Mercurial > hg > truffle
annotate src/share/vm/classfile/systemDictionary.cpp @ 515:a0401dc51d0b
6791656: nsk defclass0 asserts handles.hpp
Reviewed-by: phh, xlu
author | acorn |
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date | Thu, 08 Jan 2009 16:27:28 -0500 |
parents | c81d2ef51ca3 |
children | dca06e7f503d |
rev | line source |
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0 | 1 /* |
196 | 2 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_systemDictionary.cpp.incl" | |
27 | |
28 | |
29 Dictionary* SystemDictionary::_dictionary = NULL; | |
30 PlaceholderTable* SystemDictionary::_placeholders = NULL; | |
31 Dictionary* SystemDictionary::_shared_dictionary = NULL; | |
32 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL; | |
33 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL; | |
34 | |
35 | |
36 int SystemDictionary::_number_of_modifications = 0; | |
37 | |
38 oop SystemDictionary::_system_loader_lock_obj = NULL; | |
39 | |
132
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40 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT] |
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41 = { NULL /*, NULL...*/ }; |
0 | 42 |
43 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ }; | |
44 | |
45 oop SystemDictionary::_java_system_loader = NULL; | |
46 | |
47 bool SystemDictionary::_has_loadClassInternal = false; | |
48 bool SystemDictionary::_has_checkPackageAccess = false; | |
49 | |
50 // lazily initialized klass variables | |
51 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL; | |
52 | |
53 | |
54 // ---------------------------------------------------------------------------- | |
55 // Java-level SystemLoader | |
56 | |
57 oop SystemDictionary::java_system_loader() { | |
58 return _java_system_loader; | |
59 } | |
60 | |
61 void SystemDictionary::compute_java_system_loader(TRAPS) { | |
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62 KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass)); |
0 | 63 JavaValue result(T_OBJECT); |
64 JavaCalls::call_static(&result, | |
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65 KlassHandle(THREAD, WK_KLASS(classloader_klass)), |
0 | 66 vmSymbolHandles::getSystemClassLoader_name(), |
67 vmSymbolHandles::void_classloader_signature(), | |
68 CHECK); | |
69 | |
70 _java_system_loader = (oop)result.get_jobject(); | |
71 } | |
72 | |
73 | |
74 // ---------------------------------------------------------------------------- | |
75 // debugging | |
76 | |
77 #ifdef ASSERT | |
78 | |
79 // return true if class_name contains no '.' (internal format is '/') | |
80 bool SystemDictionary::is_internal_format(symbolHandle class_name) { | |
81 if (class_name.not_null()) { | |
82 ResourceMark rm; | |
83 char* name = class_name->as_C_string(); | |
84 return strchr(name, '.') == NULL; | |
85 } else { | |
86 return true; | |
87 } | |
88 } | |
89 | |
90 #endif | |
91 | |
92 // ---------------------------------------------------------------------------- | |
514 | 93 // Parallel class loading check |
94 | |
95 bool SystemDictionary::is_parallelCapable(Handle class_loader) { | |
96 if (UnsyncloadClass || class_loader.is_null()) return true; | |
97 if (AlwaysLockClassLoader) return false; | |
98 return java_lang_Class::parallelCapable(class_loader()); | |
99 } | |
100 // ---------------------------------------------------------------------------- | |
0 | 101 // Resolving of classes |
102 | |
103 // Forwards to resolve_or_null | |
104 | |
105 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) { | |
106 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD); | |
107 if (HAS_PENDING_EXCEPTION || klass == NULL) { | |
108 KlassHandle k_h(THREAD, klass); | |
109 // can return a null klass | |
110 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD); | |
111 } | |
112 return klass; | |
113 } | |
114 | |
115 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) { | |
116 if (HAS_PENDING_EXCEPTION) { | |
117 // If we have a pending exception we forward it to the caller, unless throw_error is true, | |
118 // in which case we have to check whether the pending exception is a ClassNotFoundException, | |
119 // and if so convert it to a NoClassDefFoundError | |
120 // And chain the original ClassNotFoundException | |
121 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) { | |
122 ResourceMark rm(THREAD); | |
123 assert(klass_h() == NULL, "Should not have result with exception pending"); | |
124 Handle e(THREAD, PENDING_EXCEPTION); | |
125 CLEAR_PENDING_EXCEPTION; | |
126 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e); | |
127 } else { | |
128 return NULL; | |
129 } | |
130 } | |
131 // Class not found, throw appropriate error or exception depending on value of throw_error | |
132 if (klass_h() == NULL) { | |
133 ResourceMark rm(THREAD); | |
134 if (throw_error) { | |
135 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string()); | |
136 } else { | |
137 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string()); | |
138 } | |
139 } | |
140 return (klassOop)klass_h(); | |
141 } | |
142 | |
143 | |
144 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, | |
145 bool throw_error, TRAPS) | |
146 { | |
147 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD); | |
148 } | |
149 | |
150 | |
151 // Forwards to resolve_instance_class_or_null | |
152 | |
153 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { | |
154 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread"); | |
155 if (FieldType::is_array(class_name())) { | |
156 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); | |
157 } else { | |
158 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL); | |
159 } | |
160 } | |
161 | |
162 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) { | |
163 return resolve_or_null(class_name, Handle(), Handle(), THREAD); | |
164 } | |
165 | |
166 // Forwards to resolve_instance_class_or_null | |
167 | |
168 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name, | |
169 Handle class_loader, | |
170 Handle protection_domain, | |
171 TRAPS) { | |
172 assert(FieldType::is_array(class_name()), "must be array"); | |
173 jint dimension; | |
174 symbolOop object_key; | |
175 klassOop k = NULL; | |
176 // dimension and object_key are assigned as a side-effect of this call | |
177 BasicType t = FieldType::get_array_info(class_name(), | |
178 &dimension, | |
179 &object_key, | |
180 CHECK_NULL); | |
181 | |
182 if (t == T_OBJECT) { | |
183 symbolHandle h_key(THREAD, object_key); | |
184 // naked oop "k" is OK here -- we assign back into it | |
185 k = SystemDictionary::resolve_instance_class_or_null(h_key, | |
186 class_loader, | |
187 protection_domain, | |
188 CHECK_NULL); | |
189 if (k != NULL) { | |
190 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL); | |
191 } | |
192 } else { | |
193 k = Universe::typeArrayKlassObj(t); | |
194 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL); | |
195 } | |
196 return k; | |
197 } | |
198 | |
199 | |
200 // Must be called for any super-class or super-interface resolution | |
201 // during class definition to allow class circularity checking | |
202 // super-interface callers: | |
203 // parse_interfaces - for defineClass & jvmtiRedefineClasses | |
204 // super-class callers: | |
205 // ClassFileParser - for defineClass & jvmtiRedefineClasses | |
206 // load_shared_class - while loading a class from shared archive | |
514 | 207 // resolve_instance_class_or_null: |
208 // via: handle_parallel_super_load | |
0 | 209 // when resolving a class that has an existing placeholder with |
210 // a saved superclass [i.e. a defineClass is currently in progress] | |
211 // if another thread is trying to resolve the class, it must do | |
212 // super-class checks on its own thread to catch class circularity | |
213 // This last call is critical in class circularity checking for cases | |
214 // where classloading is delegated to different threads and the | |
215 // classloader lock is released. | |
216 // Take the case: Base->Super->Base | |
217 // 1. If thread T1 tries to do a defineClass of class Base | |
218 // resolve_super_or_fail creates placeholder: T1, Base (super Super) | |
219 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super | |
220 // so it tries to load Super | |
221 // 3. If we load the class internally, or user classloader uses same thread | |
222 // loadClassFromxxx or defineClass via parseClassFile Super ... | |
223 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base) | |
224 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base | |
225 // 3.4 calls resolve_super_or_fail Base | |
226 // 3.5 finds T1,Base -> throws class circularity | |
227 //OR 4. If T2 tries to resolve Super via defineClass Super ... | |
228 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base) | |
229 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super) | |
230 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2 | |
231 // 4.4 finds T2, Super -> throws class circularity | |
232 // Must be called, even if superclass is null, since this is | |
233 // where the placeholder entry is created which claims this | |
234 // thread is loading this class/classloader. | |
235 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name, | |
236 symbolHandle class_name, | |
237 Handle class_loader, | |
238 Handle protection_domain, | |
239 bool is_superclass, | |
240 TRAPS) { | |
241 | |
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242 // Try to get one of the well-known klasses. |
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243 // They are trusted, and do not participate in circularities. |
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244 if (LinkWellKnownClasses) { |
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245 klassOop k = find_well_known_klass(class_name()); |
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246 if (k != NULL) { |
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247 return k; |
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248 } |
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249 } |
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250 |
0 | 251 // Double-check, if child class is already loaded, just return super-class,interface |
252 // Don't add a placedholder if already loaded, i.e. already in system dictionary | |
253 // Make sure there's a placeholder for the *child* before resolving. | |
254 // Used as a claim that this thread is currently loading superclass/classloader | |
255 // Used here for ClassCircularity checks and also for heap verification | |
256 // (every instanceKlass in the heap needs to be in the system dictionary | |
257 // or have a placeholder). | |
258 // Must check ClassCircularity before checking if super class is already loaded | |
259 // | |
260 // We might not already have a placeholder if this child_name was | |
261 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass); | |
262 // the name of the class might not be known until the stream is actually | |
263 // parsed. | |
264 // Bugs 4643874, 4715493 | |
265 // compute_hash can have a safepoint | |
266 | |
267 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader); | |
268 int d_index = dictionary()->hash_to_index(d_hash); | |
269 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader); | |
270 int p_index = placeholders()->hash_to_index(p_hash); | |
271 // can't throw error holding a lock | |
272 bool child_already_loaded = false; | |
273 bool throw_circularity_error = false; | |
274 { | |
275 MutexLocker mu(SystemDictionary_lock, THREAD); | |
276 klassOop childk = find_class(d_index, d_hash, child_name, class_loader); | |
277 klassOop quicksuperk; | |
278 // to support // loading: if child done loading, just return superclass | |
279 // if class_name, & class_loader don't match: | |
280 // if initial define, SD update will give LinkageError | |
281 // if redefine: compare_class_versions will give HIERARCHY_CHANGED | |
282 // so we don't throw an exception here. | |
283 // see: nsk redefclass014 & java.lang.instrument Instrument032 | |
284 if ((childk != NULL ) && (is_superclass) && | |
285 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) && | |
286 | |
287 ((Klass::cast(quicksuperk)->name() == class_name()) && | |
288 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) { | |
289 return quicksuperk; | |
290 } else { | |
291 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); | |
292 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) { | |
293 throw_circularity_error = true; | |
294 } | |
514 | 295 } |
296 if (!throw_circularity_error) { | |
0 | 297 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD); |
298 } | |
299 } | |
300 if (throw_circularity_error) { | |
301 ResourceMark rm(THREAD); | |
302 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string()); | |
303 } | |
304 | |
305 // java.lang.Object should have been found above | |
306 assert(class_name() != NULL, "null super class for resolving"); | |
307 // Resolve the super class or interface, check results on return | |
308 klassOop superk = NULL; | |
309 superk = SystemDictionary::resolve_or_null(class_name, | |
310 class_loader, | |
311 protection_domain, | |
312 THREAD); | |
313 | |
314 KlassHandle superk_h(THREAD, superk); | |
315 | |
316 // Note: clean up of placeholders currently in callers of | |
317 // resolve_super_or_fail - either at update_dictionary time | |
318 // or on error | |
319 { | |
320 MutexLocker mu(SystemDictionary_lock, THREAD); | |
321 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader); | |
322 if (probe != NULL) { | |
323 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER); | |
324 } | |
325 } | |
326 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) { | |
327 // can null superk | |
328 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD)); | |
329 } | |
330 | |
331 return superk_h(); | |
332 } | |
333 | |
334 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass, | |
335 Handle class_loader, | |
336 Handle protection_domain, | |
337 TRAPS) { | |
338 if(!has_checkPackageAccess()) return; | |
