-/* Find and resolve or report look-ahead conflicts for bison,
+/* Find and resolve or report lookahead conflicts for bison,
- Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005
+ Copyright (C) 1984, 1989, 1992, 2000, 2001, 2002, 2003, 2004, 2005, 2006
Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
+#include <config.h>
#include "system.h"
#include <bitset.h>
int expected_sr_conflicts = -1;
int expected_rr_conflicts = -1;
static char *conflicts;
-struct obstack solved_conflicts_obstack;
+static struct obstack solved_conflicts_obstack;
static bitset shift_set;
-static bitset look_ahead_set;
+static bitset lookahead_set;
\f
transitions *trans = s->transitions;
int i;
- bitset_reset (look_ahead_set, token);
+ bitset_reset (lookahead_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 look-ahead. Used when we resolve a shift-reduce conflict |
+| specified lookahead. Used when we resolve a shift-reduce conflict |
| in favor of the shift. |
`--------------------------------------------------------------------*/
static void
-flush_reduce (bitset look_ahead_tokens, int token)
+flush_reduce (bitset lookahead_tokens, int token)
{
- bitset_reset (look_ahead_tokens, token);
+ bitset_reset (lookahead_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. |
| |
-| RULENO is the number of the look-ahead bitset to consider. |
+| RULENO is the number of the lookahead 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 look_ahead_tokens = reds->look_ahead_tokens[ruleno];
+ bitset lookahead_tokens = reds->lookahead_tokens[ruleno];
int nerrs = 0;
for (i = 0; i < ntokens; i++)
- if (bitset_test (look_ahead_tokens, i)
- && bitset_test (look_ahead_set, i)
+ if (bitset_test (lookahead_tokens, i)
+ && bitset_test (lookahead_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 (look_ahead_tokens, i);
+ flush_reduce (lookahead_tokens, i);
}
else
/* Matching precedence levels.
switch (symbols[i]->assoc)
{
+ default:
+ abort ();
+
case right_assoc:
log_resolution (redrule, i, right_resolution);
- flush_reduce (look_ahead_tokens, i);
+ flush_reduce (lookahead_tokens, i);
break;
case left_assoc:
case non_assoc:
log_resolution (redrule, i, nonassoc_resolution);
flush_shift (s, i);
- flush_reduce (look_ahead_tokens, i);
+ flush_reduce (lookahead_tokens, i);
/* Record an explicit error for this token. */
errors[nerrs++] = symbols[i];
break;
-
- case undef_assoc:
- abort ();
}
}
| 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 |
-| look-ahead tokens on which S raises a syntax error (%nonassoc). |
+| lookahead tokens on which S raises a syntax error (%nonassoc). |
`-------------------------------------------------------------------*/
static void
if (s->consistent)
return;
- bitset_zero (look_ahead_set);
+ bitset_zero (lookahead_set);
FOR_EACH_SHIFT (trans, i)
- bitset_set (look_ahead_set, TRANSITION_SYMBOL (trans, i));
+ bitset_set (lookahead_set, TRANSITION_SYMBOL (trans, i));
- /* Loop over all rules which require look-ahead in this state. First
+ /* 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 < reds->num; ++i)
if (reds->rules[i]->prec && reds->rules[i]->prec->prec
- && !bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set))
+ && !bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
resolve_sr_conflict (s, i, errors);
- /* Loop over all rules which require look-ahead in this state. Check
+ /* Loop over all rules which require lookahead in this state. Check
for conflicts not resolved above. */
for (i = 0; i < reds->num; ++i)
{
- if (!bitset_disjoint_p (reds->look_ahead_tokens[i], look_ahead_set))
+ if (!bitset_disjoint_p (reds->lookahead_tokens[i], lookahead_set))
conflicts[s->number] = 1;
- bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]);
+ bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]);
}
}
conflicts_solve (void)
{
state_number i;
- /* List of look-ahead tokens on which we explicitly raise a syntax error. */
+ /* List of lookahead tokens on which we explicitly raise a syntax error. */
symbol **errors = xnmalloc (ntokens + 1, sizeof *errors);
conflicts = xcalloc (nstates, sizeof *conflicts);
shift_set = bitset_create (ntokens, BITSET_FIXED);
- look_ahead_set = bitset_create (ntokens, BITSET_FIXED);
+ lookahead_set = bitset_create (ntokens, BITSET_FIXED);
obstack_init (&solved_conflicts_obstack);
for (i = 0; i < nstates; i++)
if (!trans)
return 0;
- bitset_zero (look_ahead_set);
+ bitset_zero (lookahead_set);
bitset_zero (shift_set);
FOR_EACH_SHIFT (trans, i)
bitset_set (shift_set, TRANSITION_SYMBOL (trans, i));
for (i = 0; i < reds->num; ++i)
- bitset_or (look_ahead_set, look_ahead_set, reds->look_ahead_tokens[i]);
+ bitset_or (lookahead_set, lookahead_set, reds->lookahead_tokens[i]);
- bitset_and (look_ahead_set, look_ahead_set, shift_set);
+ bitset_and (lookahead_set, lookahead_set, shift_set);
- src_count = bitset_count (look_ahead_set);
+ src_count = bitset_count (lookahead_set);
return src_count;
}
int count = 0;
int j;
for (j = 0; j < reds->num; ++j)
- if (bitset_test (reds->look_ahead_tokens[j], i))
+ if (bitset_test (reds->lookahead_tokens[j], i))
count++;
if (count >= 2)
/*--------------------------------------------------------.
| 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 look-ahead as one |
+| reductions for the same state and lookahead as one |
| conflict. |
`--------------------------------------------------------*/
{
free (conflicts);
bitset_free (shift_set);
- bitset_free (look_ahead_set);
+ bitset_free (lookahead_set);
obstack_free (&solved_conflicts_obstack, NULL);
}
projects / bison.git / blobdiff