1 /*
2 * Copyright (c) 1997, 2015, 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.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "gc/shared/collectedHeap.inline.hpp"
32 #include "gc/shared/gcLocker.inline.hpp"
33 #include "memory/allocation.inline.hpp"
34 #include "memory/filemap.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "runtime/atomic.inline.hpp"
37 #include "runtime/mutexLocker.hpp"
38 #include "utilities/hashtable.inline.hpp"
39
40 // --------------------------------------------------------------------------
41 // the number of buckets a thread claims
42 const int ClaimChunkSize = 32;
43
44 SymbolTable* SymbolTable::_the_table = NULL;
45 // Static arena for symbols that are not deallocated
46 Arena* SymbolTable::_arena = NULL;
47 bool SymbolTable::_needs_rehashing = false;
48 bool SymbolTable::_lookup_shared_first = false;
49
50 CompactHashtable<Symbol*, char> SymbolTable::_shared_table;
51
52 Symbol* SymbolTable::allocate_symbol(const u1* name, int len, bool c_heap, TRAPS) {
53 assert (len <= Symbol::max_length(), "should be checked by caller");
54
55 Symbol* sym;
56
57 if (DumpSharedSpaces) {
58 // Allocate all symbols to CLD shared metaspace
59 sym = new (len, ClassLoaderData::the_null_class_loader_data(), THREAD) Symbol(name, len, PERM_REFCOUNT);
60 } else if (c_heap) {
61 // refcount starts as 1
62 sym = new (len, THREAD) Symbol(name, len, 1);
63 assert(sym != NULL, "new should call vm_exit_out_of_memory if C_HEAP is exhausted");
64 } else {
65 // Allocate to global arena
66 sym = new (len, arena(), THREAD) Symbol(name, len, PERM_REFCOUNT);
67 }
68 return sym;
69 }
70
71 void SymbolTable::initialize_symbols(int arena_alloc_size) {
72 // Initialize the arena for global symbols, size passed in depends on CDS.
73 if (arena_alloc_size == 0) {
74 _arena = new (mtSymbol) Arena(mtSymbol);
75 } else {
76 _arena = new (mtSymbol) Arena(mtSymbol, arena_alloc_size);
77 }
78 }
79
80 // Call function for all symbols in the symbol table.
81 void SymbolTable::symbols_do(SymbolClosure *cl) {
82 // all symbols from shared table
83 _shared_table.symbols_do(cl);
84
85 // all symbols from the dynamic table
86 const int n = the_table()->table_size();
87 for (int i = 0; i < n; i++) {
88 for (HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
89 p != NULL;
90 p = p->next()) {
91 cl->do_symbol(p->literal_addr());
92 }
93 }
94 }
95
96 int SymbolTable::_symbols_removed = 0;
97 int SymbolTable::_symbols_counted = 0;
98 volatile int SymbolTable::_parallel_claimed_idx = 0;
99
100 void SymbolTable::buckets_unlink(int start_idx, int end_idx, int* processed, int* removed, size_t* memory_total) {
101 for (int i = start_idx; i < end_idx; ++i) {
102 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i);
103 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i);
104 while (entry != NULL) {
105 // Shared entries are normally at the end of the bucket and if we run into
106 // a shared entry, then there is nothing more to remove. However, if we
107 // have rehashed the table, then the shared entries are no longer at the
108 // end of the bucket.
109 if (entry->is_shared() && !use_alternate_hashcode()) {
110 break;
111 }
112 Symbol* s = entry->literal();
113 (*memory_total) += s->size();
114 (*processed)++;
115 assert(s != NULL, "just checking");
116 // If reference count is zero, remove.
117 if (s->refcount() == 0) {
118 assert(!entry->is_shared(), "shared entries should be kept live");
119 delete s;
120 (*removed)++;
121 *p = entry->next();
122 the_table()->free_entry(entry);
123 } else {
124 p = entry->next_addr();
125 }
126 // get next entry
127 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p);
128 }
129 }
130 }
131
132 // Remove unreferenced symbols from the symbol table
133 // This is done late during GC.
