1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/altHashing.hpp"
27 #include "classfile/compactHashtable.inline.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/stringTable.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shared/oopStorage.inline.hpp"
33 #include "gc/shared/oopStorageParState.inline.hpp"
34 #include "logging/log.hpp"
35 #include "logging/logStream.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/filemap.hpp"
38 #include "memory/metaspaceShared.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "memory/universe.hpp"
41 #include "oops/access.inline.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/typeArrayOop.inline.hpp"
44 #include "oops/weakHandle.inline.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/handles.inline.hpp"
47 #include "runtime/mutexLocker.hpp"
48 #include "runtime/safepointVerifiers.hpp"
49 #include "runtime/timerTrace.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "services/diagnosticCommand.hpp"
52 #include "utilities/concurrentHashTable.inline.hpp"
53 #include "utilities/concurrentHashTableTasks.inline.hpp"
54 #include "utilities/macros.hpp"
55
56 // We prefer short chains of avg 2
57 #define PREF_AVG_LIST_LEN 2
58 // 2^24 is max size
59 #define END_SIZE 24
60 // If a chain gets to 32 something might be wrong
61 #define REHASH_LEN 32
62 // If we have as many dead items as 50% of the number of bucket
63 #define CLEAN_DEAD_HIGH_WATER_MARK 0.5
64
65 // --------------------------------------------------------------------------
66 StringTable* StringTable::_the_table = NULL;
67 bool StringTable::_shared_string_mapped = false;
68 CompactHashtable<oop, char> StringTable::_shared_table;
69 bool StringTable::_alt_hash = false;
70
71 static juint murmur_seed = 0;
72
73 uintx hash_string(const jchar* s, int len, bool useAlt) {
74 return useAlt ?
75 AltHashing::murmur3_32(murmur_seed, s, len) :
76 java_lang_String::hash_code(s, len);
77 }
78
79 class StringTableConfig : public StringTableHash::BaseConfig {
80 private:
81 public:
82 static uintx get_hash(WeakHandle<vm_string_table_data> const& value,
83 bool* is_dead) {
84 EXCEPTION_MARK;
85 oop val_oop = value.peek();
86 if (val_oop == NULL) {
87 *is_dead = true;
88 return 0;
89 }
90 *is_dead = false;
91 ResourceMark rm(THREAD);
92 // All String oops are hashed as unicode
93 int length;
94 jchar* chars = java_lang_String::as_unicode_string(val_oop, length, THREAD);
95 if (chars != NULL) {
96 return hash_string(chars, length, StringTable::_alt_hash);
97 }
98 vm_exit_out_of_memory(length, OOM_MALLOC_ERROR, "get hash from oop");
99 return 0;
100 }
101 // We use default allocation/deallocation but counted
102 static void* allocate_node(size_t size,
103 WeakHandle<vm_string_table_data> const& value) {
104 StringTable::item_added();
105 return StringTableHash::BaseConfig::allocate_node(size, value);
106 }
107 static void free_node(void* memory,
108 WeakHandle<vm_string_table_data> const& value) {
109 value.release();
110 StringTableHash::BaseConfig::free_node(memory, value);
111 StringTable::item_removed();
112 }
113 };
114
115 class StringTableLookupJchar : StackObj {
116 private:
117 Thread* _thread;
118 uintx _hash;
119 int _len;
120 const jchar* _str;
121 Handle _found;
122
123 public:
124 StringTableLookupJchar(Thread* thread, uintx hash, const jchar* key, int len)
125 : _thread(thread), _hash(hash), _str(key), _len(len) {
126 }
127 uintx get_hash() const {
128 return _hash;
129 }
130 bool equals(WeakHandle<vm_string_table_data>* value, bool* is_dead) {
131 oop val_oop = value->peek();
132 if (val_oop == NULL) {
133 // dead oop, mark this hash dead for cleaning
134 *is_dead = true;
135 return false;
136 }
137 bool equals = java_lang_String::equals(val_oop, (jchar*)_str, _len);
138 if (!equals) {
139 return false;
140 }
141 // Need to resolve weak handle and Handleize through possible safepoint.
142 _found = Handle(_thread, value->resolve());
143 return true;
144 }
145 };
146
147 class StringTableLookupOop : public StackObj {
148 private:
149 Thread* _thread;
150 uintx _hash;
151 Handle _find;
152 Handle _found; // Might be a different oop with the same value that's already
153 // in the table, which is the point.
