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 = -1;
  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   if (getenv ("DEBUG"))
  46     fprintf (stderr, "Creating: nsyms = %d, ntokens = %d: %s\n",
  47              nsyms, ntokens, tag);
  48   nsyms++;
  49
  50   return res;
  51 }
  52
  53
  54 /*------------.
  55 | Free THIS.  |
  56 `------------*/
  57
  58 static void
  59 symbol_free (symbol_t *this)
  60 {
  61 #if 0
  62   /* This causes crashes because one string can appear more
  63      than once.  */
  64   XFREE (this->type_name);
  65 #endif
  66   XFREE (this->tag);
  67   XFREE (this);
  68 }
  69
  70
  71
  72 /*----------------------.
  73 | A symbol_t hash table.  |
  74 `----------------------*/
  75
  76 /* Initial capacity of symbols hash table.  */
  77 #define HT_INITIAL_CAPACITY 257
  78
  79 static struct hash_table *symbol_table = NULL;
  80
  81 static bool
  82 hash_compare_symbol_t (const symbol_t *m1, const symbol_t *m2)
  83 {
  84   return strcmp (m1->tag, m2->tag) ? FALSE : TRUE;
  85 }
  86
  87 static unsigned int
  88 hash_symbol_t (const symbol_t *m, unsigned int tablesize)
  89 {
  90   return hash_string (m->tag, tablesize);
  91 }
  92
  93
  94 /*-------------------------------.
  95 | Create the symbol_t hash table.  |
  96 `-------------------------------*/
  97
  98 void
  99 symbols_new (void)
 100 {
 101   symbol_table = hash_initialize (HT_INITIAL_CAPACITY,
 102                                   NULL,
 103                                   (Hash_hasher) hash_symbol_t,
 104                                   (Hash_comparator) hash_compare_symbol_t,
 105                                   (Hash_data_freer) symbol_free);
 106 }
 107
 108
 109 /*----------------------------------------------------------------.
 110 | Find the symbol named KEY, and return it.  If it does not exist |
 111 | yet, create it.                                                 |
 112 `----------------------------------------------------------------*/
 113
 114 symbol_t *
 115 getsym (const char *key)
 116 {
 117   symbol_t probe;
 118   symbol_t *entry;
 119
 120   (const char *) probe.tag = key;
 121   entry = hash_lookup (symbol_table, &probe);
 122
 123   if (!entry)
 124     {
 125       /* First insertion in the hash. */
 126       entry = symbol_new (key);
 127       hash_insert (symbol_table, entry);
 128     }
 129   return entry;
 130 }
 131
 132
 133 /*-------------------.
 134 | Free the symbols.  |
 135 `-------------------*/
 136
 137 void
 138 symbols_free (void)
 139 {
 140   hash_free (symbol_table);
 141 }
 142
 143
 144 /*---------------------------------------------------------------.
 145 | Look for undefined symbols, report an error, and consider them |
 146 | terminals.                                                     |
 147 `---------------------------------------------------------------*/
 148
 149 void
 150 symbols_do (symbol_processor processor, void *processor_data)
 151 {
 152   hash_do_for_each (symbol_table,
 153                     (Hash_processor) processor,
 154                     processor_data);
 155 }