/* Find and resolve or report look-ahead conflicts for bison,
- Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002
+ Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004
Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
#include "symtab.h"
/* -1 stands for not specified. */
-int expected_conflicts = -1;
-static char *conflicts = NULL;
+int expected_sr_conflicts = -1;
+int expected_rr_conflicts = -1;
+static char *conflicts;
struct obstack solved_conflicts_obstack;
-static bitset shiftset;
-static bitset lookaheadset;
+static bitset shift_set;
+static bitset look_ahead_set;
\f
transitions *trans = s->transitions;
int i;
- bitset_reset (lookaheadset, token);
+ bitset_reset (look_ahead_set, token);
for (i = 0; i < trans->num; i++)
if (!TRANSITION_IS_DISABLED (trans, i)
&& TRANSITION_SYMBOL (trans, i) == 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 for the |
+| specified look-ahead. Used when we resolve a shift-reduce conflict |
+| in favor of the shift. |
+`--------------------------------------------------------------------*/
static void
-flush_reduce (bitset lookaheads, int token)
+flush_reduce (bitset look_ahead_tokens, int token)
{
- bitset_reset (lookaheads, token);
+ bitset_reset (look_ahead_tokens, token);
}
| rule has a precedence. A conflict is resolved by modifying the |
| shift or reduce tables so that there is no longer a conflict. |
| |
-| LOOKAHEAD is the number of the lookahead bitset to consider. |
+| RULENO is the number of the look-ahead bitset to consider. |
| |
| ERRORS can be used to store discovered explicit errors. |
`------------------------------------------------------------------*/
/* Find the rule to reduce by to get precedence of reduction. */
rule *redrule = reds->rules[ruleno];
int redprec = redrule->prec->prec;
- bitset lookaheads = reds->lookaheads[ruleno];
+ bitset look_ahead_tokens = reds->look_ahead_tokens[ruleno];
int nerrs = 0;
for (i = 0; i < ntokens; i++)
- if (bitset_test (lookaheads, i)
- && bitset_test (lookaheadset, i)
+ if (bitset_test (look_ahead_tokens, i)
+ && bitset_test (look_ahead_set, i)
&& symbols[i]->prec)
{
/* Shift-reduce conflict occurs for token number i
else if (symbols[i]->prec > redprec)
{
log_resolution (redrule, i, shift_resolution);
- flush_reduce (lookaheads, i);
+ flush_reduce (look_ahead_tokens, i);
}
else
/* Matching precedence levels.
{
case right_assoc:
log_resolution (redrule, i, right_resolution);
- flush_reduce (lookaheads, i);
+ flush_reduce (look_ahead_tokens, i);
break;
case left_assoc:
case non_assoc:
log_resolution (redrule, i, nonassoc_resolution);
flush_shift (s, i);
- flush_reduce (lookaheads, i);
+ flush_reduce (look_ahead_tokens, i);
/* Record an explicit error for this token. */
errors[nerrs++] = symbols[i];
break;
}
}
- /* 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 (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))
{
| Solve the S/R conflicts of state S using the |
| precedence/associativity, and flag it inconsistent if it still has |
| conflicts. ERRORS can be used as storage to compute the list of |
-| lookaheads on which S raises a syntax error (%nonassoc). |
+| look-ahead tokens on which S raises a syntax error (%nonassoc). |
`-------------------------------------------------------------------*/
static void
if (s->consistent)
return;
- bitset_zero (lookaheadset);
+ bitset_zero (look_ahead_set);
FOR_EACH_SHIFT (trans, i)
- bitset_set (lookaheadset, TRANSITION_SYMBOL (trans, i));
+ bitset_set (look_ahead_set, TRANSITION_SYMBOL (trans, i));
- /* Loop over all rules which require lookahead in this state. First
+ /* Loop over all rules which require look-ahead in this state. First
