1 /*
2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/sharedClassUtil.hpp"
28 #include "classfile/dictionary.inline.hpp"
29 #include "classfile/protectionDomainCache.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/systemDictionaryShared.hpp"
32 #include "gc/shared/gcLocker.hpp"
33 #include "logging/log.hpp"
34 #include "logging/logStream.hpp"
35 #include "memory/iterator.hpp"
36 #include "memory/metaspaceClosure.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41 #include "utilities/hashtable.inline.hpp"
42
43 // Optimization: if any dictionary needs resizing, we set this flag,
44 // so that we dont't have to walk all dictionaries to check if any actually
45 // needs resizing, which is costly to do at Safepoint.
46 bool Dictionary::_some_dictionary_needs_resizing = false;
47
48 size_t Dictionary::entry_size() {
49 if (DumpSharedSpaces) {
50 return SystemDictionaryShared::dictionary_entry_size();
51 } else {
52 return sizeof(DictionaryEntry);
53 }
54 }
55
56 Dictionary::Dictionary(ClassLoaderData* loader_data, int table_size, bool resizable)
57 : _loader_data(loader_data), _resizable(resizable), _needs_resizing(false),
58 Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size()) {
59 };
60
61
62 Dictionary::Dictionary(ClassLoaderData* loader_data,
63 int table_size, HashtableBucket<mtClass>* t,
64 int number_of_entries, bool resizable)
65 : _loader_data(loader_data), _resizable(resizable), _needs_resizing(false),
66 Hashtable<InstanceKlass*, mtClass>(table_size, (int)entry_size(), t, number_of_entries) {
67 };
68
69 Dictionary::~Dictionary() {
70 DictionaryEntry* probe = NULL;
71 for (int index = 0; index < table_size(); index++) {
72 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
73 probe = *p;
74 *p = probe->next();
75 free_entry(probe);
76 }
77 }
78 assert(number_of_entries() == 0, "should have removed all entries");
79 assert(new_entry_free_list() == NULL, "entry present on Dictionary's free list");
80 free_buckets();
81 }
82
83 DictionaryEntry* Dictionary::new_entry(unsigned int hash, InstanceKlass* klass) {
84 DictionaryEntry* entry = (DictionaryEntry*)Hashtable<InstanceKlass*, mtClass>::allocate_new_entry(hash, klass);
85 entry->set_pd_set(NULL);
86 assert(klass->is_instance_klass(), "Must be");
87 if (DumpSharedSpaces) {
88 SystemDictionaryShared::init_shared_dictionary_entry(klass, entry);
89 }
90 return entry;
91 }
92
93
94 void Dictionary::free_entry(DictionaryEntry* entry) {
95 // avoid recursion when deleting linked list
96 // pd_set is accessed during a safepoint.
97 while (entry->pd_set() != NULL) {
98 ProtectionDomainEntry* to_delete = entry->pd_set();
99 entry->set_pd_set(to_delete->next());
100 delete to_delete;
101 }
102 // Unlink from the Hashtable prior to freeing
103 unlink_entry(entry);
104 FREE_C_HEAP_ARRAY(char, entry);
105 }
106
107 const int _resize_load_trigger = 5; // load factor that will trigger the resize
108 const double _resize_factor = 2.0; // by how much we will resize using current number of entries
109 const int _resize_max_size = 40423; // the max dictionary size allowed
110 const int _primelist[] = {107, 1009, 2017, 4049, 5051, 10103, 20201, _resize_max_size};
111 const int _prime_array_size = sizeof(_primelist)/sizeof(int);
112
113 // Calculate next "good" dictionary size based on requested count
114 static int calculate_dictionary_size(int requested) {
115 int newsize = _primelist[0];
116 int index = 0;
117 for (newsize = _primelist[index]; index < (_prime_array_size - 1);
118 newsize = _primelist[++index]) {
119 if (requested <= newsize) {
120 break;
121 }
122 }
123 return newsize;
124 }
125
126 bool Dictionary::does_any_dictionary_needs_resizing() {
127 return Dictionary::_some_dictionary_needs_resizing;
128 }
129
130 void Dictionary::check_if_needs_resize() {
131 if (_resizable == true) {
132 if (number_of_entries() > (_resize_load_trigger*table_size())) {
133 _needs_resizing = true;
134 Dictionary::_some_dictionary_needs_resizing = true;
135 }
136 }
137 }
138
139 bool Dictionary::resize_if_needed() {
140 int desired_size = 0;
141 if (_needs_resizing == true) {
142 desired_size = calculate_dictionary_size((int)(_resize_factor*number_of_entries()));
143 if (desired_size >= _resize_max_size) {
144 desired_size = _resize_max_size;