154 public:
155 StringTableLookupOop(Thread* thread, uintx hash, Handle handle)
156 : _thread(thread), _hash(hash), _find(handle) { }
157
158 uintx get_hash() const {
159 return _hash;
160 }
161
162 bool equals(WeakHandle<vm_string_table_data>* value, bool* is_dead) {
163 oop val_oop = value->peek();
164 if (val_oop == NULL) {
165 // dead oop, mark this hash dead for cleaning
166 *is_dead = true;
167 return false;
168 }
169 bool equals = java_lang_String::equals(_find(), val_oop);
170 if (!equals) {
171 return false;
172 }
173 // Need to resolve weak handle and Handleize through possible safepoint.
174 _found = Handle(_thread, value->resolve());
175 return true;
176 }
177 };
178
179 static size_t ceil_pow_2(uintx val) {
180 size_t ret;
181 for (ret = 1; ((size_t)1 << ret) < val; ++ret);
182 return ret;
183 }
184
185 StringTable::StringTable() : _local_table(NULL), _current_size(0), _has_work(0),
186 _needs_rehashing(false), _weak_handles(NULL), _items(0), _uncleaned_items(0) {
187 _weak_handles = new OopStorage("StringTable weak",
188 StringTableWeakAlloc_lock,
189 StringTableWeakActive_lock);
190 size_t start_size_log_2 = ceil_pow_2(StringTableSize);
191 _current_size = ((size_t)1) << start_size_log_2;
192 log_trace(stringtable)("Start size: " SIZE_FORMAT " (" SIZE_FORMAT ")",
193 _current_size, start_size_log_2);
194 _local_table = new StringTableHash(start_size_log_2, END_SIZE, REHASH_LEN);
195 }
196
197 size_t StringTable::item_added() {
198 return Atomic::add((size_t)1, &(the_table()->_items));
199 }
200
201 size_t StringTable::add_items_to_clean(size_t ndead) {
202 size_t total = Atomic::add((size_t)ndead, &(the_table()->_uncleaned_items));
203 log_trace(stringtable)(
204 "Uncleaned items:" SIZE_FORMAT " added: " SIZE_FORMAT " total:" SIZE_FORMAT,
205 the_table()->_uncleaned_items, ndead, total);
206 return total;
207 }
208
209 void StringTable::item_removed() {
210 Atomic::add((size_t)-1, &(the_table()->_items));
211 }
212
213 double StringTable::get_load_factor() {
214 return (_items*1.0)/_current_size;
215 }
216
217 double StringTable::get_dead_factor() {
218 return (_uncleaned_items*1.0)/_current_size;
219 }
220
221 size_t StringTable::table_size(Thread* thread) {
222 return ((size_t)(1)) << _local_table->get_size_log2(thread != NULL ? thread
223 : Thread::current());
224 }
225
226 void StringTable::trigger_concurrent_work() {
227 MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
228 the_table()->_has_work = true;
229 Service_lock->notify_all();
230 }
231
232 // Probing
233 oop StringTable::lookup(Symbol* symbol) {
234 ResourceMark rm;
235 int length;
236 jchar* chars = symbol->as_unicode(length);
237 return lookup(chars, length);
238 }
239
240 oop StringTable::lookup(jchar* name, int len) {
241 unsigned int hash = java_lang_String::hash_code(name, len);
242 oop string = StringTable::the_table()->lookup_shared(name, len, hash);
243 if (string != NULL) {
244 return string;
245 }
246 if (StringTable::_alt_hash) {
247 hash = hash_string(name, len, true);
248 }
249 return StringTable::the_table()->do_lookup(name, len, hash);
250 }
251
252 class StringTableGet : public StackObj {
253 Thread* _thread;
254 Handle _return;
255 public:
256 StringTableGet(Thread* thread) : _thread(thread) {}
257 void operator()(WeakHandle<vm_string_table_data>* val) {
258 oop result = val->resolve();
259 assert(result != NULL, "Result should be reachable");
260 _return = Handle(_thread, result);
261 }
