Add --enable-cxx11 configure option

Make it simpler to enable C++11 support when building wxWidgets, in particular
take care of using the correct standard library under OS X in this case.

Notice that currently we still build the library using C++98 if no C++11
compiler is available, even with this option. We may want to change this to
give an error in such case later instead.

Also skip the check for <type_traits> in configure when C++11 is used, we know
that it's available in this case, so don't waste time checking for it (there
are probably several more checks that could be skipped in C++11 mode too...).
This commit is contained in:
Vadim Zeitlin 2016-01-24 16:19:12 +01:00
parent c3504663ef
commit b67ca545cc
5 changed files with 1624 additions and 270 deletions

6
aclocal.m4 vendored
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@ -1,7 +1,8 @@
# generated automatically by aclocal 1.10.3 -*- Autoconf -*-
# generated automatically by aclocal 1.11.6 -*- Autoconf -*-
# Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
# 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
# 2005, 2006, 2007, 2008, 2009, 2010, 2011 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.
@ -14,6 +15,7 @@
m4_include([build/aclocal/ac_raf_func_which_getservbyname_r.m4])
m4_include([build/aclocal/atomic_builtins.m4])
m4_include([build/aclocal/ax_cflags_gcc_option.m4])
m4_include([build/aclocal/ax_cxx_compile_stdcxx.m4])
m4_include([build/aclocal/ax_func_which_gethostbyname_r.m4])
m4_include([build/aclocal/ax_gcc_option.m4])
m4_include([build/aclocal/ax_gxx_version.m4])