339 | |
340 // Now we have to call back to java to check if the initating class has access | |
341 JavaValue result(T_VOID); | |
342 if (TraceProtectionDomainVerification) { | |
343 // Print out trace information | |
344 tty->print_cr("Checking package access"); | |
345 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr(); | |
346 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr(); | |
347 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr(); | |
348 } | |
349 | |
350 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader"); | |
351 | |
352 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass()); | |
353 JavaCalls::call_special(&result, | |
354 class_loader, | |
355 system_loader, | |
356 vmSymbolHandles::checkPackageAccess_name(), | |
357 vmSymbolHandles::class_protectiondomain_signature(), | |
358 Handle(THREAD, klass->java_mirror()), | |
359 protection_domain, | |
360 THREAD); | |
361 | |
362 if (TraceProtectionDomainVerification) { | |
363 if (HAS_PENDING_EXCEPTION) { | |
364 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!"); | |
365 } else { | |
366 tty->print_cr(" -> granted"); | |
367 } | |
368 tty->cr(); | |
369 } | |
370 | |
371 if (HAS_PENDING_EXCEPTION) return; | |
372 | |
373 // If no exception has been thrown, we have validated the protection domain | |
374 // Insert the protection domain of the initiating class into the set. | |
375 { | |
376 // We recalculate the entry here -- we've called out to java since | |
377 // the last time it was calculated. | |
378 symbolHandle kn(THREAD, klass->name()); | |
379 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader); | |
380 int d_index = dictionary()->hash_to_index(d_hash); | |
381 | |
382 MutexLocker mu(SystemDictionary_lock, THREAD); | |
383 { | |
384 // Note that we have an entry, and entries can be deleted only during GC, | |
385 // so we cannot allow GC to occur while we're holding this entry. | |
386 | |
387 // We're using a No_Safepoint_Verifier to catch any place where we | |
388 // might potentially do a GC at all. | |
389 // SystemDictionary::do_unloading() asserts that classes are only | |
390 // unloaded at a safepoint. | |
391 No_Safepoint_Verifier nosafepoint; | |
392 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader, | |
393 protection_domain, THREAD); | |
394 } | |
395 } | |
396 } | |
397 | |
398 // We only get here if this thread finds that another thread | |
399 // has already claimed the placeholder token for the current operation, | |
400 // but that other thread either never owned or gave up the | |
401 // object lock | |
402 // Waits on SystemDictionary_lock to indicate placeholder table updated | |
403 // On return, caller must recheck placeholder table state | |
404 // | |
405 // We only get here if | |
406 // 1) custom classLoader, i.e. not bootstrap classloader | |
407 // 2) UnsyncloadClass not set | |
408 // 3) custom classLoader has broken the class loader objectLock | |
409 // so another thread got here in parallel | |
410 // | |
411 // lockObject must be held. | |
412 // Complicated dance due to lock ordering: | |
413 // Must first release the classloader object lock to | |
414 // allow initial definer to complete the class definition | |
415 // and to avoid deadlock | |
416 // Reclaim classloader lock object with same original recursion count | |
417 // Must release SystemDictionary_lock after notify, since | |
418 // class loader lock must be claimed before SystemDictionary_lock | |
419 // to prevent deadlocks | |
420 // | |
421 // The notify allows applications that did an untimed wait() on | |
422 // the classloader object lock to not hang. | |
423 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) { | |
424 assert_lock_strong(SystemDictionary_lock); | |
425 | |
426 bool calledholdinglock | |
427 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject); | |
428 assert(calledholdinglock,"must hold lock for notify"); | |
514 | 429 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait"); |
0 | 430 ObjectSynchronizer::notifyall(lockObject, THREAD); |
431 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD); | |
432 SystemDictionary_lock->wait(); | |
433 SystemDictionary_lock->unlock(); | |
434 ObjectSynchronizer::reenter(lockObject, recursions, THREAD); | |
435 SystemDictionary_lock->lock(); | |
436 } | |
437 | |
438 // If the class in is in the placeholder table, class loading is in progress | |
439 // For cases where the application changes threads to load classes, it | |
440 // is critical to ClassCircularity detection that we try loading | |
441 // the superclass on the same thread internally, so we do parallel | |
442 // super class loading here. | |
443 // This also is critical in cases where the original thread gets stalled | |
444 // even in non-circularity situations. | |
445 // Note: only one thread can define the class, but multiple can resolve | |
446 // Note: must call resolve_super_or_fail even if null super - | |
514 | 447 // to force placeholder entry creation for this class for circularity detection |
0 | 448 // Caller must check for pending exception |
449 // Returns non-null klassOop if other thread has completed load | |
450 // and we are done, | |
451 // If return null klassOop and no pending exception, the caller must load the class | |
452 instanceKlassHandle SystemDictionary::handle_parallel_super_load( | |
453 symbolHandle name, symbolHandle superclassname, Handle class_loader, | |
454 Handle protection_domain, Handle lockObject, TRAPS) { | |
455 | |
456 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
457 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); | |
458 int d_index = dictionary()->hash_to_index(d_hash); | |
459 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
460 int p_index = placeholders()->hash_to_index(p_hash); | |
461 | |
462 // superk is not used, resolve_super called for circularity check only | |
463 // This code is reached in two situations. One if this thread | |
464 // is loading the same class twice (e.g. ClassCircularity, or | |
465 // java.lang.instrument). | |
466 // The second is if another thread started the resolve_super first | |
467 // and has not yet finished. | |
468 // In both cases the original caller will clean up the placeholder | |
469 // entry on error. | |
470 klassOop superk = SystemDictionary::resolve_super_or_fail(name, | |
471 superclassname, | |
472 class_loader, | |
473 protection_domain, | |
474 true, | |
475 CHECK_(nh)); | |
476 // We don't redefine the class, so we just need to clean up if there | |
477 // was not an error (don't want to modify any system dictionary | |
478 // data structures). | |
479 { | |
480 MutexLocker mu(SystemDictionary_lock, THREAD); | |
481 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
482 SystemDictionary_lock->notify_all(); | |
483 } | |
484 | |
514 | 485 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete |
486 // Serial class loaders and bootstrap classloader do wait for superclass loads | |
487 if (!class_loader.is_null() && is_parallelCapable(class_loader)) { | |
0 | 488 MutexLocker mu(SystemDictionary_lock, THREAD); |
489 // Check if classloading completed while we were loading superclass or waiting | |
490 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
491 if (check != NULL) { | |
492 // Klass is already loaded, so just return it | |
493 return(instanceKlassHandle(THREAD, check)); | |
494 } else { | |
495 return nh; | |
496 } | |
497 } | |
498 | |
499 // must loop to both handle other placeholder updates | |
500 // and spurious notifications | |
501 bool super_load_in_progress = true; | |
502 PlaceholderEntry* placeholder; | |
503 while (super_load_in_progress) { | |
504 MutexLocker mu(SystemDictionary_lock, THREAD); | |
505 // Check if classloading completed while we were loading superclass or waiting | |
506 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
507 if (check != NULL) { | |
508 // Klass is already loaded, so just return it | |
509 return(instanceKlassHandle(THREAD, check)); | |
510 } else { | |
511 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
512 if (placeholder && placeholder->super_load_in_progress() ){ | |
513 // Before UnsyncloadClass: | |
514 // We only get here if the application has released the | |
515 // classloader lock when another thread was in the middle of loading a | |
516 // superclass/superinterface for this class, and now | |
517 // this thread is also trying to load this class. | |
518 // To minimize surprises, the first thread that started to | |
519 // load a class should be the one to complete the loading | |
520 // with the classfile it initially expected. | |
521 // This logic has the current thread wait once it has done | |
522 // all the superclass/superinterface loading it can, until | |
523 // the original thread completes the class loading or fails | |
524 // If it completes we will use the resulting instanceKlass | |
525 // which we will find below in the systemDictionary. | |
526 // We also get here for parallel bootstrap classloader | |
527 if (class_loader.is_null()) { | |
528 SystemDictionary_lock->wait(); | |
529 } else { | |
530 double_lock_wait(lockObject, THREAD); | |
531 } | |
532 } else { | |
533 // If not in SD and not in PH, other thread's load must have failed | |
534 super_load_in_progress = false; | |
535 } | |
536 } | |
537 } | |
538 return (nh); | |
539 } | |
540 | |
541 | |
542 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) { | |
543 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name"); | |
544 // First check to see if we should remove wrapping L and ; | |
545 symbolHandle name; | |
546 if (FieldType::is_obj(class_name())) { | |
547 ResourceMark rm(THREAD); | |
548 // Ignore wrapping L and ;. | |
549 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL); | |
550 } else { | |
551 name = class_name; | |
552 } | |
553 | |
554 // UseNewReflection | |
555 // Fix for 4474172; see evaluation for more details | |
556 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader())); | |
557 | |
558 // Do lookup to see if class already exist and the protection domain | |
559 // has the right access | |
560 unsigned int d_hash = dictionary()->compute_hash(name, class_loader); | |
561 int d_index = dictionary()->hash_to_index(d_hash); | |
562 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader, | |
563 protection_domain, THREAD); | |
564 if (probe != NULL) return probe; | |
565 | |
566 | |
567 // Non-bootstrap class loaders will call out to class loader and | |
568 // define via jvm/jni_DefineClass which will acquire the | |
569 // class loader object lock to protect against multiple threads | |
570 // defining the class in parallel by accident. | |
571 // This lock must be acquired here so the waiter will find | |
572 // any successful result in the SystemDictionary and not attempt | |
573 // the define | |
514 | 574 // ParallelCapable Classloaders and the bootstrap classloader, |
0 | 575 // or all classloaders with UnsyncloadClass do not acquire lock here |
576 bool DoObjectLock = true; | |
514 | 577 if (is_parallelCapable(class_loader)) { |
0 | 578 DoObjectLock = false; |
579 } | |
580 | |
581 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
582 int p_index = placeholders()->hash_to_index(p_hash); | |
583 | |
584 // Class is not in SystemDictionary so we have to do loading. | |
585 // Make sure we are synchronized on the class loader before we proceed | |
586 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); | |
587 check_loader_lock_contention(lockObject, THREAD); | |
588 ObjectLocker ol(lockObject, THREAD, DoObjectLock); | |
589 | |
590 // Check again (after locking) if class already exist in SystemDictionary | |
591 bool class_has_been_loaded = false; | |
592 bool super_load_in_progress = false; | |
593 bool havesupername = false; | |
594 instanceKlassHandle k; | |
595 PlaceholderEntry* placeholder; | |
596 symbolHandle superclassname; | |
597 | |
598 { | |
599 MutexLocker mu(SystemDictionary_lock, THREAD); | |
600 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
601 if (check != NULL) { | |
602 // Klass is already loaded, so just return it | |
603 class_has_been_loaded = true; | |
604 k = instanceKlassHandle(THREAD, check); | |
605 } else { | |
606 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
607 if (placeholder && placeholder->super_load_in_progress()) { | |
608 super_load_in_progress = true; | |
609 if (placeholder->havesupername() == true) { | |
610 superclassname = symbolHandle(THREAD, placeholder->supername()); | |
611 havesupername = true; | |
612 } | |
613 } | |
614 } | |
615 } | |
616 | |
617 // If the class in is in the placeholder table, class loading is in progress | |
618 if (super_load_in_progress && havesupername==true) { | |
619 k = SystemDictionary::handle_parallel_super_load(name, superclassname, | |
620 class_loader, protection_domain, lockObject, THREAD); | |
621 if (HAS_PENDING_EXCEPTION) { | |
622 return NULL; | |
623 } | |
624 if (!k.is_null()) { | |
625 class_has_been_loaded = true; | |
626 } | |
627 } | |
628 | |
629 if (!class_has_been_loaded) { | |
630 | |
631 // add placeholder entry to record loading instance class | |
632 // Five cases: | |
633 // All cases need to prevent modifying bootclasssearchpath | |
634 // in parallel with a classload of same classname | |
514 | 635 // Redefineclasses uses existence of the placeholder for the duration |
636 // of the class load to prevent concurrent redefinition of not completely | |
637 // defined classes. | |
0 | 638 // case 1. traditional classloaders that rely on the classloader object lock |
639 // - no other need for LOAD_INSTANCE | |
640 // case 2. traditional classloaders that break the classloader object lock | |
641 // as a deadlock workaround. Detection of this case requires that | |
642 // this check is done while holding the classloader object lock, | |
643 // and that lock is still held when calling classloader's loadClass. | |
644 // For these classloaders, we ensure that the first requestor | |
