Files
bison/src/derives.c
Akim Demaille cc84fd5dc7 * src/derives.h: New file.
* src/main.c, src/derives.h: Use it.
Formatting changes.
* src/Makefile.am (noinst_HEADERS): Adjust.
2000-09-20 13:14:11 +00:00

116 lines
2.3 KiB
C

/* Match rules with nonterminals for bison,
Copyright (C) 1984, 1989, 2000 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
Bison is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
Bison is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Bison; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* set_derives finds, for each variable (nonterminal), which rules can
derive it. It sets up the value of derives so that derives[i -
ntokens] points to a vector of rule numbers, terminated with -1.
*/
#include "system.h"
#include "alloc.h"
#include "types.h"
#include "gram.h"
#include "derives.h"
#if DEBUG
extern char **tags;
static void
print_derives (void)
{
register int i;
register short *sp;
printf (_("\n\n\nDERIVES\n\n"));
for (i = ntokens; i < nsyms; i++)
{
printf (_("%s derives"), tags[i]);
for (sp = derives[i]; *sp > 0; sp++)
{
printf (" %d", *sp);
}
putchar ('\n');
}
putchar ('\n');
}
#endif
short **derives;
void
set_derives (void)
{
register int i;
register int lhs;
register shorts *p;
register short *q;
register shorts **dset;
register shorts *delts;
dset = NEW2 (nvars, shorts *) - ntokens;
delts = NEW2 (nrules + 1, shorts);
p = delts;
for (i = nrules; i > 0; i--)
{
lhs = rlhs[i];
if (lhs >= 0)
{
p->next = dset[lhs];
p->value = i;
dset[lhs] = p;
p++;
}
}
derives = NEW2 (nvars, short *) - ntokens;
q = NEW2 (nvars + nrules, short);
for (i = ntokens; i < nsyms; i++)
{
derives[i] = q;
p = dset[i];
while (p)
{
*q++ = p->value;
p = p->next;
}
*q++ = -1;
}
#if DEBUG
print_derives ();
#endif
FREE (dset + ntokens);
FREE (delts);
}
void
free_derives (void)
{
FREE (derives[ntokens]);
FREE (derives + ntokens);
}