145 // We have reached the limit, turn resizing off
146 _resizable = false;
147 }
148 if ((desired_size != 0) && (desired_size != table_size())) {
149 if (!resize(desired_size)) {
150 // Something went wrong, turn resizing off
151 _resizable = false;
152 }
153 }
154 }
155
156 _needs_resizing = false;
157 Dictionary::_some_dictionary_needs_resizing = false;
158
159 return (desired_size != 0);
160 }
161
162 bool DictionaryEntry::contains_protection_domain(oop protection_domain) const {
163 #ifdef ASSERT
164 if (protection_domain == instance_klass()->protection_domain()) {
165 // Ensure this doesn't show up in the pd_set (invariant)
166 bool in_pd_set = false;
167 for (ProtectionDomainEntry* current = pd_set_acquire();
168 current != NULL;
169 current = current->next()) {
170 if (current->object_no_keepalive() == protection_domain) {
171 in_pd_set = true;
172 break;
173 }
174 }
175 if (in_pd_set) {
176 assert(false, "A klass's protection domain should not show up "
177 "in its sys. dict. PD set");
178 }
179 }
180 #endif /* ASSERT */
181
182 if (protection_domain == instance_klass()->protection_domain()) {
183 // Succeeds trivially
184 return true;
185 }
186
187 for (ProtectionDomainEntry* current = pd_set_acquire();
188 current != NULL;
189 current = current->next()) {
190 if (current->object_no_keepalive() == protection_domain) return true;
191 }
192 return false;
193 }
194
195
196 void DictionaryEntry::add_protection_domain(Dictionary* dict, Handle protection_domain) {
197 assert_locked_or_safepoint(SystemDictionary_lock);
198 if (!contains_protection_domain(protection_domain())) {
199 ProtectionDomainCacheEntry* entry = SystemDictionary::cache_get(protection_domain);
200 ProtectionDomainEntry* new_head =
201 new ProtectionDomainEntry(entry, pd_set());
202 // Warning: Preserve store ordering. The SystemDictionary is read
203 // without locks. The new ProtectionDomainEntry must be
204 // complete before other threads can be allowed to see it
205 // via a store to _pd_set.
206 release_set_pd_set(new_head);
207 }
208 LogTarget(Trace, protectiondomain) lt;
209 if (lt.is_enabled()) {
210 LogStream ls(lt);
211 print_count(&ls);
212 }
213 }
214
215 // During class loading we may have cached a protection domain that has
216 // since been unreferenced, so this entry should be cleared.
217 void Dictionary::clean_cached_protection_domains(BoolObjectClosure* is_alive, DictionaryEntry* probe) {
218 assert_locked_or_safepoint(SystemDictionary_lock);
219
220 ProtectionDomainEntry* current = probe->pd_set();
221 ProtectionDomainEntry* prev = NULL;
222 while (current != NULL) {
223 if (!is_alive->do_object_b(current->object_no_keepalive())) {
224 LogTarget(Debug, protectiondomain) lt;
225 if (lt.is_enabled()) {
226 ResourceMark rm;
227 // Print out trace information
228 LogStream ls(lt);
229 ls.print_cr("PD in set is not alive:");
230 ls.print("class loader: "); loader_data()->class_loader()->print_value_on(&ls);
231 ls.print(" protection domain: "); current->object_no_keepalive()->print_value_on(&ls);
232 ls.print(" loading: "); probe->instance_klass()->print_value_on(&ls);
233 ls.cr();
234 }
235 if (probe->pd_set() == current) {
236 probe->set_pd_set(current->next());
237 } else {
238 assert(prev != NULL, "should be set by alive entry");
239 prev->set_next(current->next());
240 }
241 ProtectionDomainEntry* to_delete = current;
242 current = current->next();
243 delete to_delete;
244 } else {
245 prev = current;
246 current = current->next();
247 }
248 }
249 }
250
251
252 void Dictionary::do_unloading(BoolObjectClosure* is_alive) {
253 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
254
255 // The NULL class loader doesn't initiate loading classes from other class loaders
256 if (loader_data() == ClassLoaderData::the_null_class_loader_data()) {
257 return;
258 }
259
260 // Remove unloaded entries and classes from this dictionary
261 DictionaryEntry* probe = NULL;
262 for (int index = 0; index < table_size(); index++) {
263 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
264 probe = *p;
265 InstanceKlass* ik = probe->instance_klass();
266 ClassLoaderData* k_def_class_loader_data = ik->class_loader_data();
267
268 // If the klass that this loader initiated is dead,
269 // (determined by checking the defining class loader)
270 // remove this entry.