262 oop get_res_oop() {
263 return _return();
264 }
265 };
266
267 oop StringTable::do_lookup(jchar* name, int len, uintx hash) {
268 Thread* thread = Thread::current();
269 StringTableLookupJchar lookup(thread, hash, name, len);
270 StringTableGet stg(thread);
271 bool rehash_warning;
272 _local_table->get(thread, lookup, stg, &rehash_warning);
273 if (rehash_warning) {
274 _needs_rehashing = true;
275 }
276 return stg.get_res_oop();
277 }
278
279 // Interning
280 oop StringTable::intern(Symbol* symbol, TRAPS) {
281 if (symbol == NULL) return NULL;
282 ResourceMark rm(THREAD);
283 int length;
284 jchar* chars = symbol->as_unicode(length);
285 Handle string;
286 oop result = intern(string, chars, length, CHECK_NULL);
287 return result;
288 }
289
290 oop StringTable::intern(oop string, TRAPS) {
291 if (string == NULL) return NULL;
292 ResourceMark rm(THREAD);
293 int length;
294 Handle h_string (THREAD, string);
295 jchar* chars = java_lang_String::as_unicode_string(string, length,
296 CHECK_NULL);
297 oop result = intern(h_string, chars, length, CHECK_NULL);
298 return result;
299 }
300
301 oop StringTable::intern(const char* utf8_string, TRAPS) {
302 if (utf8_string == NULL) return NULL;
303 ResourceMark rm(THREAD);
304 int length = UTF8::unicode_length(utf8_string);
305 jchar* chars = NEW_RESOURCE_ARRAY(jchar, length);
306 UTF8::convert_to_unicode(utf8_string, chars, length);
307 Handle string;
308 oop result = intern(string, chars, length, CHECK_NULL);
309 return result;
310 }
311
312 oop StringTable::intern(Handle string_or_null_h, jchar* name, int len, TRAPS) {
313 // shared table always uses java_lang_String::hash_code
314 unsigned int hash = java_lang_String::hash_code(name, len);
315 oop found_string = StringTable::the_table()->lookup_shared(name, len, hash);
316 if (found_string != NULL) {
317 return found_string;
318 }
319 if (StringTable::_alt_hash) {
320 hash = hash_string(name, len, true);
321 }
322 found_string = StringTable::the_table()->do_lookup(name, len, hash);
323 if (found_string != NULL) {
324 return found_string;
325 }
326 return StringTable::the_table()->do_intern(string_or_null_h, name, len,
327 hash, CHECK_NULL);
328 }
329
330 class StringTableCreateEntry : public StackObj {
331 private:
332 Thread* _thread;
333 Handle _return;
334 Handle _store;
335 public:
336 StringTableCreateEntry(Thread* thread, Handle store)
337 : _thread(thread), _store(store) {}
338
339 WeakHandle<vm_string_table_data> operator()() { // No dups found
340 WeakHandle<vm_string_table_data> wh =
341 WeakHandle<vm_string_table_data>::create(_store);
342 return wh;
343 }
344 void operator()(bool inserted, WeakHandle<vm_string_table_data>* val) {
345 oop result = val->resolve();
346 assert(result != NULL, "Result should be reachable");
347 _return = Handle(_thread, result);
348 }
349 oop get_return() const {
350 return _return();
351 }
352 };
353
354 oop StringTable::do_intern(Handle string_or_null_h, jchar* name,
355 int len, uintx hash, TRAPS) {
356 HandleMark hm(THREAD); // cleanup strings created
357 Handle string_h;
358
359 if (!string_or_null_h.is_null()) {
360 string_h = string_or_null_h;
361 } else {
362 string_h = java_lang_String::create_from_unicode(name, len, CHECK_NULL);
363 }
364
365 // Deduplicate the string before it is interned. Note that we should never
366 // deduplicate a string after it has been interned. Doing so will counteract
367 // compiler optimizations done on e.g. interned string literals.
