mirror of
https://git.savannah.gnu.org/git/bison.git
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152 lines
3.0 KiB
C
152 lines
3.0 KiB
C
/* Symbol table manager for Bison,
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Copyright 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
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This file is part of Bison, the GNU Compiler Compiler.
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Bison is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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Bison is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Bison; see the file COPYING. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "system.h"
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#include "symtab.h"
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#include "gram.h"
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bucket *firstsymbol;
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static bucket *lastsymbol;
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static bucket **symtab;
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static int
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hash (const char *key)
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{
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const char *cp;
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int k;
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cp = key;
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k = 0;
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while (*cp)
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k = ((k << 1) ^ (*cp++)) & 0x3fff;
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return k % TABSIZE;
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}
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/*--------------------------------------------------------------.
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| Create a new symbol, named TAG, which hash value is HASHVAL. |
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`--------------------------------------------------------------*/
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static bucket *
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bucket_new (const char *tag, int hashval)
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{
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bucket *res = XMALLOC (bucket, 1);
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res->link = symtab[hashval];
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res->next = NULL;
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res->tag = xstrdup (tag);
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res->type_name = NULL;
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res->number = -1;
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res->prec = 0;
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res->assoc = right_assoc;
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res->user_token_number = SUNDEF;
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res->alias = NULL;
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res->class = unknown_sym;
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nsyms++;
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return res;
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}
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void
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tabinit (void)
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{
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symtab = XCALLOC (bucket *, TABSIZE);
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firstsymbol = NULL;
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lastsymbol = NULL;
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}
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/*----------------------------------------------------------------.
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| Find the symbol named KEY, and return it. If it does not exist |
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| yet, create it. |
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`----------------------------------------------------------------*/
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bucket *
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getsym (const char *key)
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{
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int hashval;
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bucket *bp;
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int found;
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hashval = hash (key);
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bp = symtab[hashval];
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found = 0;
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while (bp != NULL && found == 0)
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{
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if (strcmp (key, bp->tag) == 0)
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found = 1;
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else
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bp = bp->link;
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}
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if (found == 0)
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{
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bp = bucket_new (key, hashval);
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if (firstsymbol == NULL)
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{
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firstsymbol = bp;
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lastsymbol = bp;
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}
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else
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{
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lastsymbol->next = bp;
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lastsymbol = bp;
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}
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symtab[hashval] = bp;
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}
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return bp;
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}
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void
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free_symtab (void)
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{
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int i;
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bucket *bp, *bptmp; /* JF don't use ptr after free */
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for (i = 0; i < TABSIZE; i++)
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{
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bp = symtab[i];
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while (bp)
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{
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bptmp = bp->link;
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#if 0
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/* This causes crashes because one string can appear more
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than once. */
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if (bp->type_name)
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XFREE (bp->type_name);
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#endif
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XFREE (bp->tag);
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XFREE (bp);
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bp = bptmp;
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}
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}
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XFREE (symtab);
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}
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