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%expect-rr: fix the computation of the overall number of conflicts

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On a grammar such as

   exp: "num" | "num" | "num"

we currently report only one RR conflict, instead of two.

This bug is present since the origins of Bison

    commit 08089d5d35
    Author: David MacKenzie <djm@djmnet.org>
    Date:   Tue Apr 20 05:42:52 1993 +0000

       Initial revision

and was preserved in

    commit 676385e29c
    Author: Paul Hilfinger <Hilfinger@CS.Berkeley.EDU>
    Date:   Fri Jun 28 02:26:44 2002 +0000

       Initial check-in introducing experimental GLR parsing.  See entry in
       ChangeLog dated 2002-06-27 from Paul Hilfinger for details.

See
https://lists.gnu.org/archive/html/bison-patches/2018-11/msg00011.html

* src/conflicts.h, src/conflicts.c (count_state_rr_conflicts)
(count_rr_conflicts): Use only the correct count of conflicts.
* tests/glr-regression.at: Fix expectations.
This commit is contained in:
Akim Demaille
2018-11-08 21:46:16 +01:00
parent 260ae5481c
commit ad0b4661d1
4 changed files with 33 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/conflicts.c
View File

@@ -467,15 +467,13 @@ count_sr_conflicts (void)
/*----------------------------------------------------------------.
| 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 reduction |
| after the first for a given token. |
`----------------------------------------------------------------*/
/*-----------------------------------------------------------------.
| Count the number of reduce/reduce conflicts. Count one conflict |
| for each reduction after the first for a given token. |
`-----------------------------------------------------------------*/
static size_t
count_state_rr_conflicts (state *s, bool one_per_token)
count_state_rr_conflicts (state *s)
{
reductions *reds = s->reductions;
size_t res = 0;
@@ -486,20 +484,20 @@ count_state_rr_conflicts (state *s, bool one_per_token)
for (int j = 0; j < reds->num; ++j)
count += bitset_test (reds->lookahead_tokens[j], i);
if (count >= 2)
res += one_per_token ? 1 : count-1;
res += count-1;
}
return res;
}
static size_t
count_rr_conflicts (bool one_per_token)
count_rr_conflicts (void)
{
size_t res = 0;
/* Conflicts by state. */
for (state_number i = 0; i < nstates; ++i)
if (conflicts[i])
res += count_state_rr_conflicts (states[i], one_per_token);
res += count_state_rr_conflicts (states[i]);
return res;
}
@@ -591,7 +589,7 @@ conflicts_output (FILE *out)
if (conflicts[i])
{
int src = count_state_sr_conflicts (s);
int rrc = count_state_rr_conflicts (s, true);
int rrc = count_state_rr_conflicts (s);
fprintf (out, _("State %d "), i);
if (src && rrc)
fprintf (out,
@@ -608,17 +606,14 @@ conflicts_output (FILE *out)
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. |
`--------------------------------------------------------*/
/*--------------------------------------------.
| Total the number of S/R and R/R conflicts. |
`--------------------------------------------*/
int
conflicts_total_count (void)
{
return count_sr_conflicts () + count_rr_conflicts (false);
return count_sr_conflicts () + count_rr_conflicts ();
}
/*------------------------------.
@@ -692,7 +687,7 @@ conflicts_print (void)
}
{
int total = count_rr_conflicts (true);
int total = count_rr_conflicts ();
/* If %expect-rr is not used, but %expect is, then expect 0 rr. */
int expected =
(expected_rr_conflicts == -1 && expected_sr_conflicts != -1)

1
src/conflicts.h
View File

@@ -44,4 +44,5 @@ void conflicts_free (void);
/* Were there conflicts? */
extern int expected_sr_conflicts;
extern int expected_rr_conflicts;
#endif /* !CONFLICTS_H_ */