Reported by Uxio Prego.
https://lists.gnu.org/archive/html/help-bison/2018-11/msg00031.html
We also need to move the unreachable 'goto' to a reachable place,
otherwise clang complains about the code being unreachable anyway.
See also https://bugs.llvm.org/show_bug.cgi?id=39736.
Interestingly, we don't have to apply that trick to
`#define YYCDEBUG if (false) std::cerr`, clang does not warn when the
code comes from macro expansion.
* configure.ac: Use -Wunreachable-code when supported.
* data/lalr1.cc, data/yacc.c: Pacify clang's warning about `if (0)`
by using a macro.
Another possibility was to move this statement to a reachable place.
* tests/actions.at, tests/c++.at: Avoid generating unreachable code.
We should probably introduce some struct and functions to deal with
stack management, rather than open coding it. yyparse would be much
nicer to read, and a better model for possible other skeletons.
* data/yacc.c (yyparse::yysetstate): Avoid generating code when
neither yyoverflow nor YYSTACK_RELOCATE is defined.
Currently on a grammar such as
exp : a '1' | a '2' | a '3' | b '1' | b '2' | b '3'
a:
b:
we count only one rr-conflict on the `b:` rule, i.e., we expect:
b: %expect-rr 1
although there are 3 conflicts in total. That's because in the
conflicted state we count only a single conflict, not three (one for
each of the lookaheads: '1', '2', '3').
State 0
0 $accept: . exp $end
1 exp: . a '1'
2 | . a '2'
3 | . a '3'
4 | . b '1'
5 | . b '2'
6 | . b '3'
7 a: . %empty ['1', '2', '3']
8 b: . %empty ['1', '2', '3']
'1' reduce using rule 7 (a)
'1' [reduce using rule 8 (b)]
'2' reduce using rule 7 (a)
'2' [reduce using rule 8 (b)]
'3' reduce using rule 7 (a)
'3' [reduce using rule 8 (b)]
$default reduce using rule 7 (a)
exp go to state 1
a go to state 2
b go to state 3
See https://lists.gnu.org/archive/html/bison-patches/2013-02/msg00106.html.
* src/conflicts.c (rule_has_state_rr_conflicts): Rename as...
(count_rule_state_sr_conflicts): this.
DWIM.
(count_rule_rr_conflicts): Adjust.
* tests/conflicts.at (%expect-rr in grammar rules)
(%expect-rr too much in grammar rules)
(%expect-rr not enough in grammar rules): New.
On a grammar such as
exp: "num" | "num" | "num"
we currently report only one RR conflict, instead of two.
This bug is present since the origins of Bison
commit 08089d5d35
Author: David MacKenzie <[email protected]>
Date: Tue Apr 20 05:42:52 1993 +0000
Initial revision
and was preserved in
commit 676385e29c
Author: Paul Hilfinger <[email protected]>
Date: Fri Jun 28 02:26:44 2002 +0000
Initial check-in introducing experimental GLR parsing. See entry in
ChangeLog dated 2002-06-27 from Paul Hilfinger for details.
See
https://lists.gnu.org/archive/html/bison-patches/2018-11/msg00011.html
* src/conflicts.h, src/conflicts.c (count_state_rr_conflicts)
(count_rr_conflicts): Use only the correct count of conflicts.
* tests/glr-regression.at: Fix expectations.
Currently on a grammar such as
exp: "number" | exp "+" exp | exp "*" exp
we count only one sr-conflict for both binary rules, i.e., we expect:
exp: "number" | exp "+" exp %expect 1 | exp "*" exp %expect 1
although there are 4 conflicts in total. That's because in the states
in conflict, for instance that for the "+" rule:
State 6
2 exp: exp . "+" exp
2 | exp "+" exp . [$end, "+", "*"]
3 | exp . "*" exp
"+" shift, and go to state 4
"*" shift, and go to state 5
"+" [reduce using rule 2 (exp)]
"*" [reduce using rule 2 (exp)]
$default reduce using rule 2 (exp)
we count only a single conflict, although there are two (one on "+"
and another with "*").
