();
1150 }
1151
1152 #if INCLUDE_CDS
1153 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1154 int number_of_entries) {
1155 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1156 "bad shared dictionary size.");
1157 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1158 }
1159
1160
1161 // If there is a shared dictionary, then find the entry for the
1162 // given shared system class, if any.
1163
1164 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1165 if (shared_dictionary() != NULL) {
1166 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1167 int d_index = shared_dictionary()->hash_to_index(d_hash);
1168
1169 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1170 } else {
1171 return NULL;
1172 }
1173 }
1174
1175
1176 // Load a class from the shared spaces (found through the shared system
1177 // dictionary). Force the superclass and all interfaces to be loaded.
1178 // Update the class definition to include sibling classes and no
1179 // subclasses (yet). [Classes in the shared space are not part of the
1180 // object hierarchy until loaded.]
1181
1182 instanceKlassHandle SystemDictionary::load_shared_class(
1183 Symbol* class_name, Handle class_loader, TRAPS) {
1184 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1185 // Make sure we only return the boot class for the NULL classloader.
1186 if (ik.not_null() &&
1187 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1188 Handle protection_domain;
1189 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1190 }
1191 return instanceKlassHandle();
1192 }
1193
1194 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1195 Handle class_loader,
1196 Handle protection_domain, TRAPS) {
1197 if (ik.not_null()) {
1198 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1199 Symbol* class_name = ik->name();
1200
1201 // Found the class, now load the superclass and interfaces. If they
1202 // are shared, add them to the main system dictionary and reset
1203 // their hierarchy references (supers, subs, and interfaces).
1204
1205 if (ik->super() != NULL) {
1206 Symbol* cn = ik->super()->name();
1207 Klass *s = resolve_super_or_fail(class_name, cn,
1208 class_loader, protection_domain, true, CHECK_(nh));
1209 if (s != ik->super()) {
1210 // The dynamically resolved super class is not the same as the one we used during dump time,
1211 // so we cannot use ik.
1212 return nh;
1213 }
1214 }
1215
1216 Array<Klass*>* interfaces = ik->local_interfaces();
1217 int num_interfaces = interfaces->length();
1218 for (int index = 0; index < num_interfaces; index++) {
1219 Klass* k = interfaces->at(index);
1220
1221 // Note: can not use InstanceKlass::cast here because
1222 // interfaces' InstanceKlass's C++ vtbls haven't been
1223 // reinitialized yet (they will be once the interface classes
1224 // are loaded)
1225 Symbol* name = k->name();
1226 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1227 if (k != i) {
1228 // The dynamically resolved interface class is not the same as the one we used during dump time,
1229 // so we cannot use ik.
1230 return nh;
1231 }
1232 }
1233
1234 // Adjust methods to recover missing data. They need addresses for
1235 // interpreter entry points and their default native method address
1236 // must be reset.
1237
1238 // Updating methods must be done under a lock so multiple
1239 // threads don't update these in parallel
1240 //
1241 // Shared classes are all currently loaded by either the bootstrap or
1242 // internal parallel class loaders, so this will never cause a deadlock
1243 // on a custom class loader lock.
1244
1245 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1246 {
1247 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1248 check_loader_lock_contention(lockObject, THREAD);
1249 ObjectLocker ol(lockObject, THREAD, true);
1250 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1251 }
1252
1253 if (TraceClassLoading) {
1254 ResourceMark rm;
1255 tty->print("[Loaded %s", ik->external_name());
1256 tty->print(" from shared objects file");
1257 if (class_loader.not_null()) {
1258 tty->print(" by %s", loader_data->loader_name());
1259 }
1260 tty->print_cr("]");
1261 }
1262
1263 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1264 // Only dump the classes that can be stored into CDS archive
1265 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1266 ResourceMark rm(THREAD);
1267 classlist_file->print_cr("%s", ik->name()->as_C_string());
1268 classlist_file->flush();
1269 }
1270 }
1271
1272 // notify a class loaded from shared object
1273 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1274 true /* shared class */);
1275 }
1276 return ik;
1277 }
1278 #endif // INCLUDE_CDS
1279
1280 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1281 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1282 if (class_loader.is_null()) {
1283
1284 // Search the shared system dictionary for classes preloaded into the
1285 // shared spaces.
1286 instanceKlassHandle k;
1287 {
1288 #if INCLUDE_CDS
1289 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1290 k = load_shared_class(class_name, class_loader, THREAD);
1291 #endif
1292 }
1293
1294 if (k.is_null()) {
1295 // Use VM class loader
1296 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1297 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1298 }
1299
1300 // find_or_define_instance_class may return a different InstanceKlass
1301 if (!k.is_null()) {
1302 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1303 }
1304 return k;
1305 } else {
1306 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1307 ResourceMark rm(THREAD);
1308
1309 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1310 JavaThread* jt = (JavaThread*) THREAD;
1311
1312 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1313 ClassLoader::perf_app_classload_selftime(),
1314 ClassLoader::perf_app_classload_count(),
1315 jt->get_thread_stat()->perf_recursion_counts_addr(),
1316 jt->get_thread_stat()->perf_timers_addr(),
1317 PerfClassTraceTime::CLASS_LOAD);
1318
1319 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1320 // Translate to external class name format, i.e., convert '/' chars to '.'
1321 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1322
1323 JavaValue result(T_OBJECT);
1324
1325 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1326
1327 // Call public unsynchronized loadClass(String) directly for all class loaders
1328 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1329 // acquire a class-name based lock rather than the class loader object lock.
1330 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1331 // so the call to loadClassInternal() was not required.
1332 //
1333 // UnsyncloadClass flag means both call loadClass(String) and do
1334 // not acquire the class loader lock even for class loaders that are
1335 // not parallelCapable. This was a risky transitional
1336 // flag for diagnostic purposes only. It is risky to call
1337 // custom class loaders without synchronization.
1338 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1339 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1340 // Do NOT assume this will be supported in future releases.
1341 //
1342 // Added MustCallLoadClassInternal in case we discover in the field
1343 // a customer that counts on this call
1344 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1345 JavaCalls::call_special(&result,
1346 class_loader,
1347 spec_klass,
1348 vmSymbols::loadClassInternal_name(),
1349 vmSymbols::string_class_signature(),
1350 string,
1351 CHECK_(nh));
1352 } else {
1353 JavaCalls::call_virtual(&result,
1354 class_loader,
1355 spec_klass,
1356 vmSymbols::loadClass_name(),
1357 vmSymbols::string_class_signature(),
1358 string,
1359 CHECK_(nh));
1360 }
1361
1362 assert(result.get_type() == T_OBJECT, "just checking");
1363 oop obj = (oop) result.get_jobject();
1364
1365 // Primitive classes return null since forName() can not be
1366 // used to obtain any of the Class objects representing primitives or void
1367 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1368 instanceKlassHandle k =
1369 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1370 // For user defined Java class loaders, check that the name returned is
1371 // the same as that requested. This check is done for the bootstrap
1372 // loader when parsing the class file.
