Mon, 12 Aug 2019 18:30:40 +0300
8223147: JFR Backport
8199712: Flight Recorder
8203346: JFR: Inconsistent signature of jfr_add_string_constant
8195817: JFR.stop should require name of recording
8195818: JFR.start should increase autogenerated name by one
8195819: Remove recording=x from jcmd JFR.check output
8203921: JFR thread sampling is missing fixes from JDK-8194552
8203929: Limit amount of data for JFR.dump
8203664: JFR start failure after AppCDS archive created with JFR StartFlightRecording
8003209: JFR events for network utilization
8207392: [PPC64] Implement JFR profiling
8202835: jfr/event/os/TestSystemProcess.java fails on missing events
Summary: Backport JFR from JDK11. Initial integration
Reviewed-by: neugens
1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #if INCLUDE_CDS
34 #include "classfile/sharedClassUtil.hpp"
35 #include "classfile/systemDictionaryShared.hpp"
36 #endif
37 #include "classfile/vmSymbols.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/bytecodeStream.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "memory/filemap.hpp"
43 #include "memory/gcLocker.hpp"
44 #include "memory/oopFactory.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/instanceRefKlass.hpp"
47 #include "oops/klass.inline.hpp"
48 #include "oops/methodData.hpp"
49 #include "oops/objArrayKlass.hpp"
50 #include "oops/oop.inline.hpp"
51 #include "oops/oop.inline2.hpp"
52 #include "oops/typeArrayKlass.hpp"
53 #include "prims/jvmtiEnvBase.hpp"
54 #include "prims/methodHandles.hpp"
55 #include "runtime/arguments.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/fieldType.hpp"
58 #include "runtime/handles.inline.hpp"
59 #include "runtime/java.hpp"
60 #include "runtime/javaCalls.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/orderAccess.inline.hpp"
63 #include "runtime/signature.hpp"
64 #include "services/classLoadingService.hpp"
65 #include "services/threadService.hpp"
66 #include "utilities/macros.hpp"
67 #include "utilities/ticks.hpp"
69 Dictionary* SystemDictionary::_dictionary = NULL;
70 PlaceholderTable* SystemDictionary::_placeholders = NULL;
71 Dictionary* SystemDictionary::_shared_dictionary = NULL;
72 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
73 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
74 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
77 int SystemDictionary::_number_of_modifications = 0;
78 int SystemDictionary::_sdgeneration = 0;
79 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
80 20201,40423,99991};
82 oop SystemDictionary::_system_loader_lock_obj = NULL;
84 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
85 = { NULL /*, NULL...*/ };
87 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
89 oop SystemDictionary::_java_system_loader = NULL;
91 bool SystemDictionary::_has_loadClassInternal = false;
92 bool SystemDictionary::_has_checkPackageAccess = false;
94 // lazily initialized klass variables
95 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
98 // ----------------------------------------------------------------------------
99 // Java-level SystemLoader
101 oop SystemDictionary::java_system_loader() {
102 return _java_system_loader;
103 }
105 void SystemDictionary::compute_java_system_loader(TRAPS) {
106 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
107 JavaValue result(T_OBJECT);
108 JavaCalls::call_static(&result,
109 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
110 vmSymbols::getSystemClassLoader_name(),
111 vmSymbols::void_classloader_signature(),
112 CHECK);
114 _java_system_loader = (oop)result.get_jobject();
116 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
117 }
120 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
121 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
122 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
123 }
125 // ----------------------------------------------------------------------------
126 // debugging
128 #ifdef ASSERT
130 // return true if class_name contains no '.' (internal format is '/')
131 bool SystemDictionary::is_internal_format(Symbol* class_name) {
132 if (class_name != NULL) {
133 ResourceMark rm;
134 char* name = class_name->as_C_string();
135 return strchr(name, '.') == NULL;
136 } else {
137 return true;
138 }
139 }
141 #endif
143 // ----------------------------------------------------------------------------
144 // Parallel class loading check
146 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
147 if (UnsyncloadClass || class_loader.is_null()) return true;
148 if (AlwaysLockClassLoader) return false;
149 return java_lang_ClassLoader::parallelCapable(class_loader());
150 }
151 // ----------------------------------------------------------------------------
152 // ParallelDefineClass flag does not apply to bootclass loader
153 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
154 if (class_loader.is_null()) return false;
155 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
156 return true;
157 }
158 return false;
159 }
161 /**
162 * Returns true if the passed class loader is the extension class loader.
163 */
164 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
165 if (class_loader.is_null()) {
166 return false;
167 }
168 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
169 }
171 // ----------------------------------------------------------------------------
172 // Resolving of classes
174 // Forwards to resolve_or_null
176 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
177 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
178 if (HAS_PENDING_EXCEPTION || klass == NULL) {
179 KlassHandle k_h(THREAD, klass);
180 // can return a null klass
181 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
182 }
183 return klass;
184 }
186 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
187 if (HAS_PENDING_EXCEPTION) {
188 // If we have a pending exception we forward it to the caller, unless throw_error is true,
189 // in which case we have to check whether the pending exception is a ClassNotFoundException,
190 // and if so convert it to a NoClassDefFoundError
191 // And chain the original ClassNotFoundException
192 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
193 ResourceMark rm(THREAD);
194 assert(klass_h() == NULL, "Should not have result with exception pending");
195 Handle e(THREAD, PENDING_EXCEPTION);
196 CLEAR_PENDING_EXCEPTION;
197 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
198 } else {
199 return NULL;
200 }
201 }
202 // Class not found, throw appropriate error or exception depending on value of throw_error
203 if (klass_h() == NULL) {
204 ResourceMark rm(THREAD);
205 if (throw_error) {
206 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
207 } else {
208 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
209 }
210 }
211 return (Klass*)klass_h();
212 }
215 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
216 bool throw_error, TRAPS)
217 {
218 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
219 }
222 // Forwards to resolve_instance_class_or_null
224 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
225 assert(!THREAD->is_Compiler_thread(),
226 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
227 class_name->as_C_string(),
228 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
229 if (FieldType::is_array(class_name)) {
230 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
231 } else if (FieldType::is_obj(class_name)) {
232 ResourceMark rm(THREAD);
233 // Ignore wrapping L and ;.
234 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
235 class_name->utf8_length() - 2, CHECK_NULL);
236 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
237 } else {
238 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
239 }
240 }
242 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
243 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
244 }
246 // Forwards to resolve_instance_class_or_null
248 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
249 Handle class_loader,
250 Handle protection_domain,
251 TRAPS) {
252 assert(FieldType::is_array(class_name), "must be array");
253 Klass* k = NULL;
254 FieldArrayInfo fd;
255 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
256 // of this call
257 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
258 if (t == T_OBJECT) {
259 // naked oop "k" is OK here -- we assign back into it
260 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
261 class_loader,
262 protection_domain,
263 CHECK_NULL);
264 if (k != NULL) {
265 k = k->array_klass(fd.dimension(), CHECK_NULL);
266 }
267 } else {
268 k = Universe::typeArrayKlassObj(t);
269 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
270 }
271 return k;
272 }
275 // Must be called for any super-class or super-interface resolution
276 // during class definition to allow class circularity checking
277 // super-interface callers:
278 // parse_interfaces - for defineClass & jvmtiRedefineClasses
279 // super-class callers:
280 // ClassFileParser - for defineClass & jvmtiRedefineClasses
281 // load_shared_class - while loading a class from shared archive
282 // resolve_instance_class_or_null:
283 // via: handle_parallel_super_load
284 // when resolving a class that has an existing placeholder with
285 // a saved superclass [i.e. a defineClass is currently in progress]
286 // if another thread is trying to resolve the class, it must do
287 // super-class checks on its own thread to catch class circularity
288 // This last call is critical in class circularity checking for cases
289 // where classloading is delegated to different threads and the
290 // classloader lock is released.
291 // Take the case: Base->Super->Base
292 // 1. If thread T1 tries to do a defineClass of class Base
293 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
294 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
295 // so it tries to load Super
296 // 3. If we load the class internally, or user classloader uses same thread
297 // loadClassFromxxx or defineClass via parseClassFile Super ...
298 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
299 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
300 // 3.4 calls resolve_super_or_fail Base
301 // 3.5 finds T1,Base -> throws class circularity
302 //OR 4. If T2 tries to resolve Super via defineClass Super ...
303 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
304 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
305 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
306 // 4.4 finds T2, Super -> throws class circularity
307 // Must be called, even if superclass is null, since this is
308 // where the placeholder entry is created which claims this
309 // thread is loading this class/classloader.
310 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
311 Symbol* class_name,
312 Handle class_loader,
313 Handle protection_domain,
314 bool is_superclass,
315 TRAPS) {
316 // Double-check, if child class is already loaded, just return super-class,interface
317 // Don't add a placedholder if already loaded, i.e. already in system dictionary
318 // Make sure there's a placeholder for the *child* before resolving.
319 // Used as a claim that this thread is currently loading superclass/classloader
320 // Used here for ClassCircularity checks and also for heap verification
321 // (every InstanceKlass in the heap needs to be in the system dictionary
322 // or have a placeholder).
323 // Must check ClassCircularity before checking if super class is already loaded
324 //
325 // We might not already have a placeholder if this child_name was
326 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
327 // the name of the class might not be known until the stream is actually
328 // parsed.
329 // Bugs 4643874, 4715493
330 // compute_hash can have a safepoint
332 ClassLoaderData* loader_data = class_loader_data(class_loader);
333 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
334 int d_index = dictionary()->hash_to_index(d_hash);
335 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
336 int p_index = placeholders()->hash_to_index(p_hash);
337 // can't throw error holding a lock
338 bool child_already_loaded = false;
339 bool throw_circularity_error = false;
340 {
341 MutexLocker mu(SystemDictionary_lock, THREAD);
342 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
343 Klass* quicksuperk;
344 // to support // loading: if child done loading, just return superclass
345 // if class_name, & class_loader don't match:
346 // if initial define, SD update will give LinkageError
347 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
348 // so we don't throw an exception here.
349 // see: nsk redefclass014 & java.lang.instrument Instrument032
350 if ((childk != NULL ) && (is_superclass) &&
351 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
353 ((quicksuperk->name() == class_name) &&
354 (quicksuperk->class_loader() == class_loader()))) {
355 return quicksuperk;
356 } else {
357 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
358 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
359 throw_circularity_error = true;
360 }
361 }
362 if (!throw_circularity_error) {
363 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
364 }
365 }
366 if (throw_circularity_error) {
367 ResourceMark rm(THREAD);
368 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
369 }
371 // java.lang.Object should have been found above
372 assert(class_name != NULL, "null super class for resolving");
373 // Resolve the super class or interface, check results on return
374 Klass* superk = SystemDictionary::resolve_or_null(class_name,
375 class_loader,
376 protection_domain,
377 THREAD);
379 KlassHandle superk_h(THREAD, superk);
381 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
382 // It is no longer necessary to keep the placeholder table alive until update_dictionary
383 // or error. GC used to walk the placeholder table as strong roots.