134 void SymbolTable::unlink(int* processed, int* removed) {
135 size_t memory_total = 0;
136 buckets_unlink(0, the_table()->table_size(), processed, removed, &memory_total);
137 _symbols_removed += *removed;
138 _symbols_counted += *processed;
139 // Exclude printing for normal PrintGCDetails because people parse
140 // this output.
141 if (PrintGCDetails && Verbose && WizardMode) {
142 gclog_or_tty->print(" [Symbols=%d size=" SIZE_FORMAT "K] ", *processed,
143 (memory_total*HeapWordSize)/1024);
144 }
145 }
146
147 void SymbolTable::possibly_parallel_unlink(int* processed, int* removed) {
148 const int limit = the_table()->table_size();
149
150 size_t memory_total = 0;
151
152 for (;;) {
153 // Grab next set of buckets to scan
154 int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize;
155 if (start_idx >= limit) {
156 // End of table
157 break;
158 }
159
160 int end_idx = MIN2(limit, start_idx + ClaimChunkSize);
161 buckets_unlink(start_idx, end_idx, processed, removed, &memory_total);
162 }
163 Atomic::add(*processed, &_symbols_counted);
164 Atomic::add(*removed, &_symbols_removed);
165 // Exclude printing for normal PrintGCDetails because people parse
166 // this output.
167 if (PrintGCDetails && Verbose && WizardMode) {
168 gclog_or_tty->print(" [Symbols: scanned=%d removed=%d size=" SIZE_FORMAT "K] ", *processed, *removed,
169 (memory_total*HeapWordSize)/1024);
170 }
171 }
172
173 // Create a new table and using alternate hash code, populate the new table
174 // with the existing strings. Set flag to use the alternate hash code afterwards.
175 void SymbolTable::rehash_table() {
176 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
177 // This should never happen with -Xshare:dump but it might in testing mode.
178 if (DumpSharedSpaces) return;
179 // Create a new symbol table
180 SymbolTable* new_table = new SymbolTable();
181
182 the_table()->move_to(new_table);
183
184 // Delete the table and buckets (entries are reused in new table).
185 delete _the_table;
186 // Don't check if we need rehashing until the table gets unbalanced again.
187 // Then rehash with a new global seed.
188 _needs_rehashing = false;
189 _the_table = new_table;
190 }
191
192 // Lookup a symbol in a bucket.
193
194 Symbol* SymbolTable::lookup_dynamic(int index, const char* name,
195 int len, unsigned int hash) {
196 int count = 0;
197 for (HashtableEntry<Symbol*, mtSymbol>* e = bucket(index); e != NULL; e = e->next()) {
198 count++; // count all entries in this bucket, not just ones with same hash
199 if (e->hash() == hash) {
200 Symbol* sym = e->literal();
201 if (sym->equals(name, len)) {
202 // something is referencing this symbol now.
203 sym->increment_refcount();
204 return sym;
205 }
206 }
207 }
208 // If the bucket size is too deep check if this hash code is insufficient.
209 if (count >= rehash_count && !needs_rehashing()) {
210 _needs_rehashing = check_rehash_table(count);
211 }
212 return NULL;
213 }
214
215 Symbol* SymbolTable::lookup_shared(const char* name,
216 int len, unsigned int hash) {
217 return _shared_table.lookup(name, hash, len);
218 }
219
220 Symbol* SymbolTable::lookup(int index, const char* name,
221 int len, unsigned int hash) {
222 Symbol* sym;
223 if (_lookup_shared_first) {
224 sym = lookup_shared(name, len, hash);
225 if (sym != NULL) {
226 return sym;
227 }
228 _lookup_shared_first = false;
229 return lookup_dynamic(index, name, len, hash);
230 } else {
231 sym = lookup_dynamic(index, name, len, hash);
232 if (sym != NULL) {
233 return sym;
234 }
235 sym = lookup_shared(name, len, hash);
236 if (sym != NULL) {
237 _lookup_shared_first = true;
238 }
239 return sym;
240 }
241 }
242
243 // Pick hashing algorithm.
244 unsigned int SymbolTable::hash_symbol(const char* s, int len) {
245 return use_alternate_hashcode() ?