1373 if (class_name == k->name()) {
1374 return k;
1375 }
1376 }
1377 // Class is not found or has the wrong name, return NULL
1378 return nh;
1379 }
1380 }
1381
1382 static void class_define_event(InstanceKlass* k,
1383 const ClassLoaderData* def_cld) {
1384 #if INCLUDE_TRACE
1385 EventClassDefine event;
1386 if (event.should_commit()) {
1387 ResourceMark m;
1388 event.set_definedClass(k);
1389 event.set_definingClassLoader(def_cld);
1390 event.commit();
1391 }
1392 #endif // INCLUDE_TRACE
1393 }
1394
1395 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1396
1397 ClassLoaderData* loader_data = k->class_loader_data();
1398 Handle class_loader_h(THREAD, loader_data->class_loader());
1399
1400 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1401
1402 // for bootstrap and other parallel classloaders don't acquire lock,
1403 // use placeholder token
1404 // If a parallelCapable class loader calls define_instance_class instead of
1405 // find_or_define_instance_class to get here, we have a timing
1406 // hole with systemDictionary updates and check_constraints
1407 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1408 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1409 compute_loader_lock_object(class_loader_h, THREAD)),
1410 "define called without lock");
1411 }
1412
1413 // Check class-loading constraints. Throw exception if violation is detected.
1414 // Grabs and releases SystemDictionary_lock
1415 // The check_constraints/find_class call and update_dictionary sequence
1416 // must be "atomic" for a specific class/classloader pair so we never
1417 // define two different instanceKlasses for that class/classloader pair.
1418 // Existing classloaders will call define_instance_class with the
1419 // classloader lock held
1420 // Parallel classloaders will call find_or_define_instance_class
1421 // which will require a token to perform the define class
1422 Symbol* name_h = k->name();
1423 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1424 int d_index = dictionary()->hash_to_index(d_hash);
1425 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1426
1427 // Register class just loaded with class loader (placed in Vector)
1428 // Note we do this before updating the dictionary, as this can
1429 // fail with an OutOfMemoryError (if it does, we will *not* put this
1430 // class in the dictionary and will not update the class hierarchy).
1431 // JVMTI FollowReferences needs to find the classes this way.
1432 if (k->class_loader() != NULL) {
1433 methodHandle m(THREAD, Universe::loader_addClass_method());
1434 JavaValue result(T_VOID);
1435 JavaCallArguments args(class_loader_h);
1436 args.push_oop(Handle(THREAD, k->java_mirror()));
1437 JavaCalls::call(&result, m, &args, CHECK);
1438 }
1439
1440 // Add the new class. We need recompile lock during update of CHA.
1441 {
1442 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1443 int p_index = placeholders()->hash_to_index(p_hash);
1444
1445 MutexLocker mu_r(Compile_lock, THREAD);
1446
1447 // Add to class hierarchy, initialize vtables, and do possible
1448 // deoptimizations.
1449 add_to_hierarchy(k, CHECK); // No exception, but can block
1450
1451 // Add to systemDictionary - so other classes can see it.
1452 // Grabs and releases SystemDictionary_lock
1453 update_dictionary(d_index, d_hash, p_index, p_hash,
1454 k, class_loader_h, THREAD);
1455 }
1456 k->eager_initialize(THREAD);
1457
1458 // notify jvmti
1459 if (JvmtiExport::should_post_class_load()) {
1460 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1461 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1462
1463 }
1464
1465 class_define_event(k(), loader_data);
1466 }
1467
1468 // Support parallel classloading
1469 // All parallel class loaders, including bootstrap classloader
1470 // lock a placeholder entry for this class/class_loader pair
1471 // to allow parallel defines of different classes for this class loader
1472 // With AllowParallelDefine flag==true, in case they do not synchronize around
1473 // FindLoadedClass/DefineClass, calls, we check for parallel
1474 // loading for them, wait if a defineClass is in progress
1475 // and return the initial requestor's results
1476 // This flag does not apply to the bootstrap classloader.
1477 // With AllowParallelDefine flag==false, call through to define_instance_class
1478 // which will throw LinkageError: duplicate class definition.
1479 // False is the requested default.
1480 // For better performance, the class loaders should synchronize
1481 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1482 // potentially waste time reading and parsing the bytestream.
1483 // Note: VM callers should ensure consistency of k/class_name,class_loader
1484 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1485
1486 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1487 Symbol* name_h = k->name(); // passed in class_name may be null
1488 ClassLoaderData* loader_data = class_loader_data(class_loader);
1489
1490 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1491 int d_index = dictionary()->hash_to_index(d_hash);
1492
1493 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1494 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1495 int p_index = placeholders()->hash_to_index(p_hash);
1496 PlaceholderEntry* probe;
1497
1498 {
1499 MutexLocker mu(SystemDictionary_lock, THREAD);
1500 // First check if class already defined
1501 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1502 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1503 if (check != NULL) {
1504 return(instanceKlassHandle(THREAD, check));
1505 }
1506 }
1507
1508 // Acquire define token for this class/classloader
1509 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1510 // Wait if another thread defining in parallel
1511 // All threads wait - even those that will throw duplicate class: otherwise
1512 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1513 // if other thread has not finished updating dictionary
1514 while (probe->definer() != NULL) {
1515 SystemDictionary_lock->wait();
1516 }
1517 // Only special cases allow parallel defines and can use other thread's results
1518 // Other cases fall through, and may run into duplicate defines
1519 // caught by finding an entry in the SystemDictionary
1520 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1521 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1522 SystemDictionary_lock->notify_all();
1523 #ifdef ASSERT
1524 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1525 assert(check != NULL, "definer missed recording success");
1526 #endif
1527 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1528 } else {
1529 // This thread will define the class (even if earlier thread tried and had an error)
1530 probe->set_definer(THREAD);
1531 }
1532 }
1533
1534 define_instance_class(k, THREAD);
1535
1536 Handle linkage_exception = Handle(); // null handle
1537
1538 // definer must notify any waiting threads
1539 {
1540 MutexLocker mu(SystemDictionary_lock, THREAD);
1541 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1542 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1543 if (probe != NULL) {
1544 if (HAS_PENDING_EXCEPTION) {
1545 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1546 CLEAR_PENDING_EXCEPTION;
1547 } else {
1548 probe->set_instance_klass(k());
1549 }
1550 probe->set_definer(NULL);
1551 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1552 SystemDictionary_lock->notify_all();
1553 }
1554 }
1555
1556 // Can't throw exception while holding lock due to rank ordering
1557 if (linkage_exception() != NULL) {
1558 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1559 }
1560
1561 return k;
1562 }
1563 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1564 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1565 if (class_loader.is_null()) {
1566 return Handle(THREAD, _system_loader_lock_obj);
1567 } else {
1568 return class_loader;
1569 }
1570 }
1571
1572 // This method is added to check how often we have to wait to grab loader
1573 // lock. The results are being recorded in the performance counters defined in
1574 // ClassLoader::_sync_systemLoaderLockContentionRate and
1575 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1576 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1577 if (!UsePerfData) {
1578 return;
1579 }
1580
1581 assert(!loader_lock.is_null(), "NULL lock object");
1582
1583 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1584 == ObjectSynchronizer::owner_other) {
1585 // contention will likely happen, so increment the corresponding
1586 // contention counter.