384 // The instanceKlass is kept alive because the class loader is on the stack,
385 // which keeps the loader_data alive, as well as all instanceKlasses in
386 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
387 {
388 MutexLocker mu(SystemDictionary_lock, THREAD);
389 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
390 SystemDictionary_lock->notify_all();
391 }
392 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
393 // can null superk
394 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
395 }
397 return superk_h();
398 }
400 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
401 Handle class_loader,
402 Handle protection_domain,
403 TRAPS) {
404 if(!has_checkPackageAccess()) return;
406 // Now we have to call back to java to check if the initating class has access
407 JavaValue result(T_VOID);
408 if (TraceProtectionDomainVerification) {
409 // Print out trace information
410 tty->print_cr("Checking package access");
411 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
412 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
413 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
414 }
416 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
417 JavaCalls::call_special(&result,
418 class_loader,
419 system_loader,
420 vmSymbols::checkPackageAccess_name(),
421 vmSymbols::class_protectiondomain_signature(),
422 Handle(THREAD, klass->java_mirror()),
423 protection_domain,
424 THREAD);
426 if (TraceProtectionDomainVerification) {
427 if (HAS_PENDING_EXCEPTION) {
428 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
429 } else {
430 tty->print_cr(" -> granted");
431 }
432 tty->cr();
433 }
435 if (HAS_PENDING_EXCEPTION) return;
437 // If no exception has been thrown, we have validated the protection domain
438 // Insert the protection domain of the initiating class into the set.
439 {
440 // We recalculate the entry here -- we've called out to java since
441 // the last time it was calculated.
442 ClassLoaderData* loader_data = class_loader_data(class_loader);
444 Symbol* kn = klass->name();
445 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
446 int d_index = dictionary()->hash_to_index(d_hash);
448 MutexLocker mu(SystemDictionary_lock, THREAD);
449 {
450 // Note that we have an entry, and entries can be deleted only during GC,
451 // so we cannot allow GC to occur while we're holding this entry.
453 // We're using a No_Safepoint_Verifier to catch any place where we
454 // might potentially do a GC at all.
455 // Dictionary::do_unloading() asserts that classes in SD are only
456 // unloaded at a safepoint. Anonymous classes are not in SD.
457 No_Safepoint_Verifier nosafepoint;
458 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
459 protection_domain, THREAD);
460 }
461 }
462 }
464 // We only get here if this thread finds that another thread
465 // has already claimed the placeholder token for the current operation,
466 // but that other thread either never owned or gave up the
467 // object lock
468 // Waits on SystemDictionary_lock to indicate placeholder table updated
469 // On return, caller must recheck placeholder table state
470 //
471 // We only get here if
472 // 1) custom classLoader, i.e. not bootstrap classloader
473 // 2) UnsyncloadClass not set
474 // 3) custom classLoader has broken the class loader objectLock
475 // so another thread got here in parallel
476 //
477 // lockObject must be held.
478 // Complicated dance due to lock ordering:
479 // Must first release the classloader object lock to
480 // allow initial definer to complete the class definition
481 // and to avoid deadlock
482 // Reclaim classloader lock object with same original recursion count
483 // Must release SystemDictionary_lock after notify, since
484 // class loader lock must be claimed before SystemDictionary_lock
485 // to prevent deadlocks
486 //
487 // The notify allows applications that did an untimed wait() on
488 // the classloader object lock to not hang.
489 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
490 assert_lock_strong(SystemDictionary_lock);
492 bool calledholdinglock
493 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
494 assert(calledholdinglock,"must hold lock for notify");
495 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
496 ObjectSynchronizer::notifyall(lockObject, THREAD);
497 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
498 SystemDictionary_lock->wait();
499 SystemDictionary_lock->unlock();
500 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
501 SystemDictionary_lock->lock();
502 }
504 // If the class in is in the placeholder table, class loading is in progress
505 // For cases where the application changes threads to load classes, it
506 // is critical to ClassCircularity detection that we try loading
507 // the superclass on the same thread internally, so we do parallel
508 // super class loading here.
509 // This also is critical in cases where the original thread gets stalled
510 // even in non-circularity situations.
511 // Note: must call resolve_super_or_fail even if null super -
512 // to force placeholder entry creation for this class for circularity detection
513 // Caller must check for pending exception
514 // Returns non-null Klass* if other thread has completed load
515 // and we are done,
516 // If return null Klass* and no pending exception, the caller must load the class
517 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
518 Symbol* name, Symbol* superclassname, Handle class_loader,
519 Handle protection_domain, Handle lockObject, TRAPS) {
521 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
522 ClassLoaderData* loader_data = class_loader_data(class_loader);
523 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
524 int d_index = dictionary()->hash_to_index(d_hash);
525 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
526 int p_index = placeholders()->hash_to_index(p_hash);
528 // superk is not used, resolve_super called for circularity check only
529 // This code is reached in two situations. One if this thread
530 // is loading the same class twice (e.g. ClassCircularity, or
531 // java.lang.instrument).
532 // The second is if another thread started the resolve_super first
533 // and has not yet finished.
534 // In both cases the original caller will clean up the placeholder
535 // entry on error.
536 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
537 superclassname,
538 class_loader,
539 protection_domain,
540 true,
541 CHECK_(nh));
543 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
544 // Serial class loaders and bootstrap classloader do wait for superclass loads
545 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
546 MutexLocker mu(SystemDictionary_lock, THREAD);
547 // Check if classloading completed while we were loading superclass or waiting
548 Klass* check = find_class(d_index, d_hash, name, loader_data);
549 if (check != NULL) {
550 // Klass is already loaded, so just return it
551 return(instanceKlassHandle(THREAD, check));
552 } else {
553 return nh;
554 }
555 }
557 // must loop to both handle other placeholder updates
558 // and spurious notifications
559 bool super_load_in_progress = true;
560 PlaceholderEntry* placeholder;
561 while (super_load_in_progress) {
562 MutexLocker mu(SystemDictionary_lock, THREAD);
563 // Check if classloading completed while we were loading superclass or waiting
564 Klass* check = find_class(d_index, d_hash, name, loader_data);
565 if (check != NULL) {
566 // Klass is already loaded, so just return it
567 return(instanceKlassHandle(THREAD, check));
568 } else {
569 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
570 if (placeholder && placeholder->super_load_in_progress() ){
571 // Before UnsyncloadClass:
572 // We only get here if the application has released the
573 // classloader lock when another thread was in the middle of loading a
574 // superclass/superinterface for this class, and now
575 // this thread is also trying to load this class.
576 // To minimize surprises, the first thread that started to
577 // load a class should be the one to complete the loading
578 // with the classfile it initially expected.
579 // This logic has the current thread wait once it has done
580 // all the superclass/superinterface loading it can, until
581 // the original thread completes the class loading or fails
582 // If it completes we will use the resulting InstanceKlass
583 // which we will find below in the systemDictionary.
584 // We also get here for parallel bootstrap classloader
585 if (class_loader.is_null()) {
586 SystemDictionary_lock->wait();
587 } else {
588 double_lock_wait(lockObject, THREAD);
589 }
590 } else {
591 // If not in SD and not in PH, other thread's load must have failed
592 super_load_in_progress = false;
593 }
594 }
595 }
596 return (nh);
597 }
599 // utility function for class load event
600 static void post_class_load_event(EventClassLoad &event,
601 instanceKlassHandle k,
602 Handle initiating_loader) {
603 #if INCLUDE_JFR
604 if (event.should_commit()) {
605 event.set_loadedClass(k());
606 event.set_definingClassLoader(k->class_loader_data());
607 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
608 event.set_initiatingClassLoader(class_loader != NULL ?
609 ClassLoaderData::class_loader_data_or_null(class_loader) :
610 (ClassLoaderData*)NULL);
611 event.commit();
612 }
613 #endif // INCLUDE_JFR
614 }
616 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
617 Handle class_loader,
618 Handle protection_domain,
619 TRAPS) {
620 assert(name != NULL && !FieldType::is_array(name) &&
621 !FieldType::is_obj(name), "invalid class name");
623 EventClassLoad class_load_start_event;
625 // UseNewReflection
626 // Fix for 4474172; see evaluation for more details
627 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
628 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
630 // Do lookup to see if class already exist and the protection domain
631 // has the right access
632 // This call uses find which checks protection domain already matches
633 // All subsequent calls use find_class, and set has_loaded_class so that
634 // before we return a result we call out to java to check for valid protection domain
635 // to allow returning the Klass* and add it to the pd_set if it is valid
636 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
637 int d_index = dictionary()->hash_to_index(d_hash);
638 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
639 protection_domain, THREAD);
640 if (probe != NULL) return probe;
643 // Non-bootstrap class loaders will call out to class loader and
644 // define via jvm/jni_DefineClass which will acquire the
645 // class loader object lock to protect against multiple threads
646 // defining the class in parallel by accident.
647 // This lock must be acquired here so the waiter will find
648 // any successful result in the SystemDictionary and not attempt
649 // the define
650 // ParallelCapable Classloaders and the bootstrap classloader,
651 // or all classloaders with UnsyncloadClass do not acquire lock here
652 bool DoObjectLock = true;
653 if (is_parallelCapable(class_loader)) {
654 DoObjectLock = false;
655 }
657 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
658 int p_index = placeholders()->hash_to_index(p_hash);
660 // Class is not in SystemDictionary so we have to do loading.
661 // Make sure we are synchronized on the class loader before we proceed
662 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
663 check_loader_lock_contention(lockObject, THREAD);
664 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
666 // Check again (after locking) if class already exist in SystemDictionary
667 bool class_has_been_loaded = false;
668 bool super_load_in_progress = false;
669 bool havesupername = false;
670 instanceKlassHandle k;
671 PlaceholderEntry* placeholder;
672 Symbol* superclassname = NULL;
674 {
675 MutexLocker mu(SystemDictionary_lock, THREAD);
676 Klass* check = find_class(d_index, d_hash, name, loader_data);
677 if (check != NULL) {
678 // Klass is already loaded, so just return it
679 class_has_been_loaded = true;
680 k = instanceKlassHandle(THREAD, check);
681 } else {
682 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
683 if (placeholder && placeholder->super_load_in_progress()) {
684 super_load_in_progress = true;
685 if (placeholder->havesupername() == true) {
686 superclassname = placeholder->supername();
687 havesupername = true;
688 }
689 }
690 }
691 }
693 // If the class is in the placeholder table, class loading is in progress
694 if (super_load_in_progress && havesupername==true) {
695 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
696 class_loader, protection_domain, lockObject, THREAD);
697 if (HAS_PENDING_EXCEPTION) {
698 return NULL;
699 }
700 if (!k.is_null()) {
701 class_has_been_loaded = true;
702 }
703 }
705 bool throw_circularity_error = false;
706 if (!class_has_been_loaded) {
707 bool load_instance_added = false;
709 // add placeholder entry to record loading instance class
710 // Five cases:
711 // All cases need to prevent modifying bootclasssearchpath
712 // in parallel with a classload of same classname
713 // Redefineclasses uses existence of the placeholder for the duration
714 // of the class load to prevent concurrent redefinition of not completely
715 // defined classes.
716 // case 1. traditional classloaders that rely on the classloader object lock
717 // - no other need for LOAD_INSTANCE
718 // case 2. traditional classloaders that break the classloader object lock
719 // as a deadlock workaround. Detection of this case requires that
720 // this check is done while holding the classloader object lock,
721 // and that lock is still held when calling classloader's loadClass.
722 // For these classloaders, we ensure that the first requestor
723 // completes the load and other requestors wait for completion.
724 // case 3. UnsyncloadClass - don't use objectLocker
725 // With this flag, we allow parallel classloading of a
726 // class/classloader pair
727 // case4. Bootstrap classloader - don't own objectLocker
728 // This classloader supports parallelism at the classloader level,
729 // but only allows a single load of a class/classloader pair.
