1 /*
2 * Copyright (c) 1997, 2014, 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_interface/collectedHeap.inline.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/filemap.hpp"
34 #include "memory/gcLocker.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/oop.inline2.hpp"
37 #include "runtime/atomic.inline.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "utilities/hashtable.inline.hpp"
40
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
42
43 // --------------------------------------------------------------------------
44 // the number of buckets a thread claims
45 const int ClaimChunkSize = 32;
46
47 SymbolTable* SymbolTable::_the_table = NULL;
48 // Static arena for symbols that are not deallocated
49 Arena* SymbolTable::_arena = NULL;
50 bool SymbolTable::_needs_rehashing = false;
51 bool SymbolTable::_lookup_shared_first = false;
52
53 CompactHashtable<Symbol*, char> SymbolTable::_shared_table;
54
55 Symbol* SymbolTable::allocate_symbol(const u1* name, int len, bool c_heap, TRAPS) {
56 assert (len <= Symbol::max_length(), "should be checked by caller");
57
58 Symbol* sym;
59
60 if (DumpSharedSpaces) {
61 // Allocate all symbols to CLD shared metaspace
62 sym = new (len, ClassLoaderData::the_null_class_loader_data(), THREAD) Symbol(name, len, -1);
63 } else if (c_heap) {
64 // refcount starts as 1
65 sym = new (len, THREAD) Symbol(name, len, 1);
66 assert(sym != NULL, "new should call vm_exit_out_of_memory if C_HEAP is exhausted");
67 } else {
68 // Allocate to global arena
69 sym = new (len, arena(), THREAD) Symbol(name, len, -1);
70 }
71 return sym;
72 }
73
74 void SymbolTable::initialize_symbols(int arena_alloc_size) {
75 // Initialize the arena for global symbols, size passed in depends on CDS.
76 if (arena_alloc_size == 0) {
77 _arena = new (mtSymbol) Arena(mtSymbol);
78 } else {
79 _arena = new (mtSymbol) Arena(mtSymbol, arena_alloc_size);
80 }
81 }
82
83 // Call function for all symbols in the symbol table.
84 void SymbolTable::symbols_do(SymbolClosure *cl) {
85 // all symbols from shared table
86 _shared_table.symbols_do(cl);
87
88 // all symbols from the dynamic table
89 const int n = the_table()->table_size();
90 for (int i = 0; i < n; i++) {
91 for (HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
92 p != NULL;
93 p = p->next()) {
94 cl->do_symbol(p->literal_addr());
95 }
96 }
97 }
98
99 int SymbolTable::_symbols_removed = 0;
100 int SymbolTable::_symbols_counted = 0;
101 volatile int SymbolTable::_parallel_claimed_idx = 0;
102
103 void SymbolTable::buckets_unlink(int start_idx, int end_idx, int* processed, int* removed, size_t* memory_total) {
104 for (int i = start_idx; i < end_idx; ++i) {
105 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i);
106 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i);
107 while (entry != NULL) {
108 // Shared entries are normally at the end of the bucket and if we run into
109 // a shared entry, then there is nothing more to remove. However, if we
110 // have rehashed the table, then the shared entries are no longer at the
111 // end of the bucket.
112 if (entry->is_shared() && !use_alternate_hashcode()) {
113 break;
114 }
115 Symbol* s = entry->literal();
116 (*memory_total) += s->size();
117 (*processed)++;
118 assert(s != NULL, "just checking");
119 // If reference count is zero, remove.
120 if (s->refcount() == 0) {
121 assert(!entry->is_shared(), "shared entries should be kept live");
122 delete s;
123 (*removed)++;
124 *p = entry->next();
125 the_table()->free_entry(entry);
126 } else {
127 p = entry->next_addr();
128 }
129 // get next entry
130 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p);
131 }
132 }
133 }
134
135 // Remove unreferenced symbols from the symbol table
136 // This is done late during GC.
137 void SymbolTable::unlink(int* processed, int* removed) {
138 size_t memory_total = 0;
139 buckets_unlink(0, the_table()->table_size(), processed, removed, &memory_total);
140 _symbols_removed += *removed;
141 _symbols_counted += *processed;
142 // Exclude printing for normal PrintGCDetails because people parse
143 // this output.
