Tue, 14 May 2013 11:34:30 +0400
8014448: Purge PrintCompactFieldsSavings
Summary: Remove obsolete debugging code.
Reviewed-by: dholmes, kvn
Contributed-by: Aleksey Shipilev <aleksey.shipilev@oracle.com>
duke@435 | 1 | /* |
coleenp@4718 | 2 | * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
coleenp@3865 | 26 | #include "classfile/altHashing.hpp" |
stefank@2314 | 27 | #include "classfile/javaClasses.hpp" |
stefank@2314 | 28 | #include "classfile/symbolTable.hpp" |
stefank@2314 | 29 | #include "classfile/systemDictionary.hpp" |
stefank@2314 | 30 | #include "gc_interface/collectedHeap.inline.hpp" |
coleenp@3682 | 31 | #include "memory/allocation.inline.hpp" |
stefank@2314 | 32 | #include "memory/filemap.hpp" |
stefank@2314 | 33 | #include "memory/gcLocker.inline.hpp" |
stefank@2314 | 34 | #include "oops/oop.inline.hpp" |
stefank@2314 | 35 | #include "oops/oop.inline2.hpp" |
stefank@2314 | 36 | #include "runtime/mutexLocker.hpp" |
stefank@2314 | 37 | #include "utilities/hashtable.inline.hpp" |
coleenp@3865 | 38 | #include "utilities/numberSeq.hpp" |
duke@435 | 39 | |
duke@435 | 40 | // -------------------------------------------------------------------------- |
duke@435 | 41 | |
duke@435 | 42 | SymbolTable* SymbolTable::_the_table = NULL; |
coleenp@3682 | 43 | // Static arena for symbols that are not deallocated |
coleenp@3682 | 44 | Arena* SymbolTable::_arena = NULL; |
coleenp@3865 | 45 | bool SymbolTable::_needs_rehashing = false; |
duke@435 | 46 | |
coleenp@3682 | 47 | Symbol* SymbolTable::allocate_symbol(const u1* name, int len, bool c_heap, TRAPS) { |
coleenp@3875 | 48 | assert (len <= Symbol::max_length(), "should be checked by caller"); |
coleenp@3875 | 49 | |
coleenp@3682 | 50 | Symbol* sym; |
coleenp@4037 | 51 | |
coleenp@4718 | 52 | if (DumpSharedSpaces) { |
coleenp@4718 | 53 | // Allocate all symbols to CLD shared metaspace |
coleenp@4718 | 54 | sym = new (len, ClassLoaderData::the_null_class_loader_data(), THREAD) Symbol(name, len, -1); |
coleenp@4718 | 55 | } else if (c_heap) { |
coleenp@3682 | 56 | // refcount starts as 1 |
coleenp@3682 | 57 | sym = new (len, THREAD) Symbol(name, len, 1); |
coleenp@4037 | 58 | assert(sym != NULL, "new should call vm_exit_out_of_memory if C_HEAP is exhausted"); |
coleenp@4037 | 59 | } else { |
coleenp@4718 | 60 | // Allocate to global arena |
coleenp@3682 | 61 | sym = new (len, arena(), THREAD) Symbol(name, len, -1); |
coleenp@3682 | 62 | } |
coleenp@2497 | 63 | return sym; |
coleenp@2497 | 64 | } |
coleenp@2497 | 65 | |
coleenp@3682 | 66 | void SymbolTable::initialize_symbols(int arena_alloc_size) { |
coleenp@3682 | 67 | // Initialize the arena for global symbols, size passed in depends on CDS. |
coleenp@3682 | 68 | if (arena_alloc_size == 0) { |
zgu@3900 | 69 | _arena = new (mtSymbol) Arena(); |
coleenp@3682 | 70 | } else { |
zgu@3900 | 71 | _arena = new (mtSymbol) Arena(arena_alloc_size); |
coleenp@2497 | 72 | } |
coleenp@2497 | 73 | } |
coleenp@2497 | 74 | |
coleenp@2497 | 75 | // Call function for all symbols in the symbol table. |
coleenp@2497 | 76 | void SymbolTable::symbols_do(SymbolClosure *cl) { |
coleenp@2497 | 77 | const int n = the_table()->table_size(); |
coleenp@2497 | 78 | for (int i = 0; i < n; i++) { |
zgu@3900 | 79 | for (HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); |
coleenp@2497 | 80 | p != NULL; |
coleenp@2497 | 81 | p = p->next()) { |
coleenp@2497 | 82 | cl->do_symbol(p->literal_addr()); |
coleenp@2497 | 83 | } |
coleenp@2497 | 84 | } |
coleenp@2497 | 85 | } |
coleenp@2497 | 86 | |
coleenp@2497 | 87 | int SymbolTable::symbols_removed = 0; |
coleenp@2497 | 88 | int SymbolTable::symbols_counted = 0; |
coleenp@2497 | 89 | |
coleenp@2497 | 90 | // Remove unreferenced symbols from the symbol table |
coleenp@3682 | 91 | // This is done late during GC. |
coleenp@2497 | 92 | void SymbolTable::unlink() { |
coleenp@2497 | 93 | int removed = 0; |
coleenp@2497 | 94 | int total = 0; |
coleenp@2618 | 95 | size_t memory_total = 0; |
coleenp@2497 | 96 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 97 | HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); |
zgu@3900 | 98 | HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); |
coleenp@3875 | 99 | while (entry != NULL) { |
coleenp@3875 | 100 | // Shared entries are normally at the end of the bucket and if we run into |
coleenp@3875 | 101 | // a shared entry, then there is nothing more to remove. However, if we |
coleenp@3875 | 102 | // have rehashed the table, then the shared entries are no longer at the |
coleenp@3875 | 103 | // end of the bucket. |
coleenp@3875 | 104 | if (entry->is_shared() && !use_alternate_hashcode()) { |
coleenp@2497 | 105 | break; |
coleenp@2497 | 106 | } |
coleenp@2497 | 107 | Symbol* s = entry->literal(); |
coleenp@4037 | 108 | memory_total += s->size(); |
coleenp@2497 | 109 | total++; |
coleenp@2497 | 110 | assert(s != NULL, "just checking"); |
coleenp@2497 | 111 | // If reference count is zero, remove. |
coleenp@2497 | 112 | if (s->refcount() == 0) { |
coleenp@3875 | 113 | assert(!entry->is_shared(), "shared entries should be kept live"); |
coleenp@2497 | 114 | delete s; |
coleenp@2497 | 115 | removed++; |
coleenp@2497 | 116 | *p = entry->next(); |
coleenp@2497 | 117 | the_table()->free_entry(entry); |
coleenp@2497 | 118 | } else { |
coleenp@2497 | 119 | p = entry->next_addr(); |
coleenp@2497 | 120 | } |
coleenp@3875 | 121 | // get next entry |
