# Exercising Bison on conflicts. -*- Autotest -*-
-# Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2002-2005, 2007-2010 Free Software Foundation, Inc.
-# This program is free software; you can redistribute it and/or modify
+# 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
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
-
+#
# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-# 02110-1301, USA.
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
AT_BANNER([[Conflicts.]])
e: 'e' | /* Nothing. */;
]])
-AT_CHECK([bison -o input.c input.y], 0, [],
-[[input.y:4.9: warning: rule never reduced because of conflicts: e: /* empty */
+AT_BISON_CHECK([-o input.c input.y], 0, [],
+[[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
]])
AT_CLEANUP
int
main (int argc, const char *argv[])
{
- input = argc <= 1 ? "" : argv[1];
+ input = argc <= 1 ? "" : argv[1];
return yyparse ();
}
]])
# Specify the output files to avoid problems on different file systems.
-AT_CHECK([bison -o input.c input.y])
+AT_BISON_CHECK([-o input.c input.y])
AT_COMPILE([input])
AT_PARSER_CHECK([./input '0<0'])
-# FIXME: This is an actual bug, but a new one, in the sense that
-# no one has ever spotted it! The messages are *wrong*: there should
-# be nothing there, it should be expected eof.
AT_PARSER_CHECK([./input '0<0<0'], [1], [],
- [syntax error, unexpected '<', expecting '<' or '>'
+ [syntax error, unexpected '<'
])
AT_PARSER_CHECK([./input '0>0'])
AT_PARSER_CHECK([./input '0>0>0'], [1], [],
- [syntax error, unexpected '>', expecting '<' or '>'
+ [syntax error, unexpected '>'
])
AT_PARSER_CHECK([./input '0<0>0'], [1], [],
- [syntax error, unexpected '>', expecting '<' or '>'
+ [syntax error, unexpected '>'
+])
+
+# We must disable default reductions in inconsistent states in order to
+# have an explicit list of all expected tokens. (However, unless we use
+# canonical LR, lookahead sets are merged for different left contexts,
+# so it is still possible to have extra incorrect tokens in the expected
+# list. That just doesn't happen to be a problem for this test case.)
+
+AT_BISON_CHECK([-Dlr.default-reductions=consistent -o input.c input.y])
+AT_COMPILE([input])
+
+AT_PARSER_CHECK([./input '0<0'])
+AT_PARSER_CHECK([./input '0<0<0'], [1], [],
+ [syntax error, unexpected '<', expecting $end
+])
+
+AT_PARSER_CHECK([./input '0>0'])
+AT_PARSER_CHECK([./input '0>0>0'], [1], [],
+ [syntax error, unexpected '>', expecting $end
+])
+
+AT_PARSER_CHECK([./input '0<0>0'], [1], [],
+ [syntax error, unexpected '>', expecting $end
+])
+
+AT_CLEANUP
+
+
+
+## ------------------------------------------- ##
+## parse.error=verbose and consistent errors. ##
+## ------------------------------------------- ##
+
+AT_SETUP([[parse.error=verbose and consistent errors]])
+
+m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
+
+AT_BISON_CHECK([$1[ -o input.c input.y]])
+AT_COMPILE([[input]])
+
+m4_pushdef([AT_EXPECTING], [m4_if($3, [ab], [[, expecting 'a' or 'b']],
+ $3, [a], [[, expecting 'a']],
+ $3, [b], [[, expecting 'b']])])
+
+AT_PARSER_CHECK([[./input]], [[1]], [],
+[[syntax error, unexpected ]$2[]AT_EXPECTING[
+]])
+
+m4_popdef([AT_EXPECTING])
+
])
+AT_DATA_GRAMMAR([input.y],
+[[%code {
+ #include <assert.h>
+ #include <stdio.h>
+ int yylex (void);
+ void yyerror (char const *);
+ #define USE(Var)
+}
+
+%define parse.error verbose
+
+// The point isn't to test IELR here, but state merging happens to
+// complicate the example.
+%define lr.type ielr
+
+%nonassoc 'a'
+
+// If yylval=0 here, then we know that the 'a' destructor is being
+// invoked incorrectly for the 'b' set in the semantic action below.
+// All 'a' tokens are returned by yylex, which sets yylval=1.