271 if (k_def_class_loader_data->is_unloading()) {
272 assert(k_def_class_loader_data != loader_data(),
273 "cannot have live defining loader and unreachable klass");
274 *p = probe->next();
275 free_entry(probe);
276 continue;
277 }
278 // Clean pd_set
279 clean_cached_protection_domains(is_alive, probe);
280 p = probe->next_addr();
281 }
282 }
283 }
284
285 void Dictionary::remove_classes_in_error_state() {
286 assert(DumpSharedSpaces, "supported only when dumping");
287 DictionaryEntry* probe = NULL;
288 for (int index = 0; index < table_size(); index++) {
289 for (DictionaryEntry** p = bucket_addr(index); *p != NULL; ) {
290 probe = *p;
291 InstanceKlass* ik = probe->instance_klass();
292 if (ik->is_in_error_state()) { // purge this entry
293 *p = probe->next();
294 free_entry(probe);
295 ResourceMark rm;
296 tty->print_cr("Preload Warning: Removed error class: %s", ik->external_name());
297 continue;
298 }
299
300 p = probe->next_addr();
301 }
302 }
303 }
304
305 // Just the classes from defining class loaders
306 void Dictionary::classes_do(void f(InstanceKlass*)) {
307 for (int index = 0; index < table_size(); index++) {
308 for (DictionaryEntry* probe = bucket(index);
309 probe != NULL;
310 probe = probe->next()) {
311 InstanceKlass* k = probe->instance_klass();
312 if (loader_data() == k->class_loader_data()) {
313 f(k);
314 }
315 }
316 }
317 }
318
319 // Added for initialize_itable_for_klass to handle exceptions
320 // Just the classes from defining class loaders
321 void Dictionary::classes_do(void f(InstanceKlass*, TRAPS), TRAPS) {
322 for (int index = 0; index < table_size(); index++) {
323 for (DictionaryEntry* probe = bucket(index);
324 probe != NULL;
325 probe = probe->next()) {
326 InstanceKlass* k = probe->instance_klass();
327 if (loader_data() == k->class_loader_data()) {
328 f(k, CHECK);
329 }
330 }
331 }
332 }
333
334 // All classes, and their class loaders, including initiating class loaders
335 void Dictionary::all_entries_do(void f(InstanceKlass*, ClassLoaderData*)) {
336 for (int index = 0; index < table_size(); index++) {
337 for (DictionaryEntry* probe = bucket(index);
338 probe != NULL;
339 probe = probe->next()) {
340 InstanceKlass* k = probe->instance_klass();
341 f(k, loader_data());
342 }
343 }
344 }
345
346 // Used to scan and relocate the classes during CDS archive dump.
347 void Dictionary::classes_do(MetaspaceClosure* it) {
348 assert(DumpSharedSpaces, "dump-time only");
349 for (int index = 0; index < table_size(); index++) {
350 for (DictionaryEntry* probe = bucket(index);
351 probe != NULL;
352 probe = probe->next()) {
353 it->push(probe->klass_addr());
354 ((SharedDictionaryEntry*)probe)->metaspace_pointers_do(it);
355 }
356 }
357 }
358
359
360
361 // Add a loaded class to the dictionary.
362 // Readers of the SystemDictionary aren't always locked, so _buckets
363 // is volatile. The store of the next field in the constructor is
364 // also cast to volatile; we do this to ensure store order is maintained
365 // by the compilers.
366
367 void Dictionary::add_klass(unsigned int hash, Symbol* class_name,
368 InstanceKlass* obj) {
369 assert_locked_or_safepoint(SystemDictionary_lock);
370 assert(obj != NULL, "adding NULL obj");
371 assert(obj->name() == class_name, "sanity check on name");
372
373 DictionaryEntry* entry = new_entry(hash, obj);
374 int index = hash_to_index(hash);
375 add_entry(index, entry);
376 check_if_needs_resize();
377 }
378
379
380 // This routine does not lock the dictionary.
381 //
382 // Since readers don't hold a lock, we must make sure that system
383 // dictionary entries are only removed at a safepoint (when only one
384 // thread is running), and are added to in a safe way (all links must
385 // be updated in an MT-safe manner).
386 //
387 // Callers should be aware that an entry could be added just after
388 // _buckets[index] is read here, so the caller will not see the new entry.
