mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-09 20:33:03 +00:00
0df87bb609
the result instead of using... (src_total, rrc_total, src_count, rrc_count): Remove. (any_conflicts): Remove. (print_conflicts): Split into... (conflicts_print, conflicts_output): New. * src/conflicts.h: Adjust. * src/main.c (main): Invoke both conflicts_output and conflicts_print. * src/print.c (print_grammar): Issue `n' between to rule outputs. * tests/regression.at (Conflicts): New. Reported by Tom Lane.
741 lines
15 KiB
C
741 lines
15 KiB
C
/* Find and resolve or report look-ahead conflicts for bison,
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Copyright 1984, 1989, 1992, 2000, 2001 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 it
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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, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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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 the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA. */
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#include "system.h"
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#include "getargs.h"
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#include "files.h"
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#include "gram.h"
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#include "state.h"
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#include "lalr.h"
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#include "conflicts.h"
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#include "reader.h"
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#include "LR0.h"
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errs **err_table = NULL;
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int expected_conflicts;
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static char *conflicts = NULL;
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static unsigned *shiftset = NULL;
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static unsigned *lookaheadset = NULL;
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static inline void
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log_resolution (int state, int LAno, int token, char *resolution)
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{
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obstack_fgrow4 (&output_obstack,
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_("\
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Conflict in state %d between rule %d and token %s resolved as %s.\n"),
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state, LAruleno[LAno], tags[token], resolution);
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}
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/*------------------------------------------------------------------.
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| Turn off the shift recorded for the specified token in the |
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| specified state. Used when we resolve a shift-reduce conflict in |
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| favor of the reduction. |
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`------------------------------------------------------------------*/
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static void
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flush_shift (int state, int token)
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{
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shifts *shiftp;
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int k, i;
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shiftp = shift_table[state];
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if (shiftp)
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{
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k = shiftp->nshifts;
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for (i = 0; i < k; i++)
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{
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if (shiftp->shifts[i]
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&& token == accessing_symbol[shiftp->shifts[i]])
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(shiftp->shifts[i]) = 0;
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}
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}
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}
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/*------------------------------------------------------------------.
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| Attempt to resolve shift-reduce conflict for one rule by means of |
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| precedence declarations. It has already been checked that the |
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| rule has a precedence. A conflict is resolved by modifying the |
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| shift or reduce tables so that there is no longer a conflict. |
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`------------------------------------------------------------------*/
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static void
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resolve_sr_conflict (int state, int lookaheadnum)
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{
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int i;
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int mask;
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unsigned *fp1;
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unsigned *fp2;
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int redprec;
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errs *errp = (errs *) xcalloc (sizeof (errs) + ntokens * sizeof (short), 1);
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short *errtokens = errp->errs;
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/* find the rule to reduce by to get precedence of reduction */
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redprec = rprec[LAruleno[lookaheadnum]];
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mask = 1;
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fp1 = LA + lookaheadnum * tokensetsize;
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fp2 = lookaheadset;
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for (i = 0; i < ntokens; i++)
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{
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if ((mask & *fp2 & *fp1) && sprec[i])
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/* Shift-reduce conflict occurs for token number i
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and it has a precedence.
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The precedence of shifting is that of token i. */
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{
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if (sprec[i] < redprec)
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{
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log_resolution (state, lookaheadnum, i, _("reduce"));
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*fp2 &= ~mask; /* flush the shift for this token */
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flush_shift (state, i);
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}
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else if (sprec[i] > redprec)
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{
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log_resolution (state, lookaheadnum, i, _("shift"));
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*fp1 &= ~mask; /* flush the reduce for this token */
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}
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else
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{
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/* Matching precedence levels.
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For left association, keep only the reduction.
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For right association, keep only the shift.
