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build: strengthen the C++ standard flag test
|
From: |
Akim Demaille |
|
Subject: |
build: strengthen the C++ standard flag test |
|
Date: |
Mon, 17 Sep 2018 18:48:08 +0200 |
This is mostly a stub, it will require some improvements,
no doubts about it.
ItaEUR(TM)s based on work I did on vcsn.
commit c193a4c3291e95fd92d0274ef9e263772ffed2ae
Author: Akim Demaille <address@hidden>
Date: Sun Sep 16 18:20:56 2018 +0200
build: strengthen the C++ standard flag test
On the CI, we have this spurious failure with clang 3.9 with
-std=c++17:
In file included from list.y:23:
In file included from /usr/include/c++/4.8/iostream:39:
In file included from /usr/include/c++/4.8/ostream:38:
In file included from /usr/include/c++/4.8/ios:42:
In file included from /usr/include/c++/4.8/bits/ios_base.h:41:
In file included from
/usr/include/c++/4.8/bits/locale_classes.h:40:
In file included from /usr/include/c++/4.8/string:52:
In file included from
/usr/include/c++/4.8/bits/basic_string.h:2815:
In file included from
/usr/include/c++/4.8/ext/string_conversions.h:43:
/usr/include/c++/4.8/cstdio:120:11: error: no member named
'gets' in the global namespace
using ::gets;
~~^
This shows that our test, based on gl_WARN_ADD, is a joke. We have
to
really check for at least a bit of C++.
* m4/ax_check_compile_flag.m4, m4/bison-cxx-std.m4: New.
* configure.ac: Use them to make sure the compiler actually works.
diff --git a/configure.ac b/configure.ac
index f8faa2b7..a1c52b6d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,8 @@
# better to avoid a typo in the 'configure --help' entry for the YACC
# environment variable.
AC_PREREQ([2.68])
-m4_pattern_forbid([^gl_[A-Z]])
+m4_pattern_forbid([^_?(gl_[A-Z]|BISON_)])
+m4_pattern_allow([^BISON_USE_NLS$])
AC_INIT([GNU Bison],
m4_esyscmd([build-aux/git-version-gen .tarball-version]),
@@ -52,18 +53,6 @@ AC_CONFIG_HEADERS([lib/config.h:lib/config.in.h])
# Checks for the compiler.
AC_PROG_CC_STDC
AC_PROG_CXX
-AC_LANG_PUSH([C++])
-gl_WARN_ADD([-fno-exceptions], [NO_EXCEPTIONS_CXXFLAGS])
-gl_WARN_ADD([-std=c++98], [CXX98_CXXFLAGS])
-gl_WARN_ADD([-std=c++03], [CXX03_CXXFLAGS])
-gl_WARN_ADD([-std=c++11], [CXX11_CXXFLAGS])
-gl_WARN_ADD([-std=c++14], [CXX14_CXXFLAGS])
-gl_WARN_ADD([-std=c++17], [CXX17_CXXFLAGS])
-gl_WARN_ADD([-std=c++2a], [CXX2A_CXXFLAGS])
-AC_SUBST([STDCXX_FLAGS],
-["$CXX98_CXXFLAGS $CXX03_CXXFLAGS $CXX11_CXXFLAGS $CXX14_CXXFLAGS
$CXX17_CXXFLAGS $CXX2A_CXXFLAGS "])
-AM_CONDITIONAL([ENABLE_CXX11], [test x"$CXX11_CXXFLAGS" != x])
-AC_LANG_POP([C++])