368 Universe::heap()->deduplicate_string(string_h());
369
370 assert(java_lang_String::equals(string_h(), name, len),
371 "string must be properly initialized");
372 assert(len == java_lang_String::length(string_h()), "Must be same length");
373 StringTableLookupOop lookup(THREAD, hash, string_h);
374 StringTableCreateEntry stc(THREAD, string_h);
375
376 bool rehash_warning;
377 _local_table->get_insert_lazy(THREAD, lookup, stc, stc, &rehash_warning);
378 if (rehash_warning) {
379 _needs_rehashing = true;
380 }
381 return stc.get_return();
382 }
383
384 // GC support
385 class StringTableIsAliveCounter : public BoolObjectClosure {
386 BoolObjectClosure* _real_boc;
387 public:
388 size_t _count;
389 size_t _count_total;
390 StringTableIsAliveCounter(BoolObjectClosure* boc) : _real_boc(boc), _count(0),
391 _count_total(0) {}
392 bool do_object_b(oop obj) {
393 bool ret = _real_boc->do_object_b(obj);
394 if (!ret) {
395 ++_count;
396 }
397 ++_count_total;
398 return ret;
399 }
400 };
401
402 void StringTable::unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f,
403 int* processed, int* removed) {
404 DoNothingClosure dnc;
405 assert(is_alive != NULL, "No closure");
406 StringTableIsAliveCounter stiac(is_alive);
407 OopClosure* tmp = f != NULL ? f : &dnc;
408
409 StringTable::the_table()->_weak_handles->weak_oops_do(&stiac, tmp);
410
411 // This is the serial case without ParState.
412 // Just set the correct number and check for a cleaning phase.
413 the_table()->_uncleaned_items = stiac._count;
414 StringTable::the_table()->check_concurrent_work();
415
416 if (processed != NULL) {
417 *processed = (int) stiac._count_total;
418 }
419 if (removed != NULL) {
420 *removed = (int) stiac._count;
421 }
422 }
423
424 void StringTable::oops_do(OopClosure* f) {
425 assert(f != NULL, "No closure");
426 StringTable::the_table()->_weak_handles->oops_do(f);
427 }
428
429 void StringTable::possibly_parallel_unlink(
430 OopStorage::ParState<false, false>* _par_state_string, BoolObjectClosure* cl,
431 int* processed, int* removed)
432 {
433 DoNothingClosure dnc;
434 assert(cl != NULL, "No closure");
435 StringTableIsAliveCounter stiac(cl);
436
437 _par_state_string->weak_oops_do(&stiac, &dnc);
438
439 // Accumulate the dead strings.
440 the_table()->add_items_to_clean(stiac._count);
441
442 *processed = (int) stiac._count_total;
443 *removed = (int) stiac._count;
444 }
445
446 void StringTable::possibly_parallel_oops_do(
447 OopStorage::ParState<false /* concurrent */, false /* const */>*
448 _par_state_string, OopClosure* f)
449 {
450 assert(f != NULL, "No closure");
451 _par_state_string->oops_do(f);
452 }
453
454 // Concurrent work
455 void StringTable::grow(JavaThread* jt) {
456 StringTableHash::GrowTask gt(_local_table);
457 if (!gt.prepare(jt)) {
458 return;
459 }
460 log_trace(stringtable)("Started to grow");
461 {
462 TraceTime timer("Grow", TRACETIME_LOG(Debug, stringtable, perf));
463 while (gt.do_task(jt)) {
464 gt.pause(jt);
465 {
466 ThreadBlockInVM tbivm(jt);
467 }
468 gt.cont(jt);
469 }
470 }
471 gt.done(jt);
472 _current_size = table_size(jt);
473 log_debug(stringtable)("Grown to size:" SIZE_FORMAT, _current_size);
474 }
475
476 struct StringTableDoDelete : StackObj {
477 void operator()(WeakHandle<vm_string_table_data>* val) {
478 /* do nothing */
479 }
480 };
481
482 struct StringTableDeleteCheck : StackObj {
483 long _count;
484 long _item;
485 StringTableDeleteCheck() : _count(0), _item(0) {}
486 bool operator()(WeakHandle<vm_string_table_data>* val) {
487 ++_item;
488 oop tmp = val->peek();
489 if (tmp == NULL) {
490 ++_count;
491 return true;
492 } else {
493 return false;
494 }
495 }
496 };
497
498 void StringTable::clean_dead_entries(JavaThread* jt) {
499 StringTableHash::BulkDeleteTask bdt(_local_table);
500 if (!bdt.prepare(jt)) {
501 return;
502 }
503
504 StringTableDeleteCheck stdc;
505 StringTableDoDelete stdd;
506 {
507 TraceTime timer("Clean", TRACETIME_LOG(Debug, stringtable, perf));
508 while(bdt.do_task(jt, stdc, stdd)) {
509 bdt.pause(jt);
510 {
511 ThreadBlockInVM tbivm(jt);
512 }
513 bdt.cont(jt);
514 }
515 bdt.done(jt);
516 }
517 log_debug(stringtable)("Cleaned %ld of %ld", stdc._count, stdc._item);
518 }
519
520 void StringTable::check_concurrent_work() {
521 if (_has_work) {
522 return;
523 }
524
525 double load_factor = StringTable::get_load_factor();
526 double dead_factor = StringTable::get_dead_factor();
527 // We should clean/resize if we have more dead than alive,
528 // more items than preferred load factor or
529 // more dead items than water mark.