389 DictionaryEntry* Dictionary::get_entry(int index, unsigned int hash,
390 Symbol* class_name) {
391 for (DictionaryEntry* entry = bucket(index);
392 entry != NULL;
393 entry = entry->next()) {
394 if (entry->hash() == hash && entry->equals(class_name)) {
395 if (!DumpSharedSpaces || SystemDictionaryShared::is_builtin(entry)) {
396 return entry;
397 }
398 }
399 }
400 return NULL;
401 }
402
403
404 InstanceKlass* Dictionary::find(unsigned int hash, Symbol* name,
405 Handle protection_domain) {
406 NoSafepointVerifier nsv;
407
408 int index = hash_to_index(hash);
409 DictionaryEntry* entry = get_entry(index, hash, name);
410 if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
411 return entry->instance_klass();
412 } else {
413 return NULL;
414 }
415 }
416
417
418 InstanceKlass* Dictionary::find_class(int index, unsigned int hash,
419 Symbol* name) {
420 assert_locked_or_safepoint(SystemDictionary_lock);
421 assert (index == index_for(name), "incorrect index?");
422
423 DictionaryEntry* entry = get_entry(index, hash, name);
424 return (entry != NULL) ? entry->instance_klass() : NULL;
425 }
426
427
428 // Variant of find_class for shared classes. No locking required, as
429 // that table is static.
430
431 InstanceKlass* Dictionary::find_shared_class(int index, unsigned int hash,
432 Symbol* name) {
433 assert (index == index_for(name), "incorrect index?");
434
435 DictionaryEntry* entry = get_entry(index, hash, name);
436 return (entry != NULL) ? entry->instance_klass() : NULL;
437 }
438
439
440 void Dictionary::add_protection_domain(int index, unsigned int hash,
441 InstanceKlass* klass,
442 Handle protection_domain,
443 TRAPS) {
444 Symbol* klass_name = klass->name();
445 DictionaryEntry* entry = get_entry(index, hash, klass_name);
446
447 assert(entry != NULL,"entry must be present, we just created it");
448 assert(protection_domain() != NULL,
449 "real protection domain should be present");
450
451 entry->add_protection_domain(this, protection_domain);
452
453 #ifdef ASSERT
454 assert(loader_data() != ClassLoaderData::the_null_class_loader_data(), "doesn't make sense");
455 #endif
456
457 assert(entry->contains_protection_domain(protection_domain()),
458 "now protection domain should be present");
459 }
460
461
462 bool Dictionary::is_valid_protection_domain(unsigned int hash,
463 Symbol* name,
464 Handle protection_domain) {
465 int index = hash_to_index(hash);
466 DictionaryEntry* entry = get_entry(index, hash, name);
467 return entry->is_valid_protection_domain(protection_domain);
468 }
469
470 #if INCLUDE_CDS
471 static bool is_jfr_event_class(Klass *k) {
472 while (k) {
473 if (k->name()->equals("jdk/jfr/Event")) {
474 return true;
475 }
476 k = k->super();
477 }
478 return false;
479 }
480
481 void Dictionary::reorder_dictionary_for_sharing() {
482
483 // Copy all the dictionary entries into a single master list.
484
485 DictionaryEntry* master_list = NULL;
486 for (int i = 0; i < table_size(); ++i) {
487 DictionaryEntry* p = bucket(i);
488 while (p != NULL) {
489 DictionaryEntry* next = p->next();
490 InstanceKlass*ik = p->instance_klass();
491 if (ik->signers() != NULL) {
492 // We cannot include signed classes in the archive because the certificates
493 // used during dump time may be different than those used during
494 // runtime (due to expiration, etc).
495 ResourceMark rm;
496 tty->print_cr("Preload Warning: Skipping %s from signed JAR",
497 ik->name()->as_C_string());
498 free_entry(p);
499 } else if (is_jfr_event_class(ik)) {
500 // We cannot include JFR event classes because they need runtime-specific
501 // instrumentation in order to work with -XX:FlightRecorderOptions=retransform=false.
502 // There are only a small number of these classes, so it's not worthwhile to
503 // support them and make CDS more complicated.
504 ResourceMark rm;
505 tty->print_cr("Skipping JFR event class %s", ik->name()->as_C_string());
506 free_entry(p);
507 } else {
508 p->set_next(master_list);
509 master_list = p;
510 }
511 p = next;
512 }
513 set_entry(i, NULL);
514 }
515
516 // Add the dictionary entries back to the list in the correct buckets.