check for shift-reduce conflict, and try to resolve using
precedence. */
for (i = 0; i < reds->num; ++i)
if (reds->rules[i]->prec && reds->rules[i]->prec->prec
- && !bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
- {
- resolve_sr_conflict (s, i, errors);
- break;
- }
+ && !bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set))
+ resolve_sr_conflict (s, i, errors);
- /* Loop over all rules which require lookahead in this state. Check
+ /* Loop over all rules which require look-ahead in this state. Check
for conflicts not resolved above. */
for (i = 0; i < reds->num; ++i)
{
- if (!bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
+ if (!bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set))
conflicts[s->number] = 1;
- bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
+ bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]);
}
}
conflicts_solve (void)
{
state_number i;
- /* List of lookaheads on which we explicitly raise a syntax error. */
- symbol **errors = MALLOC (errors, ntokens + 1);
+ /* List of look-ahead tokens on which we explicitly raise a syntax error. */
+ symbol **errors = xnmalloc (ntokens + 1, sizeof *errors);
- CALLOC (conflicts, nstates);
- shiftset = bitset_create (ntokens, BITSET_FIXED);
- lookaheadset = bitset_create (ntokens, BITSET_FIXED);
+ conflicts = xcalloc (nstates, sizeof *conflicts);
+ shift_set = bitset_create (ntokens, BITSET_FIXED);
+ look_ahead_set = bitset_create (ntokens, BITSET_FIXED);
obstack_init (&solved_conflicts_obstack);
for (i = 0; i < nstates; i++)
if (!trans)
return 0;
- bitset_zero (lookaheadset);
- bitset_zero (shiftset);
+ bitset_zero (look_ahead_set);
+ bitset_zero (shift_set);
FOR_EACH_SHIFT (trans, i)
- bitset_set (shiftset, TRANSITION_SYMBOL (trans, i));
+ bitset_set (shift_set, TRANSITION_SYMBOL (trans, i));
for (i = 0; i < reds->num; ++i)
- bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
+ bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]);
- bitset_and (lookaheadset, lookaheadset, shiftset);
+ bitset_and (look_ahead_set, look_ahead_set, shift_set);
- src_count = bitset_count (lookaheadset);
+ src_count = bitset_count (look_ahead_set);
return src_count;
}
+`----------------------------------------------------------------*/
static int
-count_rr_conflicts (state *s, int one_per_token)
+count_rr_conflicts (state *s, bool one_per_token)
{
int i;
reductions *reds = s->reductions;
int count = 0;
int j;
for (j = 0; j < reds->num; ++j)
- if (bitset_test (reds->lookaheads[j], i))
+ if (bitset_test (reds->look_ahead_tokens[j], i))
count++;
if (count >= 2)
}
-/*--------------------------------------------------------------.
-| Return a human readable string which reports shift/reduce and |
-| reduce/reduce conflict numbers (SRC_NUM, RRC_NUM). |
-`--------------------------------------------------------------*/
-
-static const char *
-conflict_report (int src_num, int rrc_num)
-{
- static char res[4096];
- char *cp = res;
-
- if (src_num >= 1)
- {
- sprintf (cp, ngettext ("%d shift/reduce conflict",
- "%d shift/reduce conflicts", src_num), src_num);
- cp += strlen (cp);
- }
-
- if (src_num > 0 && rrc_num > 0)
- {
- sprintf (cp, " %s ", _("and"));
- cp += strlen (cp);
- }
-
- if (rrc_num >= 1)
- {
- sprintf (cp, ngettext ("%d reduce/reduce conflict",
- "%d reduce/reduce conflicts", rrc_num), rrc_num);
- cp += strlen (cp);
- }
-
- *cp++ = '\0';
-
- return res;
-}
-
-
-/*----------------------------------------------------------------.
-| Same as above, but report the number of conflicts a` la POSIX. |
-`----------------------------------------------------------------*/
+/*--------------------------------------------------------.