530 if ((dead_factor > load_factor) ||
531 (load_factor > PREF_AVG_LIST_LEN) ||
532 (dead_factor > CLEAN_DEAD_HIGH_WATER_MARK)) {
533 log_debug(stringtable)("Concurrent work triggered, live factor:%g dead factor:%g",
534 load_factor, dead_factor);
535 trigger_concurrent_work();
536 }
537 }
538
539 void StringTable::concurrent_work(JavaThread* jt) {
540 _has_work = false;
541 double load_factor = get_load_factor();
542 log_debug(stringtable, perf)("Concurrent work, live factor: %g", load_factor);
543 // We prefer growing, since that also removes dead items
544 if (load_factor > PREF_AVG_LIST_LEN && !_local_table->is_max_size_reached()) {
545 grow(jt);
546 } else {
547 clean_dead_entries(jt);
548 }
549 }
550
551 void StringTable::do_concurrent_work(JavaThread* jt) {
552 StringTable::the_table()->concurrent_work(jt);
553 }
554
555 // Rehash
556 bool StringTable::do_rehash() {
557 if (!_local_table->is_safepoint_safe()) {
558 return false;
559 }
560
561 // We use max size
562 StringTableHash* new_table = new StringTableHash(END_SIZE, END_SIZE, REHASH_LEN);
563 // Use alt hash from now on
564 _alt_hash = true;
565 if (!_local_table->try_move_nodes_to(Thread::current(), new_table)) {
566 _alt_hash = false;
567 delete new_table;
568 return false;
569 }
570
571 // free old table
572 delete _local_table;
573 _local_table = new_table;
574
575 return true;
576 }
577
578 void StringTable::try_rehash_table() {
579 static bool rehashed = false;
580 log_debug(stringtable)("Table imbalanced, rehashing called.");
581
582 // Grow instead of rehash.
583 if (get_load_factor() > PREF_AVG_LIST_LEN &&
584 !_local_table->is_max_size_reached()) {
585 log_debug(stringtable)("Choosing growing over rehashing.");
586 trigger_concurrent_work();
587 _needs_rehashing = false;
588 return;
589 }
590 // Already rehashed.
591 if (rehashed) {
592 log_warning(stringtable)("Rehashing already done, still long lists.");
593 trigger_concurrent_work();
594 _needs_rehashing = false;
595 return;
596 }
597
598 murmur_seed = AltHashing::compute_seed();
599 {
600 if (do_rehash()) {
601 rehashed = true;
602 } else {
603 log_info(stringtable)("Resizes in progress rehashing skipped.");
604 }
605 }
606 _needs_rehashing = false;
607 }
608
609 void StringTable::rehash_table() {
610 StringTable::the_table()->try_rehash_table();
611 }
612
613 // Statistics
614 static int literal_size(oop obj) {
615 // NOTE: this would over-count if (pre-JDK8)
616 // java_lang_Class::has_offset_field() is true and the String.value array is
617 // shared by several Strings. However, starting from JDK8, the String.value
618 // array is not shared anymore.