246 AltHashing::murmur3_32(seed(), (const jbyte*)s, len) :
247 java_lang_String::hash_code((const jbyte*)s, len);
248 }
249
250
251 // We take care not to be blocking while holding the
252 // SymbolTable_lock. Otherwise, the system might deadlock, since the
253 // symboltable is used during compilation (VM_thread) The lock free
254 // synchronization is simplified by the fact that we do not delete
255 // entries in the symbol table during normal execution (only during
256 // safepoints).
257
258 Symbol* SymbolTable::lookup(const char* name, int len, TRAPS) {
259 unsigned int hashValue = hash_symbol(name, len);
260 int index = the_table()->hash_to_index(hashValue);
261
262 Symbol* s = the_table()->lookup(index, name, len, hashValue);
263
264 // Found
265 if (s != NULL) return s;
266
267 // Grab SymbolTable_lock first.
268 MutexLocker ml(SymbolTable_lock, THREAD);
269
270 // Otherwise, add to symbol to table
271 return the_table()->basic_add(index, (u1*)name, len, hashValue, true, THREAD);
272 }
273
274 Symbol* SymbolTable::lookup(const Symbol* sym, int begin, int end, TRAPS) {
275 char* buffer;
276 int index, len;
277 unsigned int hashValue;
278 char* name;
279 {
280 debug_only(No_Safepoint_Verifier nsv;)
281
282 name = (char*)sym->base() + begin;
283 len = end - begin;
284 hashValue = hash_symbol(name, len);
285 index = the_table()->hash_to_index(hashValue);
286 Symbol* s = the_table()->lookup(index, name, len, hashValue);
287
288 // Found
289 if (s != NULL) return s;
290 }
291
292 // Otherwise, add to symbol to table. Copy to a C string first.
293 char stack_buf[128];
294 ResourceMark rm(THREAD);
295 if (len <= 128) {
296 buffer = stack_buf;
297 } else {
298 buffer = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
299 }
300 for (int i=0; i<len; i++) {
301 buffer[i] = name[i];
302 }
303 // Make sure there is no safepoint in the code above since name can't move.
304 // We can't include the code in No_Safepoint_Verifier because of the
305 // ResourceMark.
306
307 // Grab SymbolTable_lock first.
308 MutexLocker ml(SymbolTable_lock, THREAD);
309
310 return the_table()->basic_add(index, (u1*)buffer, len, hashValue, true, THREAD);
311 }
312
313 Symbol* SymbolTable::lookup_only(const char* name, int len,
314 unsigned int& hash) {
315 hash = hash_symbol(name, len);
316 int index = the_table()->hash_to_index(hash);
317
318 Symbol* s = the_table()->lookup(index, name, len, hash);
319 return s;
320 }
321
322 // Look up the address of the literal in the SymbolTable for this Symbol*
323 // Do not create any new symbols
324 // Do not increment the reference count to keep this alive
325 Symbol** SymbolTable::lookup_symbol_addr(Symbol* sym){
326 unsigned int hash = hash_symbol((char*)sym->bytes(), sym->utf8_length());
327 int index = the_table()->hash_to_index(hash);
328
329 for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(index); e != NULL; e = e->next()) {
330 if (e->hash() == hash) {
331 Symbol* literal_sym = e->literal();
332 if (sym == literal_sym) {
333 return e->literal_addr();
334 }
335 }
336 }
337 return NULL;
338 }
339
340 // Suggestion: Push unicode-based lookup all the way into the hashing
341 // and probing logic, so there is no need for convert_to_utf8 until
342 // an actual new Symbol* is created.
343 Symbol* SymbolTable::lookup_unicode(const jchar* name, int utf16_length, TRAPS) {
344 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length);
345 char stack_buf[128];
346 if (utf8_length < (int) sizeof(stack_buf)) {
347 char* chars = stack_buf;
348 UNICODE::convert_to_utf8(name, utf16_length, chars);
349 return lookup(chars, utf8_length, THREAD);
350 } else {
351 ResourceMark rm(THREAD);
352 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);;
353 UNICODE::convert_to_utf8(name, utf16_length, chars);
354 return lookup(chars, utf8_length, THREAD);
355 }
356 }
357
358 Symbol* SymbolTable::lookup_only_unicode(const jchar* name, int utf16_length,
359 unsigned int& hash) {
360 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length);
361 char stack_buf[128];
362 if (utf8_length < (int) sizeof(stack_buf)) {
363 char* chars = stack_buf;
364 UNICODE::convert_to_utf8(name, utf16_length, chars);
365 return lookup_only(chars, utf8_length, hash);
366 } else {
367 ResourceMark rm;
368 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);;
369 UNICODE::convert_to_utf8(name, utf16_length, chars);
370 return lookup_only(chars, utf8_length, hash);
371 }
372 }
373
374 void SymbolTable::add(ClassLoaderData* loader_data, constantPoolHandle cp,
375 int names_count,
376 const char** names, int* lengths, int* cp_indices,
377 unsigned int* hashValues, TRAPS) {
378 // Grab SymbolTable_lock first.
