Mon, 04 Feb 2013 13:05:32 -0500
8006949: Update hotspot for MethodParameters format change
8006907: Hotspot should reject classfiles with multiple MethodParameters attributes
Summary: Update to Hotspot's processing of MethodParameters attributes in classfiles
Reviewed-by: coleenp, jrose
1 /*
2 * Copyright (c) 1997, 2013, 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.
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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 #include "classfile/vmSymbols.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "interpreter/bytecodeStream.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/gcLocker.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "oops/instanceKlass.hpp"
40 #include "oops/instanceRefKlass.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/methodData.hpp"
43 #include "oops/objArrayKlass.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/oop.inline2.hpp"
46 #include "oops/typeArrayKlass.hpp"
47 #include "prims/jvmtiEnvBase.hpp"
48 #include "prims/methodHandles.hpp"
49 #include "runtime/biasedLocking.hpp"
50 #include "runtime/fieldType.hpp"
51 #include "runtime/handles.inline.hpp"
52 #include "runtime/java.hpp"
53 #include "runtime/javaCalls.hpp"
54 #include "runtime/mutexLocker.hpp"
55 #include "runtime/signature.hpp"
56 #include "services/classLoadingService.hpp"
57 #include "services/threadService.hpp"
60 Dictionary* SystemDictionary::_dictionary = NULL;
61 PlaceholderTable* SystemDictionary::_placeholders = NULL;
62 Dictionary* SystemDictionary::_shared_dictionary = NULL;
63 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
64 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
65 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
68 int SystemDictionary::_number_of_modifications = 0;
69 int SystemDictionary::_sdgeneration = 0;
70 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
71 20201,40423,99991};
73 oop SystemDictionary::_system_loader_lock_obj = NULL;
75 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
76 = { NULL /*, NULL...*/ };
78 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
80 oop SystemDictionary::_java_system_loader = NULL;
82 bool SystemDictionary::_has_loadClassInternal = false;
83 bool SystemDictionary::_has_checkPackageAccess = false;
85 // lazily initialized klass variables
86 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
89 // ----------------------------------------------------------------------------
90 // Java-level SystemLoader
92 oop SystemDictionary::java_system_loader() {
93 return _java_system_loader;
94 }
96 void SystemDictionary::compute_java_system_loader(TRAPS) {
97 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
98 JavaValue result(T_OBJECT);
99 JavaCalls::call_static(&result,
100 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
101 vmSymbols::getSystemClassLoader_name(),
102 vmSymbols::void_classloader_signature(),
103 CHECK);
105 _java_system_loader = (oop)result.get_jobject();
106 }
109 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
110 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
111 return ClassLoaderDataGraph::find_or_create(class_loader, CHECK_NULL);
112 }
114 // ----------------------------------------------------------------------------
115 // debugging
117 #ifdef ASSERT
119 // return true if class_name contains no '.' (internal format is '/')
120 bool SystemDictionary::is_internal_format(Symbol* class_name) {
121 if (class_name != NULL) {
122 ResourceMark rm;
123 char* name = class_name->as_C_string();
124 return strchr(name, '.') == NULL;
125 } else {
126 return true;
127 }
128 }
130 #endif
132 // ----------------------------------------------------------------------------
133 // Parallel class loading check
135 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
136 if (UnsyncloadClass || class_loader.is_null()) return true;
137 if (AlwaysLockClassLoader) return false;
138 return java_lang_ClassLoader::parallelCapable(class_loader());
139 }
140 // ----------------------------------------------------------------------------
141 // ParallelDefineClass flag does not apply to bootclass loader
142 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
143 if (class_loader.is_null()) return false;
144 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
145 return true;
146 }
147 return false;
148 }
149 // ----------------------------------------------------------------------------
150 // Resolving of classes
152 // Forwards to resolve_or_null
154 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
155 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
156 if (HAS_PENDING_EXCEPTION || klass == NULL) {
157 KlassHandle k_h(THREAD, klass);
158 // can return a null klass
159 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
160 }
161 return klass;
162 }
164 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
165 if (HAS_PENDING_EXCEPTION) {
166 // If we have a pending exception we forward it to the caller, unless throw_error is true,
167 // in which case we have to check whether the pending exception is a ClassNotFoundException,
168 // and if so convert it to a NoClassDefFoundError
169 // And chain the original ClassNotFoundException
170 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
171 ResourceMark rm(THREAD);
172 assert(klass_h() == NULL, "Should not have result with exception pending");
173 Handle e(THREAD, PENDING_EXCEPTION);
174 CLEAR_PENDING_EXCEPTION;
175 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
176 } else {
177 return NULL;
178 }
179 }
180 // Class not found, throw appropriate error or exception depending on value of throw_error
181 if (klass_h() == NULL) {
182 ResourceMark rm(THREAD);
183 if (throw_error) {
184 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
185 } else {
186 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
187 }
188 }
189 return (Klass*)klass_h();
190 }
193 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
194 bool throw_error, TRAPS)
195 {
196 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
197 }
200 // Forwards to resolve_instance_class_or_null
202 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
203 assert(!THREAD->is_Compiler_thread(),
204 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
205 class_name->as_C_string(),
206 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
207 if (FieldType::is_array(class_name)) {
208 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
209 } else if (FieldType::is_obj(class_name)) {
210 ResourceMark rm(THREAD);
211 // Ignore wrapping L and ;.
212 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
213 class_name->utf8_length() - 2, CHECK_NULL);
214 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
215 } else {
216 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
217 }
218 }
220 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
221 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
222 }
224 // Forwards to resolve_instance_class_or_null
226 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
227 Handle class_loader,
228 Handle protection_domain,
229 TRAPS) {
230 assert(FieldType::is_array(class_name), "must be array");
231 Klass* k = NULL;
232 FieldArrayInfo fd;
233 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
234 // of this call
235 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
236 if (t == T_OBJECT) {
237 // naked oop "k" is OK here -- we assign back into it
238 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
239 class_loader,
240 protection_domain,
241 CHECK_NULL);
242 if (k != NULL) {
243 k = k->array_klass(fd.dimension(), CHECK_NULL);
244 }
245 } else {
246 k = Universe::typeArrayKlassObj(t);
247 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
248 }
249 return k;
250 }
253 // Must be called for any super-class or super-interface resolution
254 // during class definition to allow class circularity checking
255 // super-interface callers:
256 // parse_interfaces - for defineClass & jvmtiRedefineClasses
257 // super-class callers:
258 // ClassFileParser - for defineClass & jvmtiRedefineClasses
259 // load_shared_class - while loading a class from shared archive
260 // resolve_instance_class_or_null:
261 // via: handle_parallel_super_load
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
289 Symbol* class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294 // Double-check, if child class is already loaded, just return super-class,interface
295 // Don't add a placedholder if already loaded, i.e. already in system dictionary
296 // Make sure there's a placeholder for the *child* before resolving.
297 // Used as a claim that this thread is currently loading superclass/classloader
298 // Used here for ClassCircularity checks and also for heap verification
299 // (every InstanceKlass in the heap needs to be in the system dictionary
300 // or have a placeholder).
301 // Must check ClassCircularity before checking if super class is already loaded
302 //
303 // We might not already have a placeholder if this child_name was
304 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
305 // the name of the class might not be known until the stream is actually
306 // parsed.
307 // Bugs 4643874, 4715493
308 // compute_hash can have a safepoint
310 ClassLoaderData* loader_data = class_loader_data(class_loader);
311 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
312 int d_index = dictionary()->hash_to_index(d_hash);
313 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
314 int p_index = placeholders()->hash_to_index(p_hash);
315 // can't throw error holding a lock
316 bool child_already_loaded = false;
317 bool throw_circularity_error = false;
318 {
319 MutexLocker mu(SystemDictionary_lock, THREAD);
320 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
321 Klass* quicksuperk;
322 // to support // loading: if child done loading, just return superclass
323 // if class_name, & class_loader don't match:
324 // if initial define, SD update will give LinkageError
325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
326 // so we don't throw an exception here.
327 // see: nsk redefclass014 & java.lang.instrument Instrument032
328 if ((childk != NULL ) && (is_superclass) &&
329 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
331 ((quicksuperk->name() == class_name) &&
332 (quicksuperk->class_loader() == class_loader()))) {
333 return quicksuperk;
334 } else {
335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
337 throw_circularity_error = true;
338 }
339 }
340 if (!throw_circularity_error) {
341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
342 }
343 }
344 if (throw_circularity_error) {
345 ResourceMark rm(THREAD);
346 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
347 }
349 // java.lang.Object should have been found above
350 assert(class_name != NULL, "null super class for resolving");
351 // Resolve the super class or interface, check results on return
352 Klass* superk = SystemDictionary::resolve_or_null(class_name,
353 class_loader,
354 protection_domain,
355 THREAD);
357 KlassHandle superk_h(THREAD, superk);
359 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
360 // It is no longer necessary to keep the placeholder table alive until update_dictionary
361 // or error. GC used to walk the placeholder table as strong roots.
362 // The instanceKlass is kept alive because the class loader is on the stack,
363 // which keeps the loader_data alive, as well as all instanceKlasses in
364 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
365 {
366 MutexLocker mu(SystemDictionary_lock, THREAD);
367 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
368 SystemDictionary_lock->notify_all();
369 }
370 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
371 // can null superk
372 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
373 }
375 return superk_h();
376 }
378 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
379 Handle class_loader,
380 Handle protection_domain,
381 TRAPS) {
382 if(!has_checkPackageAccess()) return;
384 // Now we have to call back to java to check if the initating class has access
385 JavaValue result(T_VOID);
386 if (TraceProtectionDomainVerification) {
387 // Print out trace information
388 tty->print_cr("Checking package access");
389 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
390 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
391 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
392 }
394 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
395 JavaCalls::call_special(&result,
396 class_loader,
397 system_loader,
398 vmSymbols::checkPackageAccess_name(),
399 vmSymbols::class_protectiondomain_signature(),
400 Handle(THREAD, klass->java_mirror()),
401 protection_domain,
402 THREAD);
404 if (TraceProtectionDomainVerification) {
405 if (HAS_PENDING_EXCEPTION) {
406 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
407 } else {
408 tty->print_cr(" -> granted");
409 }
410 tty->cr();
411 }
413 if (HAS_PENDING_EXCEPTION) return;
415 // If no exception has been thrown, we have validated the protection domain
416 // Insert the protection domain of the initiating class into the set.
417 {
418 // We recalculate the entry here -- we've called out to java since
419 // the last time it was calculated.
420 ClassLoaderData* loader_data = class_loader_data(class_loader);
422 Symbol* kn = klass->name();
423 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
424 int d_index = dictionary()->hash_to_index(d_hash);
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 {
428 // Note that we have an entry, and entries can be deleted only during GC,
429 // so we cannot allow GC to occur while we're holding this entry.