730 // No performance benefit and no deadlock issues.
731 // case 5. parallelCapable user level classloaders - without objectLocker
732 // Allow parallel classloading of a class/classloader pair
734 {
735 MutexLocker mu(SystemDictionary_lock, THREAD);
736 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
737 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
738 if (oldprobe) {
739 // only need check_seen_thread once, not on each loop
740 // 6341374 java/lang/Instrument with -Xcomp
741 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
742 throw_circularity_error = true;
743 } else {
744 // case 1: traditional: should never see load_in_progress.
745 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
747 // case 4: bootstrap classloader: prevent futile classloading,
748 // wait on first requestor
749 if (class_loader.is_null()) {
750 SystemDictionary_lock->wait();
751 } else {
752 // case 2: traditional with broken classloader lock. wait on first
753 // requestor.
754 double_lock_wait(lockObject, THREAD);
755 }
756 // Check if classloading completed while we were waiting
757 Klass* check = find_class(d_index, d_hash, name, loader_data);
758 if (check != NULL) {
759 // Klass is already loaded, so just return it
760 k = instanceKlassHandle(THREAD, check);
761 class_has_been_loaded = true;
762 }
763 // check if other thread failed to load and cleaned up
764 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
765 }
766 }
767 }
768 }
769 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
770 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
771 // LOAD_INSTANCE in parallel
773 if (!throw_circularity_error && !class_has_been_loaded) {
774 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
775 load_instance_added = true;
776 // For class loaders that do not acquire the classloader object lock,
777 // if they did not catch another thread holding LOAD_INSTANCE,
778 // need a check analogous to the acquire ObjectLocker/find_class
779 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
780 // one final check if the load has already completed
781 // class loaders holding the ObjectLock shouldn't find the class here
782 Klass* check = find_class(d_index, d_hash, name, loader_data);
783 if (check != NULL) {
784 // Klass is already loaded, so return it after checking/adding protection domain
785 k = instanceKlassHandle(THREAD, check);
786 class_has_been_loaded = true;
787 }
788 }
789 }
791 // must throw error outside of owning lock
792 if (throw_circularity_error) {
793 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
794 ResourceMark rm(THREAD);
795 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
796 }
798 if (!class_has_been_loaded) {
800 // Do actual loading
801 k = load_instance_class(name, class_loader, THREAD);
803 // For UnsyncloadClass only
804 // If they got a linkageError, check if a parallel class load succeeded.
805 // If it did, then for bytecode resolution the specification requires
806 // that we return the same result we did for the other thread, i.e. the
807 // successfully loaded InstanceKlass
808 // Should not get here for classloaders that support parallelism
809 // with the new cleaner mechanism, even with AllowParallelDefineClass
810 // Bootstrap goes through here to allow for an extra guarantee check
811 if (UnsyncloadClass || (class_loader.is_null())) {
812 if (k.is_null() && HAS_PENDING_EXCEPTION
813 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
814 MutexLocker mu(SystemDictionary_lock, THREAD);
815 Klass* check = find_class(d_index, d_hash, name, loader_data);
816 if (check != NULL) {
817 // Klass is already loaded, so just use it
818 k = instanceKlassHandle(THREAD, check);
819 CLEAR_PENDING_EXCEPTION;
820 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
821 }
822 }
823 }
825 // If everything was OK (no exceptions, no null return value), and
826 // class_loader is NOT the defining loader, do a little more bookkeeping.
827 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
828 k->class_loader() != class_loader()) {
830 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
832 // Need to check for a PENDING_EXCEPTION again; check_constraints
833 // can throw but we may have to remove entry from the placeholder table below.
834 if (!HAS_PENDING_EXCEPTION) {
835 // Record dependency for non-parent delegation.
836 // This recording keeps the defining class loader of the klass (k) found
837 // from being unloaded while the initiating class loader is loaded
838 // even if the reference to the defining class loader is dropped
839 // before references to the initiating class loader.
840 loader_data->record_dependency(k(), THREAD);
841 }
843 if (!HAS_PENDING_EXCEPTION) {
844 { // Grabbing the Compile_lock prevents systemDictionary updates
845 // during compilations.
846 MutexLocker mu(Compile_lock, THREAD);
847 update_dictionary(d_index, d_hash, p_index, p_hash,
848 k, class_loader, THREAD);
849 }
851 if (JvmtiExport::should_post_class_load()) {
852 Thread *thread = THREAD;
853 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
854 JvmtiExport::post_class_load((JavaThread *) thread, k());
855 }
856 }
857 }
858 } // load_instance_class loop
860 if (load_instance_added == true) {
861 // clean up placeholder entries for LOAD_INSTANCE success or error
862 // This brackets the SystemDictionary updates for both defining
863 // and initiating loaders
864 MutexLocker mu(SystemDictionary_lock, THREAD);
865 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
866 SystemDictionary_lock->notify_all();
867 }
868 }
870 if (HAS_PENDING_EXCEPTION || k.is_null()) {
871 return NULL;
872 }
874 post_class_load_event(class_load_start_event, k, class_loader);
876 #ifdef ASSERT
877 {
878 ClassLoaderData* loader_data = k->class_loader_data();
879 MutexLocker mu(SystemDictionary_lock, THREAD);
880 Klass* kk = find_class(name, loader_data);
881 assert(kk == k(), "should be present in dictionary");
882 }
883 #endif
885 // return if the protection domain in NULL
886 if (protection_domain() == NULL) return k();
888 // Check the protection domain has the right access
889 {
890 MutexLocker mu(SystemDictionary_lock, THREAD);
891 // Note that we have an entry, and entries can be deleted only during GC,
892 // so we cannot allow GC to occur while we're holding this entry.
893 // We're using a No_Safepoint_Verifier to catch any place where we
894 // might potentially do a GC at all.
895 // Dictionary::do_unloading() asserts that classes in SD are only
896 // unloaded at a safepoint. Anonymous classes are not in SD.
897 No_Safepoint_Verifier nosafepoint;
898 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
899 loader_data,
900 protection_domain)) {
901 return k();
902 }
903 }
905 // Verify protection domain. If it fails an exception is thrown
906 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
908 return k();
909 }
912 // This routine does not lock the system dictionary.
913 //
914 // Since readers don't hold a lock, we must make sure that system
915 // dictionary entries are only removed at a safepoint (when only one
916 // thread is running), and are added to in a safe way (all links must
917 // be updated in an MT-safe manner).
918 //
919 // Callers should be aware that an entry could be added just after
920 // _dictionary->bucket(index) is read here, so the caller will not see
921 // the new entry.
923 Klass* SystemDictionary::find(Symbol* class_name,
924 Handle class_loader,
925 Handle protection_domain,
926 TRAPS) {
928 // UseNewReflection
929 // The result of this call should be consistent with the result
930 // of the call to resolve_instance_class_or_null().
931 // See evaluation 6790209 and 4474172 for more details.
932 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
933 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
935 if (loader_data == NULL) {
936 // If the ClassLoaderData has not been setup,
937 // then the class loader has no entries in the dictionary.
938 return NULL;
939 }
941 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
942 int d_index = dictionary()->hash_to_index(d_hash);
944 {
945 // Note that we have an entry, and entries can be deleted only during GC,
946 // so we cannot allow GC to occur while we're holding this entry.
947 // We're using a No_Safepoint_Verifier to catch any place where we
948 // might potentially do a GC at all.
949 // Dictionary::do_unloading() asserts that classes in SD are only
950 // unloaded at a safepoint. Anonymous classes are not in SD.
951 No_Safepoint_Verifier nosafepoint;
952 return dictionary()->find(d_index, d_hash, class_name, loader_data,
953 protection_domain, THREAD);
954 }
955 }
958 // Look for a loaded instance or array klass by name. Do not do any loading.
959 // return NULL in case of error.
960 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
961 Handle class_loader,
962 Handle protection_domain,
963 TRAPS) {
964 Klass* k = NULL;
965 assert(class_name != NULL, "class name must be non NULL");
967 if (FieldType::is_array(class_name)) {
968 // The name refers to an array. Parse the name.
969 // dimension and object_key in FieldArrayInfo are assigned as a
970 // side-effect of this call
971 FieldArrayInfo fd;
972 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
973 if (t != T_OBJECT) {
974 k = Universe::typeArrayKlassObj(t);
975 } else {
976 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
977 }
978 if (k != NULL) {
979 k = k->array_klass_or_null(fd.dimension());
980 }
981 } else {
982 k = find(class_name, class_loader, protection_domain, THREAD);
983 }
984 return k;
985 }
987 // Note: this method is much like resolve_from_stream, but
988 // updates no supplemental data structures.
989 // TODO consolidate the two methods with a helper routine?
990 Klass* SystemDictionary::parse_stream(Symbol* class_name,
991 Handle class_loader,
992 Handle protection_domain,
993 ClassFileStream* st,
994 KlassHandle host_klass,
995 GrowableArray<Handle>* cp_patches,
996 TRAPS) {
997 TempNewSymbol parsed_name = NULL;
999 EventClassLoad class_load_start_event;
1001 ClassLoaderData* loader_data;
1002 if (host_klass.not_null()) {
1003 // Create a new CLD for anonymous class, that uses the same class loader
1004 // as the host_klass
1005 assert(EnableInvokeDynamic, "");
1006 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1007 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1008 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1009 loader_data->record_dependency(host_klass(), CHECK_NULL);
1010 } else {
1011 loader_data = ClassLoaderData::class_loader_data(class_loader());
1012 }
1014 // Parse the stream. Note that we do this even though this klass might
1015 // already be present in the SystemDictionary, otherwise we would not
1016 // throw potential ClassFormatErrors.
1017 //
1018 // Note: "name" is updated.
1020 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1021 loader_data,
1022 protection_domain,
1023 host_klass,
1024 cp_patches,
1025 parsed_name,
1026 true,
1027 THREAD);
1030 if (host_klass.not_null() && k.not_null()) {
1031 assert(EnableInvokeDynamic, "");
1032 // If it's anonymous, initialize it now, since nobody else will.
1034 {
1035 MutexLocker mu_r(Compile_lock, THREAD);
1037 // Add to class hierarchy, initialize vtables, and do possible
1038 // deoptimizations.
1039 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1041 // But, do not add to system dictionary.
1043 // compiled code dependencies need to be validated anyway
1044 notice_modification();
1045 }
1047 // Rewrite and patch constant pool here.
1048 k->link_class(CHECK_NULL);
1049 if (cp_patches != NULL) {
1050 k->constants()->patch_resolved_references(cp_patches);
1051 }
1052 k->eager_initialize(CHECK_NULL);
1054 // notify jvmti
1055 if (JvmtiExport::should_post_class_load()) {
1056 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1057 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1058 }
1060 post_class_load_event(class_load_start_event, k, class_loader);
1061 }
1062 assert(host_klass.not_null() || cp_patches == NULL,
1063 "cp_patches only found with host_klass");
1065 return k();
1066 }
1068 // Add a klass to the system from a stream (called by jni_DefineClass and
1069 // JVM_DefineClass).
1070 // Note: class_name can be NULL. In that case we do not know the name of
1071 // the class until we have parsed the stream.
