src/symtab.c

   1 /* Symbol table manager for Bison,
   2    Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    Bison is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    Bison is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with Bison; see the file COPYING.  If not, write to
  18    the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include "system.h"
  23 #include "hash.h"
  24 #include "symtab.h"
  25 #include "gram.h"
  26
  27 /*---------------------------------.
  28 | Create a new symbol, named TAG.  |
  29 `---------------------------------*/
  30
  31 static symbol_t *
  32 symbol_new (const char *tag)
  33 {
  34   symbol_t *res = XMALLOC (symbol_t, 1);
  35
  36   res->tag = xstrdup (tag);
  37   res->type_name = NULL;
  38   res->number = NUMBER_UNDEFINED;
  39   res->prec = 0;
  40   res->assoc = right_assoc;
  41   res->user_token_number = SUNDEF;
  42   res->alias = NULL;
  43   res->class = unknown_sym;
  44
  45   nsyms++;
  46
  47   return res;
  48 }
  49
  50
  51 /*------------.
  52 | Free THIS.  |
  53 `------------*/
  54
  55 static void
  56 symbol_free (symbol_t *this)
  57 {
  58 #if 0
  59   /* This causes crashes because one string can appear more
  60      than once.  */
  61   XFREE (this->type_name);
  62 #endif
  63   XFREE (this->tag);
  64   XFREE (this);
  65 }
  66
  67
  68
  69 /*----------------------.
  70 | A symbol_t hash table.  |
  71 `----------------------*/
  72
  73 /* Initial capacity of symbols hash table.  */
  74 #define HT_INITIAL_CAPACITY 257
  75
  76 static struct hash_table *symbol_table = NULL;
  77
  78 static bool
  79 hash_compare_symbol_t (const symbol_t *m1, const symbol_t *m2)
  80 {
  81   return strcmp (m1->tag, m2->tag) ? FALSE : TRUE;
  82 }
  83
  84 static unsigned int
  85 hash_symbol_t (const symbol_t *m, unsigned int tablesize)
  86 {
  87   return hash_string (m->tag, tablesize);
  88 }
  89
  90
  91 /*-------------------------------.
  92 | Create the symbol_t hash table.  |
  93 `-------------------------------*/
  94
  95 void
  96 symbols_new (void)
  97 {
  98   symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
  99                                   NULL,
 100                                   (Hash_hasher) hash_symbol_t,
 101                                   (Hash_comparator) hash_compare_symbol_t,
 102                                   (Hash_data_freer) symbol_free);
 103 }
 104
 105
 106 /*----------------------------------------------------------------.
 107 | Find the symbol named KEY, and return it.  If it does not exist |
 108 | yet, create it.                                                 |
 109 `----------------------------------------------------------------*/
 110
 111 symbol_t *
 112 getsym (const char *key)
 113 {
 114   symbol_t probe;
 115   symbol_t *entry;
 116
 117   (const char *) probe.tag = key;
 118   entry = hash_lookup (symbol_table, &probe);
 119
 120   if (!entry)
 121     {
 122       /* First insertion in the hash. */
 123       entry = symbol_new (key);
 124       hash_insert (symbol_table, entry);
 125     }
 126   return entry;
 127 }
 128
 129
 130 /*-------------------.
 131 | Free the symbols.  |
 132 `-------------------*/
 133
 134 void
 135 symbols_free (void)
 136 {
 137   hash_free (symbol_table);
 138 }
 139
 140
 141 /*---------------------------------------------------------------.
 142 | Look for undefined symbols, report an error, and consider them |
 143 | terminals.                                                     |
 144 `---------------------------------------------------------------*/
 145
 146 void
 147 symbols_do (symbol_processor processor, void *processor_data)
 148 {
 149   hash_do_for_each (symbol_table,
 150                     (Hash_processor) processor,
 151                     processor_data);
 152 }