645 // completes the load and other requestors wait for completion. | |
646 // case 3. UnsyncloadClass - don't use objectLocker | |
647 // With this flag, we allow parallel classloading of a | |
648 // class/classloader pair | |
649 // case4. Bootstrap classloader - don't own objectLocker | |
650 // This classloader supports parallelism at the classloader level, | |
651 // but only allows a single load of a class/classloader pair. | |
652 // No performance benefit and no deadlock issues. | |
514 | 653 // case 5. parallelCapable user level classloaders - without objectLocker |
654 // Allow parallel classloading of a class/classloader pair | |
0 | 655 symbolHandle nullsymbolHandle; |
656 bool throw_circularity_error = false; | |
657 { | |
658 MutexLocker mu(SystemDictionary_lock, THREAD); | |
514 | 659 if (class_loader.is_null() || !is_parallelCapable(class_loader)) { |
0 | 660 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); |
661 if (oldprobe) { | |
662 // only need check_seen_thread once, not on each loop | |
663 // 6341374 java/lang/Instrument with -Xcomp | |
664 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) { | |
665 throw_circularity_error = true; | |
666 } else { | |
667 // case 1: traditional: should never see load_in_progress. | |
668 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) { | |
669 | |
670 // case 4: bootstrap classloader: prevent futile classloading, | |
671 // wait on first requestor | |
672 if (class_loader.is_null()) { | |
673 SystemDictionary_lock->wait(); | |
674 } else { | |
675 // case 2: traditional with broken classloader lock. wait on first | |
676 // requestor. | |
677 double_lock_wait(lockObject, THREAD); | |
678 } | |
679 // Check if classloading completed while we were waiting | |
680 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
681 if (check != NULL) { | |
682 // Klass is already loaded, so just return it | |
683 k = instanceKlassHandle(THREAD, check); | |
684 class_has_been_loaded = true; | |
685 } | |
686 // check if other thread failed to load and cleaned up | |
687 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
688 } | |
689 } | |
690 } | |
691 } | |
692 // All cases: add LOAD_INSTANCE | |
514 | 693 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try |
0 | 694 // LOAD_INSTANCE in parallel |
695 // add placeholder entry even if error - callers will remove on error | |
514 | 696 if (!throw_circularity_error && !class_has_been_loaded) { |
0 | 697 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD); |
698 // For class loaders that do not acquire the classloader object lock, | |
699 // if they did not catch another thread holding LOAD_INSTANCE, | |
700 // need a check analogous to the acquire ObjectLocker/find_class | |
701 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL | |
702 // one final check if the load has already completed | |
514 | 703 // class loaders holding the ObjectLock shouldn't find the class here |
0 | 704 klassOop check = find_class(d_index, d_hash, name, class_loader); |
705 if (check != NULL) { | |
706 // Klass is already loaded, so just return it | |
707 k = instanceKlassHandle(THREAD, check); | |
708 class_has_been_loaded = true; | |
709 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); | |
514 | 710 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); |
711 SystemDictionary_lock->notify_all(); | |
0 | 712 } |
713 } | |
714 } | |
715 // must throw error outside of owning lock | |
716 if (throw_circularity_error) { | |
717 ResourceMark rm(THREAD); | |
718 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string()); | |
719 } | |
720 | |
721 if (!class_has_been_loaded) { | |
722 | |
723 // Do actual loading | |
724 k = load_instance_class(name, class_loader, THREAD); | |
725 | |
514 | 726 // For UnsyncloadClass and AllowParallelDefineClass only: |
0 | 727 // If they got a linkageError, check if a parallel class load succeeded. |
728 // If it did, then for bytecode resolution the specification requires | |
729 // that we return the same result we did for the other thread, i.e. the | |
730 // successfully loaded instanceKlass | |
731 // Should not get here for classloaders that support parallelism | |
514 | 732 // with the new cleaner mechanism |
733 // Bootstrap goes through here to allow for an extra guarantee check | |
0 | 734 if (UnsyncloadClass || (class_loader.is_null())) { |
735 if (k.is_null() && HAS_PENDING_EXCEPTION | |
736 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) { | |
737 MutexLocker mu(SystemDictionary_lock, THREAD); | |
738 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
739 if (check != NULL) { | |
740 // Klass is already loaded, so just use it | |
741 k = instanceKlassHandle(THREAD, check); | |
742 CLEAR_PENDING_EXCEPTION; | |
743 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?"); | |
744 } | |
745 } | |
746 } | |
747 | |
748 // clean up placeholder entries for success or error | |
749 // This cleans up LOAD_INSTANCE entries | |
750 // It also cleans up LOAD_SUPER entries on errors from | |
751 // calling load_instance_class | |
752 { | |
753 MutexLocker mu(SystemDictionary_lock, THREAD); | |
754 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader); | |
755 if (probe != NULL) { | |
756 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE); | |
757 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
758 SystemDictionary_lock->notify_all(); | |
759 } | |
760 } | |
761 | |
762 // If everything was OK (no exceptions, no null return value), and | |
763 // class_loader is NOT the defining loader, do a little more bookkeeping. | |
764 if (!HAS_PENDING_EXCEPTION && !k.is_null() && | |
765 k->class_loader() != class_loader()) { | |
766 | |
767 check_constraints(d_index, d_hash, k, class_loader, false, THREAD); | |
768 | |
769 // Need to check for a PENDING_EXCEPTION again; check_constraints | |
770 // can throw and doesn't use the CHECK macro. | |
771 if (!HAS_PENDING_EXCEPTION) { | |
772 { // Grabbing the Compile_lock prevents systemDictionary updates | |
773 // during compilations. | |
774 MutexLocker mu(Compile_lock, THREAD); | |
775 update_dictionary(d_index, d_hash, p_index, p_hash, | |
776 k, class_loader, THREAD); | |
777 } | |
778 if (JvmtiExport::should_post_class_load()) { | |
779 Thread *thread = THREAD; | |
780 assert(thread->is_Java_thread(), "thread->is_Java_thread()"); | |
781 JvmtiExport::post_class_load((JavaThread *) thread, k()); | |
782 } | |
783 } | |
784 } | |
785 if (HAS_PENDING_EXCEPTION || k.is_null()) { | |
786 // On error, clean up placeholders | |
787 { | |
788 MutexLocker mu(SystemDictionary_lock, THREAD); | |
789 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
790 SystemDictionary_lock->notify_all(); | |
791 } | |
792 return NULL; | |
793 } | |
794 } | |
795 } | |
796 | |
797 #ifdef ASSERT | |
798 { | |
799 Handle loader (THREAD, k->class_loader()); | |
800 MutexLocker mu(SystemDictionary_lock, THREAD); | |
801 oop kk = find_class_or_placeholder(name, loader); | |
802 assert(kk == k(), "should be present in dictionary"); | |
803 } | |
804 #endif | |
805 | |
806 // return if the protection domain in NULL | |
807 if (protection_domain() == NULL) return k(); | |
808 | |
809 // Check the protection domain has the right access | |
810 { | |
811 MutexLocker mu(SystemDictionary_lock, THREAD); | |
812 // Note that we have an entry, and entries can be deleted only during GC, | |
813 // so we cannot allow GC to occur while we're holding this entry. | |
814 // We're using a No_Safepoint_Verifier to catch any place where we | |
815 // might potentially do a GC at all. | |
816 // SystemDictionary::do_unloading() asserts that classes are only | |
817 // unloaded at a safepoint. | |
818 No_Safepoint_Verifier nosafepoint; | |
819 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name, | |
820 class_loader, | |
821 protection_domain)) { | |
822 return k(); | |
823 } | |
824 } | |
825 | |
826 // Verify protection domain. If it fails an exception is thrown | |
827 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL))); | |
828 | |
829 return k(); | |
830 } | |
831 | |
832 | |
833 // This routine does not lock the system dictionary. | |
834 // | |
835 // Since readers don't hold a lock, we must make sure that system | |
836 // dictionary entries are only removed at a safepoint (when only one | |
837 // thread is running), and are added to in a safe way (all links must | |
838 // be updated in an MT-safe manner). | |
839 // | |
840 // Callers should be aware that an entry could be added just after | |
841 // _dictionary->bucket(index) is read here, so the caller will not see | |
842 // the new entry. | |
843 | |
844 klassOop SystemDictionary::find(symbolHandle class_name, | |
845 Handle class_loader, | |
846 Handle protection_domain, | |
847 TRAPS) { | |
848 | |
849 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); | |
850 int d_index = dictionary()->hash_to_index(d_hash); | |
851 | |
852 { | |
853 // Note that we have an entry, and entries can be deleted only during GC, | |
854 // so we cannot allow GC to occur while we're holding this entry. | |
855 // We're using a No_Safepoint_Verifier to catch any place where we | |
856 // might potentially do a GC at all. | |
857 // SystemDictionary::do_unloading() asserts that classes are only | |
858 // unloaded at a safepoint. | |
859 No_Safepoint_Verifier nosafepoint; | |
860 return dictionary()->find(d_index, d_hash, class_name, class_loader, | |
861 protection_domain, THREAD); | |
862 } | |
863 } | |
864 | |
865 | |
866 // Look for a loaded instance or array klass by name. Do not do any loading. | |
867 // return NULL in case of error. | |
868 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name, | |
869 Handle class_loader, | |
870 Handle protection_domain, | |
871 TRAPS) { | |
872 klassOop k = NULL; | |
873 assert(class_name() != NULL, "class name must be non NULL"); | |
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874 |
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875 // Try to get one of the well-known klasses. |
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876 if (LinkWellKnownClasses) { |
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877 k = find_well_known_klass(class_name()); |
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878 if (k != NULL) { |
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879 return k; |
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880 } |
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881 } |
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882 |
0 | 883 if (FieldType::is_array(class_name())) { |
884 // The name refers to an array. Parse the name. | |
885 jint dimension; | |
886 symbolOop object_key; | |
887 | |
888 // dimension and object_key are assigned as a side-effect of this call | |
889 BasicType t = FieldType::get_array_info(class_name(), &dimension, | |
890 &object_key, CHECK_(NULL)); | |
891 if (t != T_OBJECT) { | |
892 k = Universe::typeArrayKlassObj(t); | |
893 } else { | |
894 symbolHandle h_key(THREAD, object_key); | |
895 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD); | |
896 } | |
897 if (k != NULL) { | |
898 k = Klass::cast(k)->array_klass_or_null(dimension); | |
899 } | |
900 } else { | |
901 k = find(class_name, class_loader, protection_domain, THREAD); | |
902 } | |
903 return k; | |
904 } | |
905 | |
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906 // Quick range check for names of well-known classes: |
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907 static symbolOop wk_klass_name_limits[2] = {NULL, NULL}; |
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908 |
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909 #ifndef PRODUCT |
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910 static int find_wkk_calls, find_wkk_probes, find_wkk_wins; |
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911 // counts for "hello world": 3983, 1616, 1075 |
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912 // => 60% hit after limit guard, 25% total win rate |
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913 #endif |
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914 |
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915 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) { |
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916 // A bounds-check on class_name will quickly get a negative result. |
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917 NOT_PRODUCT(find_wkk_calls++); |
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918 if (class_name >= wk_klass_name_limits[0] && |
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919 class_name <= wk_klass_name_limits[1]) { |
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920 NOT_PRODUCT(find_wkk_probes++); |
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921 vmSymbols::SID sid = vmSymbols::find_sid(class_name); |
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922 if (sid != vmSymbols::NO_SID) { |
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923 klassOop k = NULL; |
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924 switch (sid) { |
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925 #define WK_KLASS_CASE(name, symbol, ignore_option) \ |
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926 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \ |
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927 k = WK_KLASS(name); break; |
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928 WK_KLASSES_DO(WK_KLASS_CASE) |
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929 #undef WK_KLASS_CASE |
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930 } |
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931 NOT_PRODUCT(if (k != NULL) find_wkk_wins++); |
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932 return k; |
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933 } |
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934 } |
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935 return NULL; |