1073 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1074 Handle class_loader,
1075 Handle protection_domain,
1076 ClassFileStream* st,
1077 bool verify,
1078 TRAPS) {
1080 // Classloaders that support parallelism, e.g. bootstrap classloader,
1081 // or all classloaders with UnsyncloadClass do not acquire lock here
1082 bool DoObjectLock = true;
1083 if (is_parallelCapable(class_loader)) {
1084 DoObjectLock = false;
1085 }
1087 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1089 // Make sure we are synchronized on the class loader before we proceed
1090 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1091 check_loader_lock_contention(lockObject, THREAD);
1092 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1094 TempNewSymbol parsed_name = NULL;
1096 // Parse the stream. Note that we do this even though this klass might
1097 // already be present in the SystemDictionary, otherwise we would not
1098 // throw potential ClassFormatErrors.
1099 //
1100 // Note: "name" is updated.
1102 ClassFileParser parser(st);
1103 instanceKlassHandle k = parser.parseClassFile(class_name,
1104 loader_data,
1105 protection_domain,
1106 parsed_name,
1107 verify,
1108 THREAD);
1110 const char* pkg = "java/";
1111 size_t pkglen = strlen(pkg);
1112 if (!HAS_PENDING_EXCEPTION &&
1113 !class_loader.is_null() &&
1114 parsed_name != NULL &&
1115 parsed_name->utf8_length() >= (int)pkglen &&
1116 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1117 // It is illegal to define classes in the "java." package from
1118 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1119 ResourceMark rm(THREAD);
1120 char* name = parsed_name->as_C_string();
1121 char* index = strrchr(name, '/');
1122 assert(index != NULL, "must be");
1123 *index = '\0'; // chop to just the package name
1124 while ((index = strchr(name, '/')) != NULL) {
1125 *index = '.'; // replace '/' with '.' in package name
1126 }
1127 const char* fmt = "Prohibited package name: %s";
1128 size_t len = strlen(fmt) + strlen(name);
1129 char* message = NEW_RESOURCE_ARRAY(char, len);
1130 jio_snprintf(message, len, fmt, name);
1131 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1132 vmSymbols::java_lang_SecurityException(), message);
1133 }
1135 if (!HAS_PENDING_EXCEPTION) {
1136 assert(parsed_name != NULL, "Sanity");
1137 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1138 // Verification prevents us from creating names with dots in them, this
1139 // asserts that that's the case.
1140 assert(is_internal_format(parsed_name),
1141 "external class name format used internally");
1143 #if INCLUDE_JFR
1144 {
1145 InstanceKlass* ik = k();
1146 ON_KLASS_CREATION(ik, parser, THREAD);
1147 k = instanceKlassHandle(ik);
1148 }
1149 #endif
1151 // Add class just loaded
1152 // If a class loader supports parallel classloading handle parallel define requests
1153 // find_or_define_instance_class may return a different InstanceKlass
1154 if (is_parallelCapable(class_loader)) {
1155 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1156 } else {
1157 define_instance_class(k, THREAD);
1158 }
1159 }
1161 // Make sure we have an entry in the SystemDictionary on success
1162 debug_only( {
1163 if (!HAS_PENDING_EXCEPTION) {
1164 assert(parsed_name != NULL, "parsed_name is still null?");
1165 Symbol* h_name = k->name();
1166 ClassLoaderData *defining_loader_data = k->class_loader_data();
1168 MutexLocker mu(SystemDictionary_lock, THREAD);
1170 Klass* check = find_class(parsed_name, loader_data);
1171 assert(check == k(), "should be present in the dictionary");
1173 Klass* check2 = find_class(h_name, defining_loader_data);
1174 assert(check == check2, "name inconsistancy in SystemDictionary");
1175 }
1176 } );
1178 return k();
1179 }
1181 #if INCLUDE_CDS
1182 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1183 int number_of_entries) {
1184 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1185 "bad shared dictionary size.");
1186 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1187 }
1190 // If there is a shared dictionary, then find the entry for the
1191 // given shared system class, if any.
1193 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1194 if (shared_dictionary() != NULL) {
1195 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1196 int d_index = shared_dictionary()->hash_to_index(d_hash);
1198 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1199 } else {
1200 return NULL;
1201 }
1202 }
1205 // Load a class from the shared spaces (found through the shared system
1206 // dictionary). Force the superclass and all interfaces to be loaded.
1207 // Update the class definition to include sibling classes and no
1208 // subclasses (yet). [Classes in the shared space are not part of the
1209 // object hierarchy until loaded.]
1211 instanceKlassHandle SystemDictionary::load_shared_class(
1212 Symbol* class_name, Handle class_loader, TRAPS) {
1213 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1214 // Make sure we only return the boot class for the NULL classloader.
1215 if (ik.not_null() &&
1216 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1217 Handle protection_domain;
1218 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1219 }
1220 return instanceKlassHandle();
1221 }
1223 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1224 Handle class_loader,
1225 Handle protection_domain, TRAPS) {
1226 if (ik.not_null()) {
1227 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1228 Symbol* class_name = ik->name();
1230 // Found the class, now load the superclass and interfaces. If they
1231 // are shared, add them to the main system dictionary and reset
1232 // their hierarchy references (supers, subs, and interfaces).
1234 if (ik->super() != NULL) {
1235 Symbol* cn = ik->super()->name();
1236 Klass *s = resolve_super_or_fail(class_name, cn,
1237 class_loader, protection_domain, true, CHECK_(nh));
1238 if (s != ik->super()) {
1239 // The dynamically resolved super class is not the same as the one we used during dump time,
1240 // so we cannot use ik.
1241 return nh;
1242 }
1243 }
1245 Array<Klass*>* interfaces = ik->local_interfaces();
1246 int num_interfaces = interfaces->length();
1247 for (int index = 0; index < num_interfaces; index++) {
1248 Klass* k = interfaces->at(index);
1250 // Note: can not use InstanceKlass::cast here because
1251 // interfaces' InstanceKlass's C++ vtbls haven't been
1252 // reinitialized yet (they will be once the interface classes
1253 // are loaded)
1254 Symbol* name = k->name();
1255 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1256 if (k != i) {
1257 // The dynamically resolved interface class is not the same as the one we used during dump time,
1258 // so we cannot use ik.
1259 return nh;
1260 }
1261 }
1263 // Adjust methods to recover missing data. They need addresses for
1264 // interpreter entry points and their default native method address
1265 // must be reset.
1267 // Updating methods must be done under a lock so multiple
1268 // threads don't update these in parallel
1269 //
1270 // Shared classes are all currently loaded by either the bootstrap or
1271 // internal parallel class loaders, so this will never cause a deadlock
1272 // on a custom class loader lock.
1274 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1275 {
1276 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1277 check_loader_lock_contention(lockObject, THREAD);
1278 ObjectLocker ol(lockObject, THREAD, true);
1279 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1280 }
1282 if (TraceClassLoading) {
1283 ResourceMark rm;
1284 tty->print("[Loaded %s", ik->external_name());
1285 tty->print(" from shared objects file");
1286 if (class_loader.not_null()) {
1287 tty->print(" by %s", loader_data->loader_name());
1288 }
1289 tty->print_cr("]");
1290 }
1292 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1293 // Only dump the classes that can be stored into CDS archive
1294 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1295 ResourceMark rm(THREAD);
1296 classlist_file->print_cr("%s", ik->name()->as_C_string());
1297 classlist_file->flush();
1298 }
1299 }
1301 // notify a class loaded from shared object
1302 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1303 true /* shared class */);
1304 }
1305 return ik;
1306 }
1307 #endif // INCLUDE_CDS
1309 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1310 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1311 if (class_loader.is_null()) {
1313 // Search the shared system dictionary for classes preloaded into the
1314 // shared spaces.
1315 instanceKlassHandle k;
1316 {
1317 #if INCLUDE_CDS
1318 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1319 k = load_shared_class(class_name, class_loader, THREAD);
1320 #endif
1321 }
1323 if (k.is_null()) {
1324 // Use VM class loader
1325 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1326 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1327 }
1329 // find_or_define_instance_class may return a different InstanceKlass
1330 if (!k.is_null()) {
1331 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1332 }
1333 return k;
1334 } else {
1335 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1336 ResourceMark rm(THREAD);
1338 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1339 JavaThread* jt = (JavaThread*) THREAD;
1341 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1342 ClassLoader::perf_app_classload_selftime(),
1343 ClassLoader::perf_app_classload_count(),
1344 jt->get_thread_stat()->perf_recursion_counts_addr(),
1345 jt->get_thread_stat()->perf_timers_addr(),
1346 PerfClassTraceTime::CLASS_LOAD);
1348 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1349 // Translate to external class name format, i.e., convert '/' chars to '.'
1350 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1352 JavaValue result(T_OBJECT);
1354 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1356 // Call public unsynchronized loadClass(String) directly for all class loaders
1357 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1358 // acquire a class-name based lock rather than the class loader object lock.
1359 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1360 // so the call to loadClassInternal() was not required.
1361 //
1362 // UnsyncloadClass flag means both call loadClass(String) and do
1363 // not acquire the class loader lock even for class loaders that are
1364 // not parallelCapable. This was a risky transitional
1365 // flag for diagnostic purposes only. It is risky to call
1366 // custom class loaders without synchronization.
1367 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1368 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1369 // Do NOT assume this will be supported in future releases.
1370 //
1371 // Added MustCallLoadClassInternal in case we discover in the field
1372 // a customer that counts on this call
1373 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1374 JavaCalls::call_special(&result,
1375 class_loader,
1376 spec_klass,
1377 vmSymbols::loadClassInternal_name(),
1378 vmSymbols::string_class_signature(),
1379 string,
1380 CHECK_(nh));
1381 } else {
1382 JavaCalls::call_virtual(&result,
1383 class_loader,
1384 spec_klass,
1385 vmSymbols::loadClass_name(),
1386 vmSymbols::string_class_signature(),
1387 string,
1388 CHECK_(nh));
1389 }
1391 assert(result.get_type() == T_OBJECT, "just checking");
1392 oop obj = (oop) result.get_jobject();
1394 // Primitive classes return null since forName() can not be
1395 // used to obtain any of the Class objects representing primitives or void
1396 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1397 instanceKlassHandle k =
1398 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1399 // For user defined Java class loaders, check that the name returned is
1400 // the same as that requested. This check is done for the bootstrap
1401 // loader when parsing the class file.
1402 if (class_name == k->name()) {
1403 return k;
1404 }
1405 }
1406 // Class is not found or has the wrong name, return NULL
1407 return nh;
1408 }
1409 }
1411 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1412 EventClassDefine event;
1413 if (event.should_commit()) {
1414 event.set_definedClass(k);
1415 event.set_definingClassLoader(def_cld);
1416 event.commit();
1417 }
1418 }
1420 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1422 ClassLoaderData* loader_data = k->class_loader_data();
1423 Handle class_loader_h(THREAD, loader_data->class_loader());
1425 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1427 // for bootstrap and other parallel classloaders don't acquire lock,
1428 // use placeholder token
1429 // If a parallelCapable class loader calls define_instance_class instead of
1430 // find_or_define_instance_class to get here, we have a timing
1431 // hole with systemDictionary updates and check_constraints
1432 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1433 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1434 compute_loader_lock_object(class_loader_h, THREAD)),
1435 "define called without lock");
1436 }
1438 // Check class-loading constraints. Throw exception if violation is detected.