144 if (PrintGCDetails && Verbose && WizardMode) {
145 gclog_or_tty->print(" [Symbols=%d size=" SIZE_FORMAT "K] ", *processed,
146 (memory_total*HeapWordSize)/1024);
147 }
148 }
149
150 void SymbolTable::possibly_parallel_unlink(int* processed, int* removed) {
151 const int limit = the_table()->table_size();
152
153 size_t memory_total = 0;
154
155 for (;;) {
156 // Grab next set of buckets to scan
157 int start_idx = Atomic::add(ClaimChunkSize, &_parallel_claimed_idx) - ClaimChunkSize;
158 if (start_idx >= limit) {
159 // End of table
160 break;
161 }
162
163 int end_idx = MIN2(limit, start_idx + ClaimChunkSize);
164 buckets_unlink(start_idx, end_idx, processed, removed, &memory_total);
165 }
166 Atomic::add(*processed, &_symbols_counted);
167 Atomic::add(*removed, &_symbols_removed);
168 // Exclude printing for normal PrintGCDetails because people parse
169 // this output.
170 if (PrintGCDetails && Verbose && WizardMode) {
171 gclog_or_tty->print(" [Symbols: scanned=%d removed=%d size=" SIZE_FORMAT "K] ", *processed, *removed,
172 (memory_total*HeapWordSize)/1024);
173 }
174 }
175
176 // Create a new table and using alternate hash code, populate the new table
177 // with the existing strings. Set flag to use the alternate hash code afterwards.
178 void SymbolTable::rehash_table() {
179 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
180 // This should never happen with -Xshare:dump but it might in testing mode.
181 if (DumpSharedSpaces) return;
182 // Create a new symbol table
183 SymbolTable* new_table = new SymbolTable();
184
185 the_table()->move_to(new_table);
186
187 // Delete the table and buckets (entries are reused in new table).
188 delete _the_table;
189 // Don't check if we need rehashing until the table gets unbalanced again.
190 // Then rehash with a new global seed.
191 _needs_rehashing = false;
192 _the_table = new_table;
193 }
194
195 // Lookup a symbol in a bucket.
196
197 Symbol* SymbolTable::lookup_dynamic(int index, const char* name,
198 int len, unsigned int hash) {
199 int count = 0;
200 for (HashtableEntry<Symbol*, mtSymbol>* e = bucket(index); e != NULL; e = e->next()) {
201 count++; // count all entries in this bucket, not just ones with same hash
202 if (e->hash() == hash) {
203 Symbol* sym = e->literal();
204 if (sym->equals(name, len)) {
205 // something is referencing this symbol now.
206 sym->increment_refcount();
207 return sym;
208 }
209 }
210 }
211 // If the bucket size is too deep check if this hash code is insufficient.
212 if (count >= rehash_count && !needs_rehashing()) {
213 _needs_rehashing = check_rehash_table(count);
214 }
215 return NULL;
216 }
217
218 Symbol* SymbolTable::lookup_shared(const char* name,
219 int len, unsigned int hash) {
220 return _shared_table.lookup(name, hash, len);
221 }
222
223 Symbol* SymbolTable::lookup(int index, const char* name,
224 int len, unsigned int hash) {
225 Symbol* sym;
226 if (_lookup_shared_first) {
227 sym = lookup_shared(name, len, hash);
228 if (sym != NULL) {
229 return sym;
230 }
231 _lookup_shared_first = false;
232 return lookup_dynamic(index, name, len, hash);
233 } else {
234 sym = lookup_dynamic(index, name, len, hash);
235 if (sym != NULL) {
236 return sym;
237 }
238 sym = lookup_shared(name, len, hash);
239 if (sym != NULL) {
240 _lookup_shared_first = true;
241 }
242 return sym;
243 }
244 }
245
246 // Pick hashing algorithm.
247 unsigned int SymbolTable::hash_symbol(const char* s, int len) {
248 return use_alternate_hashcode() ?
