/* 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
Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
02111-1307, USA. */
#include "system.h"
-#include "bitset.h"
+
+#include <bitset.h>
+
+#include "LR0.h"
#include "complain.h"
-#include "getargs.h"
-#include "symtab.h"
+#include "conflicts.h"
#include "files.h"
+#include "getargs.h"
#include "gram.h"
-#include "state.h"
#include "lalr.h"
-#include "conflicts.h"
#include "reader.h"
-#include "LR0.h"
+#include "state.h"
+#include "symtab.h"
/* -1 stands for not specified. */
int expected_conflicts = -1;
\f
-enum conflict_resolution_e
+enum conflict_resolution
{
shift_resolution,
reduce_resolution,
left_resolution,
right_resolution,
- nonassoc_resolution,
+ nonassoc_resolution
};
+/*----------------------------------------------------------------.
+| Explain how an SR conflict between TOKEN and RULE was resolved: |
+| RESOLUTION. |
+`----------------------------------------------------------------*/
+
static inline void
-log_resolution (int lookahead, int token,
- enum conflict_resolution_e resolution)
+log_resolution (rule *r, symbol_number token,
+ enum conflict_resolution resolution)
{
if (report_flag & report_solved_conflicts)
{
switch (resolution)
{
case shift_resolution:
- case left_resolution:
+ case right_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as shift"),
- LArule[lookahead]->number,
+ r->number,
symbols[token]->tag);
break;
case reduce_resolution:
- case right_resolution:
+ case left_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as reduce"),
- LArule[lookahead]->number,
+ r->number,
symbols[token]->tag);
break;
case nonassoc_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as an error"),
- LArule[lookahead]->number,
+ r->number,
symbols[token]->tag);
break;
}
case shift_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
" (%s < %s)",
- LArule[lookahead]->prec->tag,
+ r->prec->tag,
symbols[token]->tag);
break;
obstack_fgrow2 (&solved_conflicts_obstack,
" (%s < %s)",
symbols[token]->tag,
- LArule[lookahead]->prec->tag);
+ r->prec->tag);
break;
case left_resolution:
- obstack_printf (&solved_conflicts_obstack,
+ obstack_fgrow1 (&solved_conflicts_obstack,
" (%%left %s)",
symbols[token]->tag);
break;
`------------------------------------------------------------------*/
static void
-flush_shift (state_t *state, int token)
+flush_shift (state *s, int token)
{
- shifts *shiftp = state->shifts;
+ transitions *trans = s->transitions;
int i;
bitset_reset (lookaheadset, token);
- for (i = 0; i < shiftp->nshifts; i++)
- if (!SHIFT_IS_DISABLED (shiftp, i) && SHIFT_SYMBOL (shiftp, i) == token)
- SHIFT_DISABLE (shiftp, i);
+ for (i = 0; i < trans->num; i++)
+ if (!TRANSITION_IS_DISABLED (trans, i)
+ && TRANSITION_SYMBOL (trans, i) == token)
+ TRANSITION_DISABLE (trans, i);
}
`-------------------------------------------------------------------*/
static void
-flush_reduce (int lookahead, int token)
+flush_reduce (bitset lookaheads, int token)
{
- bitset_reset (LA[lookahead], token);
+ bitset_reset (lookaheads, token);
}
| precedence declarations. It has already been checked that the |
| 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. |
+| |
+| ERRORS can be used to store discovered explicit errors. |
`------------------------------------------------------------------*/
static void
-resolve_sr_conflict (state_t *state, int lookahead)
+resolve_sr_conflict (state *s, int ruleno, symbol **errors)
{
- int i;
- /* find the rule to reduce by to get precedence of reduction */
- int redprec = LArule[lookahead]->prec->prec;
- errs *errp = errs_new (ntokens + 1);
- errp->nerrs = 0;
+ symbol_number i;
+ reductions *reds = s->reductions;
+ /* 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];
+ int nerrs = 0;
for (i = 0; i < ntokens; i++)
- if (bitset_test (LA[lookahead], i)
+ if (bitset_test (lookaheads, i)
&& bitset_test (lookaheadset, i)
&& symbols[i]->prec)
{
The precedence of shifting is that of token i. */
if (symbols[i]->prec < redprec)
{
- log_resolution (lookahead, i, reduce_resolution);
- flush_shift (state, i);
+ log_resolution (redrule, i, reduce_resolution);
+ flush_shift (s, i);
}
else if (symbols[i]->prec > redprec)
{
- log_resolution (lookahead, i, shift_resolution);
- flush_reduce (lookahead, i);
+ log_resolution (redrule, i, shift_resolution);
+ flush_reduce (lookaheads, i);
}
else
/* Matching precedence levels.
