| 1 | /* Symbol table manager for Bison, |
| 2 | Copyright 1984, 1989, 2000, 2001 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 "symtab.h" |
| 24 | #include "gram.h" |
| 25 | |
| 26 | |
| 27 | bucket *firstsymbol; |
| 28 | static bucket *lastsymbol; |
| 29 | static bucket **symtab; |
| 30 | |
| 31 | static int |
| 32 | hash (const char *key) |
| 33 | { |
| 34 | const char *cp; |
| 35 | int k; |
| 36 | |
| 37 | cp = key; |
| 38 | k = 0; |
| 39 | while (*cp) |
| 40 | k = ((k << 1) ^ (*cp++)) & 0x3fff; |
| 41 | |
| 42 | return k % TABSIZE; |
| 43 | } |
| 44 | |
| 45 | /*--------------------------------------------------------------. |
| 46 | | Create a new symbol, named TAG, which hash value is HASHVAL. | |
| 47 | `--------------------------------------------------------------*/ |
| 48 | |
| 49 | static bucket * |
| 50 | bucket_new (const char *tag, int hashval) |
| 51 | { |
| 52 | bucket *res = XMALLOC (bucket, 1); |
| 53 | |
| 54 | res->link = symtab[hashval]; |
| 55 | res->next = NULL; |
| 56 | res->tag = xstrdup (tag); |
| 57 | res->type_name = NULL; |
| 58 | res->value = 0; |
| 59 | res->prec = 0; |
| 60 | res->assoc = right_assoc; |
| 61 | res->user_token_number = SUNDEF; |
| 62 | res->alias = NULL; |
| 63 | res->class = unknown_sym; |
| 64 | |
| 65 | nsyms++; |
| 66 | |
| 67 | return res; |
| 68 | } |
| 69 | |
| 70 | |
| 71 | void |
| 72 | tabinit (void) |
| 73 | { |
| 74 | symtab = XCALLOC (bucket *, TABSIZE); |
| 75 | |
| 76 | firstsymbol = NULL; |
| 77 | lastsymbol = NULL; |
| 78 | } |
| 79 | |
| 80 | |
| 81 | /*----------------------------------------------------------------. |
| 82 | | Find the symbol named KEY, and return it. If it does not exist | |
| 83 | | yet, create it. | |
| 84 | `----------------------------------------------------------------*/ |
| 85 | |
| 86 | bucket * |
| 87 | getsym (const char *key) |
| 88 | { |
| 89 | int hashval; |
| 90 | bucket *bp; |
| 91 | int found; |
| 92 | |
| 93 | hashval = hash (key); |
| 94 | bp = symtab[hashval]; |
| 95 | |
| 96 | found = 0; |
| 97 | while (bp != NULL && found == 0) |
| 98 | { |
| 99 | if (strcmp (key, bp->tag) == 0) |
| 100 | found = 1; |
| 101 | else |
| 102 | bp = bp->link; |
| 103 | } |
| 104 | |
| 105 | if (found == 0) |
| 106 | { |
| 107 | bp = bucket_new (key, hashval); |
| 108 | |
| 109 | if (firstsymbol == NULL) |
| 110 | { |
| 111 | firstsymbol = bp; |
| 112 | lastsymbol = bp; |
| 113 | } |
| 114 | else |
| 115 | { |
| 116 | lastsymbol->next = bp; |
| 117 | lastsymbol = bp; |
| 118 | } |
| 119 | |
| 120 | symtab[hashval] = bp; |
| 121 | } |
| 122 | |
| 123 | return bp; |
| 124 | } |
| 125 | |
| 126 | |
| 127 | void |
| 128 | free_symtab (void) |
| 129 | { |
| 130 | int i; |
| 131 | bucket *bp, *bptmp; /* JF don't use ptr after free */ |
| 132 | |
| 133 | for (i = 0; i < TABSIZE; i++) |
| 134 | { |
| 135 | bp = symtab[i]; |
| 136 | while (bp) |
| 137 | { |
| 138 | bptmp = bp->link; |
| 139 | #if 0 |
| 140 | /* This causes crashes because one string can appear more |
| 141 | than once. */ |
| 142 | if (bp->type_name) |
| 143 | XFREE (bp->type_name); |
| 144 | #endif |
| 145 | XFREE (bp->tag); |
| 146 | XFREE (bp); |
| 147 | bp = bptmp; |
| 148 | } |
| 149 | } |
| 150 | XFREE (symtab); |
| 151 | } |