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For nonassociation, keep neither. */
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switch (sassoc[i])
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{
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case right_assoc:
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log_resolution (state, lookaheadnum, i, _("shift"));
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break;
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case left_assoc:
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log_resolution (state, lookaheadnum, i, _("reduce"));
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break;
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case non_assoc:
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log_resolution (state, lookaheadnum, i, _("an error"));
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break;
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}
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if (sassoc[i] != right_assoc)
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{
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*fp2 &= ~mask; /* flush the shift for this token */
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flush_shift (state, i);
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}
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if (sassoc[i] != left_assoc)
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{
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*fp1 &= ~mask; /* flush the reduce for this token */
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}
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if (sassoc[i] == non_assoc)
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{
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/* Record an explicit error for this token. */
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*errtokens++ = i;
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}
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}
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}
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mask <<= 1;
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if (mask == 0)
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{
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mask = 1;
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fp2++;
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fp1++;
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}
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}
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errp->nerrs = errtokens - errp->errs;
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if (errp->nerrs)
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{
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/* Some tokens have been explicitly made errors. Allocate
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a permanent errs structure for this state, to record them. */
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i = (char *) errtokens - (char *) errp;
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err_table[state] = (errs *) xcalloc ((unsigned int) i, 1);
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bcopy (errp, err_table[state], i);
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}
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else
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err_table[state] = 0;
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free (errp);
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}
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static void
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set_conflicts (int state)
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{
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int i;
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int k;
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shifts *shiftp;
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unsigned *fp2;
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unsigned *fp3;
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unsigned *fp4;
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unsigned *fp1;
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int symbol;
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if (consistent[state])
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return;
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for (i = 0; i < tokensetsize; i++)
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lookaheadset[i] = 0;
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shiftp = shift_table[state];
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if (shiftp)
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{
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k = shiftp->nshifts;
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for (i = 0; i < k; i++)
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{
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symbol = accessing_symbol[shiftp->shifts[i]];
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if (ISVAR (symbol))
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break;
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SETBIT (lookaheadset, symbol);
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}
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}
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k = lookaheads[state + 1];
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fp4 = lookaheadset + tokensetsize;
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/* Loop over all rules which require lookahead in this state. First
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check for shift-reduce conflict, and try to resolve using
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precedence */
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for (i = lookaheads[state]; i < k; i++)
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if (rprec[LAruleno[i]])
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{
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fp1 = LA + i * tokensetsize;
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fp2 = fp1;
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fp3 = lookaheadset;
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while (fp3 < fp4)
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{
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if (*fp2++ & *fp3++)
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{
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resolve_sr_conflict (state, i);
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break;
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}
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}
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}
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/* Loop over all rules which require lookahead in this state. Check
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for conflicts not resolved above. */
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for (i = lookaheads[state]; i < k; i++)
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{
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fp1 = LA + i * tokensetsize;
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fp2 = fp1;
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fp3 = lookaheadset;
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while (fp3 < fp4)
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if (*fp2++ & *fp3++)
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conflicts[state] = 1;
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fp2 = fp1;
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fp3 = lookaheadset;
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while (fp3 < fp4)
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*fp3++ |= *fp2++;
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}
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}
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void
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solve_conflicts (void)
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{
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int i;
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conflicts = XCALLOC (char, nstates);
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shiftset = XCALLOC (unsigned, tokensetsize);
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lookaheadset = XCALLOC (unsigned, tokensetsize);
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err_table = XCALLOC (errs *, nstates);
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for (i = 0; i < nstates; i++)
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set_conflicts (i);
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}
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/*---------------------------------------------.