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936 } |
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937 |
0 | 938 // Note: this method is much like resolve_from_stream, but |
939 // updates no supplemental data structures. | |
940 // TODO consolidate the two methods with a helper routine? | |
941 klassOop SystemDictionary::parse_stream(symbolHandle class_name, | |
942 Handle class_loader, | |
943 Handle protection_domain, | |
944 ClassFileStream* st, | |
431
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945 KlassHandle host_klass, |
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946 GrowableArray<Handle>* cp_patches, |
0 | 947 TRAPS) { |
948 symbolHandle parsed_name; | |
949 | |
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. | |
955 // Further note: a placeholder will be added for this class when | |
956 // super classes are loaded (resolve_super_or_fail). We expect this | |
957 // to be called for all classes but java.lang.Object; and we preload | |
958 // java.lang.Object through resolve_or_fail, not this path. | |
959 | |
960 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, | |
961 class_loader, | |
962 protection_domain, | |
963 parsed_name, | |
964 THREAD); | |
965 | |
514 | 966 |
0 | 967 // We don't redefine the class, so we just need to clean up whether there |
968 // was an error or not (don't want to modify any system dictionary | |
969 // data structures). | |
970 // Parsed name could be null if we threw an error before we got far | |
971 // enough along to parse it -- in that case, there is nothing to clean up. | |
972 if (!parsed_name.is_null()) { | |
973 unsigned int p_hash = placeholders()->compute_hash(parsed_name, | |
974 class_loader); | |
975 int p_index = placeholders()->hash_to_index(p_hash); | |
976 { | |
977 MutexLocker mu(SystemDictionary_lock, THREAD); | |
978 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); | |
979 SystemDictionary_lock->notify_all(); | |
980 } | |
981 } | |
982 | |
431
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983 if (host_klass.not_null() && k.not_null()) { |
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984 assert(AnonymousClasses, ""); |
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985 // If it's anonymous, initialize it now, since nobody else will. |
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986 k->set_host_klass(host_klass()); |
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987 |
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988 { |
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989 MutexLocker mu_r(Compile_lock, THREAD); |
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990 |
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991 // Add to class hierarchy, initialize vtables, and do possible |
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992 // deoptimizations. |
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993 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block |
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994 |
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995 // But, do not add to system dictionary. |
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996 } |
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997 |
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998 k->eager_initialize(THREAD); |
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999 |
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1000 // notify jvmti |
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1001 if (JvmtiExport::should_post_class_load()) { |
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1002 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); |
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1003 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); |
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1004 } |
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1005 } |
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1006 |
0 | 1007 return k(); |
1008 } | |
1009 | |
1010 // Add a klass to the system from a stream (called by jni_DefineClass and | |
1011 // JVM_DefineClass). | |
1012 // Note: class_name can be NULL. In that case we do not know the name of | |
1013 // the class until we have parsed the stream. | |
1014 | |
1015 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name, | |
1016 Handle class_loader, | |
1017 Handle protection_domain, | |
1018 ClassFileStream* st, | |
1019 TRAPS) { | |
1020 | |
514 | 1021 // Classloaders that support parallelism, e.g. bootstrap classloader, |
1022 // or all classloaders with UnsyncloadClass do not acquire lock here | |
1023 bool DoObjectLock = true; | |
1024 if (is_parallelCapable(class_loader)) { | |
1025 DoObjectLock = false; | |
1026 } | |
1027 | |
1028 // Make sure we are synchronized on the class loader before we proceed | |
0 | 1029 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); |
1030 check_loader_lock_contention(lockObject, THREAD); | |
514 | 1031 ObjectLocker ol(lockObject, THREAD, DoObjectLock); |
0 | 1032 |
1033 symbolHandle parsed_name; | |
1034 | |
1035 // Parse the stream. Note that we do this even though this klass might | |
1036 // already be present in the SystemDictionary, otherwise we would not | |
1037 // throw potential ClassFormatErrors. | |
1038 // | |
1039 // Note: "name" is updated. | |
1040 // Further note: a placeholder will be added for this class when | |
1041 // super classes are loaded (resolve_super_or_fail). We expect this | |
1042 // to be called for all classes but java.lang.Object; and we preload | |
1043 // java.lang.Object through resolve_or_fail, not this path. | |
1044 | |
1045 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name, | |
1046 class_loader, | |
1047 protection_domain, | |
1048 parsed_name, | |
1049 THREAD); | |
1050 | |
1051 const char* pkg = "java/"; | |
1052 if (!HAS_PENDING_EXCEPTION && | |
1053 !class_loader.is_null() && | |
1054 !parsed_name.is_null() && | |
1055 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) { | |
1056 // It is illegal to define classes in the "java." package from | |
1057 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader | |
1058 ResourceMark rm(THREAD); | |
1059 char* name = parsed_name->as_C_string(); | |
1060 char* index = strrchr(name, '/'); | |
1061 *index = '\0'; // chop to just the package name | |
1062 while ((index = strchr(name, '/')) != NULL) { | |
1063 *index = '.'; // replace '/' with '.' in package name | |
1064 } | |
1065 const char* fmt = "Prohibited package name: %s"; | |
1066 size_t len = strlen(fmt) + strlen(name); | |
1067 char* message = NEW_RESOURCE_ARRAY(char, len); | |
1068 jio_snprintf(message, len, fmt, name); | |
1069 Exceptions::_throw_msg(THREAD_AND_LOCATION, | |
1070 vmSymbols::java_lang_SecurityException(), message); | |
1071 } | |
1072 | |
1073 if (!HAS_PENDING_EXCEPTION) { | |
1074 assert(!parsed_name.is_null(), "Sanity"); | |
1075 assert(class_name.is_null() || class_name() == parsed_name(), | |
1076 "name mismatch"); | |
1077 // Verification prevents us from creating names with dots in them, this | |
1078 // asserts that that's the case. | |
1079 assert(is_internal_format(parsed_name), | |
1080 "external class name format used internally"); | |
1081 | |
1082 // Add class just loaded | |
514 | 1083 // If a class loader supports parallel classloading handle parallel define requests |
1084 // find_or_define_instance_class may return a different instanceKlass | |
1085 if (is_parallelCapable(class_loader)) { | |
1086 k = find_or_define_instance_class(class_name, class_loader, k, THREAD); | |
1087 } else { | |
1088 define_instance_class(k, THREAD); | |
1089 } | |
0 | 1090 } |
1091 | |
1092 // If parsing the class file or define_instance_class failed, we | |
1093 // need to remove the placeholder added on our behalf. But we | |
1094 // must make sure parsed_name is valid first (it won't be if we had | |
1095 // a format error before the class was parsed far enough to | |
1096 // find the name). | |
1097 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) { | |
1098 unsigned int p_hash = placeholders()->compute_hash(parsed_name, | |
1099 class_loader); | |
1100 int p_index = placeholders()->hash_to_index(p_hash); | |
1101 { | |
1102 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1103 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD); | |
1104 SystemDictionary_lock->notify_all(); | |
1105 } | |
1106 return NULL; | |
1107 } | |
1108 | |
1109 // Make sure that we didn't leave a place holder in the | |
1110 // SystemDictionary; this is only done on success | |
1111 debug_only( { | |
1112 if (!HAS_PENDING_EXCEPTION) { | |
1113 assert(!parsed_name.is_null(), "parsed_name is still null?"); | |
1114 symbolHandle h_name (THREAD, k->name()); | |
1115 Handle h_loader (THREAD, k->class_loader()); | |
1116 | |
1117 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1118 | |
1119 oop check = find_class_or_placeholder(parsed_name, class_loader); | |
1120 assert(check == k(), "should be present in the dictionary"); | |
1121 | |
1122 oop check2 = find_class_or_placeholder(h_name, h_loader); | |
1123 assert(check == check2, "name inconsistancy in SystemDictionary"); | |
1124 } | |
1125 } ); | |
1126 | |
1127 return k(); | |
1128 } | |
1129 | |
1130 | |
1131 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length, | |
1132 int number_of_entries) { | |
1133 assert(length == _nof_buckets * sizeof(HashtableBucket), | |
1134 "bad shared dictionary size."); | |
1135 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries); | |
1136 } | |
1137 | |
1138 | |
1139 // If there is a shared dictionary, then find the entry for the | |
1140 // given shared system class, if any. | |
1141 | |
1142 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) { | |
1143 if (shared_dictionary() != NULL) { | |
1144 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle()); | |
1145 int d_index = dictionary()->hash_to_index(d_hash); | |
1146 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name); | |
1147 } else { | |
1148 return NULL; | |
1149 } | |
1150 } | |
1151 | |
1152 | |
1153 // Load a class from the shared spaces (found through the shared system | |
1154 // dictionary). Force the superclass and all interfaces to be loaded. | |
1155 // Update the class definition to include sibling classes and no | |
1156 // subclasses (yet). [Classes in the shared space are not part of the | |
1157 // object hierarchy until loaded.] | |
1158 | |
1159 instanceKlassHandle SystemDictionary::load_shared_class( | |
1160 symbolHandle class_name, Handle class_loader, TRAPS) { | |
1161 instanceKlassHandle ik (THREAD, find_shared_class(class_name)); | |
1162 return load_shared_class(ik, class_loader, THREAD); | |
1163 } | |
1164 | |
1165 // Note well! Changes to this method may affect oop access order | |
1166 // in the shared archive. Please take care to not make changes that | |
1167 // adversely affect cold start time by changing the oop access order | |
1168 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and | |
1169 // MarkAndMoveOrderedReadWrite closures. | |
1170 instanceKlassHandle SystemDictionary::load_shared_class( | |
1171 instanceKlassHandle ik, Handle class_loader, TRAPS) { | |
1172 assert(class_loader.is_null(), "non-null classloader for shared class?"); | |
1173 if (ik.not_null()) { | |
1174 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
1175 symbolHandle class_name(THREAD, ik->name()); | |
1176 | |
1177 // Found the class, now load the superclass and interfaces. If they | |
1178 // are shared, add them to the main system dictionary and reset | |
1179 // their hierarchy references (supers, subs, and interfaces). | |
1180 | |
1181 if (ik->super() != NULL) { | |
1182 symbolHandle cn(THREAD, ik->super()->klass_part()->name()); | |
1183 resolve_super_or_fail(class_name, cn, | |
1184 class_loader, Handle(), true, CHECK_(nh)); | |
1185 } | |
1186 | |
1187 objArrayHandle interfaces (THREAD, ik->local_interfaces()); | |
1188 int num_interfaces = interfaces->length(); | |
1189 for (int index = 0; index < num_interfaces; index++) { | |
1190 klassOop k = klassOop(interfaces->obj_at(index)); | |
1191 | |
1192 // Note: can not use instanceKlass::cast here because | |
1193 // interfaces' instanceKlass's C++ vtbls haven't been | |
1194 // reinitialized yet (they will be once the interface classes | |
1195 // are loaded) | |
1196 symbolHandle name (THREAD, k->klass_part()->name()); | |
1197 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh)); | |
1198 } | |
1199 | |
1200 // Adjust methods to recover missing data. They need addresses for | |
1201 // interpreter entry points and their default native method address | |
1202 // must be reset. | |
1203 | |
1204 // Updating methods must be done under a lock so multiple | |
1205 // threads don't update these in parallel | |
1206 // Shared classes are all currently loaded by the bootstrap | |
1207 // classloader, so this will never cause a deadlock on | |
1208 // a custom class loader lock. | |
1209 | |
1210 { | |
1211 Handle lockObject = compute_loader_lock_object(class_loader, THREAD); | |
1212 check_loader_lock_contention(lockObject, THREAD); | |
1213 ObjectLocker ol(lockObject, THREAD, true); | |
1214 | |
1215 objArrayHandle methods (THREAD, ik->methods()); | |
1216 int num_methods = methods->length(); | |
1217 for (int index2 = 0; index2 < num_methods; ++index2) { | |
1218 methodHandle m(THREAD, methodOop(methods->obj_at(index2))); | |
1219 m()->link_method(m, CHECK_(nh)); | |
1220 } | |
1221 } | |
1222 | |
1223 if (TraceClassLoading) { | |
1224 ResourceMark rm; | |
1225 tty->print("[Loaded %s", ik->external_name()); | |
1226 tty->print(" from shared objects file"); | |
1227 tty->print_cr("]"); | |
1228 } | |
1229 // notify a class loaded from shared object | |
1230 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()), | |
1231 true /* shared class */); | |
1232 } | |
1233 return ik; | |
1234 } | |
1235 | |
1236 #ifdef KERNEL | |
1237 // Some classes on the bootstrap class path haven't been installed on the | |