+| Report the number of conflicts, using the Yacc format. |
+`--------------------------------------------------------*/
static void
-conflict_report_yacc (int src_num, int rrc_num)
+conflict_report (FILE *out, int src_num, int rrc_num)
{
- /* If invoked with `--yacc', use the output format specified by
- POSIX. */
- fprintf (stderr, _("conflicts: "));
- if (src_num > 0)
- fprintf (stderr, _(" %d shift/reduce"), src_num);
- if (src_num > 0 && rrc_num > 0)
- fprintf (stderr, ",");
- if (rrc_num > 0)
- fprintf (stderr, _(" %d reduce/reduce"), rrc_num);
- putc ('\n', stderr);
+ if (src_num && rrc_num)
+ fprintf (out, _("conflicts: %d shift/reduce, %d reduce/reduce\n"),
+ src_num, rrc_num);
+ else if (src_num)
+ fprintf (out, _("conflicts: %d shift/reduce\n"), src_num);
+ else if (rrc_num)
+ fprintf (out, _("conflicts: %d reduce/reduce\n"), rrc_num);
}
state *s = states[i];
if (conflicts[i])
{
- fprintf (out, _("State %d contains "), i);
- fprintf (out, "%s.\n",
- conflict_report (count_sr_conflicts (s),
- count_rr_conflicts (s, true)));
+ fprintf (out, _("State %d "), i);
+ conflict_report (out, count_sr_conflicts (s),
+ count_rr_conflicts (s, true));
printed_sth = true;
}
}
/*--------------------------------------------------------.
| Total the number of S/R and R/R conflicts. Unlike the |
| code in conflicts_output, however, count EACH pair of |
-| reductions for the same state and lookahead as one |
+| reductions for the same state and look-ahead as one |
| conflict. |
`--------------------------------------------------------*/
/* Is the number of SR conflicts OK? Either EXPECTED_CONFLICTS is
not set, and then we want 0 SR, or else it is specified, in which
case we want equality. */
- int src_ok = 0;
+ bool src_ok = false;
+ bool rrc_ok = false;
int src_total = 0;
int rrc_total = 0;
}
}
- src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts);
+ if (! glr_parser && rrc_total > 0 && expected_rr_conflicts != -1)
+ {
+ warn (_("%%expect-rr applies only to GLR parsers"));
+ expected_rr_conflicts = -1;
+ }
- /* If there are no RR conflicts, and as many SR conflicts as
+ src_ok =
+ src_total == (expected_sr_conflicts == -1 ? 0 : expected_sr_conflicts);
+ rrc_ok =
+ rrc_total == (expected_rr_conflicts == -1 ? 0 : expected_rr_conflicts);
+
+ /* If there are as many RR conflicts and SR conflicts as
expected, then there is nothing to report. */
- if (!rrc_total && src_ok)
+ if (rrc_ok && src_ok)
return;
/* Report the total number of conflicts on STDERR. */
- if (yacc_flag)
- conflict_report_yacc (src_total, rrc_total);
- else
- warn ("%s", conflict_report (src_total, rrc_total));
+ if (! yacc_flag)
+ fprintf (stderr, "%s: ", current_file);
+ conflict_report (stderr, src_total, rrc_total);
- if (expected_conflicts != -1 && !src_ok)
- complain (ngettext ("expected %d shift/reduce conflict",
+ if (expected_sr_conflicts != -1 || expected_rr_conflicts != -1)
+ {
+ int sr = expected_sr_conflicts == -1 ? 0 : expected_sr_conflicts;
+ int rr = expected_rr_conflicts == -1 ? 0 : expected_rr_conflicts;
+ if (! src_ok)
+ warn (ngettext ("expected %d shift/reduce conflict",
"expected %d shift/reduce conflicts",
- expected_conflicts),
- expected_conflicts);
+ sr), sr);
+ if (! rrc_ok)
+ warn (ngettext ("expected %d reduce/reduce conflict",
+ "expected %d reduce/reduce conflicts",
+ rr), rr);
+ }
}
conflicts_free (void)
{
free (conflicts);
- bitset_free (shiftset);
- bitset_free (lookaheadset);
+ bitset_free (shift_set);
+ bitset_free (look_ahead_set);
obstack_free (&solved_conflicts_obstack, NULL);
}
projects / bison.git / blobdiff