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@ -0,0 +1,558 @@
# ===========================================================================
# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
#
# DESCRIPTION
#
# Check for baseline language coverage in the compiler for the specified
# version of the C++ standard. If necessary, add switches to CXXFLAGS to
# enable support. VERSION may be '11' (for the C++11 standard) or '14'
# (for the C++14 standard).
#
# The second argument, if specified, indicates whether you insist on an
# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
# -std=c++11). If neither is specified, you get whatever works, with
# preference for an extended mode.
#
# The third argument, if specified 'mandatory' or if left unspecified,
# indicates that baseline support for the specified C++ standard is
# required and that the macro should error out if no mode with that
# support is found. If specified 'optional', then configuration proceeds
# regardless, after defining HAVE_CXX${VERSION} if and only if a
# supporting mode is found.
#
# LICENSE
#
# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
# Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
# Copyright (c) 2015 Paul Norman <penorman@mac.com>
# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
#
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty provided the copyright notice
# and this notice are preserved. This file is offered as-is, without any
# warranty.
#serial 1
dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
dnl (serial version number 13).
AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
m4_if([$1], [11], [],
[$1], [14], [],
[$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])],
[m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
m4_if([$2], [], [],
[$2], [ext], [],
[$2], [noext], [],
[m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
[$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
[$3], [optional], [ax_cxx_compile_cxx$1_required=false],
[m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
AC_LANG_PUSH([C++])dnl
ac_success=no
AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
ax_cv_cxx_compile_cxx$1,
[AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
[ax_cv_cxx_compile_cxx$1=yes],
[ax_cv_cxx_compile_cxx$1=no])])
if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
ac_success=yes
fi
m4_if([$2], [noext], [], [dnl
if test x$ac_success = xno; then
for switch in -std=gnu++$1 -std=gnu++0x; do
cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
$cachevar,
[ac_save_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $switch"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
[eval $cachevar=yes],
[eval $cachevar=no])
CXXFLAGS="$ac_save_CXXFLAGS"])
if eval test x\$$cachevar = xyes; then
CXXFLAGS="$CXXFLAGS $switch"
ac_success=yes
break
fi
done
fi])
m4_if([$2], [ext], [], [dnl
if test x$ac_success = xno; then
dnl HP's aCC needs +std=c++11 according to:
dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
dnl Cray's crayCC needs "-h std=c++11"
for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do
cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
$cachevar,
[ac_save_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CXXFLAGS $switch"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
[eval $cachevar=yes],
[eval $cachevar=no])
CXXFLAGS="$ac_save_CXXFLAGS"])
if eval test x\$$cachevar = xyes; then
CXXFLAGS="$CXXFLAGS $switch"
ac_success=yes
break
fi
done
fi])
AC_LANG_POP([C++])
if test x$ax_cxx_compile_cxx$1_required = xtrue; then
if test x$ac_success = xno; then
AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
fi
else
if test x$ac_success = xno; then
HAVE_CXX$1=0
AC_MSG_NOTICE([No compiler with C++$1 support was found])
else
HAVE_CXX$1=1
AC_DEFINE(HAVE_CXX$1,1,
[define if the compiler supports basic C++$1 syntax])
fi
AC_SUBST(HAVE_CXX$1)
fi
])
dnl Test body for checking C++11 support
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
)
dnl Test body for checking C++14 support
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
_AX_CXX_COMPILE_STDCXX_testbody_new_in_14
)
dnl Tests for new features in C++11
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
// If the compiler admits that it is not ready for C++11, why torture it?
// Hopefully, this will speed up the test.
#ifndef __cplusplus
#error "This is not a C++ compiler"
#elif __cplusplus < 201103L
#error "This is not a C++11 compiler"
#else
namespace cxx11
{
namespace test_static_assert
{
template <typename T>
struct check
{
static_assert(sizeof(int) <= sizeof(T), "not big enough");
};
}
namespace test_final_override
{
struct Base
{
virtual void f() {}
};
struct Derived : public Base
{
virtual void f() override {}
};
}
namespace test_double_right_angle_brackets
{
template < typename T >
struct check {};
typedef check<void> single_type;
typedef check<check<void>> double_type;
typedef check<check<check<void>>> triple_type;
typedef check<check<check<check<void>>>> quadruple_type;
}
namespace test_decltype
{
int
f()
{
int a = 1;
decltype(a) b = 2;
return a + b;
}
}
namespace test_type_deduction
{
template < typename T1, typename T2 >
struct is_same
{
static const bool value = false;