1587 if (loader_lock() == _system_loader_lock_obj) {
1588 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1589 } else {
1590 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1591 }
1592 }
1593 }
1594
1595 // ----------------------------------------------------------------------------
1596 // Lookup
1597
1598 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1599 Symbol* class_name,
1600 ClassLoaderData* loader_data) {
1601 assert_locked_or_safepoint(SystemDictionary_lock);
1602 assert (index == dictionary()->index_for(class_name, loader_data),
1603 "incorrect index?");
1604
1605 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1606 return k;
1607 }
1608
1609
1610 // Basic find on classes in the midst of being loaded
1611 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1612 ClassLoaderData* loader_data) {
1613 assert_locked_or_safepoint(SystemDictionary_lock);
1614 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1615 int p_index = placeholders()->hash_to_index(p_hash);
1616 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1617 }
1618
1619
1620 // Used for assertions and verification only
1621 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1622 #ifndef ASSERT
1623 guarantee(VerifyBeforeGC ||
1624 VerifyDuringGC ||
1625 VerifyBeforeExit ||
1626 VerifyDuringStartup ||
1627 VerifyAfterGC, "too expensive");
1628 #endif
1629 assert_locked_or_safepoint(SystemDictionary_lock);
1630
1631 // First look in the loaded class array
1632 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1633 int d_index = dictionary()->hash_to_index(d_hash);
1634 return find_class(d_index, d_hash, class_name, loader_data);
1635 }
1636
1637
1638 // Get the next class in the diictionary.
1639 Klass* SystemDictionary::try_get_next_class() {
1640 return dictionary()->try_get_next_class();
1641 }
1642
1643
1644 // ----------------------------------------------------------------------------
1645 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1646 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1647 // before a new class is used.
1648
1649 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1650 assert(k.not_null(), "just checking");
1651 assert_locked_or_safepoint(Compile_lock);
1652
1653 // Link into hierachy. Make sure the vtables are initialized before linking into
1654 k->append_to_sibling_list(); // add to superklass/sibling list
1655 k->process_interfaces(THREAD); // handle all "implements" declarations
1656 k->set_init_state(InstanceKlass::loaded);
1657 // Now flush all code that depended on old class hierarchy.
1658 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1659 // Also, first reinitialize vtable because it may have gotten out of synch
1660 // while the new class wasn't connected to the class hierarchy.
1661 Universe::flush_dependents_on(k);
1662 }
1663
1664 // ----------------------------------------------------------------------------
1665 // GC support
1666
1667 // Following roots during mark-sweep is separated in two phases.
1668 //
1669 // The first phase follows preloaded classes and all other system
1670 // classes, since these will never get unloaded anyway.
1671 //
1672 // The second phase removes (unloads) unreachable classes from the
1673 // system dictionary and follows the remaining classes' contents.
1674
1675 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1676 roots_oops_do(blk, NULL);
1677 }
1678
1679 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1680 // Follow all system classes and temporary placeholders in dictionary
1681 dictionary()->always_strong_classes_do(closure);
1682
1683 // Placeholders. These represent classes we're actively loading.
1684 placeholders()->classes_do(closure);
1685 }
1686
1687 // Calculate a "good" systemdictionary size based
1688 // on predicted or current loaded classes count
1689 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1690 int newsize = _old_default_sdsize;
1691 if ((classcount > 0) && !DumpSharedSpaces) {
1692 int desiredsize = classcount/_average_depth_goal;
1693 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1694 newsize = _primelist[++_sdgeneration]) {
1695 if (desiredsize <= newsize) {
1696 break;
1697 }
1698 }
1699 }
1700 return newsize;
1701 }
1702
1703 #ifdef ASSERT
1704 class VerifySDReachableAndLiveClosure : public OopClosure {
1705 private:
1706 BoolObjectClosure* _is_alive;
1707
1708 template <class T> void do_oop_work(T* p) {
1709 oop obj = oopDesc::load_decode_heap_oop(p);
1710 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1711 }
1712
1713 public:
1714 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1715
1716 virtual void do_oop(oop* p) { do_oop_work(p); }
1717 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1718 };
1719 #endif
1720
1721 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1722 // Note: anonymous classes are not in the SD.
1723 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1724 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1725 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1726 if (unloading_occurred) {
1727 dictionary()->do_unloading();
1728 constraints()->purge_loader_constraints();
1729 resolution_errors()->purge_resolution_errors();
1730 }
1731 // Oops referenced by the system dictionary may get unreachable independently
1732 // of the class loader (eg. cached protection domain oops). So we need to
1733 // explicitly unlink them here instead of in Dictionary::do_unloading.
1734 dictionary()->unlink(is_alive);
1735 #ifdef ASSERT
1736 VerifySDReachableAndLiveClosure cl(is_alive);
1737 dictionary()->oops_do(&cl);
1738 #endif
1739 return unloading_occurred;
1740 }
1741
1742 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1743 strong->do_oop(&_java_system_loader);
1744 strong->do_oop(&_system_loader_lock_obj);
1745 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1746
1747 // Adjust dictionary
1748 dictionary()->roots_oops_do(strong, weak);
1749
1750 // Visit extra methods
1751 invoke_method_table()->oops_do(strong);
1752 }
1753
1754 void SystemDictionary::oops_do(OopClosure* f) {
1755 f->do_oop(&_java_system_loader);
1756 f->do_oop(&_system_loader_lock_obj);
1757 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1758
1759 // Adjust dictionary
1760 dictionary()->oops_do(f);
1761
1762 // Visit extra methods
1763 invoke_method_table()->oops_do(f);
1764 }
1765
1766 // Extended Class redefinition support.
1767 // If one of these classes is replaced, we need to replace it in these places.
1768 // KlassClosure::do_klass should take the address of a class but we can
1769 // change that later.
1770 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1771 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1772 f->do_klass(_well_known_klasses[k]);
1773 }
1774
1775 {
1776 for (int i = 0; i < T_VOID+1; i++) {
1777 if (_box_klasses[i] != NULL) {
1778 assert(i >= T_BOOLEAN, "checking");
1779 f->do_klass(_box_klasses[i]);
1780 }
1781 }
1782 }
1783
1784 FilteredFieldsMap::classes_do(f);
1785 }
1786
1787 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1788 f->do_klass(_abstract_ownable_synchronizer_klass);
1789 }
1790
1791 // Just the classes from defining class loaders
1792 // Don't iterate over placeholders
1793 void SystemDictionary::classes_do(void f(Klass*)) {
1794 dictionary()->classes_do(f);
1795 }
1796
1797 // Added for initialize_itable_for_klass
1798 // Just the classes from defining class loaders
1799 // Don't iterate over placeholders
1800 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1801 dictionary()->classes_do(f, CHECK);
1802 }
1803
1804 // All classes, and their class loaders
1805 // Don't iterate over placeholders
1806 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1807 dictionary()->classes_do(f);
1808 }
1809
1810 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1811 placeholders()->entries_do(f);
1812 }
1813
1814 void SystemDictionary::methods_do(void f(Method*)) {
1815 dictionary()->methods_do(f);
1816 invoke_method_table()->methods_do(f);
1817 }
1818
1819 void SystemDictionary::remove_classes_in_error_state() {
1820 dictionary()->remove_classes_in_error_state();
1821 }
1822
1823 // ----------------------------------------------------------------------------
1824 // Lazily load klasses
1825
1826 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1827 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1828
1829 // if multiple threads calling this function, only one thread will load
1830 // the class. The other threads will find the loaded version once the
1831 // class is loaded.
