symbolTable.hpp revision 1472:c18cbe5936b8
1132720Skan/* 2117397Skan * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved. 3169691Skan * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4169691Skan * 5117397Skan * This code is free software; you can redistribute it and/or modify it 6117397Skan * under the terms of the GNU General Public License version 2 only, as 7117397Skan * published by the Free Software Foundation. 8117397Skan * 9117397Skan * This code is distributed in the hope that it will be useful, but WITHOUT 10117397Skan * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11117397Skan * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12117397Skan * version 2 for more details (a copy is included in the LICENSE file that 13117397Skan * accompanied this code). 14117397Skan * 15117397Skan * You should have received a copy of the GNU General Public License version 16117397Skan * 2 along with this work; if not, write to the Free Software Foundation, 17117397Skan * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18117397Skan * 19169691Skan * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20117397Skan * or visit www.oracle.com if you need additional information or have any 21117397Skan * questions. 22117397Skan * 23117397Skan */ 24117397Skan 25117397Skan// The symbol table holds all symbolOops and corresponding interned strings. 26117397Skan// symbolOops and literal strings should be canonicalized. 27117397Skan// 28117397Skan// The interned strings are created lazily. 29117397Skan// 30117397Skan// It is implemented as an open hash table with a fixed number of buckets. 31169691Skan// 32117397Skan// %note: 33169691Skan// - symbolTableEntrys are allocated in blocks to reduce the space overhead. 34169691Skan 35169691Skanclass BoolObjectClosure; 36132720Skan 37132720Skan 38132720Skanclass SymbolTable : public Hashtable { 39132720Skan friend class VMStructs; 40132720Skan 41132720Skanprivate: 42132720Skan // The symbol table 43132720Skan static SymbolTable* _the_table; 44132720Skan 45132720Skan // Adding elements 46132720Skan symbolOop basic_add(int index, u1* name, int len, 47132720Skan unsigned int hashValue, TRAPS); 48132720Skan bool basic_add(constantPoolHandle cp, int names_count, 49169691Skan const char** names, int* lengths, int* cp_indices, 50169691Skan unsigned int* hashValues, TRAPS); 51169691Skan 52132720Skan // Table size 53132720Skan enum { 54132720Skan symbol_table_size = 20011 55169691Skan }; 56169691Skan 57169691Skan symbolOop lookup(int index, const char* name, int len, unsigned int hash); 58132720Skan 59132720Skan SymbolTable() 60132720Skan : Hashtable(symbol_table_size, sizeof (HashtableEntry)) {} 61132720Skan 62132720Skan SymbolTable(HashtableBucket* t, int number_of_entries) 63132720Skan : Hashtable(symbol_table_size, sizeof (HashtableEntry), t, 64132720Skan number_of_entries) {} 65132720Skan 66132720Skan 67132720Skanpublic: 68132720Skan enum { 69132720Skan symbol_alloc_batch_size = 8 70132720Skan }; 71132720Skan 72132720Skan // The symbol table 73132720Skan static SymbolTable* the_table() { return _the_table; } 74132720Skan 75169691Skan static void create_table() { 76169691Skan assert(_the_table == NULL, "One symbol table allowed."); 77169691Skan _the_table = new SymbolTable(); 78132720Skan } 79132720Skan 80132720Skan static void create_table(HashtableBucket* t, int length, 81169691Skan int number_of_entries) { 82169691Skan assert(_the_table == NULL, "One symbol table allowed."); 83169691Skan assert(length == symbol_table_size * sizeof(HashtableBucket), 84132720Skan "bad shared symbol size."); 85169691Skan _the_table = new SymbolTable(t, number_of_entries); 86169691Skan } 87 88 static symbolOop lookup(const char* name, int len, TRAPS); 89 // lookup only, won't add. Also calculate hash. 90 static symbolOop lookup_only(const char* name, int len, unsigned int& hash); 91 // Only copy to C string to be added if lookup failed. 