619 if (obj == NULL) {
620 return 0;
621 } else if (obj->klass() == SystemDictionary::String_klass()) {
622 return (obj->size() + java_lang_String::value(obj)->size()) * HeapWordSize;
623 } else {
624 return obj->size();
625 }
626 }
627
628 struct SizeFunc : StackObj {
629 size_t operator()(WeakHandle<vm_string_table_data>* val) {
630 oop s = val->peek();
631 if (s == NULL) {
632 // Dead
633 return 0;
634 }
635 return literal_size(s);
636 };
637 };
638
639 TableStatistics StringTable::get_table_statistics() {
640 static TableStatistics ts;
641 SizeFunc sz;
642 ts = _local_table->statistics_get(Thread::current(), sz, ts);
643 return ts;
644 }
645
646 void StringTable::print_table_statistics(outputStream* st,
647 const char* table_name) {
648 SizeFunc sz;
649 _local_table->statistics_to(Thread::current(), sz, st, table_name);
650 }
651
652 // Verification
653 class VerifyStrings : StackObj {
654 public:
655 bool operator()(WeakHandle<vm_string_table_data>* val) {
656 oop s = val->peek();
657 if (s != NULL) {
658 assert(java_lang_String::length(s) >= 0, "Length on string must work.");
659 }
660 return true;
661 };
662 };
663
664 // This verification is part of Universe::verify() and needs to be quick.
665 void StringTable::verify() {
666 Thread* thr = Thread::current();
667 VerifyStrings vs;
668 if (!the_table()->_local_table->try_scan(thr, vs)) {
669 log_info(stringtable)("verify unavailable at this moment");
670 }
671 }
672
673 // Verification and comp
674 class VerifyCompStrings : StackObj {
675 GrowableArray<oop>* _oops;
676 public:
677 size_t _errors;
678 VerifyCompStrings(GrowableArray<oop>* oops) : _oops(oops), _errors(0) {}
679 bool operator()(WeakHandle<vm_string_table_data>* val) {
680 oop s = val->resolve();
681 if (s == NULL) {
682 return true;
683 }
684 int len = _oops->length();
685 for (int i = 0; i < len; i++) {
686 bool eq = java_lang_String::equals(s, _oops->at(i));
687 assert(!eq, "Duplicate strings");
688 if (eq) {
689 _errors++;
690 }
691 }
692 _oops->push(s);
693 return true;
694 };
695 };
696
697 size_t StringTable::verify_and_compare_entries() {
698 Thread* thr = Thread::current();
699 GrowableArray<oop>* oops =
700 new (ResourceObj::C_HEAP, mtInternal)
701 GrowableArray<oop>((int)the_table()->_current_size, true);
702
703 VerifyCompStrings vcs(oops);
704 if (!the_table()->_local_table->try_scan(thr, vcs)) {
705 log_info(stringtable)("verify unavailable at this moment");
706 }
707 delete oops;
708 return vcs._errors;
709 }
710
711 // Dumping
712 class PrintString : StackObj {
713 Thread* _thr;
714 outputStream* _st;
715 public:
716 PrintString(Thread* thr, outputStream* st) : _thr(thr), _st(st) {}
717 bool operator()(WeakHandle<vm_string_table_data>* val) {
718 oop s = val->peek();
719 if (s == NULL) {
720 return true;
721 }
722 typeArrayOop value = java_lang_String::value_no_keepalive(s);
723 int length = java_lang_String::length(s);
724 bool is_latin1 = java_lang_String::is_latin1(s);
725
726 if (length <= 0) {
727 _st->print("%d: ", length);
728 } else {
729 ResourceMark rm(_thr);
730 int utf8_length = length;
731 char* utf8_string;
732
733 if (!is_latin1) {
734 jchar* chars = value->char_at_addr(0);
735 utf8_string = UNICODE::as_utf8(chars, utf8_length);
736 } else {
737 jbyte* bytes = value->byte_at_addr(0);
738 utf8_string = UNICODE::as_utf8(bytes, utf8_length);
739 }
740
741 _st->print("%d: ", utf8_length);
742 HashtableTextDump::put_utf8(_st, utf8_string, utf8_length);
743 }
744 _st->cr();
745 return true;
746 };
747 };
748
749 void StringTable::dump(outputStream* st, bool verbose) {
750 if (!verbose) {
751 the_table()->print_table_statistics(st, "StringTable");
752 } else {
753 Thread* thr = Thread::current();
754 ResourceMark rm(thr);
755 st->print_cr("VERSION: 1.1");
756 PrintString ps(thr, st);
757 if (!the_table()->_local_table->try_scan(thr, ps)) {