379 MutexLocker ml(SymbolTable_lock, THREAD);
380
381 SymbolTable* table = the_table();
382 bool added = table->basic_add(loader_data, cp, names_count, names, lengths,
383 cp_indices, hashValues, CHECK);
384 if (!added) {
385 // do it the hard way
386 for (int i=0; i<names_count; i++) {
387 int index = table->hash_to_index(hashValues[i]);
388 bool c_heap = !loader_data->is_the_null_class_loader_data();
389 Symbol* sym = table->basic_add(index, (u1*)names[i], lengths[i], hashValues[i], c_heap, CHECK);
390 cp->symbol_at_put(cp_indices[i], sym);
391 }
392 }
393 }
394
395 Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) {
396 unsigned int hash;
397 Symbol* result = SymbolTable::lookup_only((char*)name, (int)strlen(name), hash);
398 if (result != NULL) {
399 return result;
400 }
401 // Grab SymbolTable_lock first.
402 MutexLocker ml(SymbolTable_lock, THREAD);
403
404 SymbolTable* table = the_table();
405 int index = table->hash_to_index(hash);
406 return table->basic_add(index, (u1*)name, (int)strlen(name), hash, false, THREAD);
407 }
408
409 Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len,
410 unsigned int hashValue_arg, bool c_heap, TRAPS) {
411 assert(!Universe::heap()->is_in_reserved(name),
412 "proposed name of symbol must be stable");
413
414 // Don't allow symbols to be created which cannot fit in a Symbol*.
415 if (len > Symbol::max_length()) {
416 THROW_MSG_0(vmSymbols::java_lang_InternalError(),
417 "name is too long to represent");
418 }
419
420 // Cannot hit a safepoint in this function because the "this" pointer can move.
421 No_Safepoint_Verifier nsv;
422
423 // Check if the symbol table has been rehashed, if so, need to recalculate
424 // the hash value and index.
425 unsigned int hashValue;
426 int index;
427 if (use_alternate_hashcode()) {
428 hashValue = hash_symbol((const char*)name, len);
429 index = hash_to_index(hashValue);
430 } else {
431 hashValue = hashValue_arg;
432 index = index_arg;
433 }
434
435 // Since look-up was done lock-free, we need to check if another
436 // thread beat us in the race to insert the symbol.
437 Symbol* test = lookup(index, (char*)name, len, hashValue);
438 if (test != NULL) {
439 // A race occurred and another thread introduced the symbol.
440 assert(test->refcount() != 0, "lookup should have incremented the count");
441 return test;
442 }
443
444 // Create a new symbol.
445 Symbol* sym = allocate_symbol(name, len, c_heap, CHECK_NULL);
446 assert(sym->equals((char*)name, len), "symbol must be properly initialized");
447
448 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym);
449 add_entry(index, entry);
450 return sym;
451 }
452
453 // This version of basic_add adds symbols in batch from the constant pool
454 // parsing.
455 bool SymbolTable::basic_add(ClassLoaderData* loader_data, constantPoolHandle cp,
456 int names_count,
457 const char** names, int* lengths,
458 int* cp_indices, unsigned int* hashValues,
459 TRAPS) {
460
461 // Check symbol names are not too long. If any are too long, don't add any.
462 for (int i = 0; i< names_count; i++) {
463 if (lengths[i] > Symbol::max_length()) {
464 THROW_MSG_0(vmSymbols::java_lang_InternalError(),
465 "name is too long to represent");
466 }
467 }
468
469 // Cannot hit a safepoint in this function because the "this" pointer can move.