92 static symbolOop lookup(symbolHandle sym, int begin, int end, TRAPS); 93 94 // jchar (utf16) version of lookups 95 static symbolOop lookup_unicode(const jchar* name, int len, TRAPS); 96 static symbolOop lookup_only_unicode(const jchar* name, int len, unsigned int& hash); 97 98 static void add(constantPoolHandle cp, int names_count, 99 const char** names, int* lengths, int* cp_indices, 100 unsigned int* hashValues, TRAPS); 101 102 // GC support 103 // Delete pointers to otherwise-unreachable objects. 104 static void unlink(BoolObjectClosure* cl) { 105 the_table()->Hashtable::unlink(cl); 106 } 107 108 // Invoke "f->do_oop" on the locations of all oops in the table. 109 static void oops_do(OopClosure* f) { 110 the_table()->Hashtable::oops_do(f); 111 } 112 113 // Symbol lookup 114 static symbolOop lookup(int index, const char* name, int len, TRAPS); 115 116 // Needed for preloading classes in signatures when compiling. 117 // Returns the symbol is already present in symbol table, otherwise 118 // NULL. NO ALLOCATION IS GUARANTEED! 119 static symbolOop probe(const char* name, int len) { 120 unsigned int ignore_hash; 121 return lookup_only(name, len, ignore_hash); 122 } 123 static symbolOop probe_unicode(const jchar* name, int len) { 124 unsigned int ignore_hash; 125 return lookup_only_unicode(name, len, ignore_hash); 126 } 127 128 // Histogram 129 static void print_histogram() PRODUCT_RETURN; 130 131 // Debugging 132 static void verify(); 133 134 // Sharing 135 static void copy_buckets(char** top, char*end) { 136 the_table()->Hashtable::copy_buckets(top, end); 137 } 138 static void copy_table(char** top, char*end) { 139 the_table()->Hashtable::copy_table(top, end); 140 } 141 static void reverse(void* boundary = NULL) { 142 ((Hashtable*)the_table())->reverse(boundary); 143 } 144}; 145 146 147class StringTable : public Hashtable { 148 friend class VMStructs; 149 150private: 151 // The string table 152 static StringTable* _the_table; 153 154 static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS); 155 oop basic_add(int index, Handle string_or_null, jchar* name, int len, 156 unsigned int hashValue, TRAPS); 157 158 // Table size 159 enum { 160 string_table_size = 1009 161 }; 162 163 oop lookup(int index, jchar* chars, int length, unsigned int hashValue); 164 165 StringTable() : Hashtable(string_table_size, sizeof (HashtableEntry)) {} 166 167 StringTable(HashtableBucket* t, int number_of_entries) 168 : Hashtable(string_table_size, sizeof (HashtableEntry), t, 169 number_of_entries) {} 170 171public: 172 // The string table 173 static StringTable* the_table() { return _the_table; } 174 175 static void create_table() { 176 assert(_the_table == NULL, "One string table allowed."); 177 _the_table = new StringTable(); 178 } 179 180 static void create_table(HashtableBucket* t, int length, 181 int number_of_entries) { 182 assert(_the_table == NULL, "One string table allowed."); 183 assert(length == string_table_size * sizeof(HashtableBucket), 184 "bad shared string size."); 185 _the_table = new StringTable(t, number_of_entries); 186 } 187 188 189 static int hash_string(jchar* s, int len); 190 191 192 // GC support 193 // Delete pointers to otherwise-unreachable objects. 194 static void unlink(BoolObjectClosure* cl) { 195 the_table()->Hashtable::unlink(cl); 196 } 197 198 // Invoke "f->do_oop" on the locations of all oops in the table. 199 static void oops_do(OopClosure* f) { 200 the_table()->Hashtable::oops_do(f); 201 } 202 203 // Probing 204 static oop lookup(symbolOop symbol); 205 206 // Interning 207 static oop intern(symbolOop symbol, TRAPS); 208 static oop intern(oop string, TRAPS); 209 static oop intern(const char *utf8_string, TRAPS); 210 211 // Debugging 212 static void verify(); 213 214 // Sharing 215 static void copy_buckets(char** top, char*end) { 216 the_table()->Hashtable::copy_buckets(top, end); 217 } 218 static void copy_table(char** top, char*end) { 219 the_table()->Hashtable::copy_table(top, end); 220 } 221 static void reverse() { 222 ((BasicHashtable*)the_table())->reverse(); 223 } 224}; 225