249 AltHashing::murmur3_32(seed(), (const jbyte*)s, len) :
250 java_lang_String::hash_code(s, len);
251 }
252
253
254 // We take care not to be blocking while holding the
255 // SymbolTable_lock. Otherwise, the system might deadlock, since the
256 // symboltable is used during compilation (VM_thread) The lock free
257 // synchronization is simplified by the fact that we do not delete
258 // entries in the symbol table during normal execution (only during
259 // safepoints).
260
261 Symbol* SymbolTable::lookup(const char* name, int len, TRAPS) {
262 unsigned int hashValue = hash_symbol(name, len);
263 int index = the_table()->hash_to_index(hashValue);
264
265 Symbol* s = the_table()->lookup(index, name, len, hashValue);
266
267 // Found
268 if (s != NULL) return s;
269
270 // Grab SymbolTable_lock first.
271 MutexLocker ml(SymbolTable_lock, THREAD);
272
273 // Otherwise, add to symbol to table
274 return the_table()->basic_add(index, (u1*)name, len, hashValue, true, THREAD);
275 }
276
277 Symbol* SymbolTable::lookup(const Symbol* sym, int begin, int end, TRAPS) {
278 char* buffer;
279 int index, len;
280 unsigned int hashValue;
281 char* name;
282 {
283 debug_only(No_Safepoint_Verifier nsv;)
284
285 name = (char*)sym->base() + begin;
286 len = end - begin;
287 hashValue = hash_symbol(name, len);
288 index = the_table()->hash_to_index(hashValue);
289 Symbol* s = the_table()->lookup(index, name, len, hashValue);
290
291 // Found
292 if (s != NULL) return s;
293 }
294
295 // Otherwise, add to symbol to table. Copy to a C string first.
296 char stack_buf[128];
297 ResourceMark rm(THREAD);
298 if (len <= 128) {
299 buffer = stack_buf;
300 } else {
301 buffer = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len);
302 }
303 for (int i=0; i<len; i++) {
304 buffer[i] = name[i];
305 }
306 // Make sure there is no safepoint in the code above since name can't move.
307 // We can't include the code in No_Safepoint_Verifier because of the
308 // ResourceMark.
309
310 // Grab SymbolTable_lock first.
311 MutexLocker ml(SymbolTable_lock, THREAD);
312
313 return the_table()->basic_add(index, (u1*)buffer, len, hashValue, true, THREAD);
314 }
315
316 Symbol* SymbolTable::lookup_only(const char* name, int len,
317 unsigned int& hash) {
318 hash = hash_symbol(name, len);
319 int index = the_table()->hash_to_index(hash);
320
321 Symbol* s = the_table()->lookup(index, name, len, hash);
322 return s;
323 }
324
325 // Look up the address of the literal in the SymbolTable for this Symbol*
326 // Do not create any new symbols
327 // Do not increment the reference count to keep this alive
328 Symbol** SymbolTable::lookup_symbol_addr(Symbol* sym){
329 unsigned int hash = hash_symbol((char*)sym->bytes(), sym->utf8_length());
330 int index = the_table()->hash_to_index(hash);
331
332 for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(index); e != NULL; e = e->next()) {
333 if (e->hash() == hash) {
334 Symbol* literal_sym = e->literal();
335 if (sym == literal_sym) {
336 return e->literal_addr();
337 }
338 }
339 }
340 return NULL;
341 }
342
343 // Suggestion: Push unicode-based lookup all the way into the hashing
344 // and probing logic, so there is no need for convert_to_utf8 until
345 // an actual new Symbol* is created.
346 Symbol* SymbolTable::lookup_unicode(const jchar* name, int utf16_length, TRAPS) {
347 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length);
348 char stack_buf[128];
349 if (utf8_length < (int) sizeof(stack_buf)) {
350 char* chars = stack_buf;
351 UNICODE::convert_to_utf8(name, utf16_length, chars);
352 return lookup(chars, utf8_length, THREAD);
353 } else {
354 ResourceMark rm(THREAD);
355 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);;
356 UNICODE::convert_to_utf8(name, utf16_length, chars);
357 return lookup(chars, utf8_length, THREAD);
358 }
359 }
360
361 Symbol* SymbolTable::lookup_only_unicode(const jchar* name, int utf16_length,
362 unsigned int& hash) {
363 int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length);
364 char stack_buf[128];
365 if (utf8_length < (int) sizeof(stack_buf)) {
366 char* chars = stack_buf;
367 UNICODE::convert_to_utf8(name, utf16_length, chars);
368 return lookup_only(chars, utf8_length, hash);
369 } else {
370 ResourceMark rm;
371 char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);;
372 UNICODE::convert_to_utf8(name, utf16_length, chars);
373 return lookup_only(chars, utf8_length, hash);
374 }
375 }
376
377 void SymbolTable::add(ClassLoaderData* loader_data, constantPoolHandle cp,
378 int names_count,
379 const char** names, int* lengths, int* cp_indices,
380 unsigned int* hashValues, TRAPS) {
381 // Grab SymbolTable_lock first.