470 No_Safepoint_Verifier nsv;
471
472 for (int i=0; i<names_count; i++) {
473 // Check if the symbol table has been rehashed, if so, need to recalculate
474 // the hash value.
475 unsigned int hashValue;
476 if (use_alternate_hashcode()) {
477 hashValue = hash_symbol(names[i], lengths[i]);
478 } else {
479 hashValue = hashValues[i];
480 }
481 // Since look-up was done lock-free, we need to check if another
482 // thread beat us in the race to insert the symbol.
483 int index = hash_to_index(hashValue);
484 Symbol* test = lookup(index, names[i], lengths[i], hashValue);
485 if (test != NULL) {
486 // A race occurred and another thread introduced the symbol, this one
487 // will be dropped and collected. Use test instead.
488 cp->symbol_at_put(cp_indices[i], test);
489 assert(test->refcount() != 0, "lookup should have incremented the count");
490 } else {
491 // Create a new symbol. The null class loader is never unloaded so these
492 // are allocated specially in a permanent arena.
493 bool c_heap = !loader_data->is_the_null_class_loader_data();
494 Symbol* sym = allocate_symbol((const u1*)names[i], lengths[i], c_heap, CHECK_(false));
495 assert(sym->equals(names[i], lengths[i]), "symbol must be properly initialized"); // why wouldn't it be???
496 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym);
497 add_entry(index, entry);
498 cp->symbol_at_put(cp_indices[i], sym);
499 }
500 }
501 return true;
502 }
503
504
505 void SymbolTable::verify() {
506 for (int i = 0; i < the_table()->table_size(); ++i) {
507 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
508 for ( ; p != NULL; p = p->next()) {
509 Symbol* s = (Symbol*)(p->literal());
510 guarantee(s != NULL, "symbol is NULL");
511 unsigned int h = hash_symbol((char*)s->bytes(), s->utf8_length());
512 guarantee(p->hash() == h, "broken hash in symbol table entry");
513 guarantee(the_table()->hash_to_index(h) == i,
514 "wrong index in symbol table");
515 }
516 }
517 }
518
519 void SymbolTable::dump(outputStream* st, bool verbose) {
520 if (!verbose) {
521 the_table()->dump_table(st, "SymbolTable");
522 } else {
523 st->print_cr("VERSION: 1.0");
524 for (int i = 0; i < the_table()->table_size(); ++i) {
525 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
526 for ( ; p != NULL; p = p->next()) {
527 Symbol* s = (Symbol*)(p->literal());
528 const char* utf8_string = (const char*)s->bytes();
529 int utf8_length = s->utf8_length();
530 st->print("%d %d: ", utf8_length, s->refcount());
531 HashtableTextDump::put_utf8(st, utf8_string, utf8_length);
532 st->cr();
533 }
534 }
535 }
536 }
537
538 bool SymbolTable::copy_compact_table(char** top, char*end) {
539 #if INCLUDE_CDS
540 CompactHashtableWriter ch_table(CompactHashtable<Symbol*, char>::_symbol_table,
541 the_table()->number_of_entries(),
542 &MetaspaceShared::stats()->symbol);
543 if (*top + ch_table.get_required_bytes() > end) {
544 // not enough space left
545 return false;
546 }
547
548 for (int i = 0; i < the_table()->table_size(); ++i) {
549 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
550 for ( ; p != NULL; p = p->next()) {
551 Symbol* s = (Symbol*)(p->literal());
552 unsigned int fixed_hash = hash_symbol((char*)s->bytes(), s->utf8_length());
553 assert(fixed_hash == p->hash(), "must not rehash during dumping");
554 ch_table.add(fixed_hash, s);
555 }
556 }
557
558 ch_table.dump(top, end);
559
560 *top = (char*)align_pointer_up(*top, sizeof(void*));
561 #endif
562 return true;
563 }
564
565 const char* SymbolTable::init_shared_table(const char* buffer) {
566 const char* end = _shared_table.init(
567 CompactHashtable<Symbol*, char>::_symbol_table, buffer);
568 return (const char*)align_pointer_up(end, sizeof(void*));
569 }
570