517 while (master_list != NULL) {
518 DictionaryEntry* p = master_list;
519 master_list = master_list->next();
520 p->set_next(NULL);
521 Symbol* class_name = p->instance_klass()->name();
522 // Since the null class loader data isn't copied to the CDS archive,
523 // compute the hash with NULL for loader data.
524 unsigned int hash = compute_hash(class_name);
525 int index = hash_to_index(hash);
526 p->set_hash(hash);
527 p->set_next(bucket(index));
528 set_entry(index, p);
529 }
530 }
531 #endif
532
533 SymbolPropertyTable::SymbolPropertyTable(int table_size)
534 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry))
535 {
536 }
537 SymbolPropertyTable::SymbolPropertyTable(int table_size, HashtableBucket<mtSymbol>* t,
538 int number_of_entries)
539 : Hashtable<Symbol*, mtSymbol>(table_size, sizeof(SymbolPropertyEntry), t, number_of_entries)
540 {
541 }
542
543
544 SymbolPropertyEntry* SymbolPropertyTable::find_entry(int index, unsigned int hash,
545 Symbol* sym,
546 intptr_t sym_mode) {
547 assert(index == index_for(sym, sym_mode), "incorrect index?");
548 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
549 if (p->hash() == hash && p->symbol() == sym && p->symbol_mode() == sym_mode) {
550 return p;
551 }
552 }
553 return NULL;
554 }
555
556
557 SymbolPropertyEntry* SymbolPropertyTable::add_entry(int index, unsigned int hash,
558 Symbol* sym, intptr_t sym_mode) {
559 assert_locked_or_safepoint(SystemDictionary_lock);
560 assert(index == index_for(sym, sym_mode), "incorrect index?");
561 assert(find_entry(index, hash, sym, sym_mode) == NULL, "no double entry");
562
563 SymbolPropertyEntry* p = new_entry(hash, sym, sym_mode);
564 Hashtable<Symbol*, mtSymbol>::add_entry(index, p);
565 return p;
566 }
567
568 void SymbolPropertyTable::oops_do(OopClosure* f) {
569 for (int index = 0; index < table_size(); index++) {
570 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
571 if (p->method_type() != NULL) {
572 f->do_oop(p->method_type_addr());
573 }
574 }
575 }
576 }
577
578 void SymbolPropertyTable::methods_do(void f(Method*)) {
579 for (int index = 0; index < table_size(); index++) {
580 for (SymbolPropertyEntry* p = bucket(index); p != NULL; p = p->next()) {
581 Method* prop = p->method();
582 if (prop != NULL) {
583 f((Method*)prop);
584 }
585 }
586 }
587 }
588
589
590 // ----------------------------------------------------------------------------
591
592 void Dictionary::print_on(outputStream* st) const {
593 ResourceMark rm;
594
595 assert(loader_data() != NULL, "loader data should not be null");
596 st->print_cr("Java dictionary (table_size=%d, classes=%d)",
597 table_size(), number_of_entries());
598 st->print_cr("^ indicates that initiating loader is different from defining loader");
599
600 for (int index = 0; index < table_size(); index++) {
601 for (DictionaryEntry* probe = bucket(index);
602 probe != NULL;
603 probe = probe->next()) {
604 Klass* e = probe->instance_klass();
605 bool is_defining_class =
606 (loader_data() == e->class_loader_data());
607 st->print("%4d: %s%s, loader ", index, is_defining_class ? " " : "^", e->external_name());
608 ClassLoaderData* loader_data = e->class_loader_data();
609 if (loader_data == NULL) {
610 // Shared class not restored yet in shared dictionary
611 st->print("<shared, not restored>");
612 } else {
613 loader_data->print_value_on(st);
614 }
615 st->cr();
616 }
617 }
618 tty->cr();
619 }
620
621 void DictionaryEntry::verify() {
622 Klass* e = instance_klass();
623 guarantee(e->is_instance_klass(),
624 "Verify of dictionary failed");
625 e->verify();
626 verify_protection_domain_set();
627 }
628
629 void Dictionary::verify() {
630 guarantee(number_of_entries() >= 0, "Verify of dictionary failed");
631
632 ClassLoaderData* cld = loader_data();
633 // class loader must be present; a null class loader is the
634 // boostrap loader
635 guarantee(cld != NULL || DumpSharedSpaces ||
636 cld->class_loader() == NULL ||
637 cld->class_loader()->is_instance(),
638 "checking type of class_loader");
639
640 ResourceMark rm;
641 stringStream tempst;
642 tempst.print("System Dictionary for %s", cld->loader_name());
643 verify_table<DictionaryEntry>(tempst.as_string());
644 }