switch (symbols[i]->assoc)
{
case right_assoc:
- log_resolution (lookahead, i, right_resolution);
- flush_reduce (lookahead, i);
+ log_resolution (redrule, i, right_resolution);
+ flush_reduce (lookaheads, i);
break;
case left_assoc:
- log_resolution (lookahead, i, left_resolution);
- flush_shift (state, i);
+ log_resolution (redrule, i, left_resolution);
+ flush_shift (s, i);
break;
case non_assoc:
- log_resolution (lookahead, i, nonassoc_resolution);
- flush_shift (state, i);
- flush_reduce (lookahead, i);
+ log_resolution (redrule, i, nonassoc_resolution);
+ flush_shift (s, i);
+ flush_reduce (lookaheads, i);
/* Record an explicit error for this token. */
- errp->errs[errp->nerrs++] = i;
+ errors[nerrs++] = symbols[i];
break;
+
+ case undef_assoc:
+ abort ();
}
}
- /* Some tokens have been explicitly made errors. Allocate a
- permanent errs structure for this state, to record them. */
- state->errs = errs_dup (errp);
- free (errp);
+ 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');
- state->solved_conflicts = obstack_finish (&solved_conflicts_obstack);
+ s->solved_conflicts = obstack_finish (&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). |
+`-------------------------------------------------------------------*/
+
static void
-set_conflicts (state_t *state)
+set_conflicts (state *s, symbol **errors)
{
int i;
- shifts *shiftp;
+ transitions *trans = s->transitions;
+ reductions *reds = s->reductions;
- if (state->consistent)
+ if (s->consistent)
return;
bitset_zero (lookaheadset);
- shiftp = state->shifts;
- for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
- if (!SHIFT_IS_DISABLED (shiftp, i))
- bitset_set (lookaheadset, SHIFT_SYMBOL (shiftp, i));
+ FOR_EACH_SHIFT (trans, i)
+ bitset_set (lookaheadset, TRANSITION_SYMBOL (trans, i));
/* Loop over all rules which require lookahead in this state. First
check for shift-reduce conflict, and try to resolve using
- precedence */
- for (i = 0; i < state->nlookaheads; ++i)
- if (LArule[state->lookaheadsp + i]->prec
- && LArule[state->lookaheadsp + i]->prec->prec
- && !bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset))
- {
- resolve_sr_conflict (state, state->lookaheadsp + i);
- break;
- }
+ 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);
/* Loop over all rules which require lookahead in this state. Check
for conflicts not resolved above. */
- for (i = 0; i < state->nlookaheads; ++i)
+ for (i = 0; i < reds->num; ++i)
{
- if (!bitset_disjoint_p (LA[state->lookaheadsp + i], lookaheadset))
- conflicts[state->number] = 1;
+ if (!bitset_disjoint_p (reds->lookaheads[i], lookaheadset))
+ conflicts[s->number] = 1;
- bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
+ bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
}
}
+
+/*----------------------------------------------------------------.
+| Solve all the S/R conflicts using the precedence/associativity, |
+| and flag as inconsistent the states that still have conflicts. |
+`----------------------------------------------------------------*/
+
void
conflicts_solve (void)
{
- size_t i;
+ state_number i;
+ /* List of lookaheads on which we explicitly raise a syntax error. */
+ symbol **errors = MALLOC (errors, ntokens + 1);
- conflicts = XCALLOC (char, nstates);
+ CALLOC (conflicts, nstates);
shiftset = bitset_create (ntokens, BITSET_FIXED);
lookaheadset = bitset_create (ntokens, BITSET_FIXED);
obstack_init (&solved_conflicts_obstack);
for (i = 0; i < nstates; i++)
- set_conflicts (states[i]);
+ {
+ set_conflicts (states[i], errors);
+
+ /* For uniformity of the code, make sure all the states have a valid
+ `errs' member. */
+ if (!states[i]->errs)
+ states[i]->errs = errs_new (0, 0);
+ }
+
+ free (errors);
}
`---------------------------------------------*/
static int
-count_sr_conflicts (state_t *state)
+count_sr_conflicts (state *s)
{
int i;
int src_count = 0;
- shifts *shiftp = state->shifts;
+ transitions *trans = s->transitions;
+ reductions *reds = s->reductions;
- if (!shiftp)
+ if (!trans)
return 0;
bitset_zero (lookaheadset);
bitset_zero (shiftset);
- for (i = 0; i < shiftp->nshifts && SHIFT_IS_SHIFT (shiftp, i); i++)
- if (!SHIFT_IS_DISABLED (shiftp, i))
- bitset_set (shiftset, SHIFT_SYMBOL (shiftp, i));
+ FOR_EACH_SHIFT (trans, i)
+ bitset_set (shiftset, TRANSITION_SYMBOL (trans, i));
- for (i = 0; i < state->nlookaheads; ++i)
- bitset_or (lookaheadset, lookaheadset, LA[state->lookaheadsp + i]);
+ for (i = 0; i < reds->num; ++i)
+ bitset_or (lookaheadset, lookaheadset, reds->lookaheads[i]);
bitset_and (lookaheadset, lookaheadset, shiftset);
}
-/*----------------------------------------------.
