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(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, const 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, const 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 }