# Exercising Bison on conflicts. -*- Autotest -*-
-# Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
%{
#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
#define YYERROR_VERBOSE 1
static void
}
/* The current argument. */
-static const char *input = NULL;
+static const char *input;
static int
yylex (void)
{
- /* No token stands for end of file. */
- if (input && *input)
- return *input++;
- else
- return 0;
+ static size_t toknum;
+ if (! (toknum <= strlen (input)))
+ abort ();
+ return input[toknum++];
}
%}
int
main (int argc, const char *argv[])
{
- if (argc > 1)
- input = argv[1];
+ input = argc <= 1 ? "" : argv[1];
return yyparse ();
}
]])
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c input.y], 0, [],
+AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
-input.y: warning: expected 0 shift/reduce conflicts
+input.y: expected 0 shift/reduce conflicts
])
AT_CLEANUP
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c input.y], 0, [],
+AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
-input.y: warning: expected 2 shift/reduce conflicts
+input.y: expected 2 shift/reduce conflicts
])
AT_CLEANUP
a: 'a';
]])
-AT_CHECK([bison -o input.c input.y], 0, [],
+AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 reduce/reduce
-input.y: warning: expected 0 reduce/reduce conflicts
+input.y: expected 0 reduce/reduce conflicts
])
AT_CLEANUP
AT_CHECK([bison -o input.c input.y])
AT_CLEANUP
+
+
+## ---------------------------------------------- ##
+## Unreachable States After Conflict Resolution. ##
+## ---------------------------------------------- ##
+
+AT_SETUP([[Unreachable States After Conflict Resolution]])
+
+# If conflict resolution makes states unreachable, remove those states, report
+# rules that are then unused, and don't report conflicts in those states. Test
+# what happens when a nonterminal becomes useless as a result of state removal
+# since that causes lalr.o's goto map to be rewritten.
+
+AT_DATA([[input.y]],
+[[%output "input.c"
+%left 'a'
+
+%%
+
+start: resolved_conflict 'a' reported_conflicts 'a' ;
+
+/* S/R conflict resolved as shift, so the state with item
+ * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
+ * unreachable, and the associated production is useless. */
+resolved_conflict:
+ 'a' unreachable1
+ | %prec 'a'
+ ;
+
+/* S/R conflict that need not be reported since it is unreachable because of
+ * the previous conflict resolution. Nonterminal unreachable1 and all its
+ * productions are useless. */
+unreachable1:
+ 'a' unreachable2
+ |
+ ;
+
+/* Likewise for a R/R conflict and nonterminal unreachable2. */
+unreachable2: | ;
+
+/* Make sure remaining S/R and R/R conflicts are still reported correctly even
+ * when their states are renumbered due to state removal. */
+reported_conflicts:
+ 'a'
+ | 'a'
+ |
+ ;
+
+]])
+
+AT_CHECK([[bison --report=all input.y]], 0, [],
+[[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
+input.y:12.5-20: warning: rule never reduced because of conflicts: resolved_conflict: 'a' unreachable1
+input.y:20.5-20: warning: rule never reduced because of conflicts: unreachable1: 'a' unreachable2
+input.y:21.4: warning: rule never reduced because of conflicts: unreachable1: /* empty */
+input.y:25.13: warning: rule never reduced because of conflicts: unreachable2: /* empty */
+input.y:25.16: warning: rule never reduced because of conflicts: unreachable2: /* empty */
+input.y:31.5-7: warning: rule never reduced because of conflicts: reported_conflicts: 'a'
+input.y:32.4: warning: rule never reduced because of conflicts: reported_conflicts: /* empty */
+]])
+
+AT_CHECK([[cat input.output]], 0,
+[[Rules never reduced
+
+ 2 resolved_conflict: 'a' unreachable1
+
+ 4 unreachable1: 'a' unreachable2
+ 5 | /* empty */
+
+ 6 unreachable2: /* empty */
+ 7 | /* empty */
+
+ 9 reported_conflicts: 'a'
+ 10 | /* empty */
+
+
+State 4 conflicts: 1 shift/reduce
+State 5 conflicts: 1 reduce/reduce
+
+
+Grammar
+
+ 0 $accept: start $end
+
+ 1 start: resolved_conflict 'a' reported_conflicts 'a'
+
+ 2 resolved_conflict: 'a' unreachable1
+ 3 | /* empty */
+
+ 4 unreachable1: 'a' unreachable2
+ 5 | /* empty */
+
+ 6 unreachable2: /* empty */
+ 7 | /* empty */
+
+ 8 reported_conflicts: 'a'
+ 9 | 'a'
+ 10 | /* empty */
+
+
+Terminals, with rules where they appear
+
+$end (0) 0
+'a' (97) 1 2 4 8 9
+error (256)
+
+
+Nonterminals, with rules where they appear
+
+$accept (4)
+ on left: 0
+start (5)
+ on left: 1, on right: 0
+resolved_conflict (6)
+ on left: 2 3, on right: 1
+unreachable1 (7)
+ on left: 4 5, on right: 2
+unreachable2 (8)
+ on left: 6 7, on right: 4
+reported_conflicts (9)
+ on left: 8 9 10, on right: 1
+
+
+state 0
+
+ 0 $accept: . start $end
+ 1 start: . resolved_conflict 'a' reported_conflicts 'a'
+ 2 resolved_conflict: . 'a' unreachable1
+ 3 | . ['a']
+
+ $default reduce using rule 3 (resolved_conflict)
+
+ start go to state 1
+ resolved_conflict go to state 2
+
+ Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
+
+
+state 1
+
+ 0 $accept: start . $end
+
+ $end shift, and go to state 3
+
+
+state 2
+
+ 1 start: resolved_conflict . 'a' reported_conflicts 'a'
+
+ 'a' shift, and go to state 4
+
+
+state 3
+
+ 0 $accept: start $end .
+
+ $default accept
+
+
+state 4
+
+ 1 start: resolved_conflict 'a' . reported_conflicts 'a'
+ 8 reported_conflicts: . 'a'
+ 9 | . 'a'
+ 10 | . ['a']
+
+ 'a' shift, and go to state 5
+
+ 'a' [reduce using rule 10 (reported_conflicts)]
+
+ reported_conflicts go to state 6
+
+
+state 5
+
+ 8 reported_conflicts: 'a' . ['a']
+ 9 | 'a' . ['a']
+
+ 'a' reduce using rule 8 (reported_conflicts)
+ 'a' [reduce using rule 9 (reported_conflicts)]
+ $default reduce using rule 8 (reported_conflicts)
+
+
+state 6
+
+ 1 start: resolved_conflict 'a' reported_conflicts . 'a'
+
+ 'a' shift, and go to state 7
+
+
+state 7
+
+ 1 start: resolved_conflict 'a' reported_conflicts 'a' .
+
+ $default reduce using rule 1 (start)
+]])
+
+AT_CLEANUP
projects / bison.git / blobdiff