1439 // Grabs and releases SystemDictionary_lock
1440 // The check_constraints/find_class call and update_dictionary sequence
1441 // must be "atomic" for a specific class/classloader pair so we never
1442 // define two different instanceKlasses for that class/classloader pair.
1443 // Existing classloaders will call define_instance_class with the
1444 // classloader lock held
1445 // Parallel classloaders will call find_or_define_instance_class
1446 // which will require a token to perform the define class
1447 Symbol* name_h = k->name();
1448 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1449 int d_index = dictionary()->hash_to_index(d_hash);
1450 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1452 // Register class just loaded with class loader (placed in Vector)
1453 // Note we do this before updating the dictionary, as this can
1454 // fail with an OutOfMemoryError (if it does, we will *not* put this
1455 // class in the dictionary and will not update the class hierarchy).
1456 // JVMTI FollowReferences needs to find the classes this way.
1457 if (k->class_loader() != NULL) {
1458 methodHandle m(THREAD, Universe::loader_addClass_method());
1459 JavaValue result(T_VOID);
1460 JavaCallArguments args(class_loader_h);
1461 args.push_oop(Handle(THREAD, k->java_mirror()));
1462 JavaCalls::call(&result, m, &args, CHECK);
1463 }
1465 // Add the new class. We need recompile lock during update of CHA.
1466 {
1467 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1468 int p_index = placeholders()->hash_to_index(p_hash);
1470 MutexLocker mu_r(Compile_lock, THREAD);
1472 // Add to class hierarchy, initialize vtables, and do possible
1473 // deoptimizations.
1474 add_to_hierarchy(k, CHECK); // No exception, but can block
1476 // Add to systemDictionary - so other classes can see it.
1477 // Grabs and releases SystemDictionary_lock
1478 update_dictionary(d_index, d_hash, p_index, p_hash,
1479 k, class_loader_h, THREAD);
1480 }
1481 k->eager_initialize(THREAD);
1483 // notify jvmti
1484 if (JvmtiExport::should_post_class_load()) {
1485 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1486 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1488 }
1490 post_class_define_event(k(), loader_data);
1491 }
1493 // Support parallel classloading
1494 // All parallel class loaders, including bootstrap classloader
1495 // lock a placeholder entry for this class/class_loader pair
1496 // to allow parallel defines of different classes for this class loader
1497 // With AllowParallelDefine flag==true, in case they do not synchronize around
1498 // FindLoadedClass/DefineClass, calls, we check for parallel
1499 // loading for them, wait if a defineClass is in progress
1500 // and return the initial requestor's results
1501 // This flag does not apply to the bootstrap classloader.
1502 // With AllowParallelDefine flag==false, call through to define_instance_class
1503 // which will throw LinkageError: duplicate class definition.
1504 // False is the requested default.
1505 // For better performance, the class loaders should synchronize
1506 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1507 // potentially waste time reading and parsing the bytestream.
1508 // Note: VM callers should ensure consistency of k/class_name,class_loader
1509 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1511 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1512 Symbol* name_h = k->name(); // passed in class_name may be null
1513 ClassLoaderData* loader_data = class_loader_data(class_loader);
1515 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1516 int d_index = dictionary()->hash_to_index(d_hash);
1518 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1519 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1520 int p_index = placeholders()->hash_to_index(p_hash);
1521 PlaceholderEntry* probe;
1523 {
1524 MutexLocker mu(SystemDictionary_lock, THREAD);
1525 // First check if class already defined
1526 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1527 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1528 if (check != NULL) {
1529 return(instanceKlassHandle(THREAD, check));
1530 }
1531 }
1533 // Acquire define token for this class/classloader
1534 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1535 // Wait if another thread defining in parallel
1536 // All threads wait - even those that will throw duplicate class: otherwise
1537 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1538 // if other thread has not finished updating dictionary
1539 while (probe->definer() != NULL) {
1540 SystemDictionary_lock->wait();
1541 }
1542 // Only special cases allow parallel defines and can use other thread's results
1543 // Other cases fall through, and may run into duplicate defines
1544 // caught by finding an entry in the SystemDictionary
1545 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1546 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1547 SystemDictionary_lock->notify_all();
1548 #ifdef ASSERT
1549 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1550 assert(check != NULL, "definer missed recording success");
1551 #endif
1552 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1553 } else {
1554 // This thread will define the class (even if earlier thread tried and had an error)
1555 probe->set_definer(THREAD);
1556 }
1557 }
1559 define_instance_class(k, THREAD);
1561 Handle linkage_exception = Handle(); // null handle
1563 // definer must notify any waiting threads
1564 {
1565 MutexLocker mu(SystemDictionary_lock, THREAD);
1566 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1567 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1568 if (probe != NULL) {
1569 if (HAS_PENDING_EXCEPTION) {
1570 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1571 CLEAR_PENDING_EXCEPTION;
1572 } else {
1573 probe->set_instance_klass(k());
1574 }
1575 probe->set_definer(NULL);
1576 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1577 SystemDictionary_lock->notify_all();
1578 }
1579 }
1581 // Can't throw exception while holding lock due to rank ordering
1582 if (linkage_exception() != NULL) {
1583 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1584 }
1586 return k;
1587 }
1588 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1589 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1590 if (class_loader.is_null()) {
1591 return Handle(THREAD, _system_loader_lock_obj);
1592 } else {
1593 return class_loader;
1594 }
1595 }
1597 // This method is added to check how often we have to wait to grab loader
1598 // lock. The results are being recorded in the performance counters defined in
1599 // ClassLoader::_sync_systemLoaderLockContentionRate and
1600 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1601 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1602 if (!UsePerfData) {
1603 return;
1604 }
1606 assert(!loader_lock.is_null(), "NULL lock object");
1608 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1609 == ObjectSynchronizer::owner_other) {
1610 // contention will likely happen, so increment the corresponding
1611 // contention counter.
1612 if (loader_lock() == _system_loader_lock_obj) {
1613 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1614 } else {
1615 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1616 }
1617 }
1618 }
1620 // ----------------------------------------------------------------------------
1621 // Lookup
1623 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1624 Symbol* class_name,
1625 ClassLoaderData* loader_data) {
1626 assert_locked_or_safepoint(SystemDictionary_lock);
1627 assert (index == dictionary()->index_for(class_name, loader_data),
1628 "incorrect index?");
1630 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1631 return k;
1632 }
1635 // Basic find on classes in the midst of being loaded
1636 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1637 ClassLoaderData* loader_data) {
1638 assert_locked_or_safepoint(SystemDictionary_lock);
1639 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1640 int p_index = placeholders()->hash_to_index(p_hash);
1641 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1642 }
1645 // Used for assertions and verification only
1646 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1647 #ifndef ASSERT
1648 guarantee(VerifyBeforeGC ||
1649 VerifyDuringGC ||
1650 VerifyBeforeExit ||
1651 VerifyDuringStartup ||
1652 VerifyAfterGC, "too expensive");
1653 #endif
1654 assert_locked_or_safepoint(SystemDictionary_lock);
1656 // First look in the loaded class array
1657 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1658 int d_index = dictionary()->hash_to_index(d_hash);
1659 return find_class(d_index, d_hash, class_name, loader_data);
1660 }
1663 // Get the next class in the diictionary.
1664 Klass* SystemDictionary::try_get_next_class() {
1665 return dictionary()->try_get_next_class();
1666 }
1669 // ----------------------------------------------------------------------------
1670 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1671 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1672 // before a new class is used.
1674 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1675 assert(k.not_null(), "just checking");
1676 assert_locked_or_safepoint(Compile_lock);
1678 // Link into hierachy. Make sure the vtables are initialized before linking into
1679 k->append_to_sibling_list(); // add to superklass/sibling list
1680 k->process_interfaces(THREAD); // handle all "implements" declarations
1681 k->set_init_state(InstanceKlass::loaded);
1682 // Now flush all code that depended on old class hierarchy.
1683 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1684 // Also, first reinitialize vtable because it may have gotten out of synch
1685 // while the new class wasn't connected to the class hierarchy.
1686 Universe::flush_dependents_on(k);
1687 }
1689 // ----------------------------------------------------------------------------
1690 // GC support
1692 // Following roots during mark-sweep is separated in two phases.
1693 //
1694 // The first phase follows preloaded classes and all other system
1695 // classes, since these will never get unloaded anyway.
1696 //
1697 // The second phase removes (unloads) unreachable classes from the
1698 // system dictionary and follows the remaining classes' contents.
1700 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1701 roots_oops_do(blk, NULL);
1702 }
1704 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1705 // Follow all system classes and temporary placeholders in dictionary
1706 dictionary()->always_strong_classes_do(closure);
1708 // Placeholders. These represent classes we're actively loading.
1709 placeholders()->classes_do(closure);
1710 }
1712 // Calculate a "good" systemdictionary size based
1713 // on predicted or current loaded classes count
1714 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1715 int newsize = _old_default_sdsize;
1716 if ((classcount > 0) && !DumpSharedSpaces) {
1717 int desiredsize = classcount/_average_depth_goal;
1718 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1719 newsize = _primelist[++_sdgeneration]) {
1720 if (desiredsize <= newsize) {
1721 break;
1722 }
1723 }
1724 }
1725 return newsize;
1726 }
1728 #ifdef ASSERT
1729 class VerifySDReachableAndLiveClosure : public OopClosure {
1730 private:
1731 BoolObjectClosure* _is_alive;
1733 template <class T> void do_oop_work(T* p) {
1734 oop obj = oopDesc::load_decode_heap_oop(p);
1735 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1736 }
1738 public:
1739 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1741 virtual void do_oop(oop* p) { do_oop_work(p); }
1742 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1743 };
1744 #endif
1746 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1747 // Note: anonymous classes are not in the SD.
1748 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1749 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1750 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1751 if (unloading_occurred) {
1752 dictionary()->do_unloading();
1753 constraints()->purge_loader_constraints();
1754 resolution_errors()->purge_resolution_errors();
1755 }
1756 // Oops referenced by the system dictionary may get unreachable independently
1757 // of the class loader (eg. cached protection domain oops). So we need to
1758 // explicitly unlink them here instead of in Dictionary::do_unloading.
1759 dictionary()->unlink(is_alive);
1760 #ifdef ASSERT
1761 VerifySDReachableAndLiveClosure cl(is_alive);
1762 dictionary()->oops_do(&cl);
1763 #endif
1764 return unloading_occurred;
1765 }
1767 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1768 strong->do_oop(&_java_system_loader);
1769 strong->do_oop(&_system_loader_lock_obj);
1770 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1772 // Adjust dictionary
1773 dictionary()->roots_oops_do(strong, weak);
1775 // Visit extra methods
1776 invoke_method_table()->oops_do(strong);
1777 }
1779 void SystemDictionary::oops_do(OopClosure* f) {
1780 f->do_oop(&_java_system_loader);
1781 f->do_oop(&_system_loader_lock_obj);
1782 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1784 // Adjust dictionary
1785 dictionary()->oops_do(f);
1787 // Visit extra methods
1788 invoke_method_table()->oops_do(f);
1789 }
1791 // Extended Class redefinition support.
1792 // If one of these classes is replaced, we need to replace it in these places.
1793 // KlassClosure::do_klass should take the address of a class but we can
1794 // change that later.
