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* src/conflicts.c (flush_shift): Also adjust lookaheadset.

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(flush_reduce): New.
(resolve_sr_conflict): Adjust.
This commit is contained in:
Akim Demaille
2001-12-17 17:32:08 +00:00
parent f87685c324
commit 709ae8c6ee
2 changed files with 52 additions and 47 deletions
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7
ChangeLog
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@@ -1,3 +1,10 @@
2001-12-17 Akim Demaille <akim@epita.fr>
* src/conflicts.c (flush_shift): Also adjust lookaheadset.
(flush_reduce): New.
(resolve_sr_conflict): Adjust.
2001-12-17 Akim Demaille <akim@epita.fr> 2001-12-17 Akim Demaille <akim@epita.fr>
* src/output.c (output_obstack): Be static and rename as... * src/output.c (output_obstack): Be static and rename as...

92
src/conflicts.c
View File

@@ -60,12 +60,26 @@ flush_shift (int state, int token)
shifts *shiftp = state_table[state]->shifts; shifts *shiftp = state_table[state]->shifts;
int i; int i;
RESETBIT (lookaheadset, token);
for (i = 0; i < shiftp->nshifts; i++) for (i = 0; i < shiftp->nshifts; i++)
if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token) if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token)
SHIFT_DISABLE (shiftp, i); SHIFT_DISABLE (shiftp, i);
} }
/*-------------------------------------------------------------------.
| Turn off the reduce recorded for the specified token for the |
| specified lookahead. Used when we resolve a shift-reduce conflict |
| in favor of the shift. |
`-------------------------------------------------------------------*/
static void
flush_reduce (int lookahead, int token)
{
RESETBIT (LA (lookahead), token);
}
/*------------------------------------------------------------------. /*------------------------------------------------------------------.
| Attempt to resolve shift-reduce conflict for one rule by means of | | Attempt to resolve shift-reduce conflict for one rule by means of |
| precedence declarations. It has already been checked that the | | precedence declarations. It has already been checked that the |
@@ -74,74 +88,58 @@ flush_shift (int state, int token)
`------------------------------------------------------------------*/ `------------------------------------------------------------------*/
static void static void
resolve_sr_conflict (int state, int lookaheadnum) resolve_sr_conflict (int state, int lookahead)
{ {
int i; int i;
/* find the rule to reduce by to get precedence of reduction */ /* find the rule to reduce by to get precedence of reduction */
int redprec = rule_table[LAruleno[lookaheadnum]].prec; int redprec = rule_table[LAruleno[lookahead]].prec;
errs *errp = ERRS_ALLOC (ntokens + 1); errs *errp = ERRS_ALLOC (ntokens + 1);
short *errtokens = errp->errs; short *errtokens = errp->errs;
for (i = 0; i < ntokens; i++) for (i = 0; i < ntokens; i++)
if (BITISSET (LA (lookaheadnum), i) if (BITISSET (LA (lookahead), i)
&& BITISSET (lookaheadset, i) && BITISSET (lookaheadset, i)
&& sprec[i]) && sprec[i])
/* Shift-reduce conflict occurs for token number i
and it has a precedence.
The precedence of shifting is that of token i. */
{ {
/* Shift-reduce conflict occurs for token number i
and it has a precedence.
The precedence of shifting is that of token i. */
if (sprec[i] < redprec) if (sprec[i] < redprec)
{ {
log_resolution (state, lookaheadnum, i, _("reduce")); log_resolution (state, lookahead, i, _("reduce"));
/* flush the shift for this token */
RESETBIT (lookaheadset, i);
flush_shift (state, i); flush_shift (state, i);
} }
else if (sprec[i] > redprec) else if (sprec[i] > redprec)
{ {
log_resolution (state, lookaheadnum, i, _("shift")); log_resolution (state, lookahead, i, _("shift"));
/* flush the reduce for this token */ flush_reduce (lookahead, i);
RESETBIT (LA (lookaheadnum), i);
} }
else else
{ /* Matching precedence levels.
/* Matching precedence levels. For left association, keep only the reduction.
For left association, keep only the reduction. For right association, keep only the shift.
For right association, keep only the shift. For nonassociation, keep neither. */
For nonassociation, keep neither. */
switch (sassoc[i]) switch (sassoc[i])
{ {
case right_assoc: case right_assoc:
log_resolution (state, lookaheadnum, i, _("shift")); log_resolution (state, lookahead, i, _("shift"));
break; flush_reduce (lookahead, i);
break;
case left_assoc: case left_assoc:
log_resolution (state, lookaheadnum, i, _("reduce")); log_resolution (state, lookahead, i, _("reduce"));
break; flush_shift (state, i);
break;
case non_assoc: case non_assoc:
log_resolution (state, lookaheadnum, i, _("an error")); log_resolution (state, lookahead, i, _("an error"));
break; flush_shift (state, i);
} flush_reduce (lookahead, i);
/* Record an explicit error for this token. */
if (sassoc[i] != right_assoc) *errtokens++ = i;
{ break;
/* flush the shift for this token */ }
RESETBIT (lookaheadset, i);
flush_shift (state, i);
}
if (sassoc[i] != left_assoc)
{
/* flush the reduce for this token */
RESETBIT (LA (lookaheadnum), i);
}
if (sassoc[i] == non_assoc)
{
/* Record an explicit error for this token. */
*errtokens++ = i;
}
}
} }
errp->nerrs = errtokens - errp->errs; errp->nerrs = errtokens - errp->errs;