1832 Klass* aos = _abstract_ownable_synchronizer_klass;
1833 if (aos == NULL) {
1834 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1835 // Force a fence to prevent any read before the write completes
1836 OrderAccess::fence();
1837 _abstract_ownable_synchronizer_klass = k;
1838 }
1839 }
1840
1841 // ----------------------------------------------------------------------------
1842 // Initialization
1843
1844 void SystemDictionary::initialize(TRAPS) {
1845 // Allocate arrays
1846 assert(dictionary() == NULL,
1847 "SystemDictionary should only be initialized once");
1848 _sdgeneration = 0;
1849 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1850 _placeholders = new PlaceholderTable(_nof_buckets);
1851 _number_of_modifications = 0;
1852 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1853 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1854 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1855
1856 // Allocate private object used as system class loader lock
1857 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1858 // Initialize basic classes
1859 initialize_preloaded_classes(CHECK);
1860 }
1861
1862 // Compact table of directions on the initialization of klasses:
1863 static const short wk_init_info[] = {
1864 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1865 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1866 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1867 | (int)SystemDictionary::option ),
1868 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1869 #undef WK_KLASS_INIT_INFO
1870 0
1871 };
1872
1873 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1874 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1875 int info = wk_init_info[id - FIRST_WKID];
1876 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1877 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1878 Klass** klassp = &_well_known_klasses[id];
1879 bool must_load = (init_opt < SystemDictionary::Opt);
1880 if ((*klassp) == NULL) {
1881 if (must_load) {
1882 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1883 } else {
1884 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1885 }
1886 }
1887 return ((*klassp) != NULL);
1888 }
1889
1890 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1891 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1892 for (int id = (int)start_id; id < (int)limit_id; id++) {
1893 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1894 int info = wk_init_info[id - FIRST_WKID];
1895 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1896 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1897
1898 initialize_wk_klass((WKID)id, opt, CHECK);
1899 }
1900
1901 // move the starting value forward to the limit:
1902 start_id = limit_id;
1903 }
1904
1905 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1906 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1907 // Preload commonly used klasses
1908 WKID scan = FIRST_WKID;
1909 // first do Object, then String, Class
1910 if (UseSharedSpaces) {
1911 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1912 // Initialize the constant pool for the Object_class
1913 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1914 ik->constants()->restore_unshareable_info(CHECK);
1915 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1916 } else {
1917 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1918 }
1919
1920 // Calculate offsets for String and Class classes since they are loaded and
1921 // can be used after this point.
1922 java_lang_String::compute_offsets();
1923 java_lang_Class::compute_offsets();
1924
1925 // Fixup mirrors for classes loaded before java.lang.Class.
1926 // These calls iterate over the objects currently in the perm gen
1927 // so calling them at this point is matters (not before when there
1928 // are fewer objects and not later after there are more objects
1929 // in the perm gen.
1930 Universe::initialize_basic_type_mirrors(CHECK);
1931 Universe::fixup_mirrors(CHECK);
1932
1933 // do a bunch more:
1934 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1935
1936 // Preload ref klasses and set reference types
1937 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1938 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1939
1940 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1941 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1942 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1943 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1944 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1945 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1946
1947 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
1948
1949 // JSR 292 classes
1950 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1951 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1952 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1953 if (EnableInvokeDynamic) {
1954 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1955 } else {
1956 // Skip the JSR 292 classes, if not enabled.
1957 scan = WKID(jsr292_group_end + 1);
1958 }
1959
1960 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1961
1962 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1963 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1964 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1965 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1966 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1967 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1968 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1969 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1970 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1971 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1972
1973 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1974 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1975 _has_loadClassInternal = (method != NULL);
1976 }
1977 { // Compute whether we should use checkPackageAccess or NOT
1978 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1979 _has_checkPackageAccess = (method != NULL);
1980 }
1981 }
1982
1983 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1984 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1985 BasicType SystemDictionary::box_klass_type(Klass* k) {
1986 assert(k != NULL, "");
1987 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1988 if (_box_klasses[i] == k)
1989 return (BasicType)i;
1990 }
1991 return T_OBJECT;
1992 }
1993
1994 // Constraints on class loaders. The details of the algorithm can be
1995 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1996 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1997 // that the system dictionary needs to maintain a set of contraints that
1998 // must be satisfied by all classes in the dictionary.
1999 // if defining is true, then LinkageError if already in systemDictionary
2000 // if initiating loader, then ok if InstanceKlass matches existing entry
2001
2002 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2003 instanceKlassHandle k,
2004 Handle class_loader, bool defining,
2005 TRAPS) {
2006 const char *linkage_error = NULL;
2007 {
2008 Symbol* name = k->name();
2009 ClassLoaderData *loader_data = class_loader_data(class_loader);
2010
2011 MutexLocker mu(SystemDictionary_lock, THREAD);
2012
2013 Klass* check = find_class(d_index, d_hash, name, loader_data);
2014 if (check != (Klass*)NULL) {
2015 // if different InstanceKlass - duplicate class definition,
2016 // else - ok, class loaded by a different thread in parallel,
2017 // we should only have found it if it was done loading and ok to use
2018 // system dictionary only holds instance classes, placeholders
2019 // also holds array classes
2020
2021 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2022 if ((defining == true) || (k() != check)) {
2023 linkage_error = "loader (instance of %s): attempted duplicate class "
2024 "definition for name: \"%s\"";
2025 } else {
2026 return;
2027 }
2028 }
2029
2030 #ifdef ASSERT
2031 Symbol* ph_check = find_placeholder(name, loader_data);
2032 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2033 #endif
2034
2035 if (linkage_error == NULL) {
2036 if (constraints()->check_or_update(k, class_loader, name) == false) {
2037 linkage_error = "loader constraint violation: loader (instance of %s)"
2038 " previously initiated loading for a different type with name \"%s\"";
2039 }
2040 }
2041 }
2042
2043 // Throw error now if needed (cannot throw while holding
2044 // SystemDictionary_lock because of rank ordering)
2045
2046 if (linkage_error) {
2047 ResourceMark rm(THREAD);
2048 const char* class_loader_name = loader_name(class_loader());
2049 char* type_name = k->name()->as_C_string();
2050 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2051 strlen(type_name);
2052 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2053 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2054 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2055 }
2056 }
2057
2058
2059 // Update system dictionary - done after check_constraint and add_to_hierachy
2060 // have been called.