See https://lists.gnu.org/archive/html/bison-patches/2013-02/msg00106.html.
* src/conflicts.c (rule_has_state_sr_conflicts): Rename as...
(count_rule_state_sr_conflicts): this.
DWIM.
(count_rule_sr_conflicts): Adjust.
* tests/conflicts.at (%expect in grammar rules): New.
We also lack a consistent naming for directive implementations.
`directive_skeleton` is too long, `percent_skeleton` is not very nice
looking, `process_skeleton` looks ambiguous, `do_skeleton` is somewhat
ambiguous too, but seems a better track.
* src/parse-gram.y (version_check): Rename as...
(do_require): this.
(do_skeleton): New.
Use it.
We may generate code such as
basic_symbol (typename Base::kind_type t, YY_RVREF (std::pair<int,int>) v);
which, of course, breaks, because YY_RVREF sees two arguments. Let's
not play tricks with _VA_ARGS__, I'm unsure about it portability.
Anyway, I plan to change more things in this area.
Reported by Sébastien Villemot.
http://lists.gnu.org/archive/html/bug-bison/2018-11/msg00014.html
* data/variant.hh (b4_basic_symbol_constructor_declare)
(b4_basic_symbol_constructor_define): Don't use macro on user types.
* tests/types.at: Check that we support pairs.
In C++, [[noreturn]] must not be between "static" and the rest of the
function signature, it must precede it. C's _Noreturn does not seem
to have such a constraint, but it is therefore compatible with the C++
constraint. Since we #define _Noreturn as [[noreturn]] is modern C++,
be sure to push the _Noreturn first.
Unfortunately this was not caught by the test suite, because it always
loads config.h first, and config.h contains another definition of
_Noreturn that does not use [[noreturn]], and hides ours. That's
probably a sign we should avoid always loading config.h.
* data/glr.c (yyFail, yyMemoryExhausted): here.
* tests/local.at (AT_LANG_FOR_EACH_STD): New.
(AT_REQUIRE_CXX_VERSION): Rename as...
(AT_REQUIRE_CXX_STD): this.
Accept an argument for what to do when the requirement is not met.
* tests/types.at (api.value.type): Check all the C++ stds.
The following commit introduce even more compilations/runs than
before, and with ASAN on, we go beyond to 50min credit from Travis.
* .travis.yml (Clang 7 libc++ and ASAN): Split in two.
It is unfortunate that %error_verbose was properly diagnosed as
obsoleted by "%define parse.error verbose", but %error-verbose was
not.
* src/parse-gram.y (%error-verbose): Remove support.
* src/scan-gram.l: Do it here instead, with a warning.
* tests/input.at (Deprecated directives): Check it.
These tests are skipped with GCC:
"\"".c:1:5: error: function declaration isn't a prototype [-Werror=strict-prototypes]
int main() { return 0; }
^~~~
* tests/synclines.at: Stop writing C++ in C.
* tests/local.at: Formatting changes.
* src/parse-gram.y (api.value.type): Set to union.
Replace occurrences of %union with explicit %types.
* src/scan-gram.l: Adjust yylval's field names.
(RETURN_VALUE): No longer needs the Field argument.
Use it more.
Support for DJGPP was announced to be removed in the NEWS of Bison
3.1 (2018-08-27) unless someone expressed interest. There was no answer.
* djgpp: Remove.
* NEWS, Makefile.am, cfg.mk, po/POTFILES.in: Adjust.
Reported by Andre da Costa Barros.
https://savannah.gnu.org/patch/?9716
* examples/calc++/local.mk: We no longer generate position.hh and
stack.hh. Leaving them here triggers their concurrent generation,
which fails.
(%C%_calc___CPPFLAGS): Fix the extracted headers in the source tree.
* examples/mfcalc/local.mk (%C%_mfcalc_CPPFLAGS): Ditto.
