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