431 // We're using a No_Safepoint_Verifier to catch any place where we
432 // might potentially do a GC at all.
433 // Dictionary::do_unloading() asserts that classes in SD are only
434 // unloaded at a safepoint. Anonymous classes are not in SD.
435 No_Safepoint_Verifier nosafepoint;
436 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
437 protection_domain, THREAD);
438 }
439 }
440 }
442 // We only get here if this thread finds that another thread
443 // has already claimed the placeholder token for the current operation,
444 // but that other thread either never owned or gave up the
445 // object lock
446 // Waits on SystemDictionary_lock to indicate placeholder table updated
447 // On return, caller must recheck placeholder table state
448 //
449 // We only get here if
450 // 1) custom classLoader, i.e. not bootstrap classloader
451 // 2) UnsyncloadClass not set
452 // 3) custom classLoader has broken the class loader objectLock
453 // so another thread got here in parallel
454 //
455 // lockObject must be held.
456 // Complicated dance due to lock ordering:
457 // Must first release the classloader object lock to
458 // allow initial definer to complete the class definition
459 // and to avoid deadlock
460 // Reclaim classloader lock object with same original recursion count
461 // Must release SystemDictionary_lock after notify, since
462 // class loader lock must be claimed before SystemDictionary_lock
463 // to prevent deadlocks
464 //
465 // The notify allows applications that did an untimed wait() on
466 // the classloader object lock to not hang.
467 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
468 assert_lock_strong(SystemDictionary_lock);
470 bool calledholdinglock
471 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
472 assert(calledholdinglock,"must hold lock for notify");
473 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
474 ObjectSynchronizer::notifyall(lockObject, THREAD);
475 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
476 SystemDictionary_lock->wait();
477 SystemDictionary_lock->unlock();
478 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
479 SystemDictionary_lock->lock();
480 }
482 // If the class in is in the placeholder table, class loading is in progress
483 // For cases where the application changes threads to load classes, it
484 // is critical to ClassCircularity detection that we try loading
485 // the superclass on the same thread internally, so we do parallel
486 // super class loading here.
487 // This also is critical in cases where the original thread gets stalled
488 // even in non-circularity situations.
489 // Note: must call resolve_super_or_fail even if null super -
490 // to force placeholder entry creation for this class for circularity detection
491 // Caller must check for pending exception
492 // Returns non-null Klass* if other thread has completed load
493 // and we are done,
494 // If return null Klass* and no pending exception, the caller must load the class
495 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
496 Symbol* name, Symbol* superclassname, Handle class_loader,
497 Handle protection_domain, Handle lockObject, TRAPS) {
499 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
500 ClassLoaderData* loader_data = class_loader_data(class_loader);
501 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
502 int d_index = dictionary()->hash_to_index(d_hash);
503 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
504 int p_index = placeholders()->hash_to_index(p_hash);
506 // superk is not used, resolve_super called for circularity check only
507 // This code is reached in two situations. One if this thread
508 // is loading the same class twice (e.g. ClassCircularity, or
509 // java.lang.instrument).
510 // The second is if another thread started the resolve_super first
511 // and has not yet finished.
512 // In both cases the original caller will clean up the placeholder
513 // entry on error.
514 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
515 superclassname,
516 class_loader,
517 protection_domain,
518 true,
519 CHECK_(nh));
521 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
522 // Serial class loaders and bootstrap classloader do wait for superclass loads
523 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
524 MutexLocker mu(SystemDictionary_lock, THREAD);
525 // Check if classloading completed while we were loading superclass or waiting
526 Klass* check = find_class(d_index, d_hash, name, loader_data);
527 if (check != NULL) {
528 // Klass is already loaded, so just return it
529 return(instanceKlassHandle(THREAD, check));
530 } else {
531 return nh;
532 }
533 }
535 // must loop to both handle other placeholder updates
536 // and spurious notifications
537 bool super_load_in_progress = true;
538 PlaceholderEntry* placeholder;
539 while (super_load_in_progress) {
540 MutexLocker mu(SystemDictionary_lock, THREAD);
541 // Check if classloading completed while we were loading superclass or waiting
542 Klass* check = find_class(d_index, d_hash, name, loader_data);
543 if (check != NULL) {
544 // Klass is already loaded, so just return it
545 return(instanceKlassHandle(THREAD, check));
546 } else {
547 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
548 if (placeholder && placeholder->super_load_in_progress() ){
549 // Before UnsyncloadClass:
550 // We only get here if the application has released the
551 // classloader lock when another thread was in the middle of loading a
552 // superclass/superinterface for this class, and now
553 // this thread is also trying to load this class.
554 // To minimize surprises, the first thread that started to
555 // load a class should be the one to complete the loading
556 // with the classfile it initially expected.
557 // This logic has the current thread wait once it has done
558 // all the superclass/superinterface loading it can, until
559 // the original thread completes the class loading or fails
560 // If it completes we will use the resulting InstanceKlass
561 // which we will find below in the systemDictionary.
562 // We also get here for parallel bootstrap classloader
563 if (class_loader.is_null()) {
564 SystemDictionary_lock->wait();
565 } else {
566 double_lock_wait(lockObject, THREAD);
567 }
568 } else {
569 // If not in SD and not in PH, other thread's load must have failed
570 super_load_in_progress = false;
571 }
572 }
573 }
574 return (nh);
575 }
578 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name, Handle class_loader, Handle protection_domain, TRAPS) {
579 assert(name != NULL && !FieldType::is_array(name) &&
580 !FieldType::is_obj(name), "invalid class name");
582 // UseNewReflection
583 // Fix for 4474172; see evaluation for more details
584 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
585 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
587 // Do lookup to see if class already exist and the protection domain
588 // has the right access
589 // This call uses find which checks protection domain already matches
590 // All subsequent calls use find_class, and set has_loaded_class so that
591 // before we return a result we call out to java to check for valid protection domain
592 // to allow returning the Klass* and add it to the pd_set if it is valid
593 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
594 int d_index = dictionary()->hash_to_index(d_hash);
595 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
596 protection_domain, THREAD);
597 if (probe != NULL) return probe;
600 // Non-bootstrap class loaders will call out to class loader and
601 // define via jvm/jni_DefineClass which will acquire the
602 // class loader object lock to protect against multiple threads
603 // defining the class in parallel by accident.
604 // This lock must be acquired here so the waiter will find
605 // any successful result in the SystemDictionary and not attempt
606 // the define
607 // ParallelCapable Classloaders and the bootstrap classloader,
608 // or all classloaders with UnsyncloadClass do not acquire lock here
609 bool DoObjectLock = true;
610 if (is_parallelCapable(class_loader)) {
611 DoObjectLock = false;
612 }
614 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
615 int p_index = placeholders()->hash_to_index(p_hash);
617 // Class is not in SystemDictionary so we have to do loading.
618 // Make sure we are synchronized on the class loader before we proceed
619 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
620 check_loader_lock_contention(lockObject, THREAD);
621 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
623 // Check again (after locking) if class already exist in SystemDictionary
624 bool class_has_been_loaded = false;
625 bool super_load_in_progress = false;
626 bool havesupername = false;
627 instanceKlassHandle k;
628 PlaceholderEntry* placeholder;
629 Symbol* superclassname = NULL;
631 {
632 MutexLocker mu(SystemDictionary_lock, THREAD);
633 Klass* check = find_class(d_index, d_hash, name, loader_data);
634 if (check != NULL) {
635 // Klass is already loaded, so just return it
636 class_has_been_loaded = true;
637 k = instanceKlassHandle(THREAD, check);
638 } else {
639 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
640 if (placeholder && placeholder->super_load_in_progress()) {
641 super_load_in_progress = true;
642 if (placeholder->havesupername() == true) {
643 superclassname = placeholder->supername();
644 havesupername = true;
645 }
646 }
647 }
648 }
650 // If the class is in the placeholder table, class loading is in progress
651 if (super_load_in_progress && havesupername==true) {
652 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
653 class_loader, protection_domain, lockObject, THREAD);
654 if (HAS_PENDING_EXCEPTION) {
655 return NULL;
656 }
657 if (!k.is_null()) {
658 class_has_been_loaded = true;
659 }
660 }
662 bool throw_circularity_error = false;
663 if (!class_has_been_loaded) {
664 bool load_instance_added = false;
666 // add placeholder entry to record loading instance class
667 // Five cases:
668 // All cases need to prevent modifying bootclasssearchpath
669 // in parallel with a classload of same classname
670 // Redefineclasses uses existence of the placeholder for the duration
671 // of the class load to prevent concurrent redefinition of not completely
672 // defined classes.
673 // case 1. traditional classloaders that rely on the classloader object lock
674 // - no other need for LOAD_INSTANCE
675 // case 2. traditional classloaders that break the classloader object lock
676 // as a deadlock workaround. Detection of this case requires that
677 // this check is done while holding the classloader object lock,
678 // and that lock is still held when calling classloader's loadClass.
679 // For these classloaders, we ensure that the first requestor
680 // completes the load and other requestors wait for completion.
681 // case 3. UnsyncloadClass - don't use objectLocker
682 // With this flag, we allow parallel classloading of a
683 // class/classloader pair
684 // case4. Bootstrap classloader - don't own objectLocker
685 // This classloader supports parallelism at the classloader level,
686 // but only allows a single load of a class/classloader pair.
687 // No performance benefit and no deadlock issues.
688 // case 5. parallelCapable user level classloaders - without objectLocker
689 // Allow parallel classloading of a class/classloader pair
691 {
692 MutexLocker mu(SystemDictionary_lock, THREAD);
693 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
694 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
695 if (oldprobe) {
696 // only need check_seen_thread once, not on each loop
697 // 6341374 java/lang/Instrument with -Xcomp
698 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
699 throw_circularity_error = true;
700 } else {
701 // case 1: traditional: should never see load_in_progress.
702 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
704 // case 4: bootstrap classloader: prevent futile classloading,
705 // wait on first requestor
706 if (class_loader.is_null()) {
707 SystemDictionary_lock->wait();
708 } else {
709 // case 2: traditional with broken classloader lock. wait on first
710 // requestor.
