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Improve handling of multiple S/R conflicts in the same state and of S/R

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conflicts involving multiple reductions.
* src/conflicts.c (resolve_sr_conflict): Don't assign the error action
set for a state here or Bison will abort if it is reassigned on a
later conflicted reduction in the same state.
Similarly, don't finalize and assign the solved conflicts report here
or it will be lost if it is reassigned on a later conflicted reduction
in the same state.
(set_conflicts): Instead, assign them both here after all S/R conflicts
in the state have been fully examined.
* src/print.c (shift_set): Rename to...
(no_reduce_set): ... this.
(print_reductions): Update for rename, and add %nonassoc error action
tokens to no_reduce_set so that, when printing the first remaining
reduction on an error action token, the reduction is enclosed in
brackets.
(print_results): Update for rename.
* tests/conflicts.at (Solved conflicts report for multiple reductions
in a state): New test case.
(%nonassoc error actions for multiple reductions in a state): New test
case.

* src/main.c (main): Don't depend on C99 features.
This commit is contained in:
Joel E. Denny
2007-07-17 06:56:36 +00:00
parent b541ffdf2c
commit 9d774affba
5 changed files with 211 additions and 33 deletions
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45
src/conflicts.c
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@@ -138,7 +138,7 @@ log_resolution (rule *r, symbol_number token,
/*------------------------------------------------------------------.
| Turn off the shift recorded for the specified token in the |
| specified state. Used when we resolve a shift-reduce conflict in |
| favor of the reduction. |
| favor of the reduction or as an error (%nonassoc). |
`------------------------------------------------------------------*/
static void
@@ -156,9 +156,9 @@ flush_shift (state *s, int token)
/*--------------------------------------------------------------------.
| 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. |
| Turn off the reduce recorded for the specified token in the |
| specified lookahead set. Used when we resolve a shift-reduce |
| conflict in favor of the shift or as an error (%nonassoc). |
`--------------------------------------------------------------------*/
static void
@@ -176,11 +176,12 @@ flush_reduce (bitset lookahead_tokens, int token)
| |
| RULENO is the number of the lookahead bitset to consider. |
| |
| ERRORS can be used to store discovered explicit errors. |
| ERRORS and NERRS can be used to store discovered explicit |
| errors. |
`------------------------------------------------------------------*/
static void
resolve_sr_conflict (state *s, int ruleno, symbol **errors)
resolve_sr_conflict (state *s, int ruleno, symbol **errors, int *nerrs)
{
symbol_number i;
reductions *reds = s->reductions;
@@ -188,7 +189,6 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors)
rule *redrule = reds->rules[ruleno];
int redprec = redrule->prec->prec;
bitset lookahead_tokens = reds->lookahead_tokens[ruleno];
int nerrs = 0;
for (i = 0; i < ntokens; i++)
if (bitset_test (lookahead_tokens, i)
@@ -234,23 +234,10 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors)
flush_shift (s, i);
flush_reduce (lookahead_tokens, i);
/* Record an explicit error for this token. */
errors[nerrs++] = symbols[i];
errors[(*nerrs)++] = symbols[i];
break;
}
}
if (nerrs)
{
/* Some tokens have been explicitly made errors. Allocate a
permanent errs structure for this state, to record them. */
state_errs_set (s, nerrs, errors);
}
if (obstack_object_size (&solved_conflicts_obstack))
{
obstack_1grow (&solved_conflicts_obstack, '\0');
s->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
}
}
@@ -267,6 +254,7 @@ set_conflicts (state *s, symbol **errors)
int i;
transitions *trans = s->transitions;
reductions *reds = s->reductions;
int nerrs = 0;
if (s->consistent)
return;
@@ -282,7 +270,19 @@ set_conflicts (state *s, symbol **errors)
for (i = 0; i < reds->num; ++i)
if (reds->rules[i]->prec && reds->rules[i]->prec->prec
&& !bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
resolve_sr_conflict (s, i, errors);
resolve_sr_conflict (s, i, errors, &nerrs);
if (nerrs)
{
/* Some tokens have been explicitly made errors. Allocate a
permanent errs structure for this state, to record them. */
state_errs_set (s, nerrs, errors);
}
if (obstack_object_size (&solved_conflicts_obstack))
{
obstack_1grow (&solved_conflicts_obstack, '\0');
s->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
}
/* Loop over all rules which require lookahead in this state. Check
for conflicts not resolved above. */
@@ -290,7 +290,6 @@ set_conflicts (state *s, symbol **errors)
{
if (!bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
conflicts[s->number] = 1;
bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]);
}
}