zgu@3900 | 122 | entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); |
coleenp@2497 | 123 | } |
coleenp@2497 | 124 | } |
coleenp@2497 | 125 | symbols_removed += removed; |
coleenp@2497 | 126 | symbols_counted += total; |
coleenp@2618 | 127 | // Exclude printing for normal PrintGCDetails because people parse |
coleenp@2618 | 128 | // this output. |
coleenp@2618 | 129 | if (PrintGCDetails && Verbose && WizardMode) { |
coleenp@2618 | 130 | gclog_or_tty->print(" [Symbols=%d size=" SIZE_FORMAT "K] ", total, |
coleenp@2497 | 131 | (memory_total*HeapWordSize)/1024); |
coleenp@2497 | 132 | } |
coleenp@2497 | 133 | } |
coleenp@2497 | 134 | |
coleenp@3865 | 135 | // Create a new table and using alternate hash code, populate the new table |
coleenp@3865 | 136 | // with the existing strings. Set flag to use the alternate hash code afterwards. |
coleenp@3865 | 137 | void SymbolTable::rehash_table() { |
coleenp@3865 | 138 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
coleenp@3875 | 139 | // This should never happen with -Xshare:dump but it might in testing mode. |
coleenp@3875 | 140 | if (DumpSharedSpaces) return; |
coleenp@3865 | 141 | // Create a new symbol table |
coleenp@3865 | 142 | SymbolTable* new_table = new SymbolTable(); |
coleenp@3865 | 143 | |
coleenp@3865 | 144 | the_table()->move_to(new_table); |
coleenp@3865 | 145 | |
coleenp@3865 | 146 | // Delete the table and buckets (entries are reused in new table). |
coleenp@3865 | 147 | delete _the_table; |
coleenp@3865 | 148 | // Don't check if we need rehashing until the table gets unbalanced again. |
coleenp@3865 | 149 | // Then rehash with a new global seed. |
coleenp@3865 | 150 | _needs_rehashing = false; |
coleenp@3865 | 151 | _the_table = new_table; |
coleenp@3865 | 152 | } |
coleenp@2497 | 153 | |
duke@435 | 154 | // Lookup a symbol in a bucket. |
duke@435 | 155 | |
coleenp@2497 | 156 | Symbol* SymbolTable::lookup(int index, const char* name, |
duke@435 | 157 | int len, unsigned int hash) { |
coleenp@3865 | 158 | int count = 0; |
zgu@3900 | 159 | for (HashtableEntry<Symbol*, mtSymbol>* e = bucket(index); e != NULL; e = e->next()) { |
coleenp@3865 | 160 | count++; // count all entries in this bucket, not just ones with same hash |
duke@435 | 161 | if (e->hash() == hash) { |
coleenp@2497 | 162 | Symbol* sym = e->literal(); |
duke@435 | 163 | if (sym->equals(name, len)) { |
coleenp@2497 | 164 | // something is referencing this symbol now. |
coleenp@2497 | 165 | sym->increment_refcount(); |
duke@435 | 166 | return sym; |
duke@435 | 167 | } |
duke@435 | 168 | } |
duke@435 | 169 | } |
coleenp@3865 | 170 | // If the bucket size is too deep check if this hash code is insufficient. |
zgu@3900 | 171 | if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) { |
coleenp@3865 | 172 | _needs_rehashing = check_rehash_table(count); |
coleenp@3865 | 173 | } |
duke@435 | 174 | return NULL; |
duke@435 | 175 | } |
duke@435 | 176 | |
coleenp@3875 | 177 | // Pick hashing algorithm. |
coleenp@3875 | 178 | unsigned int SymbolTable::hash_symbol(const char* s, int len) { |
coleenp@3865 | 179 | return use_alternate_hashcode() ? |
coleenp@3865 | 180 | AltHashing::murmur3_32(seed(), (const jbyte*)s, len) : |
brutisso@4335 | 181 | java_lang_String::hash_code(s, len); |
coleenp@3865 | 182 | } |
coleenp@3865 | 183 | |
duke@435 | 184 | |
duke@435 | 185 | // We take care not to be blocking while holding the |
duke@435 | 186 | // SymbolTable_lock. Otherwise, the system might deadlock, since the |
duke@435 | 187 | // symboltable is used during compilation (VM_thread) The lock free |
duke@435 | 188 | // synchronization is simplified by the fact that we do not delete |
duke@435 | 189 | // entries in the symbol table during normal execution (only during |
duke@435 | 190 | // safepoints). |
duke@435 | 191 | |
coleenp@2497 | 192 | Symbol* SymbolTable::lookup(const char* name, int len, TRAPS) { |
duke@435 | 193 | unsigned int hashValue = hash_symbol(name, len); |
duke@435 | 194 | int index = the_table()->hash_to_index(hashValue); |
duke@435 | 195 | |
coleenp@2497 | 196 | Symbol* s = the_table()->lookup(index, name, len, hashValue); |
duke@435 | 197 | |
duke@435 | 198 | // Found |
duke@435 | 199 | if (s != NULL) return s; |
duke@435 | 200 | |
coleenp@3875 | 201 | // Grab SymbolTable_lock first. |
coleenp@3875 | 202 | MutexLocker ml(SymbolTable_lock, THREAD); |
coleenp@3875 | 203 | |
duke@435 | 204 | // Otherwise, add to symbol to table |
coleenp@3682 | 205 | return the_table()->basic_add(index, (u1*)name, len, hashValue, true, CHECK_NULL); |
duke@435 | 206 | } |
duke@435 | 207 | |
coleenp@2497 | 208 | Symbol* SymbolTable::lookup(const Symbol* sym, int begin, int end, TRAPS) { |
duke@435 | 209 | char* buffer; |
duke@435 | 210 | int index, len; |
duke@435 | 211 | unsigned int hashValue; |
duke@435 | 212 | char* name; |
duke@435 | 213 | { |
duke@435 | 214 | debug_only(No_Safepoint_Verifier nsv;) |
duke@435 | 215 | |
duke@435 | 216 | name = (char*)sym->base() + begin; |
duke@435 | 217 | len = end - begin; |
duke@435 | 218 | hashValue = hash_symbol(name, len); |
duke@435 | 219 | index = the_table()->hash_to_index(hashValue); |
coleenp@2497 | 220 | Symbol* s = the_table()->lookup(index, name, len, hashValue); |
duke@435 | 221 | |
duke@435 | 222 | // Found |
duke@435 | 223 | if (s != NULL) return s; |
duke@435 | 224 | } |
duke@435 | 225 | |