711 double_lock_wait(lockObject, THREAD);
712 }
713 // Check if classloading completed while we were waiting
714 Klass* check = find_class(d_index, d_hash, name, loader_data);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 k = instanceKlassHandle(THREAD, check);
718 class_has_been_loaded = true;
719 }
720 // check if other thread failed to load and cleaned up
721 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
722 }
723 }
724 }
725 }
726 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
727 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
728 // LOAD_INSTANCE in parallel
730 if (!throw_circularity_error && !class_has_been_loaded) {
731 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
732 load_instance_added = true;
733 // For class loaders that do not acquire the classloader object lock,
734 // if they did not catch another thread holding LOAD_INSTANCE,
735 // need a check analogous to the acquire ObjectLocker/find_class
736 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
737 // one final check if the load has already completed
738 // class loaders holding the ObjectLock shouldn't find the class here
739 Klass* check = find_class(d_index, d_hash, name, loader_data);
740 if (check != NULL) {
741 // Klass is already loaded, so return it after checking/adding protection domain
742 k = instanceKlassHandle(THREAD, check);
743 class_has_been_loaded = true;
744 }
745 }
746 }
748 // must throw error outside of owning lock
749 if (throw_circularity_error) {
750 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
751 ResourceMark rm(THREAD);
752 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
753 }
755 if (!class_has_been_loaded) {
757 // Do actual loading
758 k = load_instance_class(name, class_loader, THREAD);
760 // For UnsyncloadClass only
761 // If they got a linkageError, check if a parallel class load succeeded.
762 // If it did, then for bytecode resolution the specification requires
763 // that we return the same result we did for the other thread, i.e. the
764 // successfully loaded InstanceKlass
765 // Should not get here for classloaders that support parallelism
766 // with the new cleaner mechanism, even with AllowParallelDefineClass
767 // Bootstrap goes through here to allow for an extra guarantee check
768 if (UnsyncloadClass || (class_loader.is_null())) {
769 if (k.is_null() && HAS_PENDING_EXCEPTION
770 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
771 MutexLocker mu(SystemDictionary_lock, THREAD);
772 Klass* check = find_class(d_index, d_hash, name, loader_data);
773 if (check != NULL) {
774 // Klass is already loaded, so just use it
775 k = instanceKlassHandle(THREAD, check);
776 CLEAR_PENDING_EXCEPTION;
777 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
778 }
779 }
780 }
782 // If everything was OK (no exceptions, no null return value), and
783 // class_loader is NOT the defining loader, do a little more bookkeeping.
784 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
785 k->class_loader() != class_loader()) {
787 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
789 // Need to check for a PENDING_EXCEPTION again; check_constraints
790 // can throw and doesn't use the CHECK macro.
791 if (!HAS_PENDING_EXCEPTION) {
792 { // Grabbing the Compile_lock prevents systemDictionary updates
793 // during compilations.
794 MutexLocker mu(Compile_lock, THREAD);
795 update_dictionary(d_index, d_hash, p_index, p_hash,
796 k, class_loader, THREAD);
797 }
798 if (JvmtiExport::should_post_class_load()) {
799 Thread *thread = THREAD;
800 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
801 JvmtiExport::post_class_load((JavaThread *) thread, k());
802 }
803 }
804 }
805 } // load_instance_class loop
807 if (load_instance_added == true) {
808 // clean up placeholder entries for LOAD_INSTANCE success or error
809 // This brackets the SystemDictionary updates for both defining
810 // and initiating loaders
811 MutexLocker mu(SystemDictionary_lock, THREAD);
812 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
813 SystemDictionary_lock->notify_all();
814 }
815 }
817 if (HAS_PENDING_EXCEPTION || k.is_null()) {
818 return NULL;
819 }
821 #ifdef ASSERT
822 {
823 ClassLoaderData* loader_data = k->class_loader_data();
824 MutexLocker mu(SystemDictionary_lock, THREAD);
825 Klass* kk = find_class(name, loader_data);
826 assert(kk == k(), "should be present in dictionary");
827 }
828 #endif
830 // return if the protection domain in NULL
831 if (protection_domain() == NULL) return k();
833 // Check the protection domain has the right access
834 {
835 MutexLocker mu(SystemDictionary_lock, THREAD);
836 // Note that we have an entry, and entries can be deleted only during GC,
837 // so we cannot allow GC to occur while we're holding this entry.
838 // We're using a No_Safepoint_Verifier to catch any place where we
839 // might potentially do a GC at all.
840 // Dictionary::do_unloading() asserts that classes in SD are only
841 // unloaded at a safepoint. Anonymous classes are not in SD.
842 No_Safepoint_Verifier nosafepoint;
843 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
844 loader_data,
845 protection_domain)) {
846 return k();
847 }
848 }
850 // Verify protection domain. If it fails an exception is thrown
851 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
853 return k();
854 }
857 // This routine does not lock the system dictionary.
858 //
859 // Since readers don't hold a lock, we must make sure that system
860 // dictionary entries are only removed at a safepoint (when only one
861 // thread is running), and are added to in a safe way (all links must
862 // be updated in an MT-safe manner).
863 //
864 // Callers should be aware that an entry could be added just after
865 // _dictionary->bucket(index) is read here, so the caller will not see
866 // the new entry.
868 Klass* SystemDictionary::find(Symbol* class_name,
869 Handle class_loader,
870 Handle protection_domain,
871 TRAPS) {
873 // UseNewReflection
874 // The result of this call should be consistent with the result
875 // of the call to resolve_instance_class_or_null().
876 // See evaluation 6790209 and 4474172 for more details.
877 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
878 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
880 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
881 int d_index = dictionary()->hash_to_index(d_hash);
883 {
884 // Note that we have an entry, and entries can be deleted only during GC,
885 // so we cannot allow GC to occur while we're holding this entry.
886 // We're using a No_Safepoint_Verifier to catch any place where we
887 // might potentially do a GC at all.
888 // Dictionary::do_unloading() asserts that classes in SD are only
889 // unloaded at a safepoint. Anonymous classes are not in SD.
890 No_Safepoint_Verifier nosafepoint;
891 return dictionary()->find(d_index, d_hash, class_name, loader_data,
892 protection_domain, THREAD);
893 }
894 }
897 // Look for a loaded instance or array klass by name. Do not do any loading.
898 // return NULL in case of error.
899 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
900 Handle class_loader,
901 Handle protection_domain,
902 TRAPS) {
903 Klass* k = NULL;
904 assert(class_name != NULL, "class name must be non NULL");
906 if (FieldType::is_array(class_name)) {
907 // The name refers to an array. Parse the name.
908 // dimension and object_key in FieldArrayInfo are assigned as a
909 // side-effect of this call
910 FieldArrayInfo fd;
911 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
912 if (t != T_OBJECT) {
913 k = Universe::typeArrayKlassObj(t);
914 } else {
915 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
916 }
917 if (k != NULL) {
918 k = k->array_klass_or_null(fd.dimension());
919 }
920 } else {
921 k = find(class_name, class_loader, protection_domain, THREAD);
922 }
923 return k;
924 }
926 // Note: this method is much like resolve_from_stream, but
927 // updates no supplemental data structures.
928 // TODO consolidate the two methods with a helper routine?
929 Klass* SystemDictionary::parse_stream(Symbol* class_name,
930 Handle class_loader,
931 Handle protection_domain,
932 ClassFileStream* st,
933 KlassHandle host_klass,
934 GrowableArray<Handle>* cp_patches,
935 TRAPS) {
936 TempNewSymbol parsed_name = NULL;
938 ClassLoaderData* loader_data;
939 if (host_klass.not_null()) {
940 // Create a new CLD for anonymous class, that uses the same class loader
941 // as the host_klass
942 assert(EnableInvokeDynamic, "");
943 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
944 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
945 loader_data->record_dependency(host_klass(), CHECK_NULL);
946 } else {
947 loader_data = ClassLoaderData::class_loader_data(class_loader());
948 }
950 // Parse the stream. Note that we do this even though this klass might
951 // already be present in the SystemDictionary, otherwise we would not
952 // throw potential ClassFormatErrors.
953 //
954 // Note: "name" is updated.
956 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
957 loader_data,
958 protection_domain,
959 host_klass,
960 cp_patches,
961 parsed_name,
962 true,
963 THREAD);
966 if (host_klass.not_null() && k.not_null()) {
967 assert(EnableInvokeDynamic, "");
968 k->set_host_klass(host_klass());
969 // If it's anonymous, initialize it now, since nobody else will.
971 {
972 MutexLocker mu_r(Compile_lock, THREAD);
974 // Add to class hierarchy, initialize vtables, and do possible
975 // deoptimizations.
976 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
978 // But, do not add to system dictionary.
979 }
981 // Rewrite and patch constant pool here.
982 k->link_class(CHECK_NULL);
983 if (cp_patches != NULL) {
984 k->constants()->patch_resolved_references(cp_patches);
985 }
986 k->eager_initialize(CHECK_NULL);
988 // notify jvmti
989 if (JvmtiExport::should_post_class_load()) {
990 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
991 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
992 }
993 }
994 assert(host_klass.not_null() || cp_patches == NULL,
995 "cp_patches only found with host_klass");
997 return k();
998 }
1000 // Add a klass to the system from a stream (called by jni_DefineClass and
1001 // JVM_DefineClass).
1002 // Note: class_name can be NULL. In that case we do not know the name of
1003 // the class until we have parsed the stream.
1005 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1006 Handle class_loader,
1007 Handle protection_domain,
1008 ClassFileStream* st,
1009 bool verify,
1010 TRAPS) {
1012 // Classloaders that support parallelism, e.g. bootstrap classloader,
1013 // or all classloaders with UnsyncloadClass do not acquire lock here
1014 bool DoObjectLock = true;
1015 if (is_parallelCapable(class_loader)) {
1016 DoObjectLock = false;
1017 }
1019 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1021 // Make sure we are synchronized on the class loader before we proceed
1022 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1023 check_loader_lock_contention(lockObject, THREAD);
1024 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1026 TempNewSymbol parsed_name = NULL;
1028 // Parse the stream. Note that we do this even though this klass might
1029 // already be present in the SystemDictionary, otherwise we would not
1030 // throw potential ClassFormatErrors.
1031 //
1032 // Note: "name" is updated.
1034 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1035 loader_data,
1036 protection_domain,
1037 parsed_name,
1038 verify,
1039 THREAD);
1041 const char* pkg = "java/";
1042 if (!HAS_PENDING_EXCEPTION &&
1043 !class_loader.is_null() &&
1044 parsed_name != NULL &&
1045 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1046 // It is illegal to define classes in the "java." package from
1047 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1048 ResourceMark rm(THREAD);
1049 char* name = parsed_name->as_C_string();
1050 char* index = strrchr(name, '/');
1051 *index = '\0'; // chop to just the package name
1052 while ((index = strchr(name, '/')) != NULL) {
1053 *index = '.'; // replace '/' with '.' in package name
1054 }
1055 const char* fmt = "Prohibited package name: %s";
1056 size_t len = strlen(fmt) + strlen(name);
1057 char* message = NEW_RESOURCE_ARRAY(char, len);
1058 jio_snprintf(message, len, fmt, name);
1059 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1060 vmSymbols::java_lang_SecurityException(), message);
1061 }
1063 if (!HAS_PENDING_EXCEPTION) {
1064 assert(parsed_name != NULL, "Sanity");
1065 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1066 // Verification prevents us from creating names with dots in them, this
1067 // asserts that that's the case.