571 //---------------------------------------------------------------------------
572 // Non-product code
573
574 #ifndef PRODUCT
575
576 void SymbolTable::print_histogram() {
577 MutexLocker ml(SymbolTable_lock);
578 const int results_length = 100;
579 int counts[results_length];
580 int sizes[results_length];
581 int i,j;
582
583 // initialize results to zero
584 for (j = 0; j < results_length; j++) {
585 counts[j] = 0;
586 sizes[j] = 0;
587 }
588
589 int total_size = 0;
590 int total_count = 0;
591 int total_length = 0;
592 int max_length = 0;
593 int out_of_range_count = 0;
594 int out_of_range_size = 0;
595 for (i = 0; i < the_table()->table_size(); i++) {
596 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
597 for ( ; p != NULL; p = p->next()) {
598 int size = p->literal()->size();
599 int len = p->literal()->utf8_length();
600 if (len < results_length) {
601 counts[len]++;
602 sizes[len] += size;
603 } else {
604 out_of_range_count++;
605 out_of_range_size += size;
606 }
607 total_count++;
608 total_size += size;
609 total_length += len;
610 max_length = MAX2(max_length, len);
611 }
612 }
613 tty->print_cr("Symbol Table Histogram:");
614 tty->print_cr(" Total number of symbols %7d", total_count);
615 tty->print_cr(" Total size in memory %7dK",
616 (total_size*HeapWordSize)/1024);
617 tty->print_cr(" Total counted %7d", _symbols_counted);
618 tty->print_cr(" Total removed %7d", _symbols_removed);
619 if (_symbols_counted > 0) {
620 tty->print_cr(" Percent removed %3.2f",
621 ((float)_symbols_removed/(float)_symbols_counted)* 100);
622 }
623 tty->print_cr(" Reference counts %7d", Symbol::_total_count);
624 tty->print_cr(" Symbol arena used " SIZE_FORMAT_W(7) "K", arena()->used()/1024);
625 tty->print_cr(" Symbol arena size " SIZE_FORMAT_W(7) "K", arena()->size_in_bytes()/1024);
626 tty->print_cr(" Total symbol length %7d", total_length);
627 tty->print_cr(" Maximum symbol length %7d", max_length);
628 tty->print_cr(" Average symbol length %7.2f", ((float) total_length / (float) total_count));
629 tty->print_cr(" Symbol length histogram:");
630 tty->print_cr(" %6s %10s %10s", "Length", "#Symbols", "Size");
631 for (i = 0; i < results_length; i++) {
632 if (counts[i] > 0) {
633 tty->print_cr(" %6d %10d %10dK", i, counts[i], (sizes[i]*HeapWordSize)/1024);
634 }
635 }
636 tty->print_cr(" >=%6d %10d %10dK\n", results_length,
637 out_of_range_count, (out_of_range_size*HeapWordSize)/1024);
638 }
639
640 void SymbolTable::print() {
641 for (int i = 0; i < the_table()->table_size(); ++i) {
642 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i);
643 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i);
644 if (entry != NULL) {
645 while (entry != NULL) {
646 tty->print(PTR_FORMAT " ", p2i(entry->literal()));
647 entry->literal()->print();
648 tty->print(" %d", entry->literal()->refcount());
649 p = entry->next_addr();
650 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p);
651 }
652 tty->cr();
653 }
654 }
655 }
656 #endif // PRODUCT
657
658
659 // Utility for dumping symbols
660 SymboltableDCmd::SymboltableDCmd(outputStream* output, bool heap) :
661 DCmdWithParser(output, heap),
662 _verbose("-verbose", "Dump the content of each symbol in the table",
663 "BOOLEAN", false, "false") {
664 _dcmdparser.add_dcmd_option(&_verbose);
665 }
666
667 void SymboltableDCmd::execute(DCmdSource source, TRAPS) {
668 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSymbols,
669 _verbose.value());
670 VMThread::execute(&dumper);
671 }
672
673 int SymboltableDCmd::num_arguments() {
674 ResourceMark rm;
675 SymboltableDCmd* dcmd = new SymboltableDCmd(NULL, false);
676 if (dcmd != NULL) {
677 DCmdMark mark(dcmd);
678 return dcmd->_dcmdparser.num_arguments();
679 } else {
680 return 0;
681 }
682 }