duke@435 | 226 | // Otherwise, add to symbol to table. Copy to a C string first. |
duke@435 | 227 | char stack_buf[128]; |
duke@435 | 228 | ResourceMark rm(THREAD); |
duke@435 | 229 | if (len <= 128) { |
duke@435 | 230 | buffer = stack_buf; |
duke@435 | 231 | } else { |
duke@435 | 232 | buffer = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, len); |
duke@435 | 233 | } |
duke@435 | 234 | for (int i=0; i<len; i++) { |
duke@435 | 235 | buffer[i] = name[i]; |
duke@435 | 236 | } |
duke@435 | 237 | // Make sure there is no safepoint in the code above since name can't move. |
duke@435 | 238 | // We can't include the code in No_Safepoint_Verifier because of the |
duke@435 | 239 | // ResourceMark. |
duke@435 | 240 | |
coleenp@3875 | 241 | // Grab SymbolTable_lock first. |
coleenp@3875 | 242 | MutexLocker ml(SymbolTable_lock, THREAD); |
coleenp@3875 | 243 | |
coleenp@3682 | 244 | return the_table()->basic_add(index, (u1*)buffer, len, hashValue, true, CHECK_NULL); |
duke@435 | 245 | } |
duke@435 | 246 | |
coleenp@2497 | 247 | Symbol* SymbolTable::lookup_only(const char* name, int len, |
duke@435 | 248 | unsigned int& hash) { |
duke@435 | 249 | hash = hash_symbol(name, len); |
duke@435 | 250 | int index = the_table()->hash_to_index(hash); |
duke@435 | 251 | |
coleenp@2497 | 252 | Symbol* s = the_table()->lookup(index, name, len, hash); |
coleenp@2497 | 253 | return s; |
duke@435 | 254 | } |
duke@435 | 255 | |
phh@3427 | 256 | // Look up the address of the literal in the SymbolTable for this Symbol* |
phh@3427 | 257 | // Do not create any new symbols |
phh@3427 | 258 | // Do not increment the reference count to keep this alive |
phh@3427 | 259 | Symbol** SymbolTable::lookup_symbol_addr(Symbol* sym){ |
phh@3427 | 260 | unsigned int hash = hash_symbol((char*)sym->bytes(), sym->utf8_length()); |
phh@3427 | 261 | int index = the_table()->hash_to_index(hash); |
phh@3427 | 262 | |
zgu@3900 | 263 | for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(index); e != NULL; e = e->next()) { |
phh@3427 | 264 | if (e->hash() == hash) { |
phh@3427 | 265 | Symbol* literal_sym = e->literal(); |
phh@3427 | 266 | if (sym == literal_sym) { |
phh@3427 | 267 | return e->literal_addr(); |
phh@3427 | 268 | } |
phh@3427 | 269 | } |
phh@3427 | 270 | } |
phh@3427 | 271 | return NULL; |
phh@3427 | 272 | } |
phh@3427 | 273 | |
jrose@1100 | 274 | // Suggestion: Push unicode-based lookup all the way into the hashing |
jrose@1100 | 275 | // and probing logic, so there is no need for convert_to_utf8 until |
coleenp@2497 | 276 | // an actual new Symbol* is created. |
coleenp@2497 | 277 | Symbol* SymbolTable::lookup_unicode(const jchar* name, int utf16_length, TRAPS) { |
jrose@1100 | 278 | int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); |
jrose@1100 | 279 | char stack_buf[128]; |
jrose@1100 | 280 | if (utf8_length < (int) sizeof(stack_buf)) { |
jrose@1100 | 281 | char* chars = stack_buf; |
jrose@1100 | 282 | UNICODE::convert_to_utf8(name, utf16_length, chars); |
jrose@1100 | 283 | return lookup(chars, utf8_length, THREAD); |
jrose@1100 | 284 | } else { |
jrose@1100 | 285 | ResourceMark rm(THREAD); |
jrose@1100 | 286 | char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; |
jrose@1100 | 287 | UNICODE::convert_to_utf8(name, utf16_length, chars); |
jrose@1100 | 288 | return lookup(chars, utf8_length, THREAD); |
jrose@1100 | 289 | } |
jrose@1100 | 290 | } |
jrose@1100 | 291 | |
coleenp@2497 | 292 | Symbol* SymbolTable::lookup_only_unicode(const jchar* name, int utf16_length, |
jrose@1100 | 293 | unsigned int& hash) { |
jrose@1100 | 294 | int utf8_length = UNICODE::utf8_length((jchar*) name, utf16_length); |
jrose@1100 | 295 | char stack_buf[128]; |
jrose@1100 | 296 | if (utf8_length < (int) sizeof(stack_buf)) { |
jrose@1100 | 297 | char* chars = stack_buf; |
jrose@1100 | 298 | UNICODE::convert_to_utf8(name, utf16_length, chars); |
jrose@1100 | 299 | return lookup_only(chars, utf8_length, hash); |
jrose@1100 | 300 | } else { |
jrose@1100 | 301 | ResourceMark rm; |
jrose@1100 | 302 | char* chars = NEW_RESOURCE_ARRAY(char, utf8_length + 1);; |
jrose@1100 | 303 | UNICODE::convert_to_utf8(name, utf16_length, chars); |
jrose@1100 | 304 | return lookup_only(chars, utf8_length, hash); |
jrose@1100 | 305 | } |
jrose@1100 | 306 | } |
jrose@1100 | 307 | |
coleenp@4037 | 308 | void SymbolTable::add(ClassLoaderData* loader_data, constantPoolHandle cp, |
coleenp@3682 | 309 | int names_count, |
duke@435 | 310 | const char** names, int* lengths, int* cp_indices, |
duke@435 | 311 | unsigned int* hashValues, TRAPS) { |
coleenp@3875 | 312 | // Grab SymbolTable_lock first. |
coleenp@3875 | 313 | MutexLocker ml(SymbolTable_lock, THREAD); |
coleenp@3875 | 314 | |
duke@435 | 315 | SymbolTable* table = the_table(); |
coleenp@4037 | 316 | bool added = table->basic_add(loader_data, cp, names_count, names, lengths, |
duke@435 | 317 | cp_indices, hashValues, CHECK); |
duke@435 | 318 | if (!added) { |
duke@435 | 319 | // do it the hard way |
duke@435 | 320 | for (int i=0; i<names_count; i++) { |
duke@435 | 321 | int index = table->hash_to_index(hashValues[i]); |
coleenp@4037 | 322 | bool c_heap = !loader_data->is_the_null_class_loader_data(); |
coleenp@3682 | 323 | Symbol* sym = table->basic_add(index, (u1*)names[i], lengths[i], hashValues[i], c_heap, CHECK); |
duke@435 | 324 | cp->symbol_at_put(cp_indices[i], sym); |
duke@435 | 325 | } |
duke@435 | 326 | } |