382 MutexLocker ml(SymbolTable_lock, THREAD);
383
384 SymbolTable* table = the_table();
385 bool added = table->basic_add(loader_data, cp, names_count, names, lengths,
386 cp_indices, hashValues, CHECK);
387 if (!added) {
388 // do it the hard way
389 for (int i=0; i<names_count; i++) {
390 int index = table->hash_to_index(hashValues[i]);
391 bool c_heap = !loader_data->is_the_null_class_loader_data();
392 Symbol* sym = table->basic_add(index, (u1*)names[i], lengths[i], hashValues[i], c_heap, CHECK);
393 cp->symbol_at_put(cp_indices[i], sym);
394 }
395 }
396 }
397
398 Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) {
399 unsigned int hash;
400 Symbol* result = SymbolTable::lookup_only((char*)name, (int)strlen(name), hash);
401 if (result != NULL) {
402 return result;
403 }
404 // Grab SymbolTable_lock first.
405 MutexLocker ml(SymbolTable_lock, THREAD);
406
407 SymbolTable* table = the_table();
408 int index = table->hash_to_index(hash);
409 return table->basic_add(index, (u1*)name, (int)strlen(name), hash, false, THREAD);
410 }
411
412 Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len,
413 unsigned int hashValue_arg, bool c_heap, TRAPS) {
414 assert(!Universe::heap()->is_in_reserved(name),
415 "proposed name of symbol must be stable");
416
417 // Don't allow symbols to be created which cannot fit in a Symbol*.
418 if (len > Symbol::max_length()) {
419 THROW_MSG_0(vmSymbols::java_lang_InternalError(),
420 "name is too long to represent");
421 }
422
423 // Cannot hit a safepoint in this function because the "this" pointer can move.
424 No_Safepoint_Verifier nsv;
425
426 // Check if the symbol table has been rehashed, if so, need to recalculate
427 // the hash value and index.
428 unsigned int hashValue;
429 int index;
430 if (use_alternate_hashcode()) {
431 hashValue = hash_symbol((const char*)name, len);
432 index = hash_to_index(hashValue);
433 } else {
434 hashValue = hashValue_arg;
435 index = index_arg;
436 }
437
438 // Since look-up was done lock-free, we need to check if another
439 // thread beat us in the race to insert the symbol.
440 Symbol* test = lookup(index, (char*)name, len, hashValue);
441 if (test != NULL) {
442 // A race occurred and another thread introduced the symbol.
443 assert(test->refcount() != 0, "lookup should have incremented the count");
444 return test;
445 }
446
447 // Create a new symbol.
448 Symbol* sym = allocate_symbol(name, len, c_heap, CHECK_NULL);
449 assert(sym->equals((char*)name, len), "symbol must be properly initialized");
450
451 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym);
452 add_entry(index, entry);
453 return sym;
454 }
455
456 // This version of basic_add adds symbols in batch from the constant pool
457 // parsing.
458 bool SymbolTable::basic_add(ClassLoaderData* loader_data, constantPoolHandle cp,
459 int names_count,
460 const char** names, int* lengths,
461 int* cp_indices, unsigned int* hashValues,
462 TRAPS) {
463
464 // Check symbol names are not too long. If any are too long, don't add any.
465 for (int i = 0; i< names_count; i++) {
466 if (lengths[i] > Symbol::max_length()) {
467 THROW_MSG_0(vmSymbols::java_lang_InternalError(),
468 "name is too long to represent");
469 }
470 }
471
472 // Cannot hit a safepoint in this function because the "this" pointer can move.
