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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
Download Patch File Download Diff File Expand all files Collapse all files

26
ChangeLog
View File

@@ -1,3 +1,29 @@
2007-07-17 Joel E. Denny <jdenny@ces.clemson.edu>
Improve handling of multiple S/R conflicts in the same state and of S/R
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.
2007-07-16 Joel E. Denny <jdenny@ces.clemson.edu>
* build-aux/.cvsignore: Add compile.

45
src/conflicts.c
View File

@@ -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]);
}
}

3
src/main.c
View File

@@ -116,11 +116,12 @@ main (int argc, char *argv[])
timevar_push (TV_CONFLICTS);
conflicts_solve ();
{
state_number old_to_new[nstates];
state_number *old_to_new = xnmalloc (nstates, sizeof *old_to_new);
state_number nstates_old = nstates;
state_remove_unreachable_states (old_to_new);
lalr_update_state_numbers (old_to_new, nstates_old);
conflicts_update_state_numbers (old_to_new, nstates_old);
free (old_to_new);
}
conflicts_print ();
timevar_pop (TV_CONFLICTS);

17
src/print.c
View File

@@ -40,7 +40,7 @@
#include "symtab.h"
#include "tables.h"
static bitset shift_set;
static bitset no_reduce_set;
#if 0
static void
@@ -252,9 +252,12 @@ print_reductions (FILE *out, state *s)
if (yydefact[s->number] != 0)
default_rule = &rules[yydefact[s->number] - 1];
bitset_zero (shift_set);
bitset_zero (no_reduce_set);
FOR_EACH_SHIFT (trans, i)
bitset_set (shift_set, TRANSITION_SYMBOL (trans, i));
bitset_set (no_reduce_set, TRANSITION_SYMBOL (trans, i));
for (i = 0; i < s->errs->num; ++i)
if (s->errs->symbols[i])
bitset_set (no_reduce_set, s->errs->symbols[i]->number);
/* Compute the width of the lookahead token column. */
if (default_rule)
@@ -263,7 +266,7 @@ print_reductions (FILE *out, state *s)
if (reds->lookahead_tokens)
for (i = 0; i < ntokens; i++)
{
bool count = bitset_test (shift_set, i);
bool count = bitset_test (no_reduce_set, i);
for (j = 0; j < reds->num; ++j)
if (bitset_test (reds->lookahead_tokens[j], i))
@@ -293,7 +296,7 @@ print_reductions (FILE *out, state *s)
for (i = 0; i < ntokens; i++)
{
bool defaulted = false;
bool count = bitset_test (shift_set, i);
bool count = bitset_test (no_reduce_set, i);
for (j = 0; j < reds->num; ++j)
if (bitset_test (reds->lookahead_tokens[j], i))
@@ -498,10 +501,10 @@ print_results (void)
if (report_flag & report_itemsets)
new_closure (nritems);
/* Storage for print_reductions. */
shift_set = bitset_create (ntokens, BITSET_FIXED);
no_reduce_set = bitset_create (ntokens, BITSET_FIXED);
for (i = 0; i < nstates; i++)
print_state (out, states[i]);
bitset_free (shift_set);
bitset_free (no_reduce_set);
if (report_flag & report_itemsets)
free_closure ();

153
tests/conflicts.at
View File

@@ -90,7 +90,7 @@ expr: expr '<' expr
int
main (int argc, const char *argv[])
{
input = argc <= 1 ? "" : argv[1];
input = argc <= 1 ? "" : argv[1];
return yyparse ();
}
]])
@@ -810,8 +810,157 @@ state 6
state 7
1 start: resolved_conflict 'a' reported_conflicts 'a' .
$default reduce using rule 1 (start)
]])
AT_CLEANUP
## ------------------------------------------------------------ ##
## Solved conflicts report for multiple reductions in a state. ##
## ------------------------------------------------------------ ##
AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
# Used to lose earlier solved conflict messages even within a single S/R/R.
AT_DATA([[input.y]],
[[%left 'a'
%right 'b'
%right 'c'
%right 'd'
%%
start:
'a'
| empty_a 'a'
| 'b'
| empty_b 'b'
| 'c'
| empty_c1 'c'
| empty_c2 'c'
| empty_c3 'c'
;
empty_a: %prec 'a' ;
empty_b: %prec 'b' ;
empty_c1: %prec 'c' ;
empty_c2: %prec 'c' ;
empty_c3: %prec 'd' ;
]])
AT_CHECK([[bison --report=all -o input.c input.y]], 0, [], [ignore])
AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
[[state 0
0 $accept: . start $end
1 start: . 'a'
2 | . empty_a 'a'
3 | . 'b'
4 | . empty_b 'b'
5 | . 'c'
6 | . empty_c1 'c'
7 | . empty_c2 'c'
8 | . empty_c3 'c'
9 empty_a: . ['a']
10 empty_b: . []
11 empty_c1: . []
12 empty_c2: . []
13 empty_c3: . ['c']
'b' shift, and go to state 1
'c' reduce using rule 13 (empty_c3)
$default reduce using rule 9 (empty_a)
start go to state 2
empty_a go to state 3
empty_b go to state 4
empty_c1 go to state 5
empty_c2 go to state 6
empty_c3 go to state 7
Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
state 1
]])
AT_CLEANUP
## ------------------------------------------------------------ ##
## %nonassoc error actions for multiple reductions in a state. ##
## ------------------------------------------------------------ ##
# Used to abort when trying to resolve conflicts as %nonassoc error actions for
# multiple reductions in a state.
# For a %nonassoc error action token, used to print the first remaining
# reduction on that token without brackets.
AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
AT_DATA([[input.y]],
[[%nonassoc 'a' 'b' 'c'
%%
start:
'a'
| empty_a 'a'
| 'b'
| empty_b 'b'
| 'c'
| empty_c1 'c'
| empty_c2 'c'
| empty_c3 'c'
;
empty_a: %prec 'a' ;
empty_b: %prec 'b' ;
empty_c1: %prec 'c' ;
empty_c2: %prec 'c' ;
empty_c3: %prec 'c' ;
]])
AT_CHECK([[bison --report=all -o input.c input.y]], 0, [], [ignore])
AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
[[state 0
0 $accept: . start $end
1 start: . 'a'
2 | . empty_a 'a'
3 | . 'b'
4 | . empty_b 'b'
5 | . 'c'
6 | . empty_c1 'c'
7 | . empty_c2 'c'
8 | . empty_c3 'c'
9 empty_a: . []
10 empty_b: . []
11 empty_c1: . []
12 empty_c2: . ['c']
13 empty_c3: . ['c']
'a' error (nonassociative)
'b' error (nonassociative)
'c' error (nonassociative)
'c' [reduce using rule 12 (empty_c2)]
'c' [reduce using rule 13 (empty_c3)]
start go to state 1
empty_a go to state 2
empty_b go to state 3
empty_c1 go to state 4
empty_c2 go to state 5
empty_c3 go to state 6
Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
state 1
]])
AT_CLEANUP