1238 // system yet. Call the DownloadManager method to make them appear in the | |
1239 // bootstrap class path and try again to load the named class. | |
1240 // Note that with delegation class loaders all classes in another loader will | |
1241 // first try to call this so it'd better be fast!! | |
1242 static instanceKlassHandle download_and_retry_class_load( | |
1243 symbolHandle class_name, | |
1244 TRAPS) { | |
1245 | |
1246 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass(); | |
1247 instanceKlassHandle nk; | |
1248 | |
1249 // If download manager class isn't loaded just return. | |
1250 if (dlm == NULL) return nk; | |
1251 | |
1252 { HandleMark hm(THREAD); | |
1253 ResourceMark rm(THREAD); | |
1254 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk)); | |
1255 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk)); | |
1256 | |
1257 // return value | |
1258 JavaValue result(T_OBJECT); | |
1259 | |
1260 // Call the DownloadManager. We assume that it has a lock because | |
1261 // multiple classes could be not found and downloaded at the same time. | |
1262 // class sun.misc.DownloadManager; | |
1263 // public static String getBootClassPathEntryForClass(String className); | |
1264 JavaCalls::call_static(&result, | |
1265 KlassHandle(THREAD, dlm), | |
1266 vmSymbolHandles::getBootClassPathEntryForClass_name(), | |
1267 vmSymbolHandles::string_string_signature(), | |
1268 class_string, | |
1269 CHECK_(nk)); | |
1270 | |
1271 // Get result.string and add to bootclasspath | |
1272 assert(result.get_type() == T_OBJECT, "just checking"); | |
1273 oop obj = (oop) result.get_jobject(); | |
1274 if (obj == NULL) { return nk; } | |
1275 | |
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1276 Handle h_obj(THREAD, obj); |
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1277 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj, |
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1278 CHECK_(nk)); |
0 | 1279 |
1280 // lock the loader | |
1281 // we use this lock because JVMTI does. | |
1282 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock()); | |
1283 | |
1284 ObjectLocker ol(loader_lock, THREAD); | |
1285 // add the file to the bootclasspath | |
1286 ClassLoader::update_class_path_entry_list(new_class_name, true); | |
1287 } // end HandleMark | |
1288 | |
1289 if (TraceClassLoading) { | |
1290 ClassLoader::print_bootclasspath(); | |
1291 } | |
1292 return ClassLoader::load_classfile(class_name, CHECK_(nk)); | |
1293 } | |
1294 #endif // KERNEL | |
1295 | |
1296 | |
1297 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) { | |
1298 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
1299 if (class_loader.is_null()) { | |
1300 // Search the shared system dictionary for classes preloaded into the | |
1301 // shared spaces. | |
1302 instanceKlassHandle k; | |
1303 k = load_shared_class(class_name, class_loader, THREAD); | |
1304 | |
1305 if (k.is_null()) { | |
1306 // Use VM class loader | |
1307 k = ClassLoader::load_classfile(class_name, CHECK_(nh)); | |
1308 } | |
1309 | |
1310 #ifdef KERNEL | |
1311 // If the VM class loader has failed to load the class, call the | |
1312 // DownloadManager class to make it magically appear on the classpath | |
1313 // and try again. This is only configured with the Kernel VM. | |
1314 if (k.is_null()) { | |
1315 k = download_and_retry_class_load(class_name, CHECK_(nh)); | |
1316 } | |
1317 #endif // KERNEL | |
1318 | |
514 | 1319 // find_or_define_instance_class may return a different instanceKlass |
0 | 1320 if (!k.is_null()) { |
1321 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh)); | |
1322 } | |
1323 return k; | |
1324 } else { | |
1325 // Use user specified class loader to load class. Call loadClass operation on class_loader. | |
1326 ResourceMark rm(THREAD); | |
1327 | |
1328 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh)); | |
1329 // Translate to external class name format, i.e., convert '/' chars to '.' | |
1330 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh)); | |
1331 | |
1332 JavaValue result(T_OBJECT); | |
1333 | |
1334 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass()); | |
1335 | |
514 | 1336 // Call public unsynchronized loadClass(String) directly for all class loaders |
1337 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will | |
1338 // acquire a class-name based lock rather than the class loader object lock. | |
1339 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean), | |
1340 // so the call to loadClassInternal() was not required. | |
1341 // | |
1342 // UnsyncloadClass flag means both call loadClass(String) and do | |
1343 // not acquire the class loader lock even for class loaders that are | |
1344 // not parallelCapable. This was a risky transitional | |
1345 // flag for diagnostic purposes only. It is risky to call | |
0 | 1346 // custom class loaders without synchronization. |
1347 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of | |
514 | 1348 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field. |
0 | 1349 // Do NOT assume this will be supported in future releases. |
514 | 1350 // |
1351 // Added MustCallLoadClassInternal in case we discover in the field | |
1352 // a customer that counts on this call | |
1353 if (MustCallLoadClassInternal && has_loadClassInternal()) { | |
0 | 1354 JavaCalls::call_special(&result, |
1355 class_loader, | |
1356 spec_klass, | |
1357 vmSymbolHandles::loadClassInternal_name(), | |
1358 vmSymbolHandles::string_class_signature(), | |
1359 string, | |
1360 CHECK_(nh)); | |
1361 } else { | |
1362 JavaCalls::call_virtual(&result, | |
1363 class_loader, | |
1364 spec_klass, | |
1365 vmSymbolHandles::loadClass_name(), | |
1366 vmSymbolHandles::string_class_signature(), | |
1367 string, | |
1368 CHECK_(nh)); | |
1369 } | |
1370 | |
1371 assert(result.get_type() == T_OBJECT, "just checking"); | |
1372 oop obj = (oop) result.get_jobject(); | |
1373 | |
1374 // Primitive classes return null since forName() can not be | |
1375 // used to obtain any of the Class objects representing primitives or void | |
1376 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) { | |
1377 instanceKlassHandle k = | |
1378 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj)); | |
1379 // For user defined Java class loaders, check that the name returned is | |
1380 // the same as that requested. This check is done for the bootstrap | |
1381 // loader when parsing the class file. | |
1382 if (class_name() == k->name()) { | |
1383 return k; | |
1384 } | |
1385 } | |
1386 // Class is not found or has the wrong name, return NULL | |
1387 return nh; | |
1388 } | |
1389 } | |
1390 | |
1391 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) { | |
1392 | |
1393 Handle class_loader_h(THREAD, k->class_loader()); | |
1394 | |
514 | 1395 // for bootstrap and other parallel classloaders don't acquire lock, |
1396 // use placeholder token | |
1397 // If a parallelCapable class loader calls define_instance_class instead of | |
1398 // find_or_define_instance_class to get here, we have a timing | |
1399 // hole with systemDictionary updates and check_constraints | |
1400 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) { | |
0 | 1401 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, |
1402 compute_loader_lock_object(class_loader_h, THREAD)), | |
1403 "define called without lock"); | |
1404 } | |
1405 | |
1406 // Check class-loading constraints. Throw exception if violation is detected. | |
1407 // Grabs and releases SystemDictionary_lock | |
1408 // The check_constraints/find_class call and update_dictionary sequence | |
1409 // must be "atomic" for a specific class/classloader pair so we never | |
1410 // define two different instanceKlasses for that class/classloader pair. | |
1411 // Existing classloaders will call define_instance_class with the | |
1412 // classloader lock held | |
1413 // Parallel classloaders will call find_or_define_instance_class | |
1414 // which will require a token to perform the define class | |
1415 symbolHandle name_h(THREAD, k->name()); | |
1416 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h); | |
1417 int d_index = dictionary()->hash_to_index(d_hash); | |
1418 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK); | |
1419 | |
1420 // Register class just loaded with class loader (placed in Vector) | |
1421 // Note we do this before updating the dictionary, as this can | |
1422 // fail with an OutOfMemoryError (if it does, we will *not* put this | |
1423 // class in the dictionary and will not update the class hierarchy). | |
1424 if (k->class_loader() != NULL) { | |
1425 methodHandle m(THREAD, Universe::loader_addClass_method()); | |
1426 JavaValue result(T_VOID); | |
1427 JavaCallArguments args(class_loader_h); | |
1428 args.push_oop(Handle(THREAD, k->java_mirror())); | |
1429 JavaCalls::call(&result, m, &args, CHECK); | |
1430 } | |
1431 | |
1432 // Add the new class. We need recompile lock during update of CHA. | |
1433 { | |
1434 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h); | |
1435 int p_index = placeholders()->hash_to_index(p_hash); | |
1436 | |
1437 MutexLocker mu_r(Compile_lock, THREAD); | |
1438 | |
1439 // Add to class hierarchy, initialize vtables, and do possible | |
1440 // deoptimizations. | |
1441 add_to_hierarchy(k, CHECK); // No exception, but can block | |
1442 | |
1443 // Add to systemDictionary - so other classes can see it. | |
1444 // Grabs and releases SystemDictionary_lock | |
1445 update_dictionary(d_index, d_hash, p_index, p_hash, | |
1446 k, class_loader_h, THREAD); | |
1447 } | |
1448 k->eager_initialize(THREAD); | |
1449 | |
1450 // notify jvmti | |
1451 if (JvmtiExport::should_post_class_load()) { | |
1452 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()"); | |
1453 JvmtiExport::post_class_load((JavaThread *) THREAD, k()); | |
1454 | |
1455 } | |
1456 } | |
1457 | |
1458 // Support parallel classloading | |
1459 // Initial implementation for bootstrap classloader | |
1460 // For custom class loaders that support parallel classloading, | |
514 | 1461 // With AllowParallelDefine flag==true, in case they do not synchronize around |
1462 // FindLoadedClass/DefineClass, calls, we check for parallel | |
0 | 1463 // loading for them, wait if a defineClass is in progress |
1464 // and return the initial requestor's results | |
514 | 1465 // With AllowParallelDefine flag==false, call through to define_instance_class |
1466 // which will throw LinkageError: duplicate class definition. | |
0 | 1467 // For better performance, the class loaders should synchronize |
514 | 1468 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they |
0 | 1469 // potentially waste time reading and parsing the bytestream. |
1470 // Note: VM callers should ensure consistency of k/class_name,class_loader | |
1471 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) { | |
1472 | |
1473 instanceKlassHandle nh = instanceKlassHandle(); // null Handle | |
515 | 1474 symbolHandle name_h(THREAD, k->name()); // passed in class_name may be null |
0 | 1475 |
515 | 1476 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader); |
0 | 1477 int d_index = dictionary()->hash_to_index(d_hash); |
1478 | |
1479 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS | |
515 | 1480 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader); |
0 | 1481 int p_index = placeholders()->hash_to_index(p_hash); |
1482 PlaceholderEntry* probe; | |
1483 | |
1484 { | |
1485 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1486 // First check if class already defined | |
515 | 1487 klassOop check = find_class(d_index, d_hash, name_h, class_loader); |
0 | 1488 if (check != NULL) { |
1489 return(instanceKlassHandle(THREAD, check)); | |
1490 } | |
1491 | |
1492 // Acquire define token for this class/classloader | |
1493 symbolHandle nullsymbolHandle; | |
515 | 1494 probe = placeholders()->find_and_add(p_index, p_hash, name_h, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD); |
514 | 1495 // Wait if another thread defining in parallel |
1496 // All threads wait - even those that will throw duplicate class: otherwise | |
1497 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails | |
1498 // if other thread has not finished updating dictionary | |
1499 while (probe->definer() != NULL) { | |
1500 SystemDictionary_lock->wait(); | |
1501 } | |
1502 // Only special cases allow parallel defines and can use other thread's results | |
1503 // Other cases fall through, and may run into duplicate defines | |
1504 // caught by finding an entry in the SystemDictionary | |
1505 if ((UnsyncloadClass || AllowParallelDefineClass) && (probe->instanceKlass() != NULL)) { | |
0 | 1506 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); |
515 | 1507 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); |
514 | 1508 SystemDictionary_lock->notify_all(); |
0 | 1509 #ifdef ASSERT |
515 | 1510 klassOop check = find_class(d_index, d_hash, name_h, class_loader); |
514 | 1511 assert(check != NULL, "definer missed recording success"); |
0 | 1512 #endif |
514 | 1513 return(instanceKlassHandle(THREAD, probe->instanceKlass())); |
1514 } else { | |
1515 // This thread will define the class (even if earlier thread tried and had an error) | |
1516 probe->set_definer(THREAD); | |
0 | 1517 } |
1518 } | |
1519 | |
1520 define_instance_class(k, THREAD); | |
1521 | |
1522 Handle linkage_exception = Handle(); // null handle | |
1523 | |
1524 // definer must notify any waiting threads | |
1525 { | |
1526 MutexLocker mu(SystemDictionary_lock, THREAD); | |
515 | 1527 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, class_loader); |
0 | 1528 assert(probe != NULL, "DEFINE_CLASS placeholder lost?"); |
1529 if (probe != NULL) { | |
1530 if (HAS_PENDING_EXCEPTION) { | |
1531 linkage_exception = Handle(THREAD,PENDING_EXCEPTION); | |
1532 CLEAR_PENDING_EXCEPTION; | |
1533 } else { | |
1534 probe->set_instanceKlass(k()); | |
1535 } | |
1536 probe->set_definer(NULL); | |
1537 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS); | |