2061 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2062 int p_index, unsigned int p_hash,
2063 instanceKlassHandle k,
2064 Handle class_loader,
2065 TRAPS) {
2066 // Compile_lock prevents systemDictionary updates during compilations
2067 assert_locked_or_safepoint(Compile_lock);
2068 Symbol* name = k->name();
2069 ClassLoaderData *loader_data = class_loader_data(class_loader);
2070
2071 {
2072 MutexLocker mu1(SystemDictionary_lock, THREAD);
2073
2074 // See whether biased locking is enabled and if so set it for this
2075 // klass.
2076 // Note that this must be done past the last potential blocking
2077 // point / safepoint. We enable biased locking lazily using a
2078 // VM_Operation to iterate the SystemDictionary and installing the
2079 // biasable mark word into each InstanceKlass's prototype header.
2080 // To avoid race conditions where we accidentally miss enabling the
2081 // optimization for one class in the process of being added to the
2082 // dictionary, we must not safepoint after the test of
2083 // BiasedLocking::enabled().
2084 if (UseBiasedLocking && BiasedLocking::enabled()) {
2085 // Set biased locking bit for all loaded classes; it will be
2086 // cleared if revocation occurs too often for this type
2087 // NOTE that we must only do this when the class is initally
2088 // defined, not each time it is referenced from a new class loader
2089 if (k->class_loader() == class_loader()) {
2090 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2091 }
2092 }
2093
2094 // Make a new system dictionary entry.
2095 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2096 if (sd_check == NULL) {
2097 dictionary()->add_klass(name, loader_data, k);
2098 notice_modification();
2099 }
2100 #ifdef ASSERT
2101 sd_check = find_class(d_index, d_hash, name, loader_data);
2102 assert (sd_check != NULL, "should have entry in system dictionary");
2103 // Note: there may be a placeholder entry: for circularity testing
2104 // or for parallel defines
2105 #endif
2106 SystemDictionary_lock->notify_all();
2107 }
2108 }
2109
2110
2111 // Try to find a class name using the loader constraints. The
2112 // loader constraints might know about a class that isn't fully loaded
2113 // yet and these will be ignored.
2114 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2115 Symbol* class_name, Handle class_loader, TRAPS) {
2116
2117 // First see if it has been loaded directly.
2118 // Force the protection domain to be null. (This removes protection checks.)
2119 Handle no_protection_domain;
2120 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2121 no_protection_domain, CHECK_NULL);
2122 if (klass != NULL)
2123 return klass;
2124
2125 // Now look to see if it has been loaded elsewhere, and is subject to
2126 // a loader constraint that would require this loader to return the
2127 // klass that is already loaded.
2128 if (FieldType::is_array(class_name)) {
2129 // For array classes, their Klass*s are not kept in the
2130 // constraint table. The element Klass*s are.
2131 FieldArrayInfo fd;
2132 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2133 if (t != T_OBJECT) {
2134 klass = Universe::typeArrayKlassObj(t);
2135 } else {
2136 MutexLocker mu(SystemDictionary_lock, THREAD);
2137 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2138 }
2139 // If element class already loaded, allocate array klass
2140 if (klass != NULL) {
2141 klass = klass->array_klass_or_null(fd.dimension());
2142 }
2143 } else {
2144 MutexLocker mu(SystemDictionary_lock, THREAD);
2145 // Non-array classes are easy: simply check the constraint table.
2146 klass = constraints()->find_constrained_klass(class_name, class_loader);
2147 }
2148
2149 return klass;
2150 }
2151
2152
2153 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2154 Handle class_loader1,
2155 Handle class_loader2,
2156 Thread* THREAD) {
2157 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2158 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2159
2160 Symbol* constraint_name = NULL;
2161 if (!FieldType::is_array(class_name)) {
2162 constraint_name = class_name;
2163 } else {
2164 // For array classes, their Klass*s are not kept in the
2165 // constraint table. The element classes are.
2166 FieldArrayInfo fd;
2167 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2168 // primitive types always pass
2169 if (t != T_OBJECT) {
2170 return true;
2171 } else {
2172 constraint_name = fd.object_key();
2173 }
2174 }
2175 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2176 int d_index1 = dictionary()->hash_to_index(d_hash1);
2177
2178 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2179 int d_index2 = dictionary()->hash_to_index(d_hash2);
2180 {
2181 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2182
2183 // Better never do a GC while we're holding these oops
2184 No_Safepoint_Verifier nosafepoint;
2185
2186 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2187 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2188 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2189 klass2, class_loader2);
2190 }
2191 }
2192
2193 // Add entry to resolution error table to record the error when the first
2194 // attempt to resolve a reference to a class has failed.
2195 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2196 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2197 int index = resolution_errors()->hash_to_index(hash);
2198 {
2199 MutexLocker ml(SystemDictionary_lock, Thread::current());
2200 resolution_errors()->add_entry(index, hash, pool, which, error);
2201 }
2202 }
2203
2204 // Delete a resolution error for RedefineClasses for a constant pool is going away
2205 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2206 resolution_errors()->delete_entry(pool);
2207 }
2208
2209 // Lookup resolution error table. Returns error if found, otherwise NULL.
2210 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2211 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2212 int index = resolution_errors()->hash_to_index(hash);
2213 {
2214 MutexLocker ml(SystemDictionary_lock, Thread::current());
2215 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2216 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2217 }
2218 }
2219
2220
2221 // Signature constraints ensure that callers and callees agree about
2222 // the meaning of type names in their signatures. This routine is the
2223 // intake for constraints. It collects them from several places:
2224 //
2225 // * LinkResolver::resolve_method (if check_access is true) requires
2226 // that the resolving class (the caller) and the defining class of
2227 // the resolved method (the callee) agree on each type in the
2228 // method's signature.
2229 //
2230 // * LinkResolver::resolve_interface_method performs exactly the same
2231 // checks.
2232 //
2233 // * LinkResolver::resolve_field requires that the constant pool
2234 // attempting to link to a field agree with the field's defining
2235 // class about the type of the field signature.
2236 //
2237 // * klassVtable::initialize_vtable requires that, when a class
2238 // overrides a vtable entry allocated by a superclass, that the
2239 // overriding method (i.e., the callee) agree with the superclass
2240 // on each type in the method's signature.
2241 //
2242 // * klassItable::initialize_itable requires that, when a class fills
2243 // in its itables, for each non-abstract method installed in an
2244 // itable, the method (i.e., the callee) agree with the interface
2245 // on each type in the method's signature.
2246 //
2247 // All those methods have a boolean (check_access, checkconstraints)
2248 // which turns off the checks. This is used from specialized contexts
2249 // such as bootstrapping, dumping, and debugging.