# Gnulib (early checks).
gl_EARLY
@@ -82,6 +71,19 @@ AC_CACHE_CHECK([whether pragma GCC diagnostic push
works],
[lv_cv_gcc_pragma_push_works=no])
CFLAGS=$save_CFLAGS])
+AC_LANG_PUSH([C++])
+gl_WARN_ADD([-fno-exceptions], [NO_EXCEPTIONS_CXXFLAGS])
+gl_WARN_ADD([-std=c++98], [CXX98_CXXFLAGS])
+gl_WARN_ADD([-std=c++03], [CXX03_CXXFLAGS])
+BISON_CXX_COMPILE_STDCXX_11
+BISON_CXX_COMPILE_STDCXX_14
+BISON_CXX_COMPILE_STDCXX_17
+gl_WARN_ADD([-std=c++2a], [CXX2A_CXXFLAGS])
+AC_SUBST([STDCXX_FLAGS],
+["$CXX98_CXXFLAGS $CXX03_CXXFLAGS $CXX11_CXXFLAGS $CXX14_CXXFLAGS
$CXX17_CXXFLAGS $CXX2A_CXXFLAGS "])
+AM_CONDITIONAL([ENABLE_CXX11], [test x"$CXX11_CXXFLAGS" != x])
+AC_LANG_POP([C++])
+
AC_ARG_ENABLE([gcc-warnings],
[ --enable-gcc-warnings turn on lots of GCC warnings (not
recommended).
Also, issue synclines from the examples/ to
diff --git a/m4/ax_check_compile_flag.m4 b/m4/ax_check_compile_flag.m4
new file mode 100644
index 00000000..71d4f365
--- /dev/null
+++ b/m4/ax_check_compile_flag.m4
@@ -0,0 +1,70 @@
+#
=======================================================================
====
+#
http://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
+#
=======================================================================
====
+#
+# SYNOPSIS
+#
+# AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE],
[EXTRA-FLAGS])
+#
+# DESCRIPTION
+#
+# Check whether the given FLAG works with the current language's
compiler
+# or gives an error. (Warnings, however, are ignored)
+#
+# ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+# success/failure.
+#
+# If EXTRA-FLAGS is defined, it is added to the current language's
default
+# flags (e.g. CFLAGS) when the check is done. The check is thus
made with
+# the flags: "CFLAGS EXTRA-FLAGS FLAG". This can for example be
used to
+# force the compiler to issue an error when a bad flag is given.
+#
+# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep
this
+# macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Guido U. Draheim <address@hidden>
+# Copyright (c) 2011 Maarten Bosmans <address@hidden>
+#
+# 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 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, see <http://www.gnu.org/licenses/>.
+#
+# As a special exception, the respective Autoconf Macro's copyright
owner
+# gives unlimited permission to copy, distribute and modify the
configure
+# scripts that are the output of Autoconf when processing the Macro.
You
+# need not follow the terms of the GNU General Public License when
using
+# or distributing such scripts, even though portions of the text of
the
+# Macro appear in them. The GNU General Public License (GPL) does
govern
+# all other use of the material that constitutes the Autoconf Macro.
+#
+# This special exception to the GPL applies to versions of the
Autoconf
+# Macro released by the Autoconf Archive. When you make and
distribute a
+# modified version of the Autoconf Macro, you may extend this
special
+# exception to the GPL to apply to your modified version as well.
+
+#serial 2
+
+AC_DEFUN([AX_CHECK_COMPILE_FLAG],
+[AC_PREREQ(2.59)dnl for _AC_LANG_PREFIX
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1]
)dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
+ ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
+ _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
+ AC_COMPILE_IFELSE([m4_default([$5], [AC_LANG_PROGRAM()])],
+ [AS_VAR_SET(CACHEVAR,[yes])],
+ [AS_VAR_SET(CACHEVAR,[no])])
+ _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
+AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes], [$2], [$3])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_COMPILE_FLAGS
diff --git a/m4/bison-cxx-std.m4 b/m4/bison-cxx-std.m4
new file mode 100644
index 00000000..f41216d4
--- /dev/null
+++ b/m4/bison-cxx-std.m4
@@ -0,0 +1,148 @@
+# bison-cxx-std.m4 serial 1
+
+# Copyright (C) 2018 Free Software Foundation, # Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_11_snippet],
+[#include <algorithm>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+
+ // C++11
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ using right_angle_brackets = check<check<bool>>;
+
+ auto f = std::make_shared<std::string>("shared_ptr");
+
+ int a;
+ decltype(a) b;
+
+ typedef check<int> check_type;
+ check_type c;
+ check_type&& cr = static_cast<check_type&&>(c);
+
+ auto d = a;
+
+ // Some versions of libstdc++ do not support std::set::emplace.