duke@435 | 327 | } |
duke@435 | 328 | |
coleenp@3682 | 329 | Symbol* SymbolTable::new_permanent_symbol(const char* name, TRAPS) { |
coleenp@3682 | 330 | unsigned int hash; |
coleenp@3682 | 331 | Symbol* result = SymbolTable::lookup_only((char*)name, (int)strlen(name), hash); |
coleenp@3682 | 332 | if (result != NULL) { |
coleenp@3682 | 333 | return result; |
coleenp@3682 | 334 | } |
coleenp@3875 | 335 | // Grab SymbolTable_lock first. |
coleenp@3875 | 336 | MutexLocker ml(SymbolTable_lock, THREAD); |
coleenp@3875 | 337 | |
coleenp@3682 | 338 | SymbolTable* table = the_table(); |
coleenp@3682 | 339 | int index = table->hash_to_index(hash); |
coleenp@3682 | 340 | return table->basic_add(index, (u1*)name, (int)strlen(name), hash, false, THREAD); |
coleenp@3682 | 341 | } |
coleenp@3682 | 342 | |
coleenp@3875 | 343 | Symbol* SymbolTable::basic_add(int index_arg, u1 *name, int len, |
coleenp@3865 | 344 | unsigned int hashValue_arg, bool c_heap, TRAPS) { |
duke@435 | 345 | assert(!Universe::heap()->is_in_reserved(name) || GC_locker::is_active(), |
duke@435 | 346 | "proposed name of symbol must be stable"); |
duke@435 | 347 | |
coleenp@3875 | 348 | // Don't allow symbols to be created which cannot fit in a Symbol*. |
coleenp@3875 | 349 | if (len > Symbol::max_length()) { |
coleenp@3875 | 350 | THROW_MSG_0(vmSymbols::java_lang_InternalError(), |
coleenp@3875 | 351 | "name is too long to represent"); |
coleenp@3875 | 352 | } |
coleenp@3875 | 353 | |
coleenp@3875 | 354 | // Cannot hit a safepoint in this function because the "this" pointer can move. |
coleenp@3875 | 355 | No_Safepoint_Verifier nsv; |
duke@435 | 356 | |
coleenp@3865 | 357 | // Check if the symbol table has been rehashed, if so, need to recalculate |
coleenp@3875 | 358 | // the hash value and index. |
coleenp@3875 | 359 | unsigned int hashValue; |
coleenp@3875 | 360 | int index; |
coleenp@3875 | 361 | if (use_alternate_hashcode()) { |
coleenp@3875 | 362 | hashValue = hash_symbol((const char*)name, len); |
coleenp@3875 | 363 | index = hash_to_index(hashValue); |
coleenp@3875 | 364 | } else { |
coleenp@3875 | 365 | hashValue = hashValue_arg; |
coleenp@3875 | 366 | index = index_arg; |
coleenp@3875 | 367 | } |
coleenp@3865 | 368 | |
duke@435 | 369 | // Since look-up was done lock-free, we need to check if another |
duke@435 | 370 | // thread beat us in the race to insert the symbol. |
coleenp@2497 | 371 | Symbol* test = lookup(index, (char*)name, len, hashValue); |
duke@435 | 372 | if (test != NULL) { |
coleenp@3682 | 373 | // A race occurred and another thread introduced the symbol. |
coleenp@2497 | 374 | assert(test->refcount() != 0, "lookup should have incremented the count"); |
duke@435 | 375 | return test; |
duke@435 | 376 | } |
duke@435 | 377 | |
coleenp@3682 | 378 | // Create a new symbol. |
coleenp@3682 | 379 | Symbol* sym = allocate_symbol(name, len, c_heap, CHECK_NULL); |
coleenp@3682 | 380 | assert(sym->equals((char*)name, len), "symbol must be properly initialized"); |
coleenp@3682 | 381 | |
zgu@3900 | 382 | HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); |
duke@435 | 383 | add_entry(index, entry); |
coleenp@2497 | 384 | return sym; |
duke@435 | 385 | } |
duke@435 | 386 | |
coleenp@3682 | 387 | // This version of basic_add adds symbols in batch from the constant pool |
coleenp@3682 | 388 | // parsing. |
coleenp@4037 | 389 | bool SymbolTable::basic_add(ClassLoaderData* loader_data, constantPoolHandle cp, |
coleenp@3682 | 390 | int names_count, |
duke@435 | 391 | const char** names, int* lengths, |
duke@435 | 392 | int* cp_indices, unsigned int* hashValues, |
duke@435 | 393 | TRAPS) { |
coleenp@3682 | 394 | |
coleenp@3682 | 395 | // Check symbol names are not too long. If any are too long, don't add any. |
coleenp@3682 | 396 | for (int i = 0; i< names_count; i++) { |
coleenp@3682 | 397 | if (lengths[i] > Symbol::max_length()) { |
coleenp@3682 | 398 | THROW_MSG_0(vmSymbols::java_lang_InternalError(), |
coleenp@3682 | 399 | "name is too long to represent"); |
coleenp@3682 | 400 | } |
duke@435 | 401 | } |
duke@435 | 402 | |
coleenp@3875 | 403 | // Cannot hit a safepoint in this function because the "this" pointer can move. |
coleenp@3875 | 404 | No_Safepoint_Verifier nsv; |
duke@435 | 405 | |
coleenp@2497 | 406 | for (int i=0; i<names_count; i++) { |
coleenp@3865 | 407 | // Check if the symbol table has been rehashed, if so, need to recalculate |
coleenp@3865 | 408 | // the hash value. |
coleenp@3875 | 409 | unsigned int hashValue; |
coleenp@3875 | 410 | if (use_alternate_hashcode()) { |
coleenp@3875 | 411 | hashValue = hash_symbol(names[i], lengths[i]); |
coleenp@3875 | 412 | } else { |
coleenp@3875 | 413 | hashValue = hashValues[i]; |
coleenp@3875 | 414 | } |
duke@435 | 415 | // Since look-up was done lock-free, we need to check if another |
duke@435 | 416 | // thread beat us in the race to insert the symbol. |
coleenp@3865 | 417 | int index = hash_to_index(hashValue); |
coleenp@3865 | 418 | Symbol* test = lookup(index, names[i], lengths[i], hashValue); |
duke@435 | 419 | if (test != NULL) { |
twisti@1040 | 420 | // A race occurred and another thread introduced the symbol, this one |
duke@435 | 421 | // will be dropped and collected. Use test instead. |
duke@435 | 422 | cp->symbol_at_put(cp_indices[i], test); |
coleenp@2497 | 423 | assert(test->refcount() != 0, "lookup should have incremented the count"); |