Currently, the examples are extracted on the user's side.
Unfortunately, that requires that the user has Perl, which is
otherwise not needed for Bison. Let's ship the examples instead.
The examples were handled this way so that we could depend on
configure flags: if --enable-gcc-warnings is passed, it is understood
as "I'm a maintainer", so the examples are generated with `#line`s.
Regular users should not see them, so they are now unconditionally
removed when rolling a tarball.
Reported by Mike Frysinger.
https://lists.gnu.org/archive/html/bison-patches/2015-04/msg00000.html
* examples/local.mk: Ship all the extracted files.
(examples-unline): New.
Make sure that the generated tarballs do not contain the #lines.
Also, make sure that `make dist` generates a correct tarball even if
the C++ compiler does not work.
Reported by Nelson H. F. Beebe.
* m4/cxx.m4 (BISON_CXX_WORKS): Define to true/false instead of
true/exit 77. The latter is too dangerous to use (it directly quits).
(ENABLE_CXX): New name for the Automake conditional, for consistency
with ENABLE_CXX11 etc.
* tests/local.at (AT_COMPILE, AT_COMPILE_CXX): Adjust to the new
semantics of BISON_CXX_WORKS.
* examples/c++/local.mk: Skip the variant test if C++ does not work.
* examples/calc++/local.mk: Likewise.
On some systems (x86_64-pc-solaris2.11), with Developer Studio 12.5's
CC, we get:
".../include/CC/Cstd/vector.cc", line 127: Error: Cannot assign const yy::parser::stack_symbol_type to yy::parser::stack_symbol_type without "yy::parser::stack_symbol_type::operator=(const yy::parser::stack_symbol_type&)";.
".../include/CC/Cstd/vector", line 475: Where: While instantiating "std::vector<yy::parser::stack_symbol_type>::__insert_aux(yy::parser::stack_symbol_type*, const yy::parser::stack_symbol_type&)".
".../include/CC/Cstd/vector", line 475: Where: Instantiated from non-template code.
1 Error(s) detected.
Don't expect __cplusplus to be always defined. If it's not, consider
this is C++98.
Reported by Nelson H. F. Beebe.
* data/c++.m4, data/lalr1.cc, examples/c++/variant.yy, tests/local.at,
* tests/testsuite.h:
An undefined __cplusplus means pre C++11.
On some systems, we don't use our getopt. As a consequence the error
messages vary:
$ bison --skeleton
bison: option requires an argument -- skeleton
Try 'bison --help' for more information.
instead of
bison: option '--skeleton' requires an argument
Try 'bison --help' for more information.
Reported by Jannick and Nelson H. F. Beebe.
https://lists.gnu.org/archive/html/bison-patches/2018-10/msg00140.html
* tests/input.at (Invalid number of arguments): work around getopt
portability issues.
On Solaris, GCC 7.3 defines:
-std=c++14 -std=c++17
__cplusplus 201402L 201703L
__STDC_VERSION__ 199901L 201112L
So the current #definition of _Noreturn sees that 201112 <=
__STDC_VERSION__, i.e., that C11 is supported, so it expects _Noreturn
to be supported. Apparently it is not.
This is only for C++, the test suite works for C. However, the test
suite does not try several C standards, maybe we should...
http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00064.html
* data/c.m4 (b4_attribute_define): Define _Noreturn as [[noreturn]] in
modern C++.
Does not work on Solaris 11.3 x86/64:
479. c++.at:1293: testing C++ GLR parser identifier shadowing ...
======== Testing with C++ standard flags: '-std=c++17'
./c++.at:1332: $BISON_CXX_WORKS
stderr:
stdout:
./c++.at:1332: $CXX $CXXFLAGS $CPPFLAGS $LDFLAGS -o input input.cc $LIBS
stderr:
input.cc:837:8: error: '_Noreturn' does not name a type
static _Noreturn void
^~~~~~~~~
input.cc:845:8: error: '_Noreturn' does not name a type
static _Noreturn void
^~~~~~~~~
Reported by Kiyoshi Kanazawa.
http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00051.html
* data/c.m4 (b4_attribute_define): Use the snippet which is currently
in gnulib's m4/gnulib-common.m4 (which seems a little more advanced
than lib/_Noreturn.h).