515 | 1538 placeholders()->find_and_remove(p_index, p_hash, name_h, class_loader, THREAD); |
0 | 1539 SystemDictionary_lock->notify_all(); |
1540 } | |
1541 } | |
1542 | |
1543 // Can't throw exception while holding lock due to rank ordering | |
1544 if (linkage_exception() != NULL) { | |
1545 THROW_OOP_(linkage_exception(), nh); // throws exception and returns | |
1546 } | |
1547 | |
1548 return k; | |
1549 } | |
1550 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) { | |
1551 // If class_loader is NULL we synchronize on _system_loader_lock_obj | |
1552 if (class_loader.is_null()) { | |
1553 return Handle(THREAD, _system_loader_lock_obj); | |
1554 } else { | |
1555 return class_loader; | |
1556 } | |
1557 } | |
1558 | |
1559 // This method is added to check how often we have to wait to grab loader | |
1560 // lock. The results are being recorded in the performance counters defined in | |
1561 // ClassLoader::_sync_systemLoaderLockContentionRate and | |
1562 // ClassLoader::_sync_nonSystemLoaderLockConteionRate. | |
1563 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) { | |
1564 if (!UsePerfData) { | |
1565 return; | |
1566 } | |
1567 | |
1568 assert(!loader_lock.is_null(), "NULL lock object"); | |
1569 | |
1570 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock) | |
1571 == ObjectSynchronizer::owner_other) { | |
1572 // contention will likely happen, so increment the corresponding | |
1573 // contention counter. | |
1574 if (loader_lock() == _system_loader_lock_obj) { | |
1575 ClassLoader::sync_systemLoaderLockContentionRate()->inc(); | |
1576 } else { | |
1577 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc(); | |
1578 } | |
1579 } | |
1580 } | |
1581 | |
1582 // ---------------------------------------------------------------------------- | |
1583 // Lookup | |
1584 | |
1585 klassOop SystemDictionary::find_class(int index, unsigned int hash, | |
1586 symbolHandle class_name, | |
1587 Handle class_loader) { | |
1588 assert_locked_or_safepoint(SystemDictionary_lock); | |
1589 assert (index == dictionary()->index_for(class_name, class_loader), | |
1590 "incorrect index?"); | |
1591 | |
1592 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader); | |
1593 return k; | |
1594 } | |
1595 | |
1596 | |
1597 // Basic find on classes in the midst of being loaded | |
1598 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash, | |
1599 symbolHandle class_name, | |
1600 Handle class_loader) { | |
1601 assert_locked_or_safepoint(SystemDictionary_lock); | |
1602 | |
1603 return placeholders()->find_entry(index, hash, class_name, class_loader); | |
1604 } | |
1605 | |
1606 | |
1607 // Used for assertions and verification only | |
1608 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name, | |
1609 Handle class_loader) { | |
1610 #ifndef ASSERT | |
1611 guarantee(VerifyBeforeGC || | |
1612 VerifyDuringGC || | |
1613 VerifyBeforeExit || | |
1614 VerifyAfterGC, "too expensive"); | |
1615 #endif | |
1616 assert_locked_or_safepoint(SystemDictionary_lock); | |
1617 symbolOop class_name_ = class_name(); | |
1618 oop class_loader_ = class_loader(); | |
1619 | |
1620 // First look in the loaded class array | |
1621 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader); | |
1622 int d_index = dictionary()->hash_to_index(d_hash); | |
1623 oop lookup = find_class(d_index, d_hash, class_name, class_loader); | |
1624 | |
1625 if (lookup == NULL) { | |
1626 // Next try the placeholders | |
1627 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader); | |
1628 int p_index = placeholders()->hash_to_index(p_hash); | |
1629 lookup = find_placeholder(p_index, p_hash, class_name, class_loader); | |
1630 } | |
1631 | |
1632 return lookup; | |
1633 } | |
1634 | |
1635 | |
1636 // Get the next class in the diictionary. | |
1637 klassOop SystemDictionary::try_get_next_class() { | |
1638 return dictionary()->try_get_next_class(); | |
1639 } | |
1640 | |
1641 | |
1642 // ---------------------------------------------------------------------------- | |
1643 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock | |
1644 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in | |
1645 // before a new class is used. | |
1646 | |
1647 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) { | |
1648 assert(k.not_null(), "just checking"); | |
1649 // Link into hierachy. Make sure the vtables are initialized before linking into | |
1650 k->append_to_sibling_list(); // add to superklass/sibling list | |
1651 k->process_interfaces(THREAD); // handle all "implements" declarations | |
1652 k->set_init_state(instanceKlass::loaded); | |
1653 // Now flush all code that depended on old class hierarchy. | |
1654 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97) | |
1655 // Also, first reinitialize vtable because it may have gotten out of synch | |
1656 // while the new class wasn't connected to the class hierarchy. | |
1657 Universe::flush_dependents_on(k); | |
1658 } | |
1659 | |
1660 | |
1661 // ---------------------------------------------------------------------------- | |
1662 // GC support | |
1663 | |
1664 // Following roots during mark-sweep is separated in two phases. | |
1665 // | |
1666 // The first phase follows preloaded classes and all other system | |
1667 // classes, since these will never get unloaded anyway. | |
1668 // | |
1669 // The second phase removes (unloads) unreachable classes from the | |
1670 // system dictionary and follows the remaining classes' contents. | |
1671 | |
1672 void SystemDictionary::always_strong_oops_do(OopClosure* blk) { | |
1673 // Follow preloaded classes/mirrors and system loader object | |
1674 blk->do_oop(&_java_system_loader); | |
1675 preloaded_oops_do(blk); | |
1676 always_strong_classes_do(blk); | |
1677 } | |
1678 | |
1679 | |
1680 void SystemDictionary::always_strong_classes_do(OopClosure* blk) { | |
1681 // Follow all system classes and temporary placeholders in dictionary | |
1682 dictionary()->always_strong_classes_do(blk); | |
1683 | |
1684 // Placeholders. These are *always* strong roots, as they | |
1685 // represent classes we're actively loading. | |
1686 placeholders_do(blk); | |
1687 | |
1688 // Loader constraints. We must keep the symbolOop used in the name alive. | |
1689 constraints()->always_strong_classes_do(blk); | |
1690 | |
1691 // Resolution errors keep the symbolOop for the error alive | |
1692 resolution_errors()->always_strong_classes_do(blk); | |
1693 } | |
1694 | |
1695 | |
1696 void SystemDictionary::placeholders_do(OopClosure* blk) { | |
1697 placeholders()->oops_do(blk); | |
1698 } | |
1699 | |
1700 | |
1701 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) { | |
1702 bool result = dictionary()->do_unloading(is_alive); | |
1703 constraints()->purge_loader_constraints(is_alive); | |
1704 resolution_errors()->purge_resolution_errors(is_alive); | |
1705 return result; | |
1706 } | |
1707 | |
1708 | |
1709 // The mirrors are scanned by shared_oops_do() which is | |
1710 // not called by oops_do(). In order to process oops in | |
1711 // a necessary order, shared_oops_do() is call by | |
1712 // Universe::oops_do(). | |
1713 void SystemDictionary::oops_do(OopClosure* f) { | |
1714 // Adjust preloaded classes and system loader object | |
1715 f->do_oop(&_java_system_loader); | |
1716 preloaded_oops_do(f); | |
1717 | |
1718 lazily_loaded_oops_do(f); | |
1719 | |
1720 // Adjust dictionary | |
1721 dictionary()->oops_do(f); | |
1722 | |
1723 // Partially loaded classes | |
1724 placeholders()->oops_do(f); | |
1725 | |
1726 // Adjust constraint table | |
1727 constraints()->oops_do(f); | |
1728 | |
1729 // Adjust resolution error table | |
1730 resolution_errors()->oops_do(f); | |
1731 } | |
1732 | |
1733 | |
1734 void SystemDictionary::preloaded_oops_do(OopClosure* f) { | |
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1735 f->do_oop((oop*) &wk_klass_name_limits[0]); |
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1736 f->do_oop((oop*) &wk_klass_name_limits[1]); |
0 | 1737 |
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1738 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) { |
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1739 f->do_oop((oop*) &_well_known_klasses[k]); |
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1740 } |
0 | 1741 |
1742 { | |
1743 for (int i = 0; i < T_VOID+1; i++) { | |
1744 if (_box_klasses[i] != NULL) { | |
1745 assert(i >= T_BOOLEAN, "checking"); | |
1746 f->do_oop((oop*) &_box_klasses[i]); | |
1747 } | |
1748 } | |
1749 } | |
1750 | |
1751 // The basic type mirrors would have already been processed in | |
1752 // Universe::oops_do(), via a call to shared_oops_do(), so should | |
1753 // not be processed again. | |
1754 | |
1755 f->do_oop((oop*) &_system_loader_lock_obj); | |
1756 FilteredFieldsMap::klasses_oops_do(f); | |
1757 } | |
1758 | |
1759 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) { | |
1760 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass); | |
1761 } | |
1762 | |
1763 // Just the classes from defining class loaders | |
1764 // Don't iterate over placeholders | |
1765 void SystemDictionary::classes_do(void f(klassOop)) { | |
1766 dictionary()->classes_do(f); | |
1767 } | |
1768 | |
1769 // Added for initialize_itable_for_klass | |
1770 // Just the classes from defining class loaders | |
1771 // Don't iterate over placeholders | |
1772 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) { | |
1773 dictionary()->classes_do(f, CHECK); | |
1774 } | |
1775 | |
1776 // All classes, and their class loaders | |
1777 // Don't iterate over placeholders | |
1778 void SystemDictionary::classes_do(void f(klassOop, oop)) { | |
1779 dictionary()->classes_do(f); | |
1780 } | |
1781 | |
1782 // All classes, and their class loaders | |
1783 // (added for helpers that use HandleMarks and ResourceMarks) | |
1784 // Don't iterate over placeholders | |
1785 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) { | |
1786 dictionary()->classes_do(f, CHECK); | |
1787 } | |
1788 | |
1789 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) { | |
1790 placeholders()->entries_do(f); | |
1791 } | |
1792 | |
1793 void SystemDictionary::methods_do(void f(methodOop)) { | |
1794 dictionary()->methods_do(f); | |
1795 } | |
1796 | |
1797 // ---------------------------------------------------------------------------- | |
1798 // Lazily load klasses | |
1799 | |
1800 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) { | |
1801 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later"); | |
1802 | |
1803 // if multiple threads calling this function, only one thread will load | |
1804 // the class. The other threads will find the loaded version once the | |
1805 // class is loaded. | |
1806 klassOop aos = _abstract_ownable_synchronizer_klass; | |
1807 if (aos == NULL) { | |
1808 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK); | |
1809 // Force a fence to prevent any read before the write completes | |
1810 OrderAccess::fence(); | |
1811 _abstract_ownable_synchronizer_klass = k; | |
1812 } | |
1813 } | |
1814 | |
1815 // ---------------------------------------------------------------------------- | |
1816 // Initialization | |
1817 | |
1818 void SystemDictionary::initialize(TRAPS) { | |
1819 // Allocate arrays | |
1820 assert(dictionary() == NULL, | |
1821 "SystemDictionary should only be initialized once"); | |
1822 _dictionary = new Dictionary(_nof_buckets); | |
1823 _placeholders = new PlaceholderTable(_nof_buckets); | |
1824 _number_of_modifications = 0; | |
1825 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size); | |
1826 _resolution_errors = new ResolutionErrorTable(_resolution_error_size); | |
1827 | |
1828 // Allocate private object used as system class loader lock | |
1829 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK); | |
1830 // Initialize basic classes | |
1831 initialize_preloaded_classes(CHECK); | |
1832 } | |
1833 | |
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1834 // Compact table of directions on the initialization of klasses: |
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1835 static const short wk_init_info[] = { |
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1836 #define WK_KLASS_INIT_INFO(name, symbol, option) \ |
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1837 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \ |
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1838 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \ |
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1839 | (int)SystemDictionary::option ), |
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1840 WK_KLASSES_DO(WK_KLASS_INIT_INFO) |
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1841 #undef WK_KLASS_INIT_INFO |
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1842 0 |
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1843 }; |
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1844 |
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1845 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) { |
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1846 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); |
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1847 int info = wk_init_info[id - FIRST_WKID]; |
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1848 int sid = (info >> CEIL_LG_OPTION_LIMIT); |
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1849 symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid); |
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1850 klassOop* klassp = &_well_known_klasses[id]; |
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1851 bool must_load = (init_opt < SystemDictionary::Opt); |
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1852 bool try_load = true; |
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1853 if (init_opt == SystemDictionary::Opt_Kernel) { |
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1854 #ifndef KERNEL |
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1855 try_load = false; |