duke@435 | 424 | } else { |
coleenp@3682 | 425 | // Create a new symbol. The null class loader is never unloaded so these |
coleenp@3682 | 426 | // are allocated specially in a permanent arena. |
coleenp@4037 | 427 | bool c_heap = !loader_data->is_the_null_class_loader_data(); |
coleenp@3682 | 428 | Symbol* sym = allocate_symbol((const u1*)names[i], lengths[i], c_heap, CHECK_(false)); |
coleenp@3682 | 429 | assert(sym->equals(names[i], lengths[i]), "symbol must be properly initialized"); // why wouldn't it be??? |
zgu@3900 | 430 | HashtableEntry<Symbol*, mtSymbol>* entry = new_entry(hashValue, sym); |
duke@435 | 431 | add_entry(index, entry); |
duke@435 | 432 | cp->symbol_at_put(cp_indices[i], sym); |
duke@435 | 433 | } |
duke@435 | 434 | } |
duke@435 | 435 | return true; |
duke@435 | 436 | } |
duke@435 | 437 | |
duke@435 | 438 | |
duke@435 | 439 | void SymbolTable::verify() { |
duke@435 | 440 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 441 | HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); |
duke@435 | 442 | for ( ; p != NULL; p = p->next()) { |
coleenp@2497 | 443 | Symbol* s = (Symbol*)(p->literal()); |
duke@435 | 444 | guarantee(s != NULL, "symbol is NULL"); |
duke@435 | 445 | unsigned int h = hash_symbol((char*)s->bytes(), s->utf8_length()); |
duke@435 | 446 | guarantee(p->hash() == h, "broken hash in symbol table entry"); |
duke@435 | 447 | guarantee(the_table()->hash_to_index(h) == i, |
duke@435 | 448 | "wrong index in symbol table"); |
duke@435 | 449 | } |
duke@435 | 450 | } |
duke@435 | 451 | } |
duke@435 | 452 | |
coleenp@3865 | 453 | void SymbolTable::dump(outputStream* st) { |
coleenp@3865 | 454 | NumberSeq summary; |
coleenp@3865 | 455 | for (int i = 0; i < the_table()->table_size(); ++i) { |
coleenp@3865 | 456 | int count = 0; |
zgu@3900 | 457 | for (HashtableEntry<Symbol*, mtSymbol>* e = the_table()->bucket(i); |
coleenp@3865 | 458 | e != NULL; e = e->next()) { |
coleenp@3865 | 459 | count++; |
coleenp@3865 | 460 | } |
coleenp@3865 | 461 | summary.add((double)count); |
coleenp@3865 | 462 | } |
coleenp@3865 | 463 | st->print_cr("SymbolTable statistics:"); |
coleenp@3865 | 464 | st->print_cr("Number of buckets : %7d", summary.num()); |
coleenp@3865 | 465 | st->print_cr("Average bucket size : %7.0f", summary.avg()); |
coleenp@3865 | 466 | st->print_cr("Variance of bucket size : %7.0f", summary.variance()); |
coleenp@3865 | 467 | st->print_cr("Std. dev. of bucket size: %7.0f", summary.sd()); |
coleenp@3865 | 468 | st->print_cr("Maximum bucket size : %7.0f", summary.maximum()); |
coleenp@3865 | 469 | } |
coleenp@3865 | 470 | |
duke@435 | 471 | |
duke@435 | 472 | //--------------------------------------------------------------------------- |
duke@435 | 473 | // Non-product code |
duke@435 | 474 | |
duke@435 | 475 | #ifndef PRODUCT |
duke@435 | 476 | |
duke@435 | 477 | void SymbolTable::print_histogram() { |
duke@435 | 478 | MutexLocker ml(SymbolTable_lock); |
duke@435 | 479 | const int results_length = 100; |
duke@435 | 480 | int results[results_length]; |
duke@435 | 481 | int i,j; |
duke@435 | 482 | |
duke@435 | 483 | // initialize results to zero |
duke@435 | 484 | for (j = 0; j < results_length; j++) { |
duke@435 | 485 | results[j] = 0; |
duke@435 | 486 | } |
duke@435 | 487 | |
duke@435 | 488 | int total = 0; |
duke@435 | 489 | int max_symbols = 0; |
duke@435 | 490 | int out_of_range = 0; |
coleenp@2497 | 491 | int memory_total = 0; |
coleenp@2497 | 492 | int count = 0; |
duke@435 | 493 | for (i = 0; i < the_table()->table_size(); i++) { |
zgu@3900 | 494 | HashtableEntry<Symbol*, mtSymbol>* p = the_table()->bucket(i); |
duke@435 | 495 | for ( ; p != NULL; p = p->next()) { |
coleenp@4037 | 496 | memory_total += p->literal()->size(); |
coleenp@2497 | 497 | count++; |
coleenp@2497 | 498 | int counter = p->literal()->utf8_length(); |
duke@435 | 499 | total += counter; |
duke@435 | 500 | if (counter < results_length) { |
duke@435 | 501 | results[counter]++; |
duke@435 | 502 | } else { |
duke@435 | 503 | out_of_range++; |
duke@435 | 504 | } |
duke@435 | 505 | max_symbols = MAX2(max_symbols, counter); |
duke@435 | 506 | } |
duke@435 | 507 | } |
duke@435 | 508 | tty->print_cr("Symbol Table:"); |
coleenp@2497 | 509 | tty->print_cr("Total number of symbols %5d", count); |
coleenp@2497 | 510 | tty->print_cr("Total size in memory %5dK", |
coleenp@2497 | 511 | (memory_total*HeapWordSize)/1024); |
coleenp@2497 | 512 | tty->print_cr("Total counted %5d", symbols_counted); |
coleenp@2497 | 513 | tty->print_cr("Total removed %5d", symbols_removed); |
coleenp@2497 | 514 | if (symbols_counted > 0) { |
coleenp@2497 | 515 | tty->print_cr("Percent removed %3.2f", |
coleenp@2497 | 516 | ((float)symbols_removed/(float)symbols_counted)* 100); |
coleenp@2497 | 517 | } |
coleenp@2497 | 518 | tty->print_cr("Reference counts %5d", Symbol::_total_count); |
coleenp@3682 | 519 | tty->print_cr("Symbol arena size %5d used %5d", |
coleenp@3682 | 520 | arena()->size_in_bytes(), arena()->used()); |
coleenp@2497 | 521 | tty->print_cr("Histogram of symbol length:"); |
duke@435 | 522 | tty->print_cr("%8s %5d", "Total ", total); |
duke@435 | 523 | tty->print_cr("%8s %5d", "Maximum", max_symbols); |
duke@435 | 524 | tty->print_cr("%8s %3.2f", "Average", |
duke@435 | 525 | ((float) total / (float) the_table()->table_size())); |
duke@435 | 526 | tty->print_cr("%s", "Histogram:"); |