1068 assert(is_internal_format(parsed_name),
1069 "external class name format used internally");
1071 // Add class just loaded
1072 // If a class loader supports parallel classloading handle parallel define requests
1073 // find_or_define_instance_class may return a different InstanceKlass
1074 if (is_parallelCapable(class_loader)) {
1075 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1076 } else {
1077 define_instance_class(k, THREAD);
1078 }
1079 }
1081 // Make sure we have an entry in the SystemDictionary on success
1082 debug_only( {
1083 if (!HAS_PENDING_EXCEPTION) {
1084 assert(parsed_name != NULL, "parsed_name is still null?");
1085 Symbol* h_name = k->name();
1086 ClassLoaderData *defining_loader_data = k->class_loader_data();
1088 MutexLocker mu(SystemDictionary_lock, THREAD);
1090 Klass* check = find_class(parsed_name, loader_data);
1091 assert(check == k(), "should be present in the dictionary");
1093 Klass* check2 = find_class(h_name, defining_loader_data);
1094 assert(check == check2, "name inconsistancy in SystemDictionary");
1095 }
1096 } );
1098 return k();
1099 }
1102 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1103 int number_of_entries) {
1104 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1105 "bad shared dictionary size.");
1106 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1107 }
1110 // If there is a shared dictionary, then find the entry for the
1111 // given shared system class, if any.
1113 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1114 if (shared_dictionary() != NULL) {
1115 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1116 int d_index = shared_dictionary()->hash_to_index(d_hash);
1118 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1119 } else {
1120 return NULL;
1121 }
1122 }
1125 // Load a class from the shared spaces (found through the shared system
1126 // dictionary). Force the superclass and all interfaces to be loaded.
1127 // Update the class definition to include sibling classes and no
1128 // subclasses (yet). [Classes in the shared space are not part of the
1129 // object hierarchy until loaded.]
1131 instanceKlassHandle SystemDictionary::load_shared_class(
1132 Symbol* class_name, Handle class_loader, TRAPS) {
1133 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1134 return load_shared_class(ik, class_loader, THREAD);
1135 }
1137 // Note well! Changes to this method may affect oop access order
1138 // in the shared archive. Please take care to not make changes that
1139 // adversely affect cold start time by changing the oop access order
1140 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1141 // MarkAndMoveOrderedReadWrite closures.
1142 instanceKlassHandle SystemDictionary::load_shared_class(
1143 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1144 assert(class_loader.is_null(), "non-null classloader for shared class?");
1145 if (ik.not_null()) {
1146 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1147 Symbol* class_name = ik->name();
1149 // Found the class, now load the superclass and interfaces. If they
1150 // are shared, add them to the main system dictionary and reset
1151 // their hierarchy references (supers, subs, and interfaces).
1153 if (ik->super() != NULL) {
1154 Symbol* cn = ik->super()->name();
1155 resolve_super_or_fail(class_name, cn,
1156 class_loader, Handle(), true, CHECK_(nh));
1157 }
1159 Array<Klass*>* interfaces = ik->local_interfaces();
1160 int num_interfaces = interfaces->length();
1161 for (int index = 0; index < num_interfaces; index++) {
1162 Klass* k = interfaces->at(index);
1164 // Note: can not use InstanceKlass::cast here because
1165 // interfaces' InstanceKlass's C++ vtbls haven't been
1166 // reinitialized yet (they will be once the interface classes
1167 // are loaded)
1168 Symbol* name = k->name();
1169 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1170 }
1172 // Adjust methods to recover missing data. They need addresses for
1173 // interpreter entry points and their default native method address
1174 // must be reset.
1176 // Updating methods must be done under a lock so multiple
1177 // threads don't update these in parallel
1178 // Shared classes are all currently loaded by the bootstrap
1179 // classloader, so this will never cause a deadlock on
1180 // a custom class loader lock.
1182 {
1183 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1184 check_loader_lock_contention(lockObject, THREAD);
1185 ObjectLocker ol(lockObject, THREAD, true);
1186 ik->restore_unshareable_info(CHECK_(nh));
1187 }
1189 if (TraceClassLoading) {
1190 ResourceMark rm;
1191 tty->print("[Loaded %s", ik->external_name());
1192 tty->print(" from shared objects file");
1193 tty->print_cr("]");
1194 }
1195 // notify a class loaded from shared object
1196 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1197 true /* shared class */);
1198 }
1199 return ik;
1200 }
1203 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1204 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1205 if (class_loader.is_null()) {
1207 // Search the shared system dictionary for classes preloaded into the
1208 // shared spaces.
1209 instanceKlassHandle k;
1210 {
1211 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1212 k = load_shared_class(class_name, class_loader, THREAD);
1213 }
1215 if (k.is_null()) {
1216 // Use VM class loader
1217 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1218 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1219 }
1221 // find_or_define_instance_class may return a different InstanceKlass
1222 if (!k.is_null()) {
1223 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1224 }
1225 return k;
1226 } else {
1227 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1228 ResourceMark rm(THREAD);
1230 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1231 JavaThread* jt = (JavaThread*) THREAD;
1233 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1234 ClassLoader::perf_app_classload_selftime(),
1235 ClassLoader::perf_app_classload_count(),
1236 jt->get_thread_stat()->perf_recursion_counts_addr(),
1237 jt->get_thread_stat()->perf_timers_addr(),
1238 PerfClassTraceTime::CLASS_LOAD);
1240 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1241 // Translate to external class name format, i.e., convert '/' chars to '.'
1242 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1244 JavaValue result(T_OBJECT);
1246 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1248 // Call public unsynchronized loadClass(String) directly for all class loaders
1249 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1250 // acquire a class-name based lock rather than the class loader object lock.
1251 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1252 // so the call to loadClassInternal() was not required.
1253 //
1254 // UnsyncloadClass flag means both call loadClass(String) and do
1255 // not acquire the class loader lock even for class loaders that are
1256 // not parallelCapable. This was a risky transitional
1257 // flag for diagnostic purposes only. It is risky to call
1258 // custom class loaders without synchronization.
1259 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1260 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1261 // Do NOT assume this will be supported in future releases.
1262 //
1263 // Added MustCallLoadClassInternal in case we discover in the field
1264 // a customer that counts on this call
1265 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1266 JavaCalls::call_special(&result,
1267 class_loader,
1268 spec_klass,
1269 vmSymbols::loadClassInternal_name(),
1270 vmSymbols::string_class_signature(),
1271 string,
1272 CHECK_(nh));
1273 } else {
1274 JavaCalls::call_virtual(&result,
1275 class_loader,
1276 spec_klass,
1277 vmSymbols::loadClass_name(),
1278 vmSymbols::string_class_signature(),
1279 string,
1280 CHECK_(nh));
1281 }
1283 assert(result.get_type() == T_OBJECT, "just checking");
1284 oop obj = (oop) result.get_jobject();
1286 // Primitive classes return null since forName() can not be
1287 // used to obtain any of the Class objects representing primitives or void
1288 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1289 instanceKlassHandle k =
1290 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1291 // For user defined Java class loaders, check that the name returned is
1292 // the same as that requested. This check is done for the bootstrap
1293 // loader when parsing the class file.
1294 if (class_name == k->name()) {
1295 return k;
1296 }
1297 }
1298 // Class is not found or has the wrong name, return NULL
1299 return nh;
1300 }
1301 }
1303 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1305 ClassLoaderData* loader_data = k->class_loader_data();
1306 Handle class_loader_h(THREAD, loader_data->class_loader());
1308 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1310 // for bootstrap and other parallel classloaders don't acquire lock,
1311 // use placeholder token
1312 // If a parallelCapable class loader calls define_instance_class instead of
1313 // find_or_define_instance_class to get here, we have a timing
1314 // hole with systemDictionary updates and check_constraints
1315 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1316 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1317 compute_loader_lock_object(class_loader_h, THREAD)),
1318 "define called without lock");
1319 }
1321 // Check class-loading constraints. Throw exception if violation is detected.
1322 // Grabs and releases SystemDictionary_lock
1323 // The check_constraints/find_class call and update_dictionary sequence
1324 // must be "atomic" for a specific class/classloader pair so we never
1325 // define two different instanceKlasses for that class/classloader pair.
1326 // Existing classloaders will call define_instance_class with the
1327 // classloader lock held
1328 // Parallel classloaders will call find_or_define_instance_class
1329 // which will require a token to perform the define class
1330 Symbol* name_h = k->name();
1331 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1332 int d_index = dictionary()->hash_to_index(d_hash);
1333 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1335 // Register class just loaded with class loader (placed in Vector)
1336 // Note we do this before updating the dictionary, as this can
1337 // fail with an OutOfMemoryError (if it does, we will *not* put this
1338 // class in the dictionary and will not update the class hierarchy).
1339 // JVMTI FollowReferences needs to find the classes this way.
1340 if (k->class_loader() != NULL) {
1341 methodHandle m(THREAD, Universe::loader_addClass_method());
1342 JavaValue result(T_VOID);
1343 JavaCallArguments args(class_loader_h);
1344 args.push_oop(Handle(THREAD, k->java_mirror()));
1345 JavaCalls::call(&result, m, &args, CHECK);
1346 }
1348 // Add the new class. We need recompile lock during update of CHA.
1349 {
1350 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1351 int p_index = placeholders()->hash_to_index(p_hash);
1353 MutexLocker mu_r(Compile_lock, THREAD);
1355 // Add to class hierarchy, initialize vtables, and do possible
1356 // deoptimizations.
1357 add_to_hierarchy(k, CHECK); // No exception, but can block
1359 // Add to systemDictionary - so other classes can see it.
1360 // Grabs and releases SystemDictionary_lock
1361 update_dictionary(d_index, d_hash, p_index, p_hash,
1362 k, class_loader_h, THREAD);
1363 }
1364 k->eager_initialize(THREAD);
1366 // notify jvmti
1367 if (JvmtiExport::should_post_class_load()) {
1368 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1369 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1371 }
1372 }
1374 // Support parallel classloading
1375 // All parallel class loaders, including bootstrap classloader
1376 // lock a placeholder entry for this class/class_loader pair
1377 // to allow parallel defines of different classes for this class loader
1378 // With AllowParallelDefine flag==true, in case they do not synchronize around
1379 // FindLoadedClass/DefineClass, calls, we check for parallel
1380 // loading for them, wait if a defineClass is in progress
1381 // and return the initial requestor's results
1382 // This flag does not apply to the bootstrap classloader.