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1856 #endif //KERNEL |
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1857 } |
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1858 if ((*klassp) == NULL && try_load) { |
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1859 if (must_load) { |
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1860 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class |
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1861 } else { |
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1862 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass |
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1863 } |
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1864 } |
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1865 return ((*klassp) != NULL); |
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1866 } |
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1867 |
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1868 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) { |
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1869 assert((int)start_id <= (int)limit_id, "IDs are out of order!"); |
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1870 for (int id = (int)start_id; id < (int)limit_id; id++) { |
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1871 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob"); |
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1872 int info = wk_init_info[id - FIRST_WKID]; |
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1873 int sid = (info >> CEIL_LG_OPTION_LIMIT); |
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1874 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT)); |
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1875 |
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1876 initialize_wk_klass((WKID)id, opt, CHECK); |
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1877 |
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1878 // Update limits, so find_well_known_klass can be very fast: |
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1879 symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid); |
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1880 if (wk_klass_name_limits[1] == NULL) { |
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1881 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s; |
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1882 } else if (wk_klass_name_limits[1] < s) { |
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1883 wk_klass_name_limits[1] = s; |
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1884 } else if (wk_klass_name_limits[0] > s) { |
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1885 wk_klass_name_limits[0] = s; |
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1886 } |
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1887 } |
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1888 } |
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1889 |
0 | 1890 |
1891 void SystemDictionary::initialize_preloaded_classes(TRAPS) { | |
132
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1892 assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once"); |
0 | 1893 // Preload commonly used klasses |
132
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1894 WKID scan = FIRST_WKID; |
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1895 // first do Object, String, Class |
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1896 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK); |
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1897 |
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1898 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass))); |
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1899 |
0 | 1900 // Fixup mirrors for classes loaded before java.lang.Class. |
1901 // These calls iterate over the objects currently in the perm gen | |
1902 // so calling them at this point is matters (not before when there | |
1903 // are fewer objects and not later after there are more objects | |
1904 // in the perm gen. | |
1905 Universe::initialize_basic_type_mirrors(CHECK); | |
1906 Universe::fixup_mirrors(CHECK); | |
1907 | |
132
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1908 // do a bunch more: |
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1909 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK); |
0 | 1910 |
1911 // Preload ref klasses and set reference types | |
132
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1912 instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER); |
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1913 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass)); |
0 | 1914 |
132
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1915 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK); |
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1916 instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT); |
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1917 instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK); |
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1918 instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL); |
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1919 instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM); |
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1920 |
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1921 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK); |
0 | 1922 |
132
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1923 _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass); |
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1924 _box_klasses[T_CHAR] = WK_KLASS(char_klass); |
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1925 _box_klasses[T_FLOAT] = WK_KLASS(float_klass); |
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1926 _box_klasses[T_DOUBLE] = WK_KLASS(double_klass); |
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1927 _box_klasses[T_BYTE] = WK_KLASS(byte_klass); |
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1928 _box_klasses[T_SHORT] = WK_KLASS(short_klass); |
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1929 _box_klasses[T_INT] = WK_KLASS(int_klass); |
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1930 _box_klasses[T_LONG] = WK_KLASS(long_klass); |
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1931 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass); |
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1932 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass); |
0 | 1933 |
1934 #ifdef KERNEL | |
132
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1935 if (sun_jkernel_DownloadManager_klass() == NULL) { |
0 | 1936 warning("Cannot find sun/jkernel/DownloadManager"); |
1937 } | |
1938 #endif // KERNEL | |
514 | 1939 |
0 | 1940 { // Compute whether we should use loadClass or loadClassInternal when loading classes. |
1941 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature()); | |
1942 _has_loadClassInternal = (method != NULL); | |
1943 } | |
1944 { // Compute whether we should use checkPackageAccess or NOT | |
1945 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature()); | |
1946 _has_checkPackageAccess = (method != NULL); | |
1947 } | |
1948 } | |
1949 | |
1950 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer). | |
1951 // If so, returns the basic type it holds. If not, returns T_OBJECT. | |
1952 BasicType SystemDictionary::box_klass_type(klassOop k) { | |
1953 assert(k != NULL, ""); | |
1954 for (int i = T_BOOLEAN; i < T_VOID+1; i++) { | |
1955 if (_box_klasses[i] == k) | |
1956 return (BasicType)i; | |
1957 } | |
1958 return T_OBJECT; | |
1959 } | |
1960 | |
1961 // Constraints on class loaders. The details of the algorithm can be | |
1962 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java | |
1963 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is | |
1964 // that the system dictionary needs to maintain a set of contraints that | |
1965 // must be satisfied by all classes in the dictionary. | |
1966 // if defining is true, then LinkageError if already in systemDictionary | |
1967 // if initiating loader, then ok if instanceKlass matches existing entry | |
1968 | |
1969 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash, | |
1970 instanceKlassHandle k, | |
1971 Handle class_loader, bool defining, | |
1972 TRAPS) { | |
1973 const char *linkage_error = NULL; | |
1974 { | |
1975 symbolHandle name (THREAD, k->name()); | |
1976 MutexLocker mu(SystemDictionary_lock, THREAD); | |
1977 | |
1978 klassOop check = find_class(d_index, d_hash, name, class_loader); | |
1979 if (check != (klassOop)NULL) { | |
1980 // if different instanceKlass - duplicate class definition, | |
1981 // else - ok, class loaded by a different thread in parallel, | |
1982 // we should only have found it if it was done loading and ok to use | |
1983 // system dictionary only holds instance classes, placeholders | |
1984 // also holds array classes | |
1985 | |
1986 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary"); | |
1987 if ((defining == true) || (k() != check)) { | |
1988 linkage_error = "loader (instance of %s): attempted duplicate class " | |
1989 "definition for name: \"%s\""; | |
1990 } else { | |
1991 return; | |
1992 } | |
1993 } | |
1994 | |
1995 #ifdef ASSERT | |
1996 unsigned int p_hash = placeholders()->compute_hash(name, class_loader); | |
1997 int p_index = placeholders()->hash_to_index(p_hash); | |
1998 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); | |
1999 assert(ph_check == NULL || ph_check == name(), "invalid symbol"); | |
2000 #endif | |
2001 | |
2002 if (linkage_error == NULL) { | |
2003 if (constraints()->check_or_update(k, class_loader, name) == false) { | |
2004 linkage_error = "loader constraint violation: loader (instance of %s)" | |
2005 " previously initiated loading for a different type with name \"%s\""; | |
2006 } | |
2007 } | |
2008 } | |
2009 | |
2010 // Throw error now if needed (cannot throw while holding | |
2011 // SystemDictionary_lock because of rank ordering) | |
2012 | |
2013 if (linkage_error) { | |
2014 ResourceMark rm(THREAD); | |
2015 const char* class_loader_name = loader_name(class_loader()); | |
2016 char* type_name = k->name()->as_C_string(); | |
2017 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) + | |
2018 strlen(type_name); | |
2019 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen); | |
2020 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name); | |
2021 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf); | |
2022 } | |
2023 } | |
2024 | |
2025 | |
2026 // Update system dictionary - done after check_constraint and add_to_hierachy | |
2027 // have been called. | |
2028 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash, | |
2029 int p_index, unsigned int p_hash, | |
2030 instanceKlassHandle k, | |
2031 Handle class_loader, | |
2032 TRAPS) { | |
2033 // Compile_lock prevents systemDictionary updates during compilations | |
2034 assert_locked_or_safepoint(Compile_lock); | |
2035 symbolHandle name (THREAD, k->name()); | |
2036 | |
2037 { | |
2038 MutexLocker mu1(SystemDictionary_lock, THREAD); | |
2039 | |
2040 // See whether biased locking is enabled and if so set it for this | |
2041 // klass. | |
2042 // Note that this must be done past the last potential blocking | |
2043 // point / safepoint. We enable biased locking lazily using a | |
2044 // VM_Operation to iterate the SystemDictionary and installing the | |
2045 // biasable mark word into each instanceKlass's prototype header. | |
2046 // To avoid race conditions where we accidentally miss enabling the | |
2047 // optimization for one class in the process of being added to the | |
2048 // dictionary, we must not safepoint after the test of | |
2049 // BiasedLocking::enabled(). | |
2050 if (UseBiasedLocking && BiasedLocking::enabled()) { | |
2051 // Set biased locking bit for all loaded classes; it will be | |
2052 // cleared if revocation occurs too often for this type | |
2053 // NOTE that we must only do this when the class is initally | |
2054 // defined, not each time it is referenced from a new class loader | |
2055 if (k->class_loader() == class_loader()) { | |
2056 k->set_prototype_header(markOopDesc::biased_locking_prototype()); | |
2057 } | |
2058 } | |
2059 | |
2060 // Check for a placeholder. If there, remove it and make a | |
2061 // new system dictionary entry. | |
2062 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD); | |
2063 klassOop sd_check = find_class(d_index, d_hash, name, class_loader); | |
2064 if (sd_check == NULL) { | |
2065 dictionary()->add_klass(name, class_loader, k); | |
2066 notice_modification(); | |
2067 } | |
2068 #ifdef ASSERT | |
2069 sd_check = find_class(d_index, d_hash, name, class_loader); | |
2070 assert (sd_check != NULL, "should have entry in system dictionary"); | |
2071 // Changed to allow PH to remain to complete class circularity checking | |
2072 // while only one thread can define a class at one time, multiple | |
2073 // classes can resolve the superclass for a class at one time, | |
2074 // and the placeholder is used to track that | |
2075 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader); | |
2076 // assert (ph_check == NULL, "should not have a placeholder entry"); | |
2077 #endif | |
2078 SystemDictionary_lock->notify_all(); | |
2079 } | |
2080 } | |
2081 | |
2082 | |
2083 klassOop SystemDictionary::find_constrained_instance_or_array_klass( | |
2084 symbolHandle class_name, Handle class_loader, TRAPS) { | |
2085 | |
2086 // First see if it has been loaded directly. | |
2087 // Force the protection domain to be null. (This removes protection checks.) | |
2088 Handle no_protection_domain; | |
2089 klassOop klass = find_instance_or_array_klass(class_name, class_loader, | |
2090 no_protection_domain, CHECK_NULL); | |
2091 if (klass != NULL) | |
2092 return klass; | |
2093 | |