duke@435 | 527 | tty->print_cr(" %s %29s", "Length", "Number chains that length"); |
duke@435 | 528 | for (i = 0; i < results_length; i++) { |
duke@435 | 529 | if (results[i] > 0) { |
duke@435 | 530 | tty->print_cr("%6d %10d", i, results[i]); |
duke@435 | 531 | } |
duke@435 | 532 | } |
coleenp@2497 | 533 | if (Verbose) { |
coleenp@2497 | 534 | int line_length = 70; |
coleenp@2497 | 535 | tty->print_cr("%s %30s", " Length", "Number chains that length"); |
coleenp@2497 | 536 | for (i = 0; i < results_length; i++) { |
coleenp@2497 | 537 | if (results[i] > 0) { |
coleenp@2497 | 538 | tty->print("%4d", i); |
coleenp@2497 | 539 | for (j = 0; (j < results[i]) && (j < line_length); j++) { |
coleenp@2497 | 540 | tty->print("%1s", "*"); |
coleenp@2497 | 541 | } |
coleenp@2497 | 542 | if (j == line_length) { |
coleenp@2497 | 543 | tty->print("%1s", "+"); |
coleenp@2497 | 544 | } |
coleenp@2497 | 545 | tty->cr(); |
duke@435 | 546 | } |
coleenp@2497 | 547 | } |
coleenp@2497 | 548 | } |
coleenp@2497 | 549 | tty->print_cr(" %s %d: %d\n", "Number chains longer than", |
coleenp@2497 | 550 | results_length, out_of_range); |
coleenp@2497 | 551 | } |
coleenp@2497 | 552 | |
coleenp@2497 | 553 | void SymbolTable::print() { |
coleenp@2497 | 554 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 555 | HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i); |
zgu@3900 | 556 | HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i); |
coleenp@2497 | 557 | if (entry != NULL) { |
coleenp@2497 | 558 | while (entry != NULL) { |
coleenp@2497 | 559 | tty->print(PTR_FORMAT " ", entry->literal()); |
coleenp@2497 | 560 | entry->literal()->print(); |
coleenp@2497 | 561 | tty->print(" %d", entry->literal()->refcount()); |
coleenp@2497 | 562 | p = entry->next_addr(); |
zgu@3900 | 563 | entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p); |
duke@435 | 564 | } |
duke@435 | 565 | tty->cr(); |
duke@435 | 566 | } |
duke@435 | 567 | } |
duke@435 | 568 | } |
duke@435 | 569 | #endif // PRODUCT |
duke@435 | 570 | |
duke@435 | 571 | // -------------------------------------------------------------------------- |
duke@435 | 572 | |
duke@435 | 573 | #ifdef ASSERT |
duke@435 | 574 | class StableMemoryChecker : public StackObj { |
duke@435 | 575 | enum { _bufsize = wordSize*4 }; |
duke@435 | 576 | |
duke@435 | 577 | address _region; |
duke@435 | 578 | jint _size; |
duke@435 | 579 | u1 _save_buf[_bufsize]; |
duke@435 | 580 | |
duke@435 | 581 | int sample(u1* save_buf) { |
duke@435 | 582 | if (_size <= _bufsize) { |
duke@435 | 583 | memcpy(save_buf, _region, _size); |
duke@435 | 584 | return _size; |
duke@435 | 585 | } else { |
duke@435 | 586 | // copy head and tail |
duke@435 | 587 | memcpy(&save_buf[0], _region, _bufsize/2); |
duke@435 | 588 | memcpy(&save_buf[_bufsize/2], _region + _size - _bufsize/2, _bufsize/2); |
duke@435 | 589 | return (_bufsize/2)*2; |
duke@435 | 590 | } |
duke@435 | 591 | } |
duke@435 | 592 | |
duke@435 | 593 | public: |
duke@435 | 594 | StableMemoryChecker(const void* region, jint size) { |
duke@435 | 595 | _region = (address) region; |
duke@435 | 596 | _size = size; |
duke@435 | 597 | sample(_save_buf); |
duke@435 | 598 | } |
duke@435 | 599 | |
duke@435 | 600 | bool verify() { |
duke@435 | 601 | u1 check_buf[sizeof(_save_buf)]; |
duke@435 | 602 | int check_size = sample(check_buf); |
duke@435 | 603 | return (0 == memcmp(_save_buf, check_buf, check_size)); |
duke@435 | 604 | } |
duke@435 | 605 | |
duke@435 | 606 | void set_region(const void* region) { _region = (address) region; } |
duke@435 | 607 | }; |
duke@435 | 608 | #endif |
duke@435 | 609 | |
duke@435 | 610 | |
duke@435 | 611 | // -------------------------------------------------------------------------- |
duke@435 | 612 | StringTable* StringTable::_the_table = NULL; |
duke@435 | 613 | |
coleenp@3865 | 614 | bool StringTable::_needs_rehashing = false; |
coleenp@3865 | 615 | |
coleenp@3865 | 616 | // Pick hashing algorithm |
coleenp@3875 | 617 | unsigned int StringTable::hash_string(const jchar* s, int len) { |
coleenp@3865 | 618 | return use_alternate_hashcode() ? AltHashing::murmur3_32(seed(), s, len) : |
brutisso@4335 | 619 | java_lang_String::hash_code(s, len); |
coleenp@3865 | 620 | } |
coleenp@3865 | 621 | |
duke@435 | 622 | oop StringTable::lookup(int index, jchar* name, |
duke@435 | 623 | int len, unsigned int hash) { |
coleenp@3865 | 624 | int count = 0; |
zgu@3900 | 625 | for (HashtableEntry<oop, mtSymbol>* l = bucket(index); l != NULL; l = l->next()) { |
coleenp@3865 | 626 | count++; |
duke@435 | 627 | if (l->hash() == hash) { |
duke@435 | 628 | if (java_lang_String::equals(l->literal(), name, len)) { |
duke@435 | 629 | return l->literal(); |
duke@435 | 630 | } |
duke@435 | 631 | } |
duke@435 | 632 | } |
coleenp@3865 | 633 | // If the bucket size is too deep check if this hash code is insufficient. |
zgu@3900 | 634 | if (count >= BasicHashtable<mtSymbol>::rehash_count && !needs_rehashing()) { |
coleenp@3865 | 635 | _needs_rehashing = check_rehash_table(count); |
coleenp@3865 | 636 | } |
duke@435 | 637 | return NULL; |
duke@435 | 638 | } |
duke@435 | 639 | |
duke@435 | 640 | |
coleenp@3875 | 641 | oop StringTable::basic_add(int index_arg, Handle string, jchar* name, |
coleenp@3865 | 642 | int len, unsigned int hashValue_arg, TRAPS) { |
duke@435 | 643 | |
duke@435 | 644 | assert(java_lang_String::equals(string(), name, len), |
duke@435 | 645 | "string must be properly initialized"); |