1383 // With AllowParallelDefine flag==false, call through to define_instance_class
1384 // which will throw LinkageError: duplicate class definition.
1385 // False is the requested default.
1386 // For better performance, the class loaders should synchronize
1387 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1388 // potentially waste time reading and parsing the bytestream.
1389 // Note: VM callers should ensure consistency of k/class_name,class_loader
1390 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1392 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1393 Symbol* name_h = k->name(); // passed in class_name may be null
1394 ClassLoaderData* loader_data = class_loader_data(class_loader);
1396 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1397 int d_index = dictionary()->hash_to_index(d_hash);
1399 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1400 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1401 int p_index = placeholders()->hash_to_index(p_hash);
1402 PlaceholderEntry* probe;
1404 {
1405 MutexLocker mu(SystemDictionary_lock, THREAD);
1406 // First check if class already defined
1407 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1408 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1409 if (check != NULL) {
1410 return(instanceKlassHandle(THREAD, check));
1411 }
1412 }
1414 // Acquire define token for this class/classloader
1415 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1416 // Wait if another thread defining in parallel
1417 // All threads wait - even those that will throw duplicate class: otherwise
1418 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1419 // if other thread has not finished updating dictionary
1420 while (probe->definer() != NULL) {
1421 SystemDictionary_lock->wait();
1422 }
1423 // Only special cases allow parallel defines and can use other thread's results
1424 // Other cases fall through, and may run into duplicate defines
1425 // caught by finding an entry in the SystemDictionary
1426 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1427 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1428 SystemDictionary_lock->notify_all();
1429 #ifdef ASSERT
1430 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1431 assert(check != NULL, "definer missed recording success");
1432 #endif
1433 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1434 } else {
1435 // This thread will define the class (even if earlier thread tried and had an error)
1436 probe->set_definer(THREAD);
1437 }
1438 }
1440 define_instance_class(k, THREAD);
1442 Handle linkage_exception = Handle(); // null handle
1444 // definer must notify any waiting threads
1445 {
1446 MutexLocker mu(SystemDictionary_lock, THREAD);
1447 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1448 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1449 if (probe != NULL) {
1450 if (HAS_PENDING_EXCEPTION) {
1451 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1452 CLEAR_PENDING_EXCEPTION;
1453 } else {
1454 probe->set_instance_klass(k());
1455 }
1456 probe->set_definer(NULL);
1457 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1458 SystemDictionary_lock->notify_all();
1459 }
1460 }
1462 // Can't throw exception while holding lock due to rank ordering
1463 if (linkage_exception() != NULL) {
1464 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1465 }
1467 return k;
1468 }
1469 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1470 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1471 if (class_loader.is_null()) {
1472 return Handle(THREAD, _system_loader_lock_obj);
1473 } else {
1474 return class_loader;
1475 }
1476 }
1478 // This method is added to check how often we have to wait to grab loader
1479 // lock. The results are being recorded in the performance counters defined in
1480 // ClassLoader::_sync_systemLoaderLockContentionRate and
1481 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1482 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1483 if (!UsePerfData) {
1484 return;
1485 }
1487 assert(!loader_lock.is_null(), "NULL lock object");
1489 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1490 == ObjectSynchronizer::owner_other) {
1491 // contention will likely happen, so increment the corresponding
1492 // contention counter.
1493 if (loader_lock() == _system_loader_lock_obj) {
1494 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1495 } else {
1496 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1497 }
1498 }
1499 }
1501 // ----------------------------------------------------------------------------
1502 // Lookup
1504 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1505 Symbol* class_name,
1506 ClassLoaderData* loader_data) {
1507 assert_locked_or_safepoint(SystemDictionary_lock);
1508 assert (index == dictionary()->index_for(class_name, loader_data),
1509 "incorrect index?");
1511 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1512 return k;
1513 }
1516 // Basic find on classes in the midst of being loaded
1517 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1518 ClassLoaderData* loader_data) {
1519 assert_locked_or_safepoint(SystemDictionary_lock);
1520 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1521 int p_index = placeholders()->hash_to_index(p_hash);
1522 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1523 }
1526 // Used for assertions and verification only
1527 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1528 #ifndef ASSERT
1529 guarantee(VerifyBeforeGC ||
1530 VerifyDuringGC ||
1531 VerifyBeforeExit ||
1532 VerifyAfterGC, "too expensive");
1533 #endif
1534 assert_locked_or_safepoint(SystemDictionary_lock);
1536 // First look in the loaded class array
1537 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1538 int d_index = dictionary()->hash_to_index(d_hash);
1539 return find_class(d_index, d_hash, class_name, loader_data);
1540 }
1543 // Get the next class in the diictionary.
1544 Klass* SystemDictionary::try_get_next_class() {
1545 return dictionary()->try_get_next_class();
1546 }
1549 // ----------------------------------------------------------------------------
1550 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1551 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1552 // before a new class is used.
1554 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1555 assert(k.not_null(), "just checking");
1556 assert_locked_or_safepoint(Compile_lock);
1558 // Link into hierachy. Make sure the vtables are initialized before linking into
1559 k->append_to_sibling_list(); // add to superklass/sibling list
1560 k->process_interfaces(THREAD); // handle all "implements" declarations
1561 k->set_init_state(InstanceKlass::loaded);
1562 // Now flush all code that depended on old class hierarchy.
1563 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1564 // Also, first reinitialize vtable because it may have gotten out of synch
1565 // while the new class wasn't connected to the class hierarchy.
1566 Universe::flush_dependents_on(k);
1567 }
1570 // ----------------------------------------------------------------------------
1571 // GC support
1573 // Following roots during mark-sweep is separated in two phases.
1574 //
1575 // The first phase follows preloaded classes and all other system
1576 // classes, since these will never get unloaded anyway.
1577 //
1578 // The second phase removes (unloads) unreachable classes from the
1579 // system dictionary and follows the remaining classes' contents.
1581 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1582 blk->do_oop(&_java_system_loader);
1583 blk->do_oop(&_system_loader_lock_obj);
1585 dictionary()->always_strong_oops_do(blk);
1587 // Visit extra methods
1588 invoke_method_table()->oops_do(blk);
1589 }
1591 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1592 // Follow all system classes and temporary placeholders in dictionary
1593 dictionary()->always_strong_classes_do(closure);
1595 // Placeholders. These represent classes we're actively loading.
1596 placeholders()->classes_do(closure);
1597 }
1599 // Calculate a "good" systemdictionary size based
1600 // on predicted or current loaded classes count
1601 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1602 int newsize = _old_default_sdsize;
1603 if ((classcount > 0) && !DumpSharedSpaces) {
1604 int desiredsize = classcount/_average_depth_goal;
1605 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1606 newsize = _primelist[++_sdgeneration]) {
1607 if (desiredsize <= newsize) {
1608 break;
1609 }
1610 }
1611 }
1612 return newsize;
1613 }
1614 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1615 // Note: anonymous classes are not in the SD.
1616 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1617 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1618 bool has_dead_loaders = ClassLoaderDataGraph::do_unloading(is_alive);
1619 bool unloading_occurred = false;
1620 if (has_dead_loaders) {
1621 unloading_occurred = dictionary()->do_unloading();
1622 constraints()->purge_loader_constraints();
1623 resolution_errors()->purge_resolution_errors();
1624 }
1625 return unloading_occurred;
1626 }
1628 void SystemDictionary::oops_do(OopClosure* f) {
1629 f->do_oop(&_java_system_loader);
1630 f->do_oop(&_system_loader_lock_obj);
1632 // Adjust dictionary
1633 dictionary()->oops_do(f);
1635 // Visit extra methods
1636 invoke_method_table()->oops_do(f);
1637 }
1639 // Extended Class redefinition support.
1640 // If one of these classes is replaced, we need to replace it in these places.
1641 // KlassClosure::do_klass should take the address of a class but we can
1642 // change that later.
1643 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1644 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1645 f->do_klass(_well_known_klasses[k]);
1646 }
1648 {
1649 for (int i = 0; i < T_VOID+1; i++) {
1650 if (_box_klasses[i] != NULL) {
1651 assert(i >= T_BOOLEAN, "checking");
1652 f->do_klass(_box_klasses[i]);
1653 }
1654 }
1655 }
1657 FilteredFieldsMap::classes_do(f);
1658 }
1660 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1661 f->do_klass(_abstract_ownable_synchronizer_klass);
1662 }
1664 // Just the classes from defining class loaders
1665 // Don't iterate over placeholders
1666 void SystemDictionary::classes_do(void f(Klass*)) {
1667 dictionary()->classes_do(f);
1668 }
1670 // Added for initialize_itable_for_klass
1671 // Just the classes from defining class loaders
1672 // Don't iterate over placeholders
1673 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1674 dictionary()->classes_do(f, CHECK);
1675 }
1677 // All classes, and their class loaders
1678 // Don't iterate over placeholders
1679 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1680 dictionary()->classes_do(f);
1681 }
1683 // All classes, and their class loaders
1684 // (added for helpers that use HandleMarks and ResourceMarks)
1685 // Don't iterate over placeholders
1686 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*, TRAPS), TRAPS) {
1687 dictionary()->classes_do(f, CHECK);
1688 }
1690 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1691 placeholders()->entries_do(f);
1692 }
1694 void SystemDictionary::methods_do(void f(Method*)) {
1695 dictionary()->methods_do(f);
1696 invoke_method_table()->methods_do(f);
1697 }
1699 // ----------------------------------------------------------------------------
1700 // Lazily load klasses
1702 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1703 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1705 // if multiple threads calling this function, only one thread will load
1706 // the class. The other threads will find the loaded version once the
1707 // class is loaded.