-| Count the number of reduce/reduce conflicts. |
-`----------------------------------------------*/
+/*----------------------------------------------------------------.
+| Count the number of reduce/reduce conflicts. If ONE_PER_TOKEN, |
+| count one conflict for each token that has any reduce/reduce |
+| conflicts. Otherwise, count one conflict for each pair of |
+| conflicting reductions. |
++`----------------------------------------------------------------*/
static int
-count_rr_conflicts (state_t *state)
+count_rr_conflicts (state *s, bool one_per_token)
{
int i;
+ reductions *reds = s->reductions;
int rrc_count = 0;
- if (state->nlookaheads < 2)
- return 0;
-
for (i = 0; i < ntokens; i++)
{
int count = 0;
int j;
- for (j = 0; j < state->nlookaheads; ++j)
- if (bitset_test (LA[state->lookaheadsp + j], i))
+ for (j = 0; j < reds->num; ++j)
+ if (bitset_test (reds->lookaheads[j], i))
count++;
if (count >= 2)
- rrc_count++;
+ rrc_count += one_per_token ? 1 : count-1;
}
return rrc_count;
}
-/*--------------------------------------------------------------.
-| 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;
+/*--------------------------------------------------------.
+| Report the number of conflicts, using the Yacc format. |
+`--------------------------------------------------------*/
- 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++ = '.';
- *cp++ = '\n';
- *cp++ = '\0';
-
- return res;
+static void
+conflict_report (FILE *out, int src_num, int rrc_num)
+{
+ 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);
}
void
conflicts_output (FILE *out)
{
- bool printed_sth = FALSE;
- size_t i;
+ bool printed_sth = false;
+ state_number i;
+ for (i = 0; i < nstates; i++)
+ {
+ state *s = states[i];
+ if (conflicts[i])
+ {
+ fprintf (out, _("State %d "), i);
+ conflict_report (out, count_sr_conflicts (s),
+ count_rr_conflicts (s, true));
+ printed_sth = true;
+ }
+ }
+ if (printed_sth)
+ fputs ("\n\n", out);
+}
+
+/*--------------------------------------------------------.
+| 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 |
+| conflict. |
+`--------------------------------------------------------*/
+
+int
+conflicts_total_count (void)
+{
+ state_number i;
+ int count;
+
+ /* Conflicts by state. */
+ count = 0;
for (i = 0; i < nstates; i++)
if (conflicts[i])
{
- fprintf (out, _("State %d contains "), i);
- fputs (conflict_report (count_sr_conflicts (states[i]),
- count_rr_conflicts (states[i])), out);
- printed_sth = TRUE;
+ count += count_sr_conflicts (states[i]);
+ count += count_rr_conflicts (states[i], false);
}
- if (printed_sth)
- fputs ("\n\n", out);
+ return count;
}
void
conflicts_print (void)
{
- size_t i;
-
/* 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;
int src_total = 0;
int rrc_total = 0;
/* Conflicts by state. */
- for (i = 0; i < nstates; i++)
- if (conflicts[i])
- {
- src_total += count_sr_conflicts (states[i]);
- rrc_total += count_rr_conflicts (states[i]);
- }
+ {
+ state_number i;
+
+ for (i = 0; i < nstates; i++)
+ if (conflicts[i])
+ {
+ src_total += count_sr_conflicts (states[i]);
+ rrc_total += count_rr_conflicts (states[i], true);
+ }
+ }
src_ok = src_total == (expected_conflicts == -1 ? 0 : expected_conflicts);
return;
/* Report the total number of conflicts on STDERR. */
- if (yacc_flag)
- {
- /* If invoked with `--yacc', use the output format specified by
- POSIX. */
- fprintf (stderr, _("conflicts: "));
- if (src_total > 0)
- fprintf (stderr, _(" %d shift/reduce"), src_total);
- if (src_total > 0 && rrc_total > 0)
- fprintf (stderr, ",");
- if (rrc_total > 0)
- fprintf (stderr, _(" %d reduce/reduce"), rrc_total);
- putc ('\n', stderr);
- }
- else
- {
- fprintf (stderr, _("%s contains "), infile);
- fputs (conflict_report (src_total, rrc_total), stderr);
- }
+ if (! yacc_flag)
+ fprintf (stderr, "%s: ", current_file);
+ conflict_report (stderr, src_total, rrc_total);
- if (expected_conflicts != -1 && !src_ok)
+ if (expected_conflicts != -1)
{
- complain_message_count++;
- fprintf (stderr, ngettext ("expected %d shift/reduce conflict\n",
- "expected %d shift/reduce conflicts\n",
- expected_conflicts),
- expected_conflicts);
+ if (! src_ok)
+ warn (ngettext ("expected %d shift/reduce conflict",
+ "expected %d shift/reduce conflicts",
+ expected_conflicts),
+ expected_conflicts);
+ if (rrc_total)
+ warn (_("expected 0 reduce/reduce conflicts"));
}
}
projects / bison.git / blobdiff