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| Count the number of shift/reduce conflicts. |
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`---------------------------------------------*/
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static int
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count_sr_conflicts (int state)
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{
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int i;
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int k;
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int mask;
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shifts *shiftp;
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unsigned *fp1;
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unsigned *fp2;
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unsigned *fp3;
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int symbol;
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int src_count = 0;
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shiftp = shift_table[state];
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if (!shiftp)
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return 0;
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for (i = 0; i < tokensetsize; i++)
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{
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shiftset[i] = 0;
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lookaheadset[i] = 0;
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}
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k = shiftp->nshifts;
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for (i = 0; i < k; i++)
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{
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if (!shiftp->shifts[i])
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continue;
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symbol = accessing_symbol[shiftp->shifts[i]];
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if (ISVAR (symbol))
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break;
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SETBIT (shiftset, symbol);
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}
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k = lookaheads[state + 1];
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fp3 = lookaheadset + tokensetsize;
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for (i = lookaheads[state]; i < k; i++)
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{
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fp1 = LA + i * tokensetsize;
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fp2 = lookaheadset;
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while (fp2 < fp3)
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*fp2++ |= *fp1++;
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}
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fp1 = shiftset;
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fp2 = lookaheadset;
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while (fp2 < fp3)
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*fp2++ &= *fp1++;
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mask = 1;
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fp2 = lookaheadset;
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for (i = 0; i < ntokens; i++)
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{
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if (mask & *fp2)
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src_count++;
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mask <<= 1;
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if (mask == 0)
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{
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mask = 1;
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fp2++;
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}
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}
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return src_count;
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}
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/*----------------------------------------------.
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| Count the number of reduce/reduce conflicts. |
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`----------------------------------------------*/
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static int
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count_rr_conflicts (int state)
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{
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int i;
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unsigned mask;
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unsigned *baseword;
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int rrc_count = 0;
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int m = lookaheads[state];
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int n = lookaheads[state + 1];
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if (n - m < 2)
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return 0;
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mask = 1;
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baseword = LA + m * tokensetsize;
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for (i = 0; i < ntokens; i++)
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{
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unsigned *wordp = baseword;
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int count = 0;
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int j;
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for (j = m; j < n; j++)
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{
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if (mask & *wordp)
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count++;
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wordp += tokensetsize;
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}
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if (count >= 2)
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rrc_count++;
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mask <<= 1;
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if (mask == 0)
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{
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mask = 1;
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baseword++;
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}
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}
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return rrc_count;
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}
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/*--------------------------------------------------------------.
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| Return a human readable string which reports shift/reduce and |
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| reduce/reduce conflict numbers (SRC_NUM, RRC_NUM). |
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`--------------------------------------------------------------*/
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static const char *
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conflict_report (int src_num, int rrc_num)
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{
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static char res[4096];
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char *cp = res;
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if (src_num == 1)
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{
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sprintf (cp, _(" 1 shift/reduce conflict"));
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cp += strlen (cp);
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}
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else if (src_num > 1)
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{
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sprintf (cp, _(" %d shift/reduce conflicts"), src_num);
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cp += strlen (cp);
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}
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if (src_num > 0 && rrc_num > 0)
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{
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sprintf (cp, _(" and"));
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cp += strlen (cp);
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}
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if (rrc_num == 1)
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{
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sprintf (cp, _(" 1 reduce/reduce conflict"));
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cp += strlen (cp);
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}
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else if (rrc_num > 1)
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{
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sprintf (cp, _(" %d reduce/reduce conflicts"), rrc_num);
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cp += strlen (cp);
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}
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*cp++ = '.';
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*cp++ = '\n';
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*cp++ = '\0';
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return res;
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}
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/*-----------------------------------------------------------.
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| Output the detailed description of states with conflicts. |
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`-----------------------------------------------------------*/
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void
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conflicts_output (FILE *out)
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{
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int i;
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for (i = 0; i < nstates; i++)
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if (conflicts[i])
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{
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fprintf (out, _("State %d contains"), i);
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fputs (conflict_report (count_sr_conflicts (i),
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count_rr_conflicts (i)), out);
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}
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}
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/*------------------------------------------.