2094 // Now look to see if it has been loaded elsewhere, and is subject to | |
2095 // a loader constraint that would require this loader to return the | |
2096 // klass that is already loaded. | |
2097 if (FieldType::is_array(class_name())) { | |
2098 // Array classes are hard because their klassOops are not kept in the | |
2099 // constraint table. The array klass may be constrained, but the elem class | |
2100 // may not be. | |
2101 jint dimension; | |
2102 symbolOop object_key; | |
2103 BasicType t = FieldType::get_array_info(class_name(), &dimension, | |
2104 &object_key, CHECK_(NULL)); | |
2105 if (t != T_OBJECT) { | |
2106 klass = Universe::typeArrayKlassObj(t); | |
2107 } else { | |
2108 symbolHandle elem_name(THREAD, object_key); | |
2109 MutexLocker mu(SystemDictionary_lock, THREAD); | |
2110 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD); | |
2111 } | |
2112 if (klass != NULL) { | |
2113 klass = Klass::cast(klass)->array_klass_or_null(dimension); | |
2114 } | |
2115 } else { | |
2116 MutexLocker mu(SystemDictionary_lock, THREAD); | |
2117 // Non-array classes are easy: simply check the constraint table. | |
2118 klass = constraints()->find_constrained_klass(class_name, class_loader); | |
2119 } | |
2120 | |
2121 return klass; | |
2122 } | |
2123 | |
2124 | |
2125 bool SystemDictionary::add_loader_constraint(symbolHandle class_name, | |
2126 Handle class_loader1, | |
2127 Handle class_loader2, | |
2128 Thread* THREAD) { | |
2129 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1); | |
2130 int d_index1 = dictionary()->hash_to_index(d_hash1); | |
2131 | |
2132 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2); | |
2133 int d_index2 = dictionary()->hash_to_index(d_hash2); | |
2134 | |
2135 { | |
2136 MutexLocker mu_s(SystemDictionary_lock, THREAD); | |
2137 | |
2138 // Better never do a GC while we're holding these oops | |
2139 No_Safepoint_Verifier nosafepoint; | |
2140 | |
2141 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1); | |
2142 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2); | |
2143 return constraints()->add_entry(class_name, klass1, class_loader1, | |
2144 klass2, class_loader2); | |
2145 } | |
2146 } | |
2147 | |
2148 // Add entry to resolution error table to record the error when the first | |
2149 // attempt to resolve a reference to a class has failed. | |
2150 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) { | |
2151 unsigned int hash = resolution_errors()->compute_hash(pool, which); | |
2152 int index = resolution_errors()->hash_to_index(hash); | |
2153 { | |
2154 MutexLocker ml(SystemDictionary_lock, Thread::current()); | |
2155 resolution_errors()->add_entry(index, hash, pool, which, error); | |
2156 } | |
2157 } | |
2158 | |
2159 // Lookup resolution error table. Returns error if found, otherwise NULL. | |
2160 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) { | |
2161 unsigned int hash = resolution_errors()->compute_hash(pool, which); | |
2162 int index = resolution_errors()->hash_to_index(hash); | |
2163 { | |
2164 MutexLocker ml(SystemDictionary_lock, Thread::current()); | |
2165 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which); | |
2166 return (entry != NULL) ? entry->error() : (symbolOop)NULL; | |
2167 } | |
2168 } | |
2169 | |
2170 | |
2171 // Make sure all class components (including arrays) in the given | |
2172 // signature will be resolved to the same class in both loaders. | |
2173 // Returns the name of the type that failed a loader constraint check, or | |
2174 // NULL if no constraint failed. The returned C string needs cleaning up | |
2175 // with a ResourceMark in the caller | |
2176 char* SystemDictionary::check_signature_loaders(symbolHandle signature, | |
2177 Handle loader1, Handle loader2, | |
2178 bool is_method, TRAPS) { | |
2179 // Nothing to do if loaders are the same. | |
2180 if (loader1() == loader2()) { | |
2181 return NULL; | |
2182 } | |
2183 | |
2184 SignatureStream sig_strm(signature, is_method); | |
2185 while (!sig_strm.is_done()) { | |
2186 if (sig_strm.is_object()) { | |
2187 symbolOop s = sig_strm.as_symbol(CHECK_NULL); | |
2188 symbolHandle sig (THREAD, s); | |
2189 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) { | |
2190 return sig()->as_C_string(); | |
2191 } | |
2192 } | |
2193 sig_strm.next(); | |
2194 } | |
2195 return NULL; | |
2196 } | |
2197 | |
2198 | |
2199 // Since the identity hash code for symbols changes when the symbols are | |
2200 // moved from the regular perm gen (hash in the mark word) to the shared | |
2201 // spaces (hash is the address), the classes loaded into the dictionary | |
2202 // may be in the wrong buckets. | |
2203 | |
2204 void SystemDictionary::reorder_dictionary() { | |
2205 dictionary()->reorder_dictionary(); | |
2206 } | |
2207 | |
2208 | |
2209 void SystemDictionary::copy_buckets(char** top, char* end) { | |
2210 dictionary()->copy_buckets(top, end); | |
2211 } | |
2212 | |
2213 | |
2214 void SystemDictionary::copy_table(char** top, char* end) { | |
2215 dictionary()->copy_table(top, end); | |
2216 } | |
2217 | |
2218 | |
2219 void SystemDictionary::reverse() { | |
2220 dictionary()->reverse(); | |
2221 } | |
2222 | |
2223 int SystemDictionary::number_of_classes() { | |
2224 return dictionary()->number_of_entries(); | |
2225 } | |
2226 | |
2227 | |
2228 // ---------------------------------------------------------------------------- | |
2229 #ifndef PRODUCT | |
2230 | |
2231 void SystemDictionary::print() { | |
2232 dictionary()->print(); | |
2233 | |
2234 // Placeholders | |
2235 GCMutexLocker mu(SystemDictionary_lock); | |
2236 placeholders()->print(); | |
2237 | |
2238 // loader constraints - print under SD_lock | |
2239 constraints()->print(); | |
2240 } | |
2241 | |
2242 #endif | |
2243 | |
2244 void SystemDictionary::verify() { | |
2245 guarantee(dictionary() != NULL, "Verify of system dictionary failed"); | |
2246 guarantee(constraints() != NULL, | |
2247 "Verify of loader constraints failed"); | |
2248 guarantee(dictionary()->number_of_entries() >= 0 && | |
2249 placeholders()->number_of_entries() >= 0, | |
2250 "Verify of system dictionary failed"); | |
2251 | |
2252 // Verify dictionary | |
2253 dictionary()->verify(); | |
2254 | |
2255 GCMutexLocker mu(SystemDictionary_lock); | |
2256 placeholders()->verify(); | |
2257 | |
2258 // Verify constraint table | |
2259 guarantee(constraints() != NULL, "Verify of loader constraints failed"); | |
2260 constraints()->verify(dictionary()); | |
2261 } | |
2262 | |
2263 | |
2264 void SystemDictionary::verify_obj_klass_present(Handle obj, | |
2265 symbolHandle class_name, | |
2266 Handle class_loader) { | |
2267 GCMutexLocker mu(SystemDictionary_lock); | |
2268 oop probe = find_class_or_placeholder(class_name, class_loader); | |
2269 if (probe == NULL) { | |
2270 probe = SystemDictionary::find_shared_class(class_name); | |
2271 } | |
2272 guarantee(probe != NULL && | |
2273 (!probe->is_klass() || probe == obj()), | |
2274 "Loaded klasses should be in SystemDictionary"); | |
2275 } | |
2276 | |
2277 #ifndef PRODUCT | |
2278 | |
2279 // statistics code | |
2280 class ClassStatistics: AllStatic { | |
2281 private: | |
2282 static int nclasses; // number of classes | |
2283 static int nmethods; // number of methods | |
2284 static int nmethoddata; // number of methodData | |
2285 static int class_size; // size of class objects in words | |
2286 static int method_size; // size of method objects in words | |
2287 static int debug_size; // size of debug info in methods | |
2288 static int methoddata_size; // size of methodData objects in words | |
2289 | |
2290 static void do_class(klassOop k) { | |
2291 nclasses++; | |
2292 class_size += k->size(); | |
2293 if (k->klass_part()->oop_is_instance()) { | |
2294 instanceKlass* ik = (instanceKlass*)k->klass_part(); | |
2295 class_size += ik->methods()->size(); | |
2296 class_size += ik->constants()->size(); | |
2297 class_size += ik->local_interfaces()->size(); | |
2298 class_size += ik->transitive_interfaces()->size(); | |
2299 // We do not have to count implementors, since we only store one! | |
2300 class_size += ik->fields()->size(); | |
2301 } | |
2302 } | |
2303 | |
2304 static void do_method(methodOop m) { | |
2305 nmethods++; | |
2306 method_size += m->size(); | |
2307 // class loader uses same objArray for empty vectors, so don't count these | |
2308 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size(); | |
2309 if (m->has_stackmap_table()) { | |
2310 method_size += m->stackmap_data()->size(); | |
2311 } | |
2312 | |
2313 methodDataOop mdo = m->method_data(); | |
2314 if (mdo != NULL) { | |
2315 nmethoddata++; | |
2316 methoddata_size += mdo->size(); | |
2317 } | |
2318 } | |
2319 | |
2320 public: | |
2321 static void print() { | |
2322 SystemDictionary::classes_do(do_class); | |
2323 SystemDictionary::methods_do(do_method); | |
2324 tty->print_cr("Class statistics:"); | |
2325 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize); | |
2326 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods, | |
2327 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize); | |
2328 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize); | |
2329 } | |
2330 }; | |
2331 | |
2332 | |
2333 int ClassStatistics::nclasses = 0; | |
2334 int ClassStatistics::nmethods = 0; | |
2335 int ClassStatistics::nmethoddata = 0; | |
2336 int ClassStatistics::class_size = 0; | |
2337 int ClassStatistics::method_size = 0; | |
2338 int ClassStatistics::debug_size = 0; | |
2339 int ClassStatistics::methoddata_size = 0; | |
2340 | |
2341 void SystemDictionary::print_class_statistics() { | |
2342 ResourceMark rm; | |
2343 ClassStatistics::print(); | |
2344 } | |
2345 | |
2346 | |
2347 class MethodStatistics: AllStatic { | |
2348 public: | |
2349 enum { | |
2350 max_parameter_size = 10 | |
2351 }; | |
2352 private: | |
2353 | |
2354 static int _number_of_methods; | |
2355 static int _number_of_final_methods; | |
2356 static int _number_of_static_methods; | |
2357 static int _number_of_native_methods; | |
2358 static int _number_of_synchronized_methods; | |
2359 static int _number_of_profiled_methods; | |
2360 static int _number_of_bytecodes; | |
2361 static int _parameter_size_profile[max_parameter_size]; | |
2362 static int _bytecodes_profile[Bytecodes::number_of_java_codes]; | |
2363 | |
2364 static void initialize() { | |
2365 _number_of_methods = 0; | |
2366 _number_of_final_methods = 0; | |
2367 _number_of_static_methods = 0; | |
2368 _number_of_native_methods = 0; | |
2369 _number_of_synchronized_methods = 0; | |
2370 _number_of_profiled_methods = 0; | |
2371 _number_of_bytecodes = 0; | |
2372 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0; | |
2373 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0; | |
2374 }; | |
2375 | |
2376 static void do_method(methodOop m) { | |
2377 _number_of_methods++; | |
2378 // collect flag info | |
2379 if (m->is_final() ) _number_of_final_methods++; | |
2380 if (m->is_static() ) _number_of_static_methods++; | |
2381 if (m->is_native() ) _number_of_native_methods++; | |
2382 if (m->is_synchronized()) _number_of_synchronized_methods++; | |
2383 if (m->method_data() != NULL) _number_of_profiled_methods++; | |
2384 // collect parameter size info (add one for receiver, if any) | |
2385 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++; | |
2386 // collect bytecodes info | |
2387 { | |
2388 Thread *thread = Thread::current(); | |
2389 HandleMark hm(thread); | |
2390 BytecodeStream s(methodHandle(thread, m)); | |
2391 Bytecodes::Code c; | |
2392 while ((c = s.next()) >= 0) { | |
2393 _number_of_bytecodes++; | |
2394 _bytecodes_profile[c]++; | |
2395 } | |
2396 } | |
2397 } | |
2398 | |
2399 public: | |
2400 static void print() { | |
2401 initialize(); | |
2402 SystemDictionary::methods_do(do_method); | |
2403 // generate output | |
2404 tty->cr(); | |
2405 tty->print_cr("Method statistics (static):"); | |
2406 // flag distribution | |
2407 tty->cr(); | |
2408 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods); | |
2409 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods); | |
2410 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods); | |
2411 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods); | |
2412 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods); | |
2413 // parameter size profile | |
2414 tty->cr(); | |
2415 { int tot = 0; | |
2416 int avg = 0; | |
2417 for (int i = 0; i < max_parameter_size; i++) { | |
2418 int n = _parameter_size_profile[i]; | |
2419 tot += n; | |
2420 avg += n*i; | |
2421 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods); | |
2422 } | |
2423 assert(tot == _number_of_methods, "should be the same"); | |
2424 tty->print_cr(" %6d methods 100.0%%", _number_of_methods); | |
2425 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods); | |
2426 } | |
2427 // bytecodes profile | |
2428 tty->cr(); | |
2429 { int tot = 0; | |
2430 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) { | |
2431 if (Bytecodes::is_defined(i)) { | |
2432 Bytecodes::Code c = Bytecodes::cast(i); | |
2433 int n = _bytecodes_profile[c]; | |
2434 tot += n; | |
2435 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c)); | |
2436 } | |
2437 } | |
2438 assert(tot == _number_of_bytecodes, "should be the same"); | |
2439 tty->print_cr("%9d 100.000%%", _number_of_bytecodes); | |
2440 } | |
2441 tty->cr(); | |
2442 } | |
2443 }; | |
2444 | |
2445 int MethodStatistics::_number_of_methods; | |
2446 int MethodStatistics::_number_of_final_methods; | |
2447 int MethodStatistics::_number_of_static_methods; | |
2448 int MethodStatistics::_number_of_native_methods; | |
2449 int MethodStatistics::_number_of_synchronized_methods; | |
2450 int MethodStatistics::_number_of_profiled_methods; | |
2451 int MethodStatistics::_number_of_bytecodes; | |
2452 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size]; | |
2453 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes]; | |
2454 | |
2455 | |
2456 void SystemDictionary::print_method_statistics() { | |
2457 MethodStatistics::print(); | |
2458 } | |
2459 | |
2460 #endif // PRODUCT |