+%destructor {
+ if (!$$)
+ fprintf (stderr, "Wrong destructor.\n");
+} 'a'
+
+%%
+
+// The lookahead assigned by the semantic action isn't needed before
+// either error action is encountered. In a previous version of Bison,
+// this was a problem as it meant yychar was not translated into yytoken
+// before either error action. The second error action thus invoked a
+// destructor that it selected according to the incorrect yytoken. The
+// first error action would have reported an incorrect unexpected token
+// except that, due to another bug, the unexpected token is not reported
+// at all because the error action is the default action in a consistent
+// state. That bug still needs to be fixed.
+start: error-reduce consistent-error 'a' { USE ($3); } ;
+
+error-reduce:
+ 'a' 'a' consistent-reduction consistent-error 'a'
+ { USE (($1, $2, $5)); }
+| 'a' error
+ { USE ($1); }
+;
+
+consistent-reduction: /*empty*/ {
+ assert (yychar == YYEMPTY);
+ yylval = 0;
+ yychar = 'b';
+} ;
+
+consistent-error:
+ 'a' { USE ($1); }
+| /*empty*/ %prec 'a'
+;
+
+// Provide another context in which all rules are useful so that this
+// test case looks a little more realistic.
+start: 'b' consistent-error 'b' ;
+
+%%
+
+int
+yylex (void)
+{
+ static char const *input = "aa";
+ yylval = 1;
+ return *input++;
+}
+
+void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+
+# See comments in grammar for why this test doesn't succeed.
+AT_XFAIL_IF([[:]])
+
+AT_CONSISTENT_ERRORS_CHECK([], [['b']], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=consistent]],
+ [['b']], [[none]])
+
+# Canonical LR doesn't foresee the error for 'a'!
+AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=accepting]],
+ [[$end]], [[a]])
+AT_CONSISTENT_ERRORS_CHECK([[-Flr.type=canonical-lr]], [[$end]], [[a]])
+
+m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
+
AT_CLEANUP
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c --report=all input.y], 0, [],
+AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
[input.y: conflicts: 1 shift/reduce
])
state 5
- 1 exp: exp . OP exp [$end, OP]
+ 1 exp: exp . OP exp
1 | exp OP exp . [$end, OP]
OP shift, and go to state 4
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c --report=all input.y])
+AT_BISON_CHECK([-o input.c --report=all input.y])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
state 5
- 1 exp: exp . OP exp [$end, OP]
+ 1 exp: exp . OP exp
1 | exp OP exp . [$end, OP]
$default reduce using rule 1 (exp)
AT_CLEANUP
+## ---------------------- ##
+## %precedence suffices. ##
+## ---------------------- ##
+
+AT_SETUP([%precedence suffices])
+
+AT_DATA([input.y],
+[[%precedence "then"
+%precedence "else"
+%%
+stmt:
+ "if" cond "then" stmt
+| "if" cond "then" stmt "else" stmt
+| "stmt"
+;
+
+cond:
+ "exp"
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+
+AT_CLEANUP
+
+
+## ------------------------------ ##
+## %precedence does not suffice. ##
+## ------------------------------ ##
+
+AT_SETUP([%precedence does not suffice])
+
+AT_DATA([input.y],
+[[%precedence "then"
+%precedence "else"
+%%
+stmt:
+ "if" cond "then" stmt
+| "if" cond "then" stmt "else" stmt
+| "stmt"
+;
+
+cond:
+ "exp"
+| cond "then" cond
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y], 0, [],
+[[input.y: conflicts: 1 shift/reduce
+input.y:12.3-18: warning: rule useless in parser due to conflicts: cond: cond "then" cond
+]])
+
+AT_CLEANUP
+
+
## -------------------------------- ##
## Defaulted Conflicted Reduction. ##
## -------------------------------- ##
%%
]])
-AT_CHECK([bison -o input.c --report=all input.y], 0, [],
+AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
[[input.y: conflicts: 1 reduce/reduce
-input.y:4.6-8: warning: rule never reduced because of conflicts: id: '0'
+input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
]])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
-[[Rules never reduced
+[[Rules useless in parser due to conflicts
4 id: '0'
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c input.y], 1, [],
+AT_BISON_CHECK([-o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
input.y: expected 0 shift/reduce conflicts
])
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c input.y])
+AT_BISON_CHECK([-o input.c input.y])
AT_CLEANUP
exp: exp OP exp | NUM;
]])
-AT_CHECK([bison -o input.c input.y], 1, [],
+AT_BISON_CHECK([-o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
input.y: expected 2 shift/reduce conflicts
])
AT_CLEANUP
-## ------------------------------ ##
-## %expect with reduce conflicts ##
-## ------------------------------ ##
+## ------------------------------- ##
+## %expect with reduce conflicts. ##
+## ------------------------------- ##
AT_SETUP([%expect with reduce conflicts])
a: 'a';
]])