1795 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1796 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1797 f->do_klass(_well_known_klasses[k]);
1798 }
1800 {
1801 for (int i = 0; i < T_VOID+1; i++) {
1802 if (_box_klasses[i] != NULL) {
1803 assert(i >= T_BOOLEAN, "checking");
1804 f->do_klass(_box_klasses[i]);
1805 }
1806 }
1807 }
1809 FilteredFieldsMap::classes_do(f);
1810 }
1812 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1813 f->do_klass(_abstract_ownable_synchronizer_klass);
1814 }
1816 // Just the classes from defining class loaders
1817 // Don't iterate over placeholders
1818 void SystemDictionary::classes_do(void f(Klass*)) {
1819 dictionary()->classes_do(f);
1820 }
1822 // Added for initialize_itable_for_klass
1823 // Just the classes from defining class loaders
1824 // Don't iterate over placeholders
1825 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1826 dictionary()->classes_do(f, CHECK);
1827 }
1829 // All classes, and their class loaders
1830 // Don't iterate over placeholders
1831 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1832 dictionary()->classes_do(f);
1833 }
1835 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1836 placeholders()->entries_do(f);
1837 }
1839 void SystemDictionary::methods_do(void f(Method*)) {
1840 dictionary()->methods_do(f);
1841 invoke_method_table()->methods_do(f);
1842 }
1844 void SystemDictionary::remove_classes_in_error_state() {
1845 dictionary()->remove_classes_in_error_state();
1846 }
1848 // ----------------------------------------------------------------------------
1849 // Lazily load klasses
1851 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1852 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1854 // if multiple threads calling this function, only one thread will load
1855 // the class. The other threads will find the loaded version once the
1856 // class is loaded.
1857 Klass* aos = _abstract_ownable_synchronizer_klass;
1858 if (aos == NULL) {
1859 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1860 // Force a fence to prevent any read before the write completes
1861 OrderAccess::fence();
1862 _abstract_ownable_synchronizer_klass = k;
1863 }
1864 }
1866 // ----------------------------------------------------------------------------
1867 // Initialization
1869 void SystemDictionary::initialize(TRAPS) {
1870 // Allocate arrays
1871 assert(dictionary() == NULL,
1872 "SystemDictionary should only be initialized once");
1873 _sdgeneration = 0;
1874 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1875 _placeholders = new PlaceholderTable(_nof_buckets);
1876 _number_of_modifications = 0;
1877 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1878 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1879 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1881 // Allocate private object used as system class loader lock
1882 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1883 // Initialize basic classes
1884 initialize_preloaded_classes(CHECK);
1885 }
1887 // Compact table of directions on the initialization of klasses:
1888 static const short wk_init_info[] = {
1889 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1890 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1891 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1892 | (int)SystemDictionary::option ),
1893 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1894 #undef WK_KLASS_INIT_INFO
1895 0
1896 };
1898 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1899 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1900 int info = wk_init_info[id - FIRST_WKID];
1901 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1902 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1903 Klass** klassp = &_well_known_klasses[id];
1904 bool must_load = (init_opt < SystemDictionary::Opt);
1905 if ((*klassp) == NULL) {
1906 if (must_load) {
1907 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1908 } else {
1909 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1910 }
1911 }
1912 return ((*klassp) != NULL);
1913 }
1915 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1916 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1917 for (int id = (int)start_id; id < (int)limit_id; id++) {
1918 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1919 int info = wk_init_info[id - FIRST_WKID];
1920 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1921 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1923 initialize_wk_klass((WKID)id, opt, CHECK);
1924 }
1926 // move the starting value forward to the limit:
1927 start_id = limit_id;
1928 }
1930 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1931 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1932 // Preload commonly used klasses
1933 WKID scan = FIRST_WKID;
1934 // first do Object, then String, Class
1935 if (UseSharedSpaces) {
1936 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1937 // Initialize the constant pool for the Object_class
1938 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1939 ik->constants()->restore_unshareable_info(CHECK);
1940 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1941 } else {
1942 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1943 }
1945 // Calculate offsets for String and Class classes since they are loaded and
1946 // can be used after this point.
1947 java_lang_String::compute_offsets();
1948 java_lang_Class::compute_offsets();
1950 // Fixup mirrors for classes loaded before java.lang.Class.
1951 // These calls iterate over the objects currently in the perm gen
1952 // so calling them at this point is matters (not before when there
1953 // are fewer objects and not later after there are more objects
1954 // in the perm gen.
1955 Universe::initialize_basic_type_mirrors(CHECK);
1956 Universe::fixup_mirrors(CHECK);
1958 // do a bunch more:
1959 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1961 // Preload ref klasses and set reference types
1962 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1963 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1965 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1966 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1967 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1968 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1969 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1970 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
1972 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
1974 // JSR 292 classes
1975 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1976 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1977 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1978 if (EnableInvokeDynamic) {
1979 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1980 } else {
1981 // Skip the JSR 292 classes, if not enabled.
1982 scan = WKID(jsr292_group_end + 1);
1983 }
1985 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1987 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1988 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1989 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1990 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1991 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1992 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1993 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1994 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1995 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1996 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1998 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1999 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2000 _has_loadClassInternal = (method != NULL);
2001 }
2002 { // Compute whether we should use checkPackageAccess or NOT
2003 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2004 _has_checkPackageAccess = (method != NULL);
2005 }
2006 }
2008 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2009 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2010 BasicType SystemDictionary::box_klass_type(Klass* k) {
2011 assert(k != NULL, "");
2012 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2013 if (_box_klasses[i] == k)
2014 return (BasicType)i;
2015 }
2016 return T_OBJECT;
2017 }
2019 // Constraints on class loaders. The details of the algorithm can be
2020 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2021 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2022 // that the system dictionary needs to maintain a set of contraints that
2023 // must be satisfied by all classes in the dictionary.
2024 // if defining is true, then LinkageError if already in systemDictionary
2025 // if initiating loader, then ok if InstanceKlass matches existing entry
2027 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2028 instanceKlassHandle k,
2029 Handle class_loader, bool defining,
2030 TRAPS) {
2031 const char *linkage_error = NULL;
2032 {
2033 Symbol* name = k->name();
2034 ClassLoaderData *loader_data = class_loader_data(class_loader);
2036 MutexLocker mu(SystemDictionary_lock, THREAD);
2038 Klass* check = find_class(d_index, d_hash, name, loader_data);
2039 if (check != (Klass*)NULL) {
2040 // if different InstanceKlass - duplicate class definition,
2041 // else - ok, class loaded by a different thread in parallel,
2042 // we should only have found it if it was done loading and ok to use
2043 // system dictionary only holds instance classes, placeholders
2044 // also holds array classes
2046 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2047 if ((defining == true) || (k() != check)) {
2048 linkage_error = "loader (instance of %s): attempted duplicate class "
2049 "definition for name: \"%s\"";
2050 } else {
2051 return;
2052 }
2053 }
2055 #ifdef ASSERT
2056 Symbol* ph_check = find_placeholder(name, loader_data);
2057 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2058 #endif
2060 if (linkage_error == NULL) {
2061 if (constraints()->check_or_update(k, class_loader, name) == false) {
2062 linkage_error = "loader constraint violation: loader (instance of %s)"
2063 " previously initiated loading for a different type with name \"%s\"";
2064 }
2065 }
2066 }
2068 // Throw error now if needed (cannot throw while holding
2069 // SystemDictionary_lock because of rank ordering)
2071 if (linkage_error) {
2072 ResourceMark rm(THREAD);
2073 const char* class_loader_name = loader_name(class_loader());
2074 char* type_name = k->name()->as_C_string();
2075 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2076 strlen(type_name);
2077 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2078 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2079 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2080 }
2081 }
2084 // Update system dictionary - done after check_constraint and add_to_hierachy
2085 // have been called.
2086 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2087 int p_index, unsigned int p_hash,
2088 instanceKlassHandle k,
2089 Handle class_loader,
2090 TRAPS) {
2091 // Compile_lock prevents systemDictionary updates during compilations
2092 assert_locked_or_safepoint(Compile_lock);
2093 Symbol* name = k->name();
2094 ClassLoaderData *loader_data = class_loader_data(class_loader);
2096 {
2097 MutexLocker mu1(SystemDictionary_lock, THREAD);
2099 // See whether biased locking is enabled and if so set it for this
2100 // klass.
2101 // Note that this must be done past the last potential blocking
2102 // point / safepoint. We enable biased locking lazily using a
2103 // VM_Operation to iterate the SystemDictionary and installing the
2104 // biasable mark word into each InstanceKlass's prototype header.
2105 // To avoid race conditions where we accidentally miss enabling the
2106 // optimization for one class in the process of being added to the
2107 // dictionary, we must not safepoint after the test of
2108 // BiasedLocking::enabled().
2109 if (UseBiasedLocking && BiasedLocking::enabled()) {
2110 // Set biased locking bit for all loaded classes; it will be
2111 // cleared if revocation occurs too often for this type
2112 // NOTE that we must only do this when the class is initally
2113 // defined, not each time it is referenced from a new class loader
2114 if (k->class_loader() == class_loader()) {
2115 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2116 }
2117 }
2119 // Make a new system dictionary entry.
2120 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2121 if (sd_check == NULL) {
2122 dictionary()->add_klass(name, loader_data, k);
2123 notice_modification();
2124 }
2125 #ifdef ASSERT
2126 sd_check = find_class(d_index, d_hash, name, loader_data);
2127 assert (sd_check != NULL, "should have entry in system dictionary");
2128 // Note: there may be a placeholder entry: for circularity testing
2129 // or for parallel defines
2130 #endif
2131 SystemDictionary_lock->notify_all();
2132 }
2133 }
2136 // Try to find a class name using the loader constraints. The
2137 // loader constraints might know about a class that isn't fully loaded
2138 // yet and these will be ignored.
2139 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2140 Symbol* class_name, Handle class_loader, TRAPS) {
2142 // First see if it has been loaded directly.
2143 // Force the protection domain to be null. (This removes protection checks.)
2144 Handle no_protection_domain;
2145 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2146 no_protection_domain, CHECK_NULL);
2147 if (klass != NULL)
2148 return klass;
2150 // Now look to see if it has been loaded elsewhere, and is subject to
2151 // a loader constraint that would require this loader to return the
2152 // klass that is already loaded.
2153 if (FieldType::is_array(class_name)) {
2154 // For array classes, their Klass*s are not kept in the
2155 // constraint table. The element Klass*s are.
2156 FieldArrayInfo fd;
2157 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2158 if (t != T_OBJECT) {
2159 klass = Universe::typeArrayKlassObj(t);
2160 } else {
2161 MutexLocker mu(SystemDictionary_lock, THREAD);
2162 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2163 }
2164 // If element class already loaded, allocate array klass
2165 if (klass != NULL) {
2166 klass = klass->array_klass_or_null(fd.dimension());
2167 }
2168 } else {
2169 MutexLocker mu(SystemDictionary_lock, THREAD);
2170 // Non-array classes are easy: simply check the constraint table.
2171 klass = constraints()->find_constrained_klass(class_name, class_loader);
2172 }
2174 return klass;
2175 }
2178 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2179 Handle class_loader1,
2180 Handle class_loader2,
2181 Thread* THREAD) {
2182 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2183 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2185 Symbol* constraint_name = NULL;
2186 if (!FieldType::is_array(class_name)) {
2187 constraint_name = class_name;
2188 } else {
2189 // For array classes, their Klass*s are not kept in the
2190 // constraint table. The element classes are.