1708 Klass* aos = _abstract_ownable_synchronizer_klass;
1709 if (aos == NULL) {
1710 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1711 // Force a fence to prevent any read before the write completes
1712 OrderAccess::fence();
1713 _abstract_ownable_synchronizer_klass = k;
1714 }
1715 }
1717 // ----------------------------------------------------------------------------
1718 // Initialization
1720 void SystemDictionary::initialize(TRAPS) {
1721 // Allocate arrays
1722 assert(dictionary() == NULL,
1723 "SystemDictionary should only be initialized once");
1724 _sdgeneration = 0;
1725 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1726 _placeholders = new PlaceholderTable(_nof_buckets);
1727 _number_of_modifications = 0;
1728 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1729 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1730 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1732 // Allocate private object used as system class loader lock
1733 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1734 // Initialize basic classes
1735 initialize_preloaded_classes(CHECK);
1736 }
1738 // Compact table of directions on the initialization of klasses:
1739 static const short wk_init_info[] = {
1740 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1741 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1742 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1743 | (int)SystemDictionary::option ),
1744 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1745 #undef WK_KLASS_INIT_INFO
1746 0
1747 };
1749 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1750 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1751 int info = wk_init_info[id - FIRST_WKID];
1752 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1753 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1754 Klass** klassp = &_well_known_klasses[id];
1755 bool must_load = (init_opt < SystemDictionary::Opt);
1756 if ((*klassp) == NULL) {
1757 if (must_load) {
1758 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1759 } else {
1760 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1761 }
1762 }
1763 return ((*klassp) != NULL);
1764 }
1766 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1767 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1768 for (int id = (int)start_id; id < (int)limit_id; id++) {
1769 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1770 int info = wk_init_info[id - FIRST_WKID];
1771 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1772 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1774 initialize_wk_klass((WKID)id, opt, CHECK);
1775 }
1777 // move the starting value forward to the limit:
1778 start_id = limit_id;
1779 }
1781 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1782 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1783 // Preload commonly used klasses
1784 WKID scan = FIRST_WKID;
1785 // first do Object, then String, Class
1786 if (UseSharedSpaces) {
1787 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1788 // Initialize the constant pool for the Object_class
1789 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1790 ik->constants()->restore_unshareable_info(CHECK);
1791 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1792 } else {
1793 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1794 }
1796 // Calculate offsets for String and Class classes since they are loaded and
1797 // can be used after this point.
1798 java_lang_String::compute_offsets();
1799 java_lang_Class::compute_offsets();
1801 // Fixup mirrors for classes loaded before java.lang.Class.
1802 // These calls iterate over the objects currently in the perm gen
1803 // so calling them at this point is matters (not before when there
1804 // are fewer objects and not later after there are more objects
1805 // in the perm gen.
1806 Universe::initialize_basic_type_mirrors(CHECK);
1807 Universe::fixup_mirrors(CHECK);
1809 // do a bunch more:
1810 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1812 // Preload ref klasses and set reference types
1813 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1814 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1816 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1817 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1818 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1819 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1820 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1822 // JSR 292 classes
1823 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
1824 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
1825 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
1826 if (EnableInvokeDynamic) {
1827 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
1828 } else {
1829 // Skip the JSR 292 classes, if not enabled.
1830 scan = WKID(jsr292_group_end + 1);
1831 }
1833 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1835 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
1836 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
1837 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
1838 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
1839 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
1840 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
1841 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
1842 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
1843 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1844 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1846 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1847 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1848 _has_loadClassInternal = (method != NULL);
1849 }
1850 { // Compute whether we should use checkPackageAccess or NOT
1851 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1852 _has_checkPackageAccess = (method != NULL);
1853 }
1854 }
1856 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1857 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1858 BasicType SystemDictionary::box_klass_type(Klass* k) {
1859 assert(k != NULL, "");
1860 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1861 if (_box_klasses[i] == k)
1862 return (BasicType)i;
1863 }
1864 return T_OBJECT;
1865 }
1867 // Constraints on class loaders. The details of the algorithm can be
1868 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1869 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1870 // that the system dictionary needs to maintain a set of contraints that
1871 // must be satisfied by all classes in the dictionary.
1872 // if defining is true, then LinkageError if already in systemDictionary
1873 // if initiating loader, then ok if InstanceKlass matches existing entry
1875 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1876 instanceKlassHandle k,
1877 Handle class_loader, bool defining,
1878 TRAPS) {
1879 const char *linkage_error = NULL;
1880 {
1881 Symbol* name = k->name();
1882 ClassLoaderData *loader_data = class_loader_data(class_loader);
1884 MutexLocker mu(SystemDictionary_lock, THREAD);
1886 Klass* check = find_class(d_index, d_hash, name, loader_data);
1887 if (check != (Klass*)NULL) {
1888 // if different InstanceKlass - duplicate class definition,
1889 // else - ok, class loaded by a different thread in parallel,
1890 // we should only have found it if it was done loading and ok to use
1891 // system dictionary only holds instance classes, placeholders
1892 // also holds array classes
1894 assert(check->oop_is_instance(), "noninstance in systemdictionary");
1895 if ((defining == true) || (k() != check)) {
1896 linkage_error = "loader (instance of %s): attempted duplicate class "
1897 "definition for name: \"%s\"";
1898 } else {
1899 return;
1900 }
1901 }
1903 #ifdef ASSERT
1904 Symbol* ph_check = find_placeholder(name, loader_data);
1905 assert(ph_check == NULL || ph_check == name, "invalid symbol");
1906 #endif
1908 if (linkage_error == NULL) {
1909 if (constraints()->check_or_update(k, class_loader, name) == false) {
1910 linkage_error = "loader constraint violation: loader (instance of %s)"
1911 " previously initiated loading for a different type with name \"%s\"";
1912 }
1913 }
1914 }
1916 // Throw error now if needed (cannot throw while holding
1917 // SystemDictionary_lock because of rank ordering)
1919 if (linkage_error) {
1920 ResourceMark rm(THREAD);
1921 const char* class_loader_name = loader_name(class_loader());
1922 char* type_name = k->name()->as_C_string();
1923 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1924 strlen(type_name);
1925 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1926 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1927 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1928 }
1929 }
1932 // Update system dictionary - done after check_constraint and add_to_hierachy
1933 // have been called.
1934 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1935 int p_index, unsigned int p_hash,
1936 instanceKlassHandle k,
1937 Handle class_loader,
1938 TRAPS) {
1939 // Compile_lock prevents systemDictionary updates during compilations
1940 assert_locked_or_safepoint(Compile_lock);
1941 Symbol* name = k->name();
1942 ClassLoaderData *loader_data = class_loader_data(class_loader);
1944 {
1945 MutexLocker mu1(SystemDictionary_lock, THREAD);
1947 // See whether biased locking is enabled and if so set it for this
1948 // klass.
1949 // Note that this must be done past the last potential blocking
1950 // point / safepoint. We enable biased locking lazily using a
1951 // VM_Operation to iterate the SystemDictionary and installing the
1952 // biasable mark word into each InstanceKlass's prototype header.
1953 // To avoid race conditions where we accidentally miss enabling the
1954 // optimization for one class in the process of being added to the
1955 // dictionary, we must not safepoint after the test of
1956 // BiasedLocking::enabled().
1957 if (UseBiasedLocking && BiasedLocking::enabled()) {
1958 // Set biased locking bit for all loaded classes; it will be
1959 // cleared if revocation occurs too often for this type
1960 // NOTE that we must only do this when the class is initally
1961 // defined, not each time it is referenced from a new class loader
1962 if (k->class_loader() == class_loader()) {
1963 k->set_prototype_header(markOopDesc::biased_locking_prototype());
1964 }
1965 }
1967 // Assign a classid if one has not already been assigned. The
1968 // counter does not need to be atomically incremented since this
1969 // is only done while holding the SystemDictionary_lock.
1970 // All loaded classes get a unique ID.
1971 TRACE_INIT_ID(k);
1973 // Make a new system dictionary entry.
1974 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
1975 if (sd_check == NULL) {
1976 dictionary()->add_klass(name, loader_data, k);
1977 notice_modification();
1978 }
1979 #ifdef ASSERT
1980 sd_check = find_class(d_index, d_hash, name, loader_data);
1981 assert (sd_check != NULL, "should have entry in system dictionary");
1982 // Note: there may be a placeholder entry: for circularity testing
1983 // or for parallel defines
1984 #endif
1985 SystemDictionary_lock->notify_all();
1986 }
1987 }
1990 // Try to find a class name using the loader constraints. The
1991 // loader constraints might know about a class that isn't fully loaded
1992 // yet and these will be ignored.
1993 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
1994 Symbol* class_name, Handle class_loader, TRAPS) {
1996 // First see if it has been loaded directly.
1997 // Force the protection domain to be null. (This removes protection checks.)
1998 Handle no_protection_domain;
1999 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2000 no_protection_domain, CHECK_NULL);
2001 if (klass != NULL)
2002 return klass;
2004 // Now look to see if it has been loaded elsewhere, and is subject to
2005 // a loader constraint that would require this loader to return the
2006 // klass that is already loaded.
2007 if (FieldType::is_array(class_name)) {
2008 // For array classes, their Klass*s are not kept in the
2009 // constraint table. The element Klass*s are.
2010 FieldArrayInfo fd;
2011 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2012 if (t != T_OBJECT) {
2013 klass = Universe::typeArrayKlassObj(t);
2014 } else {
2015 MutexLocker mu(SystemDictionary_lock, THREAD);
2016 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2017 }
2018 // If element class already loaded, allocate array klass
2019 if (klass != NULL) {
2020 klass = klass->array_klass_or_null(fd.dimension());
2021 }
2022 } else {
2023 MutexLocker mu(SystemDictionary_lock, THREAD);
2024 // Non-array classes are easy: simply check the constraint table.
2025 klass = constraints()->find_constrained_klass(class_name, class_loader);
2026 }
2028 return klass;
2029 }
2032 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2033 Handle class_loader1,
2034 Handle class_loader2,
2035 Thread* THREAD) {
2036 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2037 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2039 Symbol* constraint_name = NULL;
2040 if (!FieldType::is_array(class_name)) {
2041 constraint_name = class_name;
2042 } else {
2043 // For array classes, their Klass*s are not kept in the
2044 // constraint table. The element classes are.
2045 FieldArrayInfo fd;
2046 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2047 // primitive types always pass
2048 if (t != T_OBJECT) {
2049 return true;
2050 } else {
2051 constraint_name = fd.object_key();
2052 }
2053 }
2054 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2055 int d_index1 = dictionary()->hash_to_index(d_hash1);
2057 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2058 int d_index2 = dictionary()->hash_to_index(d_hash2);
2059 {
2060 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2062 // Better never do a GC while we're holding these oops
2063 No_Safepoint_Verifier nosafepoint;
2065 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2066 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2067 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2068 klass2, class_loader2);
2069 }
2070 }
2072 // Add entry to resolution error table to record the error when the first
2073 // attempt to resolve a reference to a class has failed.
2074 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2075 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2076 int index = resolution_errors()->hash_to_index(hash);
2077 {
2078 MutexLocker ml(SystemDictionary_lock, Thread::current());
2079 resolution_errors()->add_entry(index, hash, pool, which, error);
2080 }
2081 }
2083 // Delete a resolution error for RedefineClasses for a constant pool is going away
2084 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2085 resolution_errors()->delete_entry(pool);
2086 }
2088 // Lookup resolution error table. Returns error if found, otherwise NULL.