-AT_CHECK([bison -o input.c input.y], 1, [],
+AT_BISON_CHECK([-o input.c input.y], 1, [],
[input.y: conflicts: 1 reduce/reduce
input.y: expected 0 reduce/reduce conflicts
])
AT_CLEANUP
-## ------------------------------- ##
-## %no-default-prec without %prec ##
-## ------------------------------- ##
+## ------------------------- ##
+## %prec with user strings. ##
+## ------------------------- ##
+
+AT_SETUP([%prec with user string])
+
+AT_DATA([[input.y]],
+[[%%
+exp:
+ "foo" %prec "foo"
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+AT_CLEANUP
+
+
+## -------------------------------- ##
+## %no-default-prec without %prec. ##
+## -------------------------------- ##
AT_SETUP([%no-default-prec without %prec])
;
]])
-AT_CHECK([bison -o input.c input.y], 0, [],
+AT_BISON_CHECK([-o input.c input.y], 0, [],
[[input.y: conflicts: 4 shift/reduce
]])
AT_CLEANUP
-## ---------------------------- ##
-## %no-default-prec with %prec ##
-## ---------------------------- ##
+## ----------------------------- ##
+## %no-default-prec with %prec. ##
+## ----------------------------- ##
AT_SETUP([%no-default-prec with %prec])
;
]])
-AT_CHECK([bison -o input.c input.y])
+AT_BISON_CHECK([-o input.c input.y])
AT_CLEANUP
-## ---------------- ##
-## %default-prec ##
-## ---------------- ##
+## --------------- ##
+## %default-prec. ##
+## --------------- ##
AT_SETUP([%default-prec])
;
]])
-AT_CHECK([bison -o input.c input.y])
+AT_BISON_CHECK([-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 reduce, 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_BISON_CHECK([[--report=all input.y]], 0, [],
+[[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
+input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
+input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
+input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
+input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
+input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
+]])
+
+AT_CHECK([[cat input.output]], 0,
+[[Rules useless in parser due to conflicts
+
+ 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' .
+
+ $default reduce using rule 1 (start)
+]])
+
+AT_DATA([[input-keep.y]],
+[[%define lr.keep-unreachable-states
+]])
+AT_CHECK([[cat input.y >> input-keep.y]])
+
+AT_BISON_CHECK([[input-keep.y]], 0, [],
+[[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
+input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
+input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
+input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------ ##
+## Solved conflicts report for multiple reductions in a state. ##
+## ------------------------------------------------------------ ##
+
+AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
+
+# Used to lose earlier solved conflict messages even within a single S/R/R.
+
+AT_DATA([[input.y]],
+[[%left 'a'
+%right 'b'
+%right 'c'
+%right 'd'
+%%
+start:
+ 'a'
+ | empty_a 'a'
+ | 'b'
+ | empty_b 'b'
+ | 'c'
+ | empty_c1 'c'
+ | empty_c2 'c'
+ | empty_c3 'c'
+ ;
+empty_a: %prec 'a' ;
+empty_b: %prec 'b' ;
+empty_c1: %prec 'c' ;
+empty_c2: %prec 'c' ;
+empty_c3: %prec 'd' ;
+]])
+AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
+AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^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)
+ $default reduce using rule 9 (empty_a)
+
+ start go to state 2
+ empty_a go to state 3
+ empty_b go to state 4
+ empty_c1 go to state 5
+ empty_c2 go to state 6
+ empty_c3 go to state 7
+
+ Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
+ Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
+ Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
+ Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
+ Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
+
+
+state 1
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------ ##
+## %nonassoc error actions for multiple reductions in a state. ##
+## ------------------------------------------------------------ ##
+
+# Used to abort when trying to resolve conflicts as %nonassoc error actions for
+# multiple reductions in a state.
+
+# For a %nonassoc error action token, used to print the first remaining
+# reduction on that token without brackets.
+
+AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
+
+AT_DATA([[input.y]],
+[[%nonassoc 'a' 'b' 'c'
+%%
+start:
+ 'a'
+ | empty_a 'a'
+ | 'b'
+ | empty_b 'b'
+ | 'c'
+ | empty_c1 'c'
+ | empty_c2 'c'
+ | empty_c3 'c'
+ ;
+empty_a: %prec 'a' ;
+empty_b: %prec 'b' ;
+empty_c1: %prec 'c' ;
+empty_c2: %prec 'c' ;
+empty_c3: %prec 'c' ;
+]])
+
+AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
+AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^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
projects / bison.git / blobdiff