2250 //
2251 // No direct constraint is placed between the class and its
2252 // supertypes. Constraints are only placed along linked relations
2253 // between callers and callees. When a method overrides or implements
2254 // an abstract method in a supertype (superclass or interface), the
2255 // constraints are placed as if the supertype were the caller to the
2256 // overriding method. (This works well, since callers to the
2257 // supertype have already established agreement between themselves and
2258 // the supertype.) As a result of all this, a class can disagree with
2259 // its supertype about the meaning of a type name, as long as that
2260 // class neither calls a relevant method of the supertype, nor is
2261 // called (perhaps via an override) from the supertype.
2262 //
2263 //
2264 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2265 //
2266 // Make sure all class components (including arrays) in the given
2267 // signature will be resolved to the same class in both loaders.
2268 // Returns the name of the type that failed a loader constraint check, or
2269 // NULL if no constraint failed. No exception except OOME is thrown.
2270 // Arrays are not added to the loader constraint table, their elements are.
2271 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2272 Handle loader1, Handle loader2,
2273 bool is_method, TRAPS) {
2274 // Nothing to do if loaders are the same.
2275 if (loader1() == loader2()) {
2276 return NULL;
2277 }
2278
2279 SignatureStream sig_strm(signature, is_method);
2280 while (!sig_strm.is_done()) {
2281 if (sig_strm.is_object()) {
2282 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2283 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2284 return sig;
2285 }
2286 }
2287 sig_strm.next();
2288 }
2289 return NULL;
2290 }
2291
2292
2293 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2294 Symbol* signature,
2295 TRAPS) {
2296 methodHandle empty;
2297 assert(EnableInvokeDynamic, "");
2298 assert(MethodHandles::is_signature_polymorphic(iid) &&
2299 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2300 iid != vmIntrinsics::_invokeGeneric,
2301 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2302
2303 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2304 int index = invoke_method_table()->hash_to_index(hash);
2305 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2306 methodHandle m;
2307 if (spe == NULL || spe->method() == NULL) {
2308 spe = NULL;
2309 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2310 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2311 if (!Arguments::is_interpreter_only()) {
2312 // Generate a compiled form of the MH intrinsic.
2313 AdapterHandlerLibrary::create_native_wrapper(m);
2314 // Check if have the compiled code.
2315 if (!m->has_compiled_code()) {
2316 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2317 "out of space in CodeCache for method handle intrinsic", empty);
2318 }
2319 }
2320 // Now grab the lock. We might have to throw away the new method,
2321 // if a racing thread has managed to install one at the same time.
2322 {
2323 MutexLocker ml(SystemDictionary_lock, THREAD);
2324 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2325 if (spe == NULL)
2326 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2327 if (spe->method() == NULL)
2328 spe->set_method(m());
2329 }
2330 }
2331
2332 assert(spe != NULL && spe->method() != NULL, "");
2333 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2334 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2335 "MH intrinsic invariant");
2336 return spe->method();
2337 }
2338
2339 // Helper for unpacking the return value from linkMethod and linkCallSite.
2340 static methodHandle unpack_method_and_appendix(Handle mname,
2341 KlassHandle accessing_klass,
2342 objArrayHandle appendix_box,
2343 Handle* appendix_result,
2344 TRAPS) {
2345 methodHandle empty;
2346 if (mname.not_null()) {
2347 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2348 if (vmtarget != NULL && vmtarget->is_method()) {
2349 Method* m = (Method*)vmtarget;
2350 oop appendix = appendix_box->obj_at(0);
2351 if (TraceMethodHandles) {
2352 #ifndef PRODUCT
2353 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2354 m->print();
2355 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2356 tty->cr();
2357 #endif //PRODUCT
2358 }
2359 (*appendix_result) = Handle(THREAD, appendix);
2360 // the target is stored in the cpCache and if a reference to this
2361 // MethodName is dropped we need a way to make sure the
2362 // class_loader containing this method is kept alive.
2363 // FIXME: the appendix might also preserve this dependency.
2364 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2365 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2366 return methodHandle(THREAD, m);
2367 }
2368 }
2369 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2370 return empty;
2371 }
2372
2373 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2374 Symbol* signature,
2375 KlassHandle accessing_klass,
2376 Handle *appendix_result,
2377 Handle *method_type_result,
2378 TRAPS) {
2379 methodHandle empty;
2380 assert(EnableInvokeDynamic, "");
2381 assert(!THREAD->is_Compiler_thread(), "");
2382 Handle method_type =
2383 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2384
2385 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2386 int ref_kind = JVM_REF_invokeVirtual;
2387 Handle name_str = StringTable::intern(name, CHECK_(empty));
2388 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2389 assert(appendix_box->obj_at(0) == NULL, "");
2390
2391 // This should not happen. JDK code should take care of that.
2392 if (accessing_klass.is_null() || method_type.is_null()) {
2393 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2394 }
2395
2396 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2397 JavaCallArguments args;
2398 args.push_oop(accessing_klass()->java_mirror());
2399 args.push_int(ref_kind);
2400 args.push_oop(mh_klass()->java_mirror());
2401 args.push_oop(name_str());
2402 args.push_oop(method_type());
2403 args.push_oop(appendix_box());
2404 JavaValue result(T_OBJECT);
2405 JavaCalls::call_static(&result,
2406 SystemDictionary::MethodHandleNatives_klass(),
2407 vmSymbols::linkMethod_name(),
2408 vmSymbols::linkMethod_signature(),
2409 &args, CHECK_(empty));
2410 Handle mname(THREAD, (oop) result.get_jobject());
2411 (*method_type_result) = method_type;
2412 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2413 }
2414
2415 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2416 // We must ensure that all class loaders everywhere will reach this class, for any client.
2417 // This is a safe bet for public classes in java.lang, such as Object and String.
2418 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2419 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2420 static bool is_always_visible_class(oop mirror) {
2421 Klass* klass = java_lang_Class::as_Klass(mirror);
2422 if (klass->oop_is_objArray()) {
2423 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2424 }
2425 if (klass->oop_is_typeArray()) {
2426 return true; // primitive array
2427 }
2428 assert(klass->oop_is_instance(), klass->external_name());
2429 return klass->is_public() &&
2430 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2431 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2432 }
2433
2434 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2435 // signature, as interpreted relative to the given class loader.
2436 // Because of class loader constraints, all method handle usage must be
2437 // consistent with this loader.
2438 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2439 KlassHandle accessing_klass,
2440 TRAPS) {
2441 Handle empty;
2442 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2443 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2444 int index = invoke_method_table()->hash_to_index(hash);
2445 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2446 if (spe != NULL && spe->method_type() != NULL) {
2447 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2448 return Handle(THREAD, spe->method_type());
2449 } else if (THREAD->is_Compiler_thread()) {
2450 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2451 return Handle(); // do not attempt from within compiler, unless it was cached
2452 }
2453
2454 Handle class_loader, protection_domain;
2455 if (accessing_klass.not_null()) {
2456 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2457 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2458 }
2459 bool can_be_cached = true;
2460 int npts = ArgumentCount(signature).size();
2461 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2462 int arg = 0;
2463 Handle rt; // the return type from the signature
2464 ResourceMark rm(THREAD);
2465 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2466 oop mirror = NULL;
2467 if (can_be_cached) {
2468 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2469 mirror = ss.as_java_mirror(Handle(), Handle(),
2470 SignatureStream::ReturnNull, CHECK_(empty));
2471 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2472 // Fall back to accessing_klass context.