2191 FieldArrayInfo fd;
2192 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2193 // primitive types always pass
2194 if (t != T_OBJECT) {
2195 return true;
2196 } else {
2197 constraint_name = fd.object_key();
2198 }
2199 }
2200 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2201 int d_index1 = dictionary()->hash_to_index(d_hash1);
2203 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2204 int d_index2 = dictionary()->hash_to_index(d_hash2);
2205 {
2206 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2208 // Better never do a GC while we're holding these oops
2209 No_Safepoint_Verifier nosafepoint;
2211 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2212 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2213 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2214 klass2, class_loader2);
2215 }
2216 }
2218 // Add entry to resolution error table to record the error when the first
2219 // attempt to resolve a reference to a class has failed.
2220 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2221 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2222 int index = resolution_errors()->hash_to_index(hash);
2223 {
2224 MutexLocker ml(SystemDictionary_lock, Thread::current());
2225 resolution_errors()->add_entry(index, hash, pool, which, error);
2226 }
2227 }
2229 // Delete a resolution error for RedefineClasses for a constant pool is going away
2230 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2231 resolution_errors()->delete_entry(pool);
2232 }
2234 // Lookup resolution error table. Returns error if found, otherwise NULL.
2235 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2236 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2237 int index = resolution_errors()->hash_to_index(hash);
2238 {
2239 MutexLocker ml(SystemDictionary_lock, Thread::current());
2240 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2241 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2242 }
2243 }
2246 // Signature constraints ensure that callers and callees agree about
2247 // the meaning of type names in their signatures. This routine is the
2248 // intake for constraints. It collects them from several places:
2249 //
2250 // * LinkResolver::resolve_method (if check_access is true) requires
2251 // that the resolving class (the caller) and the defining class of
2252 // the resolved method (the callee) agree on each type in the
2253 // method's signature.
2254 //
2255 // * LinkResolver::resolve_interface_method performs exactly the same
2256 // checks.
2257 //
2258 // * LinkResolver::resolve_field requires that the constant pool
2259 // attempting to link to a field agree with the field's defining
2260 // class about the type of the field signature.
2261 //
2262 // * klassVtable::initialize_vtable requires that, when a class
2263 // overrides a vtable entry allocated by a superclass, that the
2264 // overriding method (i.e., the callee) agree with the superclass
2265 // on each type in the method's signature.
2266 //
2267 // * klassItable::initialize_itable requires that, when a class fills
2268 // in its itables, for each non-abstract method installed in an
2269 // itable, the method (i.e., the callee) agree with the interface
2270 // on each type in the method's signature.
2271 //
2272 // All those methods have a boolean (check_access, checkconstraints)
2273 // which turns off the checks. This is used from specialized contexts
2274 // such as bootstrapping, dumping, and debugging.
2275 //
2276 // No direct constraint is placed between the class and its
2277 // supertypes. Constraints are only placed along linked relations
2278 // between callers and callees. When a method overrides or implements
2279 // an abstract method in a supertype (superclass or interface), the
2280 // constraints are placed as if the supertype were the caller to the
2281 // overriding method. (This works well, since callers to the
2282 // supertype have already established agreement between themselves and
2283 // the supertype.) As a result of all this, a class can disagree with
2284 // its supertype about the meaning of a type name, as long as that
2285 // class neither calls a relevant method of the supertype, nor is
2286 // called (perhaps via an override) from the supertype.
2287 //
2288 //
2289 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2290 //
2291 // Make sure all class components (including arrays) in the given
2292 // signature will be resolved to the same class in both loaders.
2293 // Returns the name of the type that failed a loader constraint check, or
2294 // NULL if no constraint failed. No exception except OOME is thrown.
2295 // Arrays are not added to the loader constraint table, their elements are.
2296 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2297 Handle loader1, Handle loader2,
2298 bool is_method, TRAPS) {
2299 // Nothing to do if loaders are the same.
2300 if (loader1() == loader2()) {
2301 return NULL;
2302 }
2304 SignatureStream sig_strm(signature, is_method);
2305 while (!sig_strm.is_done()) {
2306 if (sig_strm.is_object()) {
2307 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2308 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2309 return sig;
2310 }
2311 }
2312 sig_strm.next();
2313 }
2314 return NULL;
2315 }
2318 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2319 Symbol* signature,
2320 TRAPS) {
2321 methodHandle empty;
2322 assert(EnableInvokeDynamic, "");
2323 assert(MethodHandles::is_signature_polymorphic(iid) &&
2324 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2325 iid != vmIntrinsics::_invokeGeneric,
2326 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2328 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2329 int index = invoke_method_table()->hash_to_index(hash);
2330 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2331 methodHandle m;
2332 if (spe == NULL || spe->method() == NULL) {
2333 spe = NULL;
2334 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2335 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2336 if (!Arguments::is_interpreter_only()) {
2337 // Generate a compiled form of the MH intrinsic.
2338 AdapterHandlerLibrary::create_native_wrapper(m);
2339 // Check if have the compiled code.
2340 if (!m->has_compiled_code()) {
2341 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2342 "out of space in CodeCache for method handle intrinsic", empty);
2343 }
2344 }
2345 // Now grab the lock. We might have to throw away the new method,
2346 // if a racing thread has managed to install one at the same time.
2347 {
2348 MutexLocker ml(SystemDictionary_lock, THREAD);
2349 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2350 if (spe == NULL)
2351 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2352 if (spe->method() == NULL)
2353 spe->set_method(m());
2354 }
2355 }
2357 assert(spe != NULL && spe->method() != NULL, "");
2358 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2359 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2360 "MH intrinsic invariant");
2361 return spe->method();
2362 }
2364 // Helper for unpacking the return value from linkMethod and linkCallSite.
2365 static methodHandle unpack_method_and_appendix(Handle mname,
2366 KlassHandle accessing_klass,
2367 objArrayHandle appendix_box,
2368 Handle* appendix_result,
2369 TRAPS) {
2370 methodHandle empty;
2371 if (mname.not_null()) {
2372 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2373 if (vmtarget != NULL && vmtarget->is_method()) {
2374 Method* m = (Method*)vmtarget;
2375 oop appendix = appendix_box->obj_at(0);
2376 if (TraceMethodHandles) {
2377 #ifndef PRODUCT
2378 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2379 m->print();
2380 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2381 tty->cr();
2382 #endif //PRODUCT
2383 }
2384 (*appendix_result) = Handle(THREAD, appendix);
2385 // the target is stored in the cpCache and if a reference to this
2386 // MethodName is dropped we need a way to make sure the
2387 // class_loader containing this method is kept alive.
2388 // FIXME: the appendix might also preserve this dependency.
2389 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2390 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2391 return methodHandle(THREAD, m);
2392 }
2393 }
2394 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2395 return empty;
2396 }
2398 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2399 Symbol* signature,
2400 KlassHandle accessing_klass,
2401 Handle *appendix_result,
2402 Handle *method_type_result,
2403 TRAPS) {
2404 methodHandle empty;
2405 assert(EnableInvokeDynamic, "");
2406 assert(!THREAD->is_Compiler_thread(), "");
2407 Handle method_type =
2408 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2410 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2411 int ref_kind = JVM_REF_invokeVirtual;
2412 Handle name_str = StringTable::intern(name, CHECK_(empty));
2413 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2414 assert(appendix_box->obj_at(0) == NULL, "");
2416 // This should not happen. JDK code should take care of that.
2417 if (accessing_klass.is_null() || method_type.is_null()) {
2418 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2419 }
2421 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2422 JavaCallArguments args;
2423 args.push_oop(accessing_klass()->java_mirror());
2424 args.push_int(ref_kind);
2425 args.push_oop(mh_klass()->java_mirror());
2426 args.push_oop(name_str());
2427 args.push_oop(method_type());
2428 args.push_oop(appendix_box());
2429 JavaValue result(T_OBJECT);
2430 JavaCalls::call_static(&result,
2431 SystemDictionary::MethodHandleNatives_klass(),
2432 vmSymbols::linkMethod_name(),
2433 vmSymbols::linkMethod_signature(),
2434 &args, CHECK_(empty));
2435 Handle mname(THREAD, (oop) result.get_jobject());
2436 (*method_type_result) = method_type;
2437 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2438 }
2440 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2441 // We must ensure that all class loaders everywhere will reach this class, for any client.
2442 // This is a safe bet for public classes in java.lang, such as Object and String.
2443 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2444 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2445 static bool is_always_visible_class(oop mirror) {
2446 Klass* klass = java_lang_Class::as_Klass(mirror);
2447 if (klass->oop_is_objArray()) {
2448 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2449 }
2450 if (klass->oop_is_typeArray()) {
2451 return true; // primitive array
2452 }
2453 assert(klass->oop_is_instance(), klass->external_name());
2454 return klass->is_public() &&
2455 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2456 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2457 }
2459 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2460 // signature, as interpreted relative to the given class loader.
2461 // Because of class loader constraints, all method handle usage must be
2462 // consistent with this loader.
2463 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2464 KlassHandle accessing_klass,
2465 TRAPS) {
2466 Handle empty;
2467 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2468 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2469 int index = invoke_method_table()->hash_to_index(hash);
2470 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2471 if (spe != NULL && spe->method_type() != NULL) {
2472 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2473 return Handle(THREAD, spe->method_type());
2474 } else if (THREAD->is_Compiler_thread()) {
2475 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2476 return Handle(); // do not attempt from within compiler, unless it was cached
2477 }
2479 Handle class_loader, protection_domain;
2480 if (accessing_klass.not_null()) {
2481 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2482 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2483 }
2484 bool can_be_cached = true;
2485 int npts = ArgumentCount(signature).size();
2486 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2487 int arg = 0;
2488 Handle rt; // the return type from the signature
2489 ResourceMark rm(THREAD);
2490 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2491 oop mirror = NULL;
2492 if (can_be_cached) {
2493 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2494 mirror = ss.as_java_mirror(Handle(), Handle(),
2495 SignatureStream::ReturnNull, CHECK_(empty));
2496 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2497 // Fall back to accessing_klass context.
2498 can_be_cached = false;
2499 }
2500 }
2501 if (!can_be_cached) {
2502 // Resolve, throwing a real error if it doesn't work.
2503 mirror = ss.as_java_mirror(class_loader, protection_domain,
2504 SignatureStream::NCDFError, CHECK_(empty));
2505 }
2506 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2507 if (ss.at_return_type())
2508 rt = Handle(THREAD, mirror);
2509 else
2510 pts->obj_at_put(arg++, mirror);
2512 // Check accessibility.
2513 if (ss.is_object() && accessing_klass.not_null()) {
2514 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2515 mirror = NULL; // safety
2516 // Emulate ConstantPool::verify_constant_pool_resolve.
2517 if (sel_klass->oop_is_objArray())
2518 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2519 if (sel_klass->oop_is_instance()) {
2520 KlassHandle sel_kh(THREAD, sel_klass);
2521 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2522 }
2523 }
2524 }
2525 assert(arg == npts, "");
2527 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2528 JavaCallArguments args(Handle(THREAD, rt()));
2529 args.push_oop(pts());
2530 JavaValue result(T_OBJECT);
2531 JavaCalls::call_static(&result,
2532 SystemDictionary::MethodHandleNatives_klass(),
2533 vmSymbols::findMethodHandleType_name(),
2534 vmSymbols::findMethodHandleType_signature(),
2535 &args, CHECK_(empty));
2536 Handle method_type(THREAD, (oop) result.get_jobject());
2538 if (can_be_cached) {
2539 // We can cache this MethodType inside the JVM.