+ void foo()
+ {
+ std::set<int> is;
+ is.emplace(42);
+ }
+
+ // Clang++ 3.5, for a while, was unable to process properly
+ // the for-loop because its variable, r, is a typedef...
+ // It failed as follows:
+ //
+ // error: unexpected ':' in nested name specifier; did you mean
'::'?
+ // for (auto r: std::set<int>{1, 2})
+ // ^
+ // ::
+ using r = std::set<int>;
+ void bar()
+ {
+ for (int r: std::set<int>{1, 2})
+ continue;
+ }
+])
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_14_snippet],
+[ // C++14
+ void mismatch()
+ {
+ using ints = std::vector<int>;
+ auto v1 = ints{1, 2, 3};
+ auto v2 = ints{1, 2};
+ std::mismatch(std::begin(v1), std::end(v1),
+ std::begin(v2), std::end(v2));
+ }
+])
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_17_snippet],
+[ // C++17
+ namespace ns1::ns2::ns3 {}
+
+#include <optional>
+ auto opt_string = std::optional<std::string>{};
+ auto out = std::ostringstream{};
+])
+
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_11_testbody],
+[AC_LANG_SOURCE([
+_BISON_CXX_COMPILE_STDCXX_11_snippet
+])])
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_14_testbody],
+[AC_LANG_SOURCE([
+_BISON_CXX_COMPILE_STDCXX_11_snippet
+_BISON_CXX_COMPILE_STDCXX_14_snippet
+])])
+
+m4_define([_BISON_CXX_COMPILE_STDCXX_17_testbody],
+[AC_LANG_SOURCE([
+_BISON_CXX_COMPILE_STDCXX_11_snippet
+_BISON_CXX_COMPILE_STDCXX_14_snippet
+_BISON_CXX_COMPILE_STDCXX_17_snippet
+])])
+
+
+
+AC_DEFUN([BISON_CXX_COMPILE_STDCXX_11],
+[AC_REQUIRE([AC_PROG_CXX])
+AC_LANG_PUSH([C++])
+for f in '-std=c++11' '-std=c++11 -stdlib=libc++'
+do
+ AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true],
[], [],
+ [_BISON_CXX_COMPILE_STDCXX_11_testbody])
+ if "${stdpass-false}"; then
+ CXX11_CXXFLAGS=$f
+ break
+ fi
+done
+AC_LANG_POP([C++])
+])
+
+
+AC_DEFUN([BISON_CXX_COMPILE_STDCXX_14],
+[AC_REQUIRE([AC_PROG_CXX])
+AC_LANG_PUSH([C++])
+for f in '-std=c++14' '-std=c++14 -stdlib=libc++'
+do
+ AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true],
[], [],
+ [_BISON_CXX_COMPILE_STDCXX_14_testbody])
+ if "${stdpass-false}"; then
+ CXX14_CXXFLAGS=$f
+ break
+ fi
+done
+AC_LANG_POP([C++])
+])
+
+
+AC_DEFUN([BISON_CXX_COMPILE_STDCXX_17],
+[AC_REQUIRE([AC_PROG_CXX])
+AC_LANG_PUSH([C++])
+for f in '-std=c++17' '-std=c++17 -stdlib=libc++' \
+ '-std=c++1z' '-std=c++1z -stdlib=libc++'
+do
+ AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true],
[], [],
+ [_BISON_CXX_COMPILE_STDCXX_17_testbody])
+ if "${stdpass-false}"; then
+ CXX17_CXXFLAGS=$f
+ break
+ fi
+done
+AC_LANG_POP([C++])
+])