473 No_Safepoint_Verifier nsv;
474
475 for (int i=0; i<names_count; i++) {
476 // Check if the symbol table has been rehashed, if so, need to recalculate
477 // the hash value.
478 unsigned int hashValue;
479 if (use_alternate_hashcode()) {
480 hashValue = hash_symbol(names[i], lengths[i]);
481 } else {
482 hashValue = hashValues[i];
483 }
484 // Since look-up was done lock-free, we need to check if another
485 // thread beat us in the race to insert the symbol.
486 int index = hash_to_index(hashValue);
487 Symbol* test = lookup(index, names[i], lengths[i], hashValue);
488 if (test != NULL) {
489 // A race occurred and another thread introduced the symbol, this one
490 // will be dropped and collected. Use test instead.
491 cp->symbol_at_put(cp_indices[i], test);
492 assert(test->refcount() != 0, "lookup should have incremented the count");
493 } else {
494 // Create a new symbol. The null class loader is never unloaded so these
495 // are allocated specially in a permanent arena.
496 bool c_heap = !loader_data->is_the_null_class_loader_data();
497 Symbol* sym = allocate_symbol((const u1*)names[i], lengths[i], c_heap, CHECK_(false));
498 assert(sym->equals(names[i], lengths[i]), "symbol must be properly initialized"); // why wouldn't it be???
499 HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym);
500 add_entry(index, entry);
501 cp->symbol_at_put(cp_indices[i], sym);
502 }
503 }
504 return true;
505 }
506
507
508 void SymbolTable::verify() {
509 for (int i = 0; i < the_table()->table_size(); ++i) {
510 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
511 for ( ; p != NULL; p = p->next()) {
512 Symbol* s = (Symbol*)(p->literal());
513 guarantee(s != NULL, "symbol is NULL");
514 unsigned int h = hash_symbol((char*)s->bytes(), s->utf8_length());
515 guarantee(p->hash() == h, "broken hash in symbol table entry");
516 guarantee(the_table()->hash_to_index(h) == i,
517 "wrong index in symbol table");
518 }
519 }
520 }
521
522 void SymbolTable::dump(outputStream* st, bool verbose) {
523 if (!verbose) {
524 the_table()->dump_table(st, "SymbolTable");
525 } else {
526 st->print_cr("VERSION: 1.0");
527 for (int i = 0; i < the_table()->table_size(); ++i) {
528 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
529 for ( ; p != NULL; p = p->next()) {
530 Symbol* s = (Symbol*)(p->literal());
531 const char* utf8_string = (const char*)s->bytes();
532 int utf8_length = s->utf8_length();
533 st->print("%d %d: ", utf8_length, s->refcount());
534 HashtableTextDump::put_utf8(st, utf8_string, utf8_length);
535 st->cr();
536 }
537 }
538 }
539 }
540
541 bool SymbolTable::copy_compact_table(char** top, char*end) {
542 #if INCLUDE_CDS
543 CompactHashtableWriter ch_table("symbol", the_table()->number_of_entries(),
544 &MetaspaceShared::stats()->symbol);
545 if (*top + ch_table.get_required_bytes() > end) {
546 // not enough space left
547 return false;
548 }
549
550 for (int i = 0; i < the_table()->table_size(); ++i) {
551 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
552 for ( ; p != NULL; p = p->next()) {
553 Symbol* s = (Symbol*)(p->literal());
554 unsigned int fixed_hash = hash_symbol((char*)s->bytes(), s->utf8_length());
555 assert(fixed_hash == p->hash(), "must not rehash during dumping");
556 ch_table.add(fixed_hash, s);
557 }
558 }
559
560 char* old_top = *top;
561 ch_table.dump(top, end);
562
563 *top = (char*)align_pointer_up(*top, sizeof(void*));
564 #endif
565 return true;
566 }
567
568 const char* SymbolTable::init_shared_table(const char* buffer) {
569 const char* end = _shared_table.init(buffer);
570 return (const char*)align_pointer_up(end, sizeof(void*));
571 }
572
573 //---------------------------------------------------------------------------