2540 MutexLocker ml(SystemDictionary_lock, THREAD);
2541 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2542 if (spe == NULL)
2543 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2544 if (spe->method_type() == NULL) {
2545 spe->set_method_type(method_type());
2546 }
2547 }
2549 // report back to the caller with the MethodType
2550 return method_type;
2551 }
2553 // Ask Java code to find or construct a method handle constant.
2554 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2555 int ref_kind, //e.g., JVM_REF_invokeVirtual
2556 KlassHandle callee,
2557 Symbol* name_sym,
2558 Symbol* signature,
2559 TRAPS) {
2560 Handle empty;
2561 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2562 Handle type;
2563 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2564 type = find_method_handle_type(signature, caller, CHECK_(empty));
2565 } else if (caller.is_null()) {
2566 // This should not happen. JDK code should take care of that.
2567 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2568 } else {
2569 ResourceMark rm(THREAD);
2570 SignatureStream ss(signature, false);
2571 if (!ss.is_done()) {
2572 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2573 SignatureStream::NCDFError, CHECK_(empty));
2574 type = Handle(THREAD, mirror);
2575 ss.next();
2576 if (!ss.is_done()) type = Handle(); // error!
2577 }
2578 }
2579 if (type.is_null()) {
2580 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2581 }
2583 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2584 JavaCallArguments args;
2585 args.push_oop(caller->java_mirror()); // the referring class
2586 args.push_int(ref_kind);
2587 args.push_oop(callee->java_mirror()); // the target class
2588 args.push_oop(name());
2589 args.push_oop(type());
2590 JavaValue result(T_OBJECT);
2591 JavaCalls::call_static(&result,
2592 SystemDictionary::MethodHandleNatives_klass(),
2593 vmSymbols::linkMethodHandleConstant_name(),
2594 vmSymbols::linkMethodHandleConstant_signature(),
2595 &args, CHECK_(empty));
2596 return Handle(THREAD, (oop) result.get_jobject());
2597 }
2599 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2600 // name and signature, as interpreted relative to the given class loader.
2601 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2602 Handle bootstrap_specifier,
2603 Symbol* name,
2604 Symbol* type,
2605 Handle *appendix_result,
2606 Handle *method_type_result,
2607 TRAPS) {
2608 methodHandle empty;
2609 Handle bsm, info;
2610 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2611 bsm = bootstrap_specifier;
2612 } else {
2613 assert(bootstrap_specifier->is_objArray(), "");
2614 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2615 int len = args->length();
2616 assert(len >= 1, "");
2617 bsm = Handle(THREAD, args->obj_at(0));
2618 if (len > 1) {
2619 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2620 for (int i = 1; i < len; i++)
2621 args1->obj_at_put(i-1, args->obj_at(i));
2622 info = Handle(THREAD, args1);
2623 }
2624 }
2625 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2626 "caller must supply a valid BSM");
2628 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2629 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2631 // This should not happen. JDK code should take care of that.
2632 if (caller.is_null() || method_type.is_null()) {
2633 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2634 }
2636 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2637 assert(appendix_box->obj_at(0) == NULL, "");
2639 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2640 JavaCallArguments args;
2641 args.push_oop(caller->java_mirror());
2642 args.push_oop(bsm());
2643 args.push_oop(method_name());
2644 args.push_oop(method_type());
2645 args.push_oop(info());
2646 args.push_oop(appendix_box);
2647 JavaValue result(T_OBJECT);
2648 JavaCalls::call_static(&result,
2649 SystemDictionary::MethodHandleNatives_klass(),
2650 vmSymbols::linkCallSite_name(),
2651 vmSymbols::linkCallSite_signature(),
2652 &args, CHECK_(empty));
2653 Handle mname(THREAD, (oop) result.get_jobject());
2654 (*method_type_result) = method_type;
2655 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2656 }
2658 // Since the identity hash code for symbols changes when the symbols are
2659 // moved from the regular perm gen (hash in the mark word) to the shared
2660 // spaces (hash is the address), the classes loaded into the dictionary
2661 // may be in the wrong buckets.
2663 void SystemDictionary::reorder_dictionary() {
2664 dictionary()->reorder_dictionary();
2665 }
2668 void SystemDictionary::copy_buckets(char** top, char* end) {
2669 dictionary()->copy_buckets(top, end);
2670 }
2673 void SystemDictionary::copy_table(char** top, char* end) {
2674 dictionary()->copy_table(top, end);
2675 }
2678 void SystemDictionary::reverse() {
2679 dictionary()->reverse();
2680 }
2682 int SystemDictionary::number_of_classes() {
2683 return dictionary()->number_of_entries();
2684 }
2687 // ----------------------------------------------------------------------------
2688 void SystemDictionary::print_shared(bool details) {
2689 shared_dictionary()->print(details);
2690 }
2692 void SystemDictionary::print(bool details) {
2693 dictionary()->print(details);
2695 // Placeholders
2696 GCMutexLocker mu(SystemDictionary_lock);
2697 placeholders()->print();
2699 // loader constraints - print under SD_lock
2700 constraints()->print();
2701 }
2704 void SystemDictionary::verify() {
2705 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2706 guarantee(constraints() != NULL,
2707 "Verify of loader constraints failed");
2708 guarantee(dictionary()->number_of_entries() >= 0 &&
2709 placeholders()->number_of_entries() >= 0,
2710 "Verify of system dictionary failed");
2712 // Verify dictionary
2713 dictionary()->verify();
2715 GCMutexLocker mu(SystemDictionary_lock);
2716 placeholders()->verify();
2718 // Verify constraint table
2719 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2720 constraints()->verify(dictionary(), placeholders());
2721 }
2723 #ifndef PRODUCT
2725 // statistics code
2726 class ClassStatistics: AllStatic {
2727 private:
2728 static int nclasses; // number of classes
2729 static int nmethods; // number of methods
2730 static int nmethoddata; // number of methodData
2731 static int class_size; // size of class objects in words
2732 static int method_size; // size of method objects in words
2733 static int debug_size; // size of debug info in methods
2734 static int methoddata_size; // size of methodData objects in words
2736 static void do_class(Klass* k) {
2737 nclasses++;
2738 class_size += k->size();
2739 if (k->oop_is_instance()) {
2740 InstanceKlass* ik = (InstanceKlass*)k;
2741 class_size += ik->methods()->size();
2742 class_size += ik->constants()->size();
2743 class_size += ik->local_interfaces()->size();
2744 class_size += ik->transitive_interfaces()->size();
2745 // We do not have to count implementors, since we only store one!
2746 // SSS: How should these be accounted now that they have moved?
2747 // class_size += ik->fields()->length();
2748 }
2749 }
2751 static void do_method(Method* m) {
2752 nmethods++;
2753 method_size += m->size();
2754 // class loader uses same objArray for empty vectors, so don't count these
2755 if (m->has_stackmap_table()) {
2756 method_size += m->stackmap_data()->size();
2757 }
2759 MethodData* mdo = m->method_data();
2760 if (mdo != NULL) {
2761 nmethoddata++;
2762 methoddata_size += mdo->size();
2763 }
2764 }
2766 public:
2767 static void print() {
2768 SystemDictionary::classes_do(do_class);
2769 SystemDictionary::methods_do(do_method);
2770 tty->print_cr("Class statistics:");
2771 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2772 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2773 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2774 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2775 }
2776 };
2779 int ClassStatistics::nclasses = 0;
2780 int ClassStatistics::nmethods = 0;
2781 int ClassStatistics::nmethoddata = 0;
2782 int ClassStatistics::class_size = 0;
2783 int ClassStatistics::method_size = 0;
2784 int ClassStatistics::debug_size = 0;
2785 int ClassStatistics::methoddata_size = 0;
2787 void SystemDictionary::print_class_statistics() {
2788 ResourceMark rm;
2789 ClassStatistics::print();
2790 }
2793 class MethodStatistics: AllStatic {
2794 public:
2795 enum {
2796 max_parameter_size = 10
2797 };
2798 private:
2800 static int _number_of_methods;
2801 static int _number_of_final_methods;
2802 static int _number_of_static_methods;
2803 static int _number_of_native_methods;
2804 static int _number_of_synchronized_methods;
2805 static int _number_of_profiled_methods;
2806 static int _number_of_bytecodes;
2807 static int _parameter_size_profile[max_parameter_size];
2808 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2810 static void initialize() {
2811 _number_of_methods = 0;
2812 _number_of_final_methods = 0;
2813 _number_of_static_methods = 0;
2814 _number_of_native_methods = 0;
2815 _number_of_synchronized_methods = 0;
2816 _number_of_profiled_methods = 0;
2817 _number_of_bytecodes = 0;
2818 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2819 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2820 };
2822 static void do_method(Method* m) {
2823 _number_of_methods++;
2824 // collect flag info
2825 if (m->is_final() ) _number_of_final_methods++;
2826 if (m->is_static() ) _number_of_static_methods++;
2827 if (m->is_native() ) _number_of_native_methods++;
2828 if (m->is_synchronized()) _number_of_synchronized_methods++;
2829 if (m->method_data() != NULL) _number_of_profiled_methods++;
2830 // collect parameter size info (add one for receiver, if any)
2831 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2832 // collect bytecodes info
2833 {
2834 Thread *thread = Thread::current();
2835 HandleMark hm(thread);
2836 BytecodeStream s(methodHandle(thread, m));
2837 Bytecodes::Code c;
2838 while ((c = s.next()) >= 0) {
2839 _number_of_bytecodes++;
2840 _bytecodes_profile[c]++;
2841 }
2842 }
2843 }
2845 public:
2846 static void print() {
2847 initialize();
2848 SystemDictionary::methods_do(do_method);
2849 // generate output
2850 tty->cr();
2851 tty->print_cr("Method statistics (static):");
2852 // flag distribution
2853 tty->cr();
2854 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2855 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2856 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2857 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2858 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2859 // parameter size profile
2860 tty->cr();
2861 { int tot = 0;
2862 int avg = 0;
2863 for (int i = 0; i < max_parameter_size; i++) {
2864 int n = _parameter_size_profile[i];
2865 tot += n;
2866 avg += n*i;
2867 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2868 }
2869 assert(tot == _number_of_methods, "should be the same");
2870 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2871 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2872 }
2873 // bytecodes profile
2874 tty->cr();
2875 { int tot = 0;
2876 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2877 if (Bytecodes::is_defined(i)) {
2878 Bytecodes::Code c = Bytecodes::cast(i);
2879 int n = _bytecodes_profile[c];
2880 tot += n;
2881 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2882 }
2883 }
2884 assert(tot == _number_of_bytecodes, "should be the same");
2885 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2886 }
2887 tty->cr();
2888 }
2889 };
2891 int MethodStatistics::_number_of_methods;
2892 int MethodStatistics::_number_of_final_methods;
2893 int MethodStatistics::_number_of_static_methods;
2894 int MethodStatistics::_number_of_native_methods;
2895 int MethodStatistics::_number_of_synchronized_methods;
2896 int MethodStatistics::_number_of_profiled_methods;
2897 int MethodStatistics::_number_of_bytecodes;
2898 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2899 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2902 void SystemDictionary::print_method_statistics() {
2903 MethodStatistics::print();
2904 }
2906 #endif // PRODUCT