2089 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2090 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2091 int index = resolution_errors()->hash_to_index(hash);
2092 {
2093 MutexLocker ml(SystemDictionary_lock, Thread::current());
2094 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2095 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2096 }
2097 }
2100 // Signature constraints ensure that callers and callees agree about
2101 // the meaning of type names in their signatures. This routine is the
2102 // intake for constraints. It collects them from several places:
2103 //
2104 // * LinkResolver::resolve_method (if check_access is true) requires
2105 // that the resolving class (the caller) and the defining class of
2106 // the resolved method (the callee) agree on each type in the
2107 // method's signature.
2108 //
2109 // * LinkResolver::resolve_interface_method performs exactly the same
2110 // checks.
2111 //
2112 // * LinkResolver::resolve_field requires that the constant pool
2113 // attempting to link to a field agree with the field's defining
2114 // class about the type of the field signature.
2115 //
2116 // * klassVtable::initialize_vtable requires that, when a class
2117 // overrides a vtable entry allocated by a superclass, that the
2118 // overriding method (i.e., the callee) agree with the superclass
2119 // on each type in the method's signature.
2120 //
2121 // * klassItable::initialize_itable requires that, when a class fills
2122 // in its itables, for each non-abstract method installed in an
2123 // itable, the method (i.e., the callee) agree with the interface
2124 // on each type in the method's signature.
2125 //
2126 // All those methods have a boolean (check_access, checkconstraints)
2127 // which turns off the checks. This is used from specialized contexts
2128 // such as bootstrapping, dumping, and debugging.
2129 //
2130 // No direct constraint is placed between the class and its
2131 // supertypes. Constraints are only placed along linked relations
2132 // between callers and callees. When a method overrides or implements
2133 // an abstract method in a supertype (superclass or interface), the
2134 // constraints are placed as if the supertype were the caller to the
2135 // overriding method. (This works well, since callers to the
2136 // supertype have already established agreement between themselves and
2137 // the supertype.) As a result of all this, a class can disagree with
2138 // its supertype about the meaning of a type name, as long as that
2139 // class neither calls a relevant method of the supertype, nor is
2140 // called (perhaps via an override) from the supertype.
2141 //
2142 //
2143 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2144 //
2145 // Make sure all class components (including arrays) in the given
2146 // signature will be resolved to the same class in both loaders.
2147 // Returns the name of the type that failed a loader constraint check, or
2148 // NULL if no constraint failed. The returned C string needs cleaning up
2149 // with a ResourceMark in the caller. No exception except OOME is thrown.
2150 // Arrays are not added to the loader constraint table, their elements are.
2151 char* SystemDictionary::check_signature_loaders(Symbol* signature,
2152 Handle loader1, Handle loader2,
2153 bool is_method, TRAPS) {
2154 // Nothing to do if loaders are the same.
2155 if (loader1() == loader2()) {
2156 return NULL;
2157 }
2159 ResourceMark rm(THREAD);
2160 SignatureStream sig_strm(signature, is_method);
2161 while (!sig_strm.is_done()) {
2162 if (sig_strm.is_object()) {
2163 Symbol* s = sig_strm.as_symbol(CHECK_NULL);
2164 Symbol* sig = s;
2165 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2166 return sig->as_C_string();
2167 }
2168 }
2169 sig_strm.next();
2170 }
2171 return NULL;
2172 }
2175 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2176 Symbol* signature,
2177 TRAPS) {
2178 methodHandle empty;
2179 assert(EnableInvokeDynamic, "");
2180 assert(MethodHandles::is_signature_polymorphic(iid) &&
2181 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2182 iid != vmIntrinsics::_invokeGeneric,
2183 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2185 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2186 int index = invoke_method_table()->hash_to_index(hash);
2187 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2188 methodHandle m;
2189 if (spe == NULL || spe->method() == NULL) {
2190 spe = NULL;
2191 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2192 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2193 CompileBroker::compile_method(m, InvocationEntryBci, CompLevel_highest_tier,
2194 methodHandle(), CompileThreshold, "MH", CHECK_(empty));
2196 // Now grab the lock. We might have to throw away the new method,
2197 // if a racing thread has managed to install one at the same time.
2198 {
2199 MutexLocker ml(SystemDictionary_lock, THREAD);
2200 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2201 if (spe == NULL)
2202 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2203 if (spe->method() == NULL)
2204 spe->set_method(m());
2205 }
2206 }
2208 assert(spe != NULL && spe->method() != NULL, "");
2209 return spe->method();
2210 }
2212 // Helper for unpacking the return value from linkMethod and linkCallSite.
2213 static methodHandle unpack_method_and_appendix(Handle mname,
2214 KlassHandle accessing_klass,
2215 objArrayHandle appendix_box,
2216 Handle* appendix_result,
2217 TRAPS) {
2218 methodHandle empty;
2219 if (mname.not_null()) {
2220 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2221 if (vmtarget != NULL && vmtarget->is_method()) {
2222 Method* m = (Method*)vmtarget;
2223 oop appendix = appendix_box->obj_at(0);
2224 if (TraceMethodHandles) {
2225 #ifndef PRODUCT
2226 tty->print("Linked method="INTPTR_FORMAT": ", m);
2227 m->print();
2228 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2229 tty->cr();
2230 #endif //PRODUCT
2231 }
2232 (*appendix_result) = Handle(THREAD, appendix);
2233 // the target is stored in the cpCache and if a reference to this
2234 // MethodName is dropped we need a way to make sure the
2235 // class_loader containing this method is kept alive.
2236 // FIXME: the appendix might also preserve this dependency.
2237 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2238 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2239 return methodHandle(THREAD, m);
2240 }
2241 }
2242 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2243 return empty;
2244 }
2246 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2247 Symbol* signature,
2248 KlassHandle accessing_klass,
2249 Handle *appendix_result,
2250 Handle *method_type_result,
2251 TRAPS) {
2252 methodHandle empty;
2253 assert(EnableInvokeDynamic, "");
2254 assert(!THREAD->is_Compiler_thread(), "");
2255 Handle method_type =
2256 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2257 if (false) { // FIXME: Decide if the Java upcall should resolve signatures.
2258 method_type = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2259 }
2261 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2262 int ref_kind = JVM_REF_invokeVirtual;
2263 Handle name_str = StringTable::intern(name, CHECK_(empty));
2264 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2265 assert(appendix_box->obj_at(0) == NULL, "");
2267 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2268 JavaCallArguments args;
2269 args.push_oop(accessing_klass()->java_mirror());
2270 args.push_int(ref_kind);
2271 args.push_oop(mh_klass()->java_mirror());
2272 args.push_oop(name_str());
2273 args.push_oop(method_type());
2274 args.push_oop(appendix_box());
2275 JavaValue result(T_OBJECT);
2276 JavaCalls::call_static(&result,
2277 SystemDictionary::MethodHandleNatives_klass(),
2278 vmSymbols::linkMethod_name(),
2279 vmSymbols::linkMethod_signature(),
2280 &args, CHECK_(empty));
2281 Handle mname(THREAD, (oop) result.get_jobject());
2282 (*method_type_result) = method_type;
2283 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2284 }
2287 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2288 // signature, as interpreted relative to the given class loader.
2289 // Because of class loader constraints, all method handle usage must be
2290 // consistent with this loader.
2291 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2292 KlassHandle accessing_klass,
2293 TRAPS) {
2294 Handle empty;
2295 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2296 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2297 int index = invoke_method_table()->hash_to_index(hash);
2298 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2299 if (spe != NULL && spe->method_type() != NULL) {
2300 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2301 return Handle(THREAD, spe->method_type());
2302 } else if (THREAD->is_Compiler_thread()) {
2303 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2304 return Handle(); // do not attempt from within compiler, unless it was cached
2305 }
2307 Handle class_loader, protection_domain;
2308 bool is_on_bcp = true; // keep this true as long as we can materialize from the boot classloader
2309 int npts = ArgumentCount(signature).size();
2310 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2311 int arg = 0;
2312 Handle rt; // the return type from the signature
2313 ResourceMark rm(THREAD);
2314 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2315 oop mirror = NULL;
2316 if (is_on_bcp) {
2317 // Note: class_loader & protection_domain are both null at this point.
2318 mirror = ss.as_java_mirror(class_loader, protection_domain,
2319 SignatureStream::ReturnNull, CHECK_(empty));
2320 if (mirror == NULL) {
2321 // fall back from BCP to accessing_klass
2322 if (accessing_klass.not_null()) {
2323 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2324 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2325 }
2326 is_on_bcp = false;
2327 }
2328 }
2329 if (!is_on_bcp) {
2330 // Resolve, throwing a real error if it doesn't work.
2331 mirror = ss.as_java_mirror(class_loader, protection_domain,
2332 SignatureStream::NCDFError, CHECK_(empty));
2333 }
2334 if (ss.at_return_type())
2335 rt = Handle(THREAD, mirror);
2336 else
2337 pts->obj_at_put(arg++, mirror);
2339 // Check accessibility.
2340 if (ss.is_object() && accessing_klass.not_null()) {
2341 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2342 mirror = NULL; // safety
2343 // Emulate ConstantPool::verify_constant_pool_resolve.
2344 if (sel_klass->oop_is_objArray())
2345 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2346 if (sel_klass->oop_is_instance()) {
2347 KlassHandle sel_kh(THREAD, sel_klass);
2348 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2349 }
2350 }
2351 }
2352 assert(arg == npts, "");
2354 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2355 JavaCallArguments args(Handle(THREAD, rt()));
2356 args.push_oop(pts());
2357 JavaValue result(T_OBJECT);
2358 JavaCalls::call_static(&result,
2359 SystemDictionary::MethodHandleNatives_klass(),
2360 vmSymbols::findMethodHandleType_name(),
2361 vmSymbols::findMethodHandleType_signature(),
2362 &args, CHECK_(empty));
2363 Handle method_type(THREAD, (oop) result.get_jobject());
2365 if (is_on_bcp) {
2366 // We can cache this MethodType inside the JVM.
2367 MutexLocker ml(SystemDictionary_lock, THREAD);
2368 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2369 if (spe == NULL)
2370 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2371 if (spe->method_type() == NULL) {
2372 spe->set_method_type(method_type());
2373 }
2374 }
2376 // report back to the caller with the MethodType
2377 return method_type;
2378 }
2380 // Ask Java code to find or construct a method handle constant.
2381 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2382 int ref_kind, //e.g., JVM_REF_invokeVirtual
2383 KlassHandle callee,
2384 Symbol* name_sym,
2385 Symbol* signature,
2386 TRAPS) {
2387 Handle empty;
2388 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2389 Handle type;
2390 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2391 type = find_method_handle_type(signature, caller, CHECK_(empty));
2392 } else {
2393 ResourceMark rm(THREAD);
2394 SignatureStream ss(signature, false);
2395 if (!ss.is_done()) {
2396 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2397 SignatureStream::NCDFError, CHECK_(empty));
2398 type = Handle(THREAD, mirror);
2399 ss.next();
2400 if (!ss.is_done()) type = Handle(); // error!