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| Reporting the total number of conflicts. |
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`------------------------------------------*/
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void
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conflicts_print (void)
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{
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int i;
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int src_total = 0;
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int rrc_total = 0;
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/* Conflicts by state. */
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for (i = 0; i < nstates; i++)
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if (conflicts[i])
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{
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src_total += count_sr_conflicts (i);
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rrc_total += count_rr_conflicts (i);
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}
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/* Report the total number of conflicts on STDERR. */
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if (src_total || rrc_total)
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if (yacc_flag)
|
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{
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/* If invoked with `--yacc', use the output format specified by
|
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POSIX. */
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fprintf (stderr, _("conflicts: "));
|
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if (src_total > 0)
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fprintf (stderr, _(" %d shift/reduce"), src_total);
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if (src_total > 0 && rrc_total > 0)
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fprintf (stderr, ",");
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if (rrc_total > 0)
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fprintf (stderr, _(" %d reduce/reduce"), rrc_total);
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putc ('\n', stderr);
|
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}
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else
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{
|
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fprintf (stderr, _("%s contains"), infile);
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fputs (conflict_report (src_total, rrc_total), stderr);
|
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}
|
||
}
|
||
|
||
|
||
void
|
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print_reductions (int state)
|
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{
|
||
int i;
|
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int j;
|
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int k;
|
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unsigned *fp1;
|
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unsigned *fp2;
|
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unsigned *fp3;
|
||
unsigned *fp4;
|
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int rule;
|
||
int symbol;
|
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unsigned mask;
|
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int m;
|
||
int n;
|
||
int default_LA;
|
||
int default_rule = 0;
|
||
int cmax;
|
||
int count;
|
||
shifts *shiftp;
|
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errs *errp;
|
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int nodefault = 0;
|
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|
||
for (i = 0; i < tokensetsize; i++)
|
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shiftset[i] = 0;
|
||
|
||
shiftp = shift_table[state];
|
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if (shiftp)
|
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{
|
||
k = shiftp->nshifts;
|
||
for (i = 0; i < k; i++)
|
||
{
|
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if (!shiftp->shifts[i])