574 // Non-product code
575
576 #ifndef PRODUCT
577
578 void SymbolTable::print_histogram() {
579 MutexLocker ml(SymbolTable_lock);
580 const int results_length = 100;
581 int counts[results_length];
582 int sizes[results_length];
583 int i,j;
584
585 // initialize results to zero
586 for (j = 0; j < results_length; j++) {
587 counts[j] = 0;
588 sizes[j] = 0;
589 }
590
591 int total_size = 0;
592 int total_count = 0;
593 int total_length = 0;
594 int max_length = 0;
595 int out_of_range_count = 0;
596 int out_of_range_size = 0;
597 for (i = 0; i < the_table()->table_size(); i++) {
598 HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i);
599 for ( ; p != NULL; p = p->next()) {
600 int size = p->literal()->size();
601 int len = p->literal()->utf8_length();
602 if (len < results_length) {
603 counts[len]++;
604 sizes[len] += size;
605 } else {
606 out_of_range_count++;
607 out_of_range_size += size;
608 }
609 total_count++;
610 total_size += size;
611 total_length += len;
612 max_length = MAX2(max_length, len);
613 }
614 }
615 tty->print_cr("Symbol Table Histogram:");
616 tty->print_cr(" Total number of symbols %7d", total_count);
617 tty->print_cr(" Total size in memory %7dK",
618 (total_size*HeapWordSize)/1024);
619 tty->print_cr(" Total counted %7d", _symbols_counted);
620 tty->print_cr(" Total removed %7d", _symbols_removed);
621 if (_symbols_counted > 0) {
622 tty->print_cr(" Percent removed %3.2f",
623 ((float)_symbols_removed/(float)_symbols_counted)* 100);
624 }
625 tty->print_cr(" Reference counts %7d", Symbol::_total_count);
626 tty->print_cr(" Symbol arena used %7dK", arena()->used()/1024);
627 tty->print_cr(" Symbol arena size %7dK", arena()->size_in_bytes()/1024);
628 tty->print_cr(" Total symbol length %7d", total_length);
629 tty->print_cr(" Maximum symbol length %7d", max_length);
630 tty->print_cr(" Average symbol length %7.2f", ((float) total_length / (float) total_count));
631 tty->print_cr(" Symbol length histogram:");
632 tty->print_cr(" %6s %10s %10s", "Length", "#Symbols", "Size");
633 for (i = 0; i < results_length; i++) {
634 if (counts[i] > 0) {
635 tty->print_cr(" %6d %10d %10dK", i, counts[i], (sizes[i]*HeapWordSize)/1024);
636 }
637 }
638 tty->print_cr(" >=%6d %10d %10dK\n", results_length,
639 out_of_range_count, (out_of_range_size*HeapWordSize)/1024);
640 }
641
642 void SymbolTable::print() {
643 for (int i = 0; i < the_table()->table_size(); ++i) {
644 HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i);
645 HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i);
646 if (entry != NULL) {
647 while (entry != NULL) {
648 tty->print(PTR_FORMAT " ", entry->literal());
649 entry->literal()->print();
650 tty->print(" %d", entry->literal()->refcount());
651 p = entry->next_addr();
652 entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p);
653 }
654 tty->cr();
655 }
656 }
657 }
658 #endif // PRODUCT
659
660
661 // Utility for dumping symbols
662 SymboltableDCmd::SymboltableDCmd(outputStream* output, bool heap) :
663 DCmdWithParser(output, heap),
664 _verbose("-verbose", "Dump the content of each symbol in the table",
665 "BOOLEAN", false, "false") {
666 _dcmdparser.add_dcmd_option(&_verbose);
667 }
668
669 void SymboltableDCmd::execute(DCmdSource source, TRAPS) {
670 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSymbols,
671 _verbose.value());
672 VMThread::execute(&dumper);
673 }
674
675 int SymboltableDCmd::num_arguments() {
676 ResourceMark rm;
677 SymboltableDCmd* dcmd = new SymboltableDCmd(NULL, false);
678 if (dcmd != NULL) {
679 DCmdMark mark(dcmd);
680 return dcmd->_dcmdparser.num_arguments();
681 } else {
682 return 0;
683 }
684 }