2401 }
2402 }
2403 if (type.is_null()) {
2404 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2405 }
2407 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2408 JavaCallArguments args;
2409 args.push_oop(caller->java_mirror()); // the referring class
2410 args.push_int(ref_kind);
2411 args.push_oop(callee->java_mirror()); // the target class
2412 args.push_oop(name());
2413 args.push_oop(type());
2414 JavaValue result(T_OBJECT);
2415 JavaCalls::call_static(&result,
2416 SystemDictionary::MethodHandleNatives_klass(),
2417 vmSymbols::linkMethodHandleConstant_name(),
2418 vmSymbols::linkMethodHandleConstant_signature(),
2419 &args, CHECK_(empty));
2420 return Handle(THREAD, (oop) result.get_jobject());
2421 }
2423 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2424 // name and signature, as interpreted relative to the given class loader.
2425 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2426 Handle bootstrap_specifier,
2427 Symbol* name,
2428 Symbol* type,
2429 Handle *appendix_result,
2430 Handle *method_type_result,
2431 TRAPS) {
2432 methodHandle empty;
2433 Handle bsm, info;
2434 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2435 bsm = bootstrap_specifier;
2436 } else {
2437 assert(bootstrap_specifier->is_objArray(), "");
2438 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2439 int len = args->length();
2440 assert(len >= 1, "");
2441 bsm = Handle(THREAD, args->obj_at(0));
2442 if (len > 1) {
2443 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2444 for (int i = 1; i < len; i++)
2445 args1->obj_at_put(i-1, args->obj_at(i));
2446 info = Handle(THREAD, args1);
2447 }
2448 }
2449 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2450 "caller must supply a valid BSM");
2452 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2453 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2455 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2456 assert(appendix_box->obj_at(0) == NULL, "");
2458 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2459 JavaCallArguments args;
2460 args.push_oop(caller->java_mirror());
2461 args.push_oop(bsm());
2462 args.push_oop(method_name());
2463 args.push_oop(method_type());
2464 args.push_oop(info());
2465 args.push_oop(appendix_box);
2466 JavaValue result(T_OBJECT);
2467 JavaCalls::call_static(&result,
2468 SystemDictionary::MethodHandleNatives_klass(),
2469 vmSymbols::linkCallSite_name(),
2470 vmSymbols::linkCallSite_signature(),
2471 &args, CHECK_(empty));
2472 Handle mname(THREAD, (oop) result.get_jobject());
2473 (*method_type_result) = method_type;
2474 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2475 }
2477 // Since the identity hash code for symbols changes when the symbols are
2478 // moved from the regular perm gen (hash in the mark word) to the shared
2479 // spaces (hash is the address), the classes loaded into the dictionary
2480 // may be in the wrong buckets.
2482 void SystemDictionary::reorder_dictionary() {
2483 dictionary()->reorder_dictionary();
2484 }
2487 void SystemDictionary::copy_buckets(char** top, char* end) {
2488 dictionary()->copy_buckets(top, end);
2489 }
2492 void SystemDictionary::copy_table(char** top, char* end) {
2493 dictionary()->copy_table(top, end);
2494 }
2497 void SystemDictionary::reverse() {
2498 dictionary()->reverse();
2499 }
2501 int SystemDictionary::number_of_classes() {
2502 return dictionary()->number_of_entries();
2503 }
2506 // ----------------------------------------------------------------------------
2507 #ifndef PRODUCT
2509 void SystemDictionary::print() {
2510 dictionary()->print();
2512 // Placeholders
2513 GCMutexLocker mu(SystemDictionary_lock);
2514 placeholders()->print();
2516 // loader constraints - print under SD_lock
2517 constraints()->print();
2518 }
2520 #endif
2522 void SystemDictionary::verify() {
2523 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2524 guarantee(constraints() != NULL,
2525 "Verify of loader constraints failed");
2526 guarantee(dictionary()->number_of_entries() >= 0 &&
2527 placeholders()->number_of_entries() >= 0,
2528 "Verify of system dictionary failed");
2530 // Verify dictionary
2531 dictionary()->verify();
2533 GCMutexLocker mu(SystemDictionary_lock);
2534 placeholders()->verify();
2536 // Verify constraint table
2537 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2538 constraints()->verify(dictionary(), placeholders());
2539 }
2542 void SystemDictionary::verify_obj_klass_present(Symbol* class_name,
2543 ClassLoaderData* loader_data) {
2544 GCMutexLocker mu(SystemDictionary_lock);
2545 Symbol* name;
2547 Klass* probe = find_class(class_name, loader_data);
2548 if (probe == NULL) {
2549 probe = SystemDictionary::find_shared_class(class_name);
2550 if (probe == NULL) {
2551 name = find_placeholder(class_name, loader_data);
2552 }
2553 }
2554 guarantee(probe != NULL || name != NULL,
2555 "Loaded klasses should be in SystemDictionary");
2556 }
2558 #ifndef PRODUCT
2560 // statistics code
2561 class ClassStatistics: AllStatic {
2562 private:
2563 static int nclasses; // number of classes
2564 static int nmethods; // number of methods
2565 static int nmethoddata; // number of methodData
2566 static int class_size; // size of class objects in words
2567 static int method_size; // size of method objects in words
2568 static int debug_size; // size of debug info in methods
2569 static int methoddata_size; // size of methodData objects in words
2571 static void do_class(Klass* k) {
2572 nclasses++;
2573 class_size += k->size();
2574 if (k->oop_is_instance()) {
2575 InstanceKlass* ik = (InstanceKlass*)k;
2576 class_size += ik->methods()->size();
2577 class_size += ik->constants()->size();
2578 class_size += ik->local_interfaces()->size();
2579 class_size += ik->transitive_interfaces()->size();
2580 // We do not have to count implementors, since we only store one!
2581 // SSS: How should these be accounted now that they have moved?
2582 // class_size += ik->fields()->length();
2583 }
2584 }
2586 static void do_method(Method* m) {
2587 nmethods++;
2588 method_size += m->size();
2589 // class loader uses same objArray for empty vectors, so don't count these
2590 if (m->has_stackmap_table()) {
2591 method_size += m->stackmap_data()->size();
2592 }
2594 MethodData* mdo = m->method_data();
2595 if (mdo != NULL) {
2596 nmethoddata++;
2597 methoddata_size += mdo->size();
2598 }
2599 }
2601 public:
2602 static void print() {
2603 SystemDictionary::classes_do(do_class);
2604 SystemDictionary::methods_do(do_method);
2605 tty->print_cr("Class statistics:");
2606 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2607 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2608 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2609 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2610 }
2611 };
2614 int ClassStatistics::nclasses = 0;
2615 int ClassStatistics::nmethods = 0;
2616 int ClassStatistics::nmethoddata = 0;
2617 int ClassStatistics::class_size = 0;
2618 int ClassStatistics::method_size = 0;
2619 int ClassStatistics::debug_size = 0;
2620 int ClassStatistics::methoddata_size = 0;
2622 void SystemDictionary::print_class_statistics() {
2623 ResourceMark rm;
2624 ClassStatistics::print();
2625 }
2628 class MethodStatistics: AllStatic {
2629 public:
2630 enum {
2631 max_parameter_size = 10
2632 };
2633 private:
2635 static int _number_of_methods;
2636 static int _number_of_final_methods;
2637 static int _number_of_static_methods;
2638 static int _number_of_native_methods;
2639 static int _number_of_synchronized_methods;
2640 static int _number_of_profiled_methods;
2641 static int _number_of_bytecodes;
2642 static int _parameter_size_profile[max_parameter_size];
2643 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2645 static void initialize() {
2646 _number_of_methods = 0;
2647 _number_of_final_methods = 0;
2648 _number_of_static_methods = 0;
2649 _number_of_native_methods = 0;
2650 _number_of_synchronized_methods = 0;
2651 _number_of_profiled_methods = 0;
2652 _number_of_bytecodes = 0;
2653 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2654 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2655 };
2657 static void do_method(Method* m) {
2658 _number_of_methods++;
2659 // collect flag info
2660 if (m->is_final() ) _number_of_final_methods++;
2661 if (m->is_static() ) _number_of_static_methods++;
2662 if (m->is_native() ) _number_of_native_methods++;
2663 if (m->is_synchronized()) _number_of_synchronized_methods++;
2664 if (m->method_data() != NULL) _number_of_profiled_methods++;
2665 // collect parameter size info (add one for receiver, if any)
2666 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2667 // collect bytecodes info
2668 {
2669 Thread *thread = Thread::current();
2670 HandleMark hm(thread);
2671 BytecodeStream s(methodHandle(thread, m));
2672 Bytecodes::Code c;
2673 while ((c = s.next()) >= 0) {
2674 _number_of_bytecodes++;
2675 _bytecodes_profile[c]++;
2676 }
2677 }
2678 }
2680 public:
2681 static void print() {
2682 initialize();
2683 SystemDictionary::methods_do(do_method);
2684 // generate output
2685 tty->cr();
2686 tty->print_cr("Method statistics (static):");
2687 // flag distribution
2688 tty->cr();
2689 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2690 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2691 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2692 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2693 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2694 // parameter size profile
2695 tty->cr();
2696 { int tot = 0;
2697 int avg = 0;
2698 for (int i = 0; i < max_parameter_size; i++) {
2699 int n = _parameter_size_profile[i];
2700 tot += n;
2701 avg += n*i;
2702 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2703 }
2704 assert(tot == _number_of_methods, "should be the same");
2705 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2706 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2707 }
2708 // bytecodes profile
2709 tty->cr();
2710 { int tot = 0;
2711 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2712 if (Bytecodes::is_defined(i)) {
2713 Bytecodes::Code c = Bytecodes::cast(i);
2714 int n = _bytecodes_profile[c];
2715 tot += n;
2716 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2717 }
2718 }
2719 assert(tot == _number_of_bytecodes, "should be the same");
2720 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2721 }
2722 tty->cr();
2723 }
2724 };
2726 int MethodStatistics::_number_of_methods;
2727 int MethodStatistics::_number_of_final_methods;
2728 int MethodStatistics::_number_of_static_methods;
2729 int MethodStatistics::_number_of_native_methods;
2730 int MethodStatistics::_number_of_synchronized_methods;
2731 int MethodStatistics::_number_of_profiled_methods;
2732 int MethodStatistics::_number_of_bytecodes;
2733 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2734 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2737 void SystemDictionary::print_method_statistics() {
2738 MethodStatistics::print();
2739 }
2741 #endif // PRODUCT