|
||
continue;
|
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symbol = accessing_symbol[shiftp->shifts[i]];
|
||
if (ISVAR (symbol))
|
||
break;
|
||
/* if this state has a shift for the error token,
|
||
don't use a default rule. */
|
||
if (symbol == error_token_number)
|
||
nodefault = 1;
|
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SETBIT (shiftset, symbol);
|
||
}
|
||
}
|
||
|
||
errp = err_table[state];
|
||
if (errp)
|
||
{
|
||
k = errp->nerrs;
|
||
for (i = 0; i < k; i++)
|
||
{
|
||
if (!errp->errs[i])
|
||
continue;
|
||
symbol = errp->errs[i];
|
||
SETBIT (shiftset, symbol);
|
||
}
|
||
}
|
||
|
||
m = lookaheads[state];
|
||
n = lookaheads[state + 1];
|
||
|
||
if (n - m == 1 && !nodefault)
|
||
{
|
||
default_rule = LAruleno[m];
|
||
|
||
fp1 = LA + m * tokensetsize;
|
||
fp2 = shiftset;
|
||
fp3 = lookaheadset;
|
||
fp4 = lookaheadset + tokensetsize;
|
||
|
||
while (fp3 < fp4)
|
||
*fp3++ = *fp1++ & *fp2++;
|
||
|
||
mask = 1;
|
||
fp3 = lookaheadset;
|
||
|
||
for (i = 0; i < ntokens; i++)
|
||
{
|
||
if (mask & *fp3)
|
||
obstack_fgrow3 (&output_obstack,
|
||
_(" %-4s\t[reduce using rule %d (%s)]\n"),
|
||
tags[i], default_rule, tags[rlhs[default_rule]]);
|
||
|
||
mask <<= 1;
|
||
if (mask == 0)
|
||
{
|
||
mask = 1;
|
||
fp3++;
|
||
}
|
||
}
|
||
|
||
obstack_fgrow2 (&output_obstack,
|
||
_(" $default\treduce using rule %d (%s)\n\n"),
|
||
default_rule, tags[rlhs[default_rule]]);
|
||
}
|
||
else if (n - m >= 1)
|
||
{
|
||
cmax = 0;
|
||
default_LA = -1;
|
||
fp4 = lookaheadset + tokensetsize;
|
||
|
||
if (!nodefault)
|
||
for (i = m; i < n; i++)
|
||
{
|
||
fp1 = LA + i * tokensetsize;
|
||
fp2 = shiftset;
|
||
fp3 = lookaheadset;
|
||
|
||
while (fp3 < fp4)
|
||
*fp3++ = *fp1++ & (~(*fp2++));
|
||
|
||
count = 0;
|
||
mask = 1;
|
||
fp3 = lookaheadset;
|
||
for (j = 0; j < ntokens; j++)
|
||
{
|
||
if (mask & *fp3)
|
||
count++;
|
||
|
||
mask <<= 1;
|
||
if (mask == 0)
|
||
{
|
||
mask = 1;
|
||
fp3++;
|
||
}
|
||
}
|
||
|
||
if (count > cmax)
|
||
{
|
||
cmax = count;
|
||
default_LA = i;
|
||
default_rule = LAruleno[i];
|
||
}
|
||
|
||
fp2 = shiftset;
|
||
fp3 = lookaheadset;
|
||
|
||
while (fp3 < fp4)
|
||
*fp2++ |= *fp3++;
|
||
}
|
||
|
||
for (i = 0; i < tokensetsize; i++)
|
||
shiftset[i] = 0;
|
||
|
||
if (shiftp)
|
||
{
|
||
k = shiftp->nshifts;
|
||
for (i = 0; i < k; i++)
|
||
{
|
||
if (!shiftp->shifts[i])
|
||
continue;
|
||
symbol = accessing_symbol[shiftp->shifts[i]];
|
||
if (ISVAR (symbol))
|
||
break;
|
||
SETBIT (shiftset, symbol);
|
||
}
|
||
}
|
||
|
||
mask = 1;
|
||
fp1 = LA + m * tokensetsize;
|
||
fp2 = shiftset;
|
||
for (i = 0; i < ntokens; i++)
|
||
{
|
||
int defaulted = 0;
|
||
|
||
if (mask & *fp2)
|
||
count = 1;
|
||
else
|
||
count = 0;
|
||
|
||
fp3 = fp1;
|
||
for (j = m; j < n; j++)
|
||
{
|
||
if (mask & *fp3)
|
||
{
|
||
if (count == 0)
|
||
{
|
||
if (j != default_LA)
|
||
{
|
||
rule = LAruleno[j];
|
||
obstack_fgrow3 (&output_obstack,
|
||
_(" %-4s\treduce using rule %d (%s)\n"),
|
||
tags[i], rule, tags[rlhs[rule]]);
|
||
}
|
||
else
|
||
defaulted = 1;
|
||
|
||
count++;
|
||
}
|
||
else
|
||
{
|
||
if (defaulted)
|
||
{
|
||
rule = LAruleno[default_LA];
|
||
obstack_fgrow3 (&output_obstack,
|
||
_(" %-4s\treduce using rule %d (%s)\n"),
|
||
tags[i], rule, tags[rlhs[rule]]);
|
||
defaulted = 0;
|
||
}
|
||
rule = LAruleno[j];
|
||
obstack_fgrow3 (&output_obstack,
|
||
_(" %-4s\t[reduce using rule %d (%s)]\n"),
|
||
tags[i], rule, tags[rlhs[rule]]);
|
||
}
|
||
}
|
||
|
||
fp3 += tokensetsize;
|
||
}
|
||
|
||
mask <<= 1;
|
||
if (mask == 0)
|
||
{
|
||
mask = 1;
|
||
/* We tried incrementing just fp1, and just fp2; both seem wrong.
|
||
It seems necessary to increment both in sync. */
|
||
fp1++;
|
||
fp2++;
|
||
}
|
||
}
|
||
|
||
if (default_LA >= 0)
|
||
obstack_fgrow2 (&output_obstack,
|
||
_(" $default\treduce using rule %d (%s)\n"),
|
||
default_rule, tags[rlhs[default_rule]]);
|
||
|
||
obstack_1grow (&output_obstack, '\n');
|
||
}
|
||
}
|
||
|
||
|
||
void
|
||
free_conflicts (void)
|
||
{
|
||
XFREE (conflicts);
|
||
XFREE (shiftset);
|
||
XFREE (lookaheadset);
|
||
}
|