mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-10 04:43:03 +00:00
427c0dda0c
* src/lalr.c, src/LR0.c, src/relation.c, src/tables.c: Don't translate maintainer only messages.
127 lines
3.4 KiB
C
127 lines
3.4 KiB
C
/* Grammar reduction for Bison.
|
|
Copyright (C) 2002 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. */
|
|
|
|
/* Reduce the grammar: Look for injections. Akim Demaille. */
|
|
|
|
#include "system.h"
|
|
#include "quotearg.h"
|
|
#include "bitsetv.h"
|
|
#include "bitsetv-print.h"
|
|
#include "complain.h"
|
|
#include "gram.h"
|
|
#include "getargs.h"
|
|
#include "derives.h"
|
|
#include "injections.h"
|
|
|
|
/* Set of all nonterminals which are not useless. */
|
|
static bitsetv injects;
|
|
|
|
#define INJECTS(Var) injects[(Var) - ntokens]
|
|
|
|
/*-----------------------------------------------------------.
|
|
| Free the global sets used to compute the reduced grammar. |
|
|
`-----------------------------------------------------------*/
|
|
|
|
void
|
|
injections_new (void)
|
|
{
|
|
if (!injects)
|
|
injects = bitsetv_create (nvars, nvars, BITSET_FIXED);
|
|
else
|
|
bitsetv_zero (injects);
|
|
}
|
|
|
|
void
|
|
injections_free (void)
|
|
{
|
|
bitsetv_free (injects);
|
|
injects = NULL;
|
|
}
|
|
|
|
|
|
/*------------------------------.
|
|
| Dump the list of injections. |
|
|
`------------------------------*/
|
|
|
|
static void
|
|
injections_print (const char *title)
|
|
{
|
|
int i, j;
|
|
|
|
fprintf (stderr, "%s\n", title);
|
|
for (i = ntokens; i < nsyms; i++)
|
|
if (bitset_count (INJECTS (i)))
|
|
{
|
|
fprintf (stderr, "\t%s injects\n",
|
|
quotearg_style (escape_quoting_style, symbols[i]->tag));
|
|
for (j = 0; j < nvars; j++)
|
|
if (bitset_test (INJECTS (i), j))
|
|
fprintf (stderr, "\t\t%s\n",
|
|
quotearg_style (escape_quoting_style,
|
|
symbols[j + ntokens]->tag));
|
|
}
|
|
fprintf (stderr, "\n\n");
|
|
}
|
|
|
|
|
|
/*-----------------------------------------------------------------.
|
|
| Set INJECTS[i, j] if the nonterminal j derives the nonterminal j |
|
|
| (typically, `i -> j' is a rule, plus transitive closure). |
|
|
`-----------------------------------------------------------------*/
|
|
|
|
static void
|
|
injections_compute (void)
|
|
{
|
|
int i, j;
|
|
|
|
injections_new ();
|
|
for (i = ntokens; i < nsyms; i++)
|
|
for (j = 0; derives[i][j] >= 0; ++j)
|
|
{
|
|
int symbol = rules[derives[i][j]].rhs[0];
|
|
if (ISVAR (symbol) && rules[derives[i][j]].rhs[1] < 0)
|
|
bitset_set (INJECTS (i), symbol - ntokens);
|
|
}
|
|
|
|
if (trace_flag & trace_sets)
|
|
injections_print ("syntactic direct injections");
|
|
bitsetv_transitive_closure (injects);
|
|
if (trace_flag & trace_sets)
|
|
injections_print ("syntactic injections");
|
|
}
|
|
|
|
|
|
|
|
/*--------------------------------------------------------------.
|
|
| Look for infinitely ambiguous grammars: they contain cycles. |
|
|
`--------------------------------------------------------------*/
|
|
|
|
void
|
|
injections_check_cycles (void)
|
|
{
|
|
int i;
|
|
|
|
injections_compute ();
|
|
for (i = ntokens; i < nsyms; i++)
|
|
if (bitset_test (INJECTS (i), i - ntokens))
|
|
complain (_("infinitely ambiguous grammar: %s derives itself"),
|
|
symbols[i]->tag);
|
|
}
|