758 st->print_cr("dump unavailable at this moment");
759 }
760 }
761 }
762
763 // Utility for dumping strings
764 StringtableDCmd::StringtableDCmd(outputStream* output, bool heap) :
765 DCmdWithParser(output, heap),
766 _verbose("-verbose", "Dump the content of each string in the table",
767 "BOOLEAN", false, "false") {
768 _dcmdparser.add_dcmd_option(&_verbose);
769 }
770
771 void StringtableDCmd::execute(DCmdSource source, TRAPS) {
772 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpStrings,
773 _verbose.value());
774 VMThread::execute(&dumper);
775 }
776
777 int StringtableDCmd::num_arguments() {
778 ResourceMark rm;
779 StringtableDCmd* dcmd = new StringtableDCmd(NULL, false);
780 if (dcmd != NULL) {
781 DCmdMark mark(dcmd);
782 return dcmd->_dcmdparser.num_arguments();
783 } else {
784 return 0;
785 }
786 }
787
788 // Sharing
789 #if INCLUDE_CDS_JAVA_HEAP
790 oop StringTable::lookup_shared(jchar* name, int len, unsigned int hash) {
791 assert(hash == java_lang_String::hash_code(name, len),
792 "hash must be computed using java_lang_String::hash_code");
793 return _shared_table.lookup((const char*)name, hash, len);
794 }
795
796 oop StringTable::create_archived_string(oop s, Thread* THREAD) {
797 assert(DumpSharedSpaces, "this function is only used with -Xshare:dump");
798
799 if (MetaspaceShared::is_archive_object(s)) {
800 return s;
801 }
802
803 oop new_s = NULL;
804 typeArrayOop v = java_lang_String::value_no_keepalive(s);
805 typeArrayOop new_v =
806 (typeArrayOop)MetaspaceShared::archive_heap_object(v, THREAD);
807 if (new_v == NULL) {
808 return NULL;
809 }
810 new_s = MetaspaceShared::archive_heap_object(s, THREAD);
811 if (new_s == NULL) {
812 return NULL;
813 }
814
815 // adjust the pointer to the 'value' field in the new String oop
816 java_lang_String::set_value_raw(new_s, new_v);
817 return new_s;
818 }
819
820 struct CopyToArchive : StackObj {
821 CompactStringTableWriter* _writer;
822 CopyToArchive(CompactStringTableWriter* writer) : _writer(writer) {}
823 bool operator()(WeakHandle<vm_string_table_data>* val) {
824 oop s = val->peek();
825 if (s == NULL) {
826 return true;
827 }
828 unsigned int hash = java_lang_String::hash_code(s);
829 if (hash == 0) {
830 return true;
831 }
832
833 java_lang_String::set_hash(s, hash);
834 oop new_s = StringTable::create_archived_string(s, Thread::current());
835 if (new_s == NULL) {
836 return true;
837 }
838
839 val->replace(new_s);
840 // add to the compact table
841 _writer->add(hash, new_s);
842 return true;
843 }
844 };
845
846 void StringTable::copy_shared_string_table(CompactStringTableWriter* writer) {
847 assert(MetaspaceShared::is_heap_object_archiving_allowed(), "must be");
848
849 CopyToArchive copy(writer);
850 StringTable::the_table()->_local_table->do_scan(Thread::current(), copy);
851 }
852
853 void StringTable::write_to_archive() {
854 assert(MetaspaceShared::is_heap_object_archiving_allowed(), "must be");
855
856 _shared_table.reset();
857 int num_buckets = the_table()->_items / SharedSymbolTableBucketSize;
858 // calculation of num_buckets can result in zero buckets, we need at least one
859 CompactStringTableWriter writer(num_buckets > 1 ? num_buckets : 1,
860 &MetaspaceShared::stats()->string);
861
862 // Copy the interned strings into the "string space" within the java heap
863 copy_shared_string_table(&writer);
864 writer.dump(&_shared_table);
865 }
866
867 void StringTable::serialize(SerializeClosure* soc) {
868 _shared_table.set_type(CompactHashtable<oop, char>::_string_table);
869 _shared_table.serialize(soc);
870
871 if (soc->writing()) {
872 // Sanity. Make sure we don't use the shared table at dump time
873 _shared_table.reset();
874 } else if (!_shared_string_mapped) {
875 _shared_table.reset();
876 }
877 }
878
879 void StringTable::shared_oops_do(OopClosure* f) {
880 _shared_table.oops_do(f);
881 }
882 #endif //INCLUDE_CDS_JAVA_HEAP