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