coleenp@3875 | 646 | // Cannot hit a safepoint in this function because the "this" pointer can move. |
coleenp@3875 | 647 | No_Safepoint_Verifier nsv; |
duke@435 | 648 | |
coleenp@3865 | 649 | // Check if the symbol table has been rehashed, if so, need to recalculate |
coleenp@3875 | 650 | // the hash value and index before second lookup. |
coleenp@3875 | 651 | unsigned int hashValue; |
coleenp@3875 | 652 | int index; |
coleenp@3875 | 653 | if (use_alternate_hashcode()) { |
coleenp@3875 | 654 | hashValue = hash_string(name, len); |
coleenp@3875 | 655 | index = hash_to_index(hashValue); |
coleenp@3875 | 656 | } else { |
coleenp@3875 | 657 | hashValue = hashValue_arg; |
coleenp@3875 | 658 | index = index_arg; |
coleenp@3875 | 659 | } |
coleenp@3865 | 660 | |
duke@435 | 661 | // Since look-up was done lock-free, we need to check if another |
duke@435 | 662 | // thread beat us in the race to insert the symbol. |
duke@435 | 663 | |
duke@435 | 664 | oop test = lookup(index, name, len, hashValue); // calls lookup(u1*, int) |
duke@435 | 665 | if (test != NULL) { |
duke@435 | 666 | // Entry already added |
duke@435 | 667 | return test; |
duke@435 | 668 | } |
duke@435 | 669 | |
zgu@3900 | 670 | HashtableEntry<oop, mtSymbol>* entry = new_entry(hashValue, string()); |
duke@435 | 671 | add_entry(index, entry); |
duke@435 | 672 | return string(); |
duke@435 | 673 | } |
duke@435 | 674 | |
duke@435 | 675 | |
coleenp@2497 | 676 | oop StringTable::lookup(Symbol* symbol) { |
duke@435 | 677 | ResourceMark rm; |
duke@435 | 678 | int length; |
duke@435 | 679 | jchar* chars = symbol->as_unicode(length); |
mgerdin@4850 | 680 | return lookup(chars, length); |
mgerdin@4850 | 681 | } |
mgerdin@4850 | 682 | |
mgerdin@4850 | 683 | |
mgerdin@4850 | 684 | oop StringTable::lookup(jchar* name, int len) { |
mgerdin@4850 | 685 | unsigned int hash = hash_string(name, len); |
mgerdin@4850 | 686 | int index = the_table()->hash_to_index(hash); |
mgerdin@4850 | 687 | return the_table()->lookup(index, name, len, hash); |
duke@435 | 688 | } |
duke@435 | 689 | |
duke@435 | 690 | |
duke@435 | 691 | oop StringTable::intern(Handle string_or_null, jchar* name, |
duke@435 | 692 | int len, TRAPS) { |
coleenp@3865 | 693 | unsigned int hashValue = hash_string(name, len); |
duke@435 | 694 | int index = the_table()->hash_to_index(hashValue); |
coleenp@3875 | 695 | oop found_string = the_table()->lookup(index, name, len, hashValue); |
duke@435 | 696 | |
duke@435 | 697 | // Found |
coleenp@3875 | 698 | if (found_string != NULL) return found_string; |
coleenp@3875 | 699 | |
coleenp@3875 | 700 | debug_only(StableMemoryChecker smc(name, len * sizeof(name[0]))); |
coleenp@3875 | 701 | assert(!Universe::heap()->is_in_reserved(name) || GC_locker::is_active(), |
coleenp@3875 | 702 | "proposed name of symbol must be stable"); |
coleenp@3875 | 703 | |
coleenp@3875 | 704 | Handle string; |
coleenp@3875 | 705 | // try to reuse the string if possible |
coleenp@4037 | 706 | if (!string_or_null.is_null()) { |
coleenp@3875 | 707 | string = string_or_null; |
coleenp@3875 | 708 | } else { |
coleenp@4037 | 709 | string = java_lang_String::create_from_unicode(name, len, CHECK_NULL); |
coleenp@3875 | 710 | } |
coleenp@3875 | 711 | |
coleenp@3875 | 712 | // Grab the StringTable_lock before getting the_table() because it could |
coleenp@3875 | 713 | // change at safepoint. |
coleenp@3875 | 714 | MutexLocker ml(StringTable_lock, THREAD); |
duke@435 | 715 | |
duke@435 | 716 | // Otherwise, add to symbol to table |
coleenp@3875 | 717 | return the_table()->basic_add(index, string, name, len, |
duke@435 | 718 | hashValue, CHECK_NULL); |
duke@435 | 719 | } |
duke@435 | 720 | |
coleenp@2497 | 721 | oop StringTable::intern(Symbol* symbol, TRAPS) { |
duke@435 | 722 | if (symbol == NULL) return NULL; |
duke@435 | 723 | ResourceMark rm(THREAD); |
duke@435 | 724 | int length; |
duke@435 | 725 | jchar* chars = symbol->as_unicode(length); |
duke@435 | 726 | Handle string; |
duke@435 | 727 | oop result = intern(string, chars, length, CHECK_NULL); |
duke@435 | 728 | return result; |
duke@435 | 729 | } |
duke@435 | 730 | |
duke@435 | 731 | |
duke@435 | 732 | oop StringTable::intern(oop string, TRAPS) |
duke@435 | 733 | { |
duke@435 | 734 | if (string == NULL) return NULL; |
duke@435 | 735 | ResourceMark rm(THREAD); |
duke@435 | 736 | int length; |
duke@435 | 737 | Handle h_string (THREAD, string); |
hseigel@4987 | 738 | jchar* chars = java_lang_String::as_unicode_string(string, length, CHECK_NULL); |
duke@435 | 739 | oop result = intern(h_string, chars, length, CHECK_NULL); |
duke@435 | 740 | return result; |
duke@435 | 741 | } |
duke@435 | 742 | |
duke@435 | 743 | |
duke@435 | 744 | oop StringTable::intern(const char* utf8_string, TRAPS) { |
duke@435 | 745 | if (utf8_string == NULL) return NULL; |
duke@435 | 746 | ResourceMark rm(THREAD); |
duke@435 | 747 | int length = UTF8::unicode_length(utf8_string); |
duke@435 | 748 | jchar* chars = NEW_RESOURCE_ARRAY(jchar, length); |
duke@435 | 749 | UTF8::convert_to_unicode(utf8_string, chars, length); |
duke@435 | 750 | Handle string; |
duke@435 | 751 | oop result = intern(string, chars, length, CHECK_NULL); |
duke@435 | 752 | return result; |
duke@435 | 753 | } |
duke@435 | 754 | |
coleenp@2497 | 755 | void StringTable::unlink(BoolObjectClosure* is_alive) { |
coleenp@2497 | 756 | // Readers of the table are unlocked, so we should only be removing |