The "Report translation bugs to..." part of --help is issued only on
glibc systems. So if the tarball is not wrapped on such a system, and
used on such a system (or the converse), then bison.help will differ
on the user's system, and help2man will be called to update bison.1.
But help2man should not be a requirement.
Reported by Alexandre Duret-Lutz.
* doc/local.mk (doc/bison.help): Remove the possible doc about
translation bugs.
Pass LC_ALL=C, as reported in src/getargs.c's usage().
(doc/cross-options.texi): Use bison.help instead of calling bison
--help.
Some users rely on this sentence to know that the file can be ignored.
Reported by Alexandre Duret-Lutz.
* data/bison.m4 (b4_generated_by): New.
(b4_copyright): Use it.
* data/location.cc, data/stack.hh: Use it too, for the stub files
(position.hh and stack.hh).
* doc/bison.texi (Calc++ Scanner): Show how exception can be thrown
from auxiliary functions.
Clarify the meaning of the various flex %options we use.
Get rid of a warning.
(Calc++ Parsing Driver): Use the parser as a functor.
* doc/bison.texi: Simplify wording.
Fix Texinfo error.
(Complete Symbols): Handle the token EOF.
(Calc++ Parser): In the modern C++ world, prefer assignment to swap.
(Strings are Destroyed): Prefer an explicit 'continue' to a comment.
The CI is using Flex 2.5.35. And ICC is too picky for it. Let's stop
making these warnings errors. I wish I could disable them in the
source files using the ICC version and the Flex version, but ICC's
pragma support is unclear, and I'm tired of fighting it.
* configure.ac (FLEX_SCANNER_CXXFLAGS): Make warnings warnings.
* examples/c++/local.mk: Comment changes.
Suggested by Victor Khomenko.
http://lists.gnu.org/archive/html/bug-bison/2018-08/msg00037.html
* doc/bison.texi (A Simple C++ Example): New.
* examples/c++/local.mk, examples/c++/simple.test: New.
Extract, check, and install this new example.
* examples/local.mk: Adjust.
* examples/test: Adjust to the case where the dirname differs
from the test name.
* build-aux/local.mk, cfg.mk, examples/calc++/local.mk,
* examples/local.mk, examples/mfcalc/local.mk,
* examples/rpcalc/local.mk, lib/local.mk, src/local.mk,
* tests/local.mk:
Use Automake comments so that we don't get a copy of each in the
generated Makefile.
On the CI, both GCC and Clang report:
src/parse-gram.c: In function 'yy_lac':
src/parse-gram.c:1479:29: error: format '%hd' expects argument of type 'int',
but argument 3 has type 'yytype_int16 {aka long int}' [-Werror=format=]
YYDPRINTF ((stderr, " G%hd", yystate));
^
Although yytype_int16 is supposed to be a short int, not a long int.
This must be explored.
* data/yacc.c (yy_lac): Work around typing issue.
* data/glr.c: Don't use `foo |= bar` with foo and bar being yybool:
the result appears to be an int, not a yybool.
Use yybool where appropriate.
Add casts where needed.
Reported by Derek Clegg.
http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00018.html
Rather than adding casts, we should be more careful with types. For
instance yystate should be a yytype_int16. But currently we can't: it
is also used sometimes for storing other things that state numbers.
* data/yacc.c (yyparse): Add missing casts.
The yacc.c skeleton is old, and was using many tricks to save
registers. Today's register allocators can do this themselves. Let's
keep the code simpler to read and let compilers do their job.
* data/yacc.c: Avoid using yystate for different types of content.
An inline function would be better, but doing this portably will be
a problem.
Akim Demaille