2473 can_be_cached = false;
2474 }
2475 }
2476 if (!can_be_cached) {
2477 // Resolve, throwing a real error if it doesn't work.
2478 mirror = ss.as_java_mirror(class_loader, protection_domain,
2479 SignatureStream::NCDFError, CHECK_(empty));
2480 }
2481 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2482 if (ss.at_return_type())
2483 rt = Handle(THREAD, mirror);
2484 else
2485 pts->obj_at_put(arg++, mirror);
2486
2487 // Check accessibility.
2488 if (ss.is_object() && accessing_klass.not_null()) {
2489 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2490 mirror = NULL; // safety
2491 // Emulate ConstantPool::verify_constant_pool_resolve.
2492 if (sel_klass->oop_is_objArray())
2493 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2494 if (sel_klass->oop_is_instance()) {
2495 KlassHandle sel_kh(THREAD, sel_klass);
2496 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2497 }
2498 }
2499 }
2500 assert(arg == npts, "");
2501
2502 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2503 JavaCallArguments args(Handle(THREAD, rt()));
2504 args.push_oop(pts());
2505 JavaValue result(T_OBJECT);
2506 JavaCalls::call_static(&result,
2507 SystemDictionary::MethodHandleNatives_klass(),
2508 vmSymbols::findMethodHandleType_name(),
2509 vmSymbols::findMethodHandleType_signature(),
2510 &args, CHECK_(empty));
2511 Handle method_type(THREAD, (oop) result.get_jobject());
2512
2513 if (can_be_cached) {
2514 // We can cache this MethodType inside the JVM.
2515 MutexLocker ml(SystemDictionary_lock, THREAD);
2516 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2517 if (spe == NULL)
2518 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2519 if (spe->method_type() == NULL) {
2520 spe->set_method_type(method_type());
2521 }
2522 }
2523
2524 // report back to the caller with the MethodType
2525 return method_type;
2526 }
2527
2528 // Ask Java code to find or construct a method handle constant.
2529 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2530 int ref_kind, //e.g., JVM_REF_invokeVirtual
2531 KlassHandle callee,
2532 Symbol* name_sym,
2533 Symbol* signature,
2534 TRAPS) {
2535 Handle empty;
2536 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2537 Handle type;
2538 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2539 type = find_method_handle_type(signature, caller, CHECK_(empty));
2540 } else if (caller.is_null()) {
2541 // This should not happen. JDK code should take care of that.
2542 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2543 } else {
2544 ResourceMark rm(THREAD);
2545 SignatureStream ss(signature, false);
2546 if (!ss.is_done()) {
2547 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2548 SignatureStream::NCDFError, CHECK_(empty));
2549 type = Handle(THREAD, mirror);
2550 ss.next();
2551 if (!ss.is_done()) type = Handle(); // error!
2552 }
2553 }
2554 if (type.is_null()) {
2555 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2556 }
2557
2558 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2559 JavaCallArguments args;
2560 args.push_oop(caller->java_mirror()); // the referring class
2561 args.push_int(ref_kind);
2562 args.push_oop(callee->java_mirror()); // the target class
2563 args.push_oop(name());
2564 args.push_oop(type());
2565 JavaValue result(T_OBJECT);
2566 JavaCalls::call_static(&result,
2567 SystemDictionary::MethodHandleNatives_klass(),
2568 vmSymbols::linkMethodHandleConstant_name(),
2569 vmSymbols::linkMethodHandleConstant_signature(),
2570 &args, CHECK_(empty));
2571 return Handle(THREAD, (oop) result.get_jobject());
2572 }
2573
2574 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2575 // name and signature, as interpreted relative to the given class loader.
2576 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2577 Handle bootstrap_specifier,
2578 Symbol* name,
2579 Symbol* type,
2580 Handle *appendix_result,
2581 Handle *method_type_result,
2582 TRAPS) {
2583 methodHandle empty;
2584 Handle bsm, info;
2585 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2586 bsm = bootstrap_specifier;
2587 } else {
2588 assert(bootstrap_specifier->is_objArray(), "");
2589 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2590 int len = args->length();
2591 assert(len >= 1, "");
2592 bsm = Handle(THREAD, args->obj_at(0));
2593 if (len > 1) {
2594 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2595 for (int i = 1; i < len; i++)
2596 args1->obj_at_put(i-1, args->obj_at(i));
2597 info = Handle(THREAD, args1);
2598 }
2599 }
2600 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2601 "caller must supply a valid BSM");
2602
2603 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2604 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2605
2606 // This should not happen. JDK code should take care of that.
2607 if (caller.is_null() || method_type.is_null()) {
2608 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2609 }
2610
2611 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2612 assert(appendix_box->obj_at(0) == NULL, "");
2613
2614 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2615 JavaCallArguments args;
2616 args.push_oop(caller->java_mirror());
2617 args.push_oop(bsm());
2618 args.push_oop(method_name());
2619 args.push_oop(method_type());
2620 args.push_oop(info());
2621 args.push_oop(appendix_box);
2622 JavaValue result(T_OBJECT);
2623 JavaCalls::call_static(&result,
2624 SystemDictionary::MethodHandleNatives_klass(),
2625 vmSymbols::linkCallSite_name(),
2626 vmSymbols::linkCallSite_signature(),
2627 &args, CHECK_(empty));
2628 Handle mname(THREAD, (oop) result.get_jobject());
2629 (*method_type_result) = method_type;
2630 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2631 }
2632
2633 // Since the identity hash code for symbols changes when the symbols are
2634 // moved from the regular perm gen (hash in the mark word) to the shared
2635 // spaces (hash is the address), the classes loaded into the dictionary
2636 // may be in the wrong buckets.