coleenp@2497 | 757 | // entries at a safepoint. |
coleenp@2497 | 758 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
coleenp@2497 | 759 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 760 | HashtableEntry<oop, mtSymbol>** p = the_table()->bucket_addr(i); |
zgu@3900 | 761 | HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); |
coleenp@3875 | 762 | while (entry != NULL) { |
coleenp@3875 | 763 | // Shared entries are normally at the end of the bucket and if we run into |
coleenp@3875 | 764 | // a shared entry, then there is nothing more to remove. However, if we |
coleenp@3875 | 765 | // have rehashed the table, then the shared entries are no longer at the |
coleenp@3875 | 766 | // end of the bucket. |
coleenp@3875 | 767 | if (entry->is_shared() && !use_alternate_hashcode()) { |
coleenp@2497 | 768 | break; |
coleenp@2497 | 769 | } |
coleenp@2497 | 770 | assert(entry->literal() != NULL, "just checking"); |
coleenp@3875 | 771 | if (entry->is_shared() || is_alive->do_object_b(entry->literal())) { |
coleenp@2497 | 772 | p = entry->next_addr(); |
coleenp@2497 | 773 | } else { |
coleenp@2497 | 774 | *p = entry->next(); |
coleenp@2497 | 775 | the_table()->free_entry(entry); |
coleenp@2497 | 776 | } |
zgu@3900 | 777 | entry = (HashtableEntry<oop, mtSymbol>*)HashtableEntry<oop, mtSymbol>::make_ptr(*p); |
coleenp@2497 | 778 | } |
coleenp@2497 | 779 | } |
coleenp@2497 | 780 | } |
coleenp@2497 | 781 | |
coleenp@2497 | 782 | void StringTable::oops_do(OopClosure* f) { |
coleenp@2497 | 783 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 784 | HashtableEntry<oop, mtSymbol>** p = the_table()->bucket_addr(i); |
zgu@3900 | 785 | HashtableEntry<oop, mtSymbol>* entry = the_table()->bucket(i); |
coleenp@2497 | 786 | while (entry != NULL) { |
coleenp@2497 | 787 | f->do_oop((oop*)entry->literal_addr()); |
coleenp@2497 | 788 | |
coleenp@2497 | 789 | // Did the closure remove the literal from the table? |
coleenp@2497 | 790 | if (entry->literal() == NULL) { |
coleenp@2497 | 791 | assert(!entry->is_shared(), "immutable hashtable entry?"); |
coleenp@2497 | 792 | *p = entry->next(); |
coleenp@2497 | 793 | the_table()->free_entry(entry); |
coleenp@2497 | 794 | } else { |
coleenp@2497 | 795 | p = entry->next_addr(); |
coleenp@2497 | 796 | } |
zgu@3900 | 797 | entry = (HashtableEntry<oop, mtSymbol>*)HashtableEntry<oop, mtSymbol>::make_ptr(*p); |
coleenp@2497 | 798 | } |
coleenp@2497 | 799 | } |
coleenp@2497 | 800 | } |
coleenp@2497 | 801 | |
duke@435 | 802 | void StringTable::verify() { |
duke@435 | 803 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 804 | HashtableEntry<oop, mtSymbol>* p = the_table()->bucket(i); |
duke@435 | 805 | for ( ; p != NULL; p = p->next()) { |
duke@435 | 806 | oop s = p->literal(); |
duke@435 | 807 | guarantee(s != NULL, "interned string is NULL"); |
never@2700 | 808 | unsigned int h = java_lang_String::hash_string(s); |
duke@435 | 809 | guarantee(p->hash() == h, "broken hash in string table entry"); |
duke@435 | 810 | guarantee(the_table()->hash_to_index(h) == i, |
duke@435 | 811 | "wrong index in string table"); |
duke@435 | 812 | } |
duke@435 | 813 | } |
duke@435 | 814 | } |
coleenp@3865 | 815 | |
coleenp@3865 | 816 | void StringTable::dump(outputStream* st) { |
coleenp@3865 | 817 | NumberSeq summary; |
coleenp@3865 | 818 | for (int i = 0; i < the_table()->table_size(); ++i) { |
zgu@3900 | 819 | HashtableEntry<oop, mtSymbol>* p = the_table()->bucket(i); |
coleenp@3865 | 820 | int count = 0; |
coleenp@3865 | 821 | for ( ; p != NULL; p = p->next()) { |
coleenp@3865 | 822 | count++; |
coleenp@3865 | 823 | } |
coleenp@3865 | 824 | summary.add((double)count); |
coleenp@3865 | 825 | } |
coleenp@3865 | 826 | st->print_cr("StringTable statistics:"); |
coleenp@3865 | 827 | st->print_cr("Number of buckets : %7d", summary.num()); |
coleenp@3865 | 828 | st->print_cr("Average bucket size : %7.0f", summary.avg()); |
coleenp@3865 | 829 | st->print_cr("Variance of bucket size : %7.0f", summary.variance()); |
coleenp@3865 | 830 | st->print_cr("Std. dev. of bucket size: %7.0f", summary.sd()); |
coleenp@3865 | 831 | st->print_cr("Maximum bucket size : %7.0f", summary.maximum()); |
coleenp@3865 | 832 | } |
coleenp@3865 | 833 | |
coleenp@3865 | 834 | |
coleenp@3865 | 835 | // Create a new table and using alternate hash code, populate the new table |
coleenp@3865 | 836 | // with the existing strings. Set flag to use the alternate hash code afterwards. |
coleenp@3865 | 837 | void StringTable::rehash_table() { |
coleenp@3865 | 838 | assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
coleenp@3875 | 839 | // This should never happen with -Xshare:dump but it might in testing mode. |
coleenp@3875 | 840 | if (DumpSharedSpaces) return; |
coleenp@3865 | 841 | StringTable* new_table = new StringTable(); |
coleenp@3865 | 842 | |
coleenp@3865 | 843 | // Rehash the table |
coleenp@3865 | 844 | the_table()->move_to(new_table); |
coleenp@3865 | 845 | |
coleenp@3865 | 846 | // Delete the table and buckets (entries are reused in new table). |
coleenp@3865 | 847 | delete _the_table; |
coleenp@3865 | 848 | // Don't check if we need rehashing until the table gets unbalanced again. |
coleenp@3865 | 849 | // Then rehash with a new global seed. |
coleenp@3865 | 850 | _needs_rehashing = false; |
coleenp@3865 | 851 | _the_table = new_table; |
coleenp@3865 | 852 | } |