2637
2638 void SystemDictionary::reorder_dictionary() {
2639 dictionary()->reorder_dictionary();
2640 }
2641
2642
2643 void SystemDictionary::copy_buckets(char** top, char* end) {
2644 dictionary()->copy_buckets(top, end);
2645 }
2646
2647
2648 void SystemDictionary::copy_table(char** top, char* end) {
2649 dictionary()->copy_table(top, end);
2650 }
2651
2652
2653 void SystemDictionary::reverse() {
2654 dictionary()->reverse();
2655 }
2656
2657 int SystemDictionary::number_of_classes() {
2658 return dictionary()->number_of_entries();
2659 }
2660
2661
2662 // ----------------------------------------------------------------------------
2663 void SystemDictionary::print_shared(bool details) {
2664 shared_dictionary()->print(details);
2665 }
2666
2667 void SystemDictionary::print(bool details) {
2668 dictionary()->print(details);
2669
2670 // Placeholders
2671 GCMutexLocker mu(SystemDictionary_lock);
2672 placeholders()->print();
2673
2674 // loader constraints - print under SD_lock
2675 constraints()->print();
2676 }
2677
2678
2679 void SystemDictionary::verify() {
2680 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2681 guarantee(constraints() != NULL,
2682 "Verify of loader constraints failed");
2683 guarantee(dictionary()->number_of_entries() >= 0 &&
2684 placeholders()->number_of_entries() >= 0,
2685 "Verify of system dictionary failed");
2686
2687 // Verify dictionary
2688 dictionary()->verify();
2689
2690 GCMutexLocker mu(SystemDictionary_lock);
2691 placeholders()->verify();
2692
2693 // Verify constraint table
2694 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2695 constraints()->verify(dictionary(), placeholders());
2696 }
2697
2698 // utility function for class load event
2699 void SystemDictionary::post_class_load_event(const Ticks& start_time,
2700 instanceKlassHandle k,
2701 Handle initiating_loader) {
2702 #if INCLUDE_TRACE
2703 EventClassLoad event;
2704 if (event.should_commit()) {
2705 event.set_loadedClass(k());
2706 event.set_definingClassLoader(k->class_loader_data());
2707 event.set_initiatingClassLoader(ClassLoaderData::class_loader_data_or_null(initiating_loader()));
2708 event.commit();
2709 }
2710 #endif // INCLUDE_TRACE
2711 }
2712
2713 #ifndef PRODUCT
2714
2715 // statistics code
2716 class ClassStatistics: AllStatic {
2717 private:
2718 static int nclasses; // number of classes
2719 static int nmethods; // number of methods
2720 static int nmethoddata; // number of methodData
2721 static int class_size; // size of class objects in words
2722 static int method_size; // size of method objects in words
2723 static int debug_size; // size of debug info in methods
2724 static int methoddata_size; // size of methodData objects in words
2725
2726 static void do_class(Klass* k) {
2727 nclasses++;
2728 class_size += k->size();
2729 if (k->oop_is_instance()) {
2730 InstanceKlass* ik = (InstanceKlass*)k;
2731 class_size += ik->methods()->size();
2732 class_size += ik->constants()->size();
2733 class_size += ik->local_interfaces()->size();
2734 class_size += ik->transitive_interfaces()->size();
2735 // We do not have to count implementors, since we only store one!
2736 // SSS: How should these be accounted now that they have moved?
2737 // class_size += ik->fields()->length();
2738 }
2739 }
2740
2741 static void do_method(Method* m) {
2742 nmethods++;
2743 method_size += m->size();
2744 // class loader uses same objArray for empty vectors, so don't count these
2745 if (m->has_stackmap_table()) {
2746 method_size += m->stackmap_data()->size();
2747 }
2748
2749 MethodData* mdo = m->method_data();
2750 if (mdo != NULL) {
2751 nmethoddata++;
2752 methoddata_size += mdo->size();
2753 }
2754 }
2755
2756 public:
2757 static void print() {
2758 SystemDictionary::classes_do(do_class);
2759 SystemDictionary::methods_do(do_method);
2760 tty->print_cr("Class statistics:");
2761 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2762 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2763 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2764 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2765 }
2766 };
2767
2768
2769 int ClassStatistics::nclasses = 0;
2770 int ClassStatistics::nmethods = 0;
2771 int ClassStatistics::nmethoddata = 0;
2772 int ClassStatistics::class_size = 0;
2773 int ClassStatistics::method_size = 0;
2774 int ClassStatistics::debug_size = 0;
2775 int ClassStatistics::methoddata_size = 0;
2776
2777 void SystemDictionary::print_class_statistics() {
2778 ResourceMark rm;
2779 ClassStatistics::print();
2780 }
2781
2782
2783 class MethodStatistics: AllStatic {
2784 public:
2785 enum {
2786 max_parameter_size = 10
2787 };
2788 private:
2789
2790 static int _number_of_methods;
2791 static int _number_of_final_methods;
2792 static int _number_of_static_methods;
2793 static int _number_of_native_methods;
2794 static int _number_of_synchronized_methods;
2795 static int _number_of_profiled_methods;
2796 static int _number_of_bytecodes;
2797 static int _parameter_size_profile[max_parameter_size];
2798 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2799
2800 static void initialize() {
2801 _number_of_methods = 0;
2802 _number_of_final_methods = 0;
2803 _number_of_static_methods = 0;
2804 _number_of_native_methods = 0;
2805 _number_of_synchronized_methods = 0;
2806 _number_of_profiled_methods = 0;
2807 _number_of_bytecodes = 0;
2808 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2809 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2810 };
2811
2812 static void do_method(Method* m) {
2813 _number_of_methods++;
2814 // collect flag info
2815 if (m->is_final() ) _number_of_final_methods++;
2816 if (m->is_static() ) _number_of_static_methods++;
2817 if (m->is_native() ) _number_of_native_methods++;
2818 if (m->is_synchronized()) _number_of_synchronized_methods++;
2819 if (m->method_data() != NULL) _number_of_profiled_methods++;
2820 // collect parameter size info (add one for receiver, if any)
2821 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2822 // collect bytecodes info
2823 {
2824 Thread *thread = Thread::current();
2825 HandleMark hm(thread);
2826 BytecodeStream s(methodHandle(thread, m));
2827 Bytecodes::Code c;
2828 while ((c = s.next()) >= 0) {
2829 _number_of_bytecodes++;
2830 _bytecodes_profile[c]++;
2831 }
2832 }
2833 }
2834
2835 public:
2836 static void print() {
2837 initialize();
2838 SystemDictionary::methods_do(do_method);
2839 // generate output
2840 tty->cr();
2841 tty->print_cr("Method statistics (static):");
2842 // flag distribution
2843 tty->cr();
2844 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2845 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2846 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2847 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2848 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2849 // parameter size profile
2850 tty->cr();
2851 { int tot = 0;
2852 int avg = 0;
2853 for (int i = 0; i < max_parameter_size; i++) {
2854 int n = _parameter_size_profile[i];
2855 tot += n;
2856 avg += n*i;
2857 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2858 }
2859 assert(tot == _number_of_methods, "should be the same");
2860 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2861 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2862 }
2863 // bytecodes profile
2864 tty->cr();
2865 { int tot = 0;
2866 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2867 if (Bytecodes::is_defined(i)) {
2868 Bytecodes::Code c = Bytecodes::cast(i);
2869 int n = _bytecodes_profile[c];
2870 tot += n;
2871 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2872 }
2873 }
2874 assert(tot == _number_of_bytecodes, "should be the same");
2875 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2876 }
2877 tty->cr();
2878 }
2879 };
2880
2881 int MethodStatistics::_number_of_methods;
2882 int MethodStatistics::_number_of_final_methods;
2883 int MethodStatistics::_number_of_static_methods;
2884 int MethodStatistics::_number_of_native_methods;
2885 int MethodStatistics::_number_of_synchronized_methods;
2886 int MethodStatistics::_number_of_profiled_methods;
2887 int MethodStatistics::_number_of_bytecodes;
2888 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2889 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2890
2891
2892 void SystemDictionary::print_method_statistics() {
2893 MethodStatistics::print();
2894 }
2895
2896 #endif // PRODUCT