};
template < typename T >
struct is_same<T, T>
{
static const bool value = true;
};
template < typename T1, typename T2 >
auto
add(T1 a1, T2 a2) -> decltype(a1 + a2)
{
return a1 + a2;
}
int
test(const int c, volatile int v)
{
static_assert(is_same<int, decltype(0)>::value == true, "");
static_assert(is_same<int, decltype(c)>::value == false, "");
static_assert(is_same<int, decltype(v)>::value == false, "");
auto ac = c;
auto av = v;
auto sumi = ac + av + 'x';
auto sumf = ac + av + 1.0;
static_assert(is_same<int, decltype(ac)>::value == true, "");
static_assert(is_same<int, decltype(av)>::value == true, "");
static_assert(is_same<int, decltype(sumi)>::value == true, "");
static_assert(is_same<int, decltype(sumf)>::value == false, "");
static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
return (sumf > 0.0) ? sumi : add(c, v);
}
}
namespace test_noexcept
{
int f() { return 0; }
int g() noexcept { return 0; }
static_assert(noexcept(f()) == false, "");
static_assert(noexcept(g()) == true, "");
}
namespace test_constexpr
{
template < typename CharT >
unsigned long constexpr
strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
{
return *s ? strlen_c_r(s + 1, acc + 1) : acc;
}
template < typename CharT >
unsigned long constexpr
strlen_c(const CharT *const s) noexcept
{
return strlen_c_r(s, 0UL);
}
static_assert(strlen_c("") == 0UL, "");
static_assert(strlen_c("1") == 1UL, "");
static_assert(strlen_c("example") == 7UL, "");
static_assert(strlen_c("another\0example") == 7UL, "");
}
namespace test_rvalue_references
{
template < int N >
struct answer
{
static constexpr int value = N;
};
answer<1> f(int&) { return answer<1>(); }
answer<2> f(const int&) { return answer<2>(); }
answer<3> f(int&&) { return answer<3>(); }
void
test()
{
int i = 0;
const int c = 0;
static_assert(decltype(f(i))::value == 1, "");
static_assert(decltype(f(c))::value == 2, "");
static_assert(decltype(f(0))::value == 3, "");
}
}
namespace test_uniform_initialization
{
struct test
{
static const int zero {};
static const int one {1};
};
static_assert(test::zero == 0, "");
static_assert(test::one == 1, "");
}
namespace test_lambdas
{
void
test1()
{
auto lambda1 = [](){};
auto lambda2 = lambda1;
lambda1();
lambda2();
}
int
test2()
{
auto a = [](int i, int j){ return i + j; }(1, 2);
auto b = []() -> int { return '0'; }();
auto c = [=](){ return a + b; }();
auto d = [&](){ return c; }();
auto e = [a, &b](int x) mutable {
const auto identity = [](int y){ return y; };
for (auto i = 0; i < a; ++i)
a += b--;
return x + identity(a + b);
}(0);
return a + b + c + d + e;
}
int
test3()
{
const auto nullary = [](){ return 0; };
const auto unary = [](int x){ return x; };
using nullary_t = decltype(nullary);
using unary_t = decltype(unary);
const auto higher1st = [](nullary_t f){ return f(); };
const auto higher2nd = [unary](nullary_t f1){
return [unary, f1](unary_t f2){ return f2(unary(f1())); };
};
return higher1st(nullary) + higher2nd(nullary)(unary);
}
}
namespace test_variadic_templates
{
template <int...>
struct sum;
template <int N0, int... N1toN>
struct sum<N0, N1toN...>
{
static constexpr auto value = N0 + sum<N1toN...>::value;
};
template <>
struct sum<>
{
static constexpr auto value = 0;
};
static_assert(sum<>::value == 0, "");
static_assert(sum<1>::value == 1, "");
static_assert(sum<23>::value == 23, "");
static_assert(sum<1, 2>::value == 3, "");
static_assert(sum<5, 5, 11>::value == 21, "");
static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
}
// http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
// Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
// because of this.
namespace test_template_alias_sfinae
{
struct foo {};
template<typename T>
using member = typename T::member_type;
template<typename T>
void func(...) {}
template<typename T>
void func(member<T>*) {}
void test();
void test() { func<foo>(0); }
}
} // namespace cxx11
#endif // __cplusplus >= 201103L
]])
dnl Tests for new features in C++14
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
// If the compiler admits that it is not ready for C++14, why torture it?
// Hopefully, this will speed up the test.
#ifndef __cplusplus
#error "This is not a C++ compiler"
#elif __cplusplus < 201402L
#error "This is not a C++14 compiler"
#else
namespace cxx14
{
namespace test_polymorphic_lambdas
{
int
test()
{
const auto lambda = [](auto&&... args){
const auto istiny = [](auto x){
return (sizeof(x) == 1UL) ? 1 : 0;
};
const int aretiny[] = { istiny(args)... };
return aretiny[0];
};
return lambda(1, 1L, 1.0f, '1');
}
}
namespace test_binary_literals
{
constexpr auto ivii = 0b0000000000101010;
static_assert(ivii == 42, "wrong value");
}
namespace test_generalized_constexpr
{
template < typename CharT >
constexpr unsigned long
strlen_c(const CharT *const s) noexcept
{
auto length = 0UL;
for (auto p = s; *p; ++p)
++length;
return length;
}
static_assert(strlen_c("") == 0UL, "");
static_assert(strlen_c("x") == 1UL, "");
static_assert(strlen_c("test") == 4UL, "");
static_assert(strlen_c("another\0test") == 7UL, "");
}
namespace test_lambda_init_capture
{
int
test()
{
auto x = 0;
const auto lambda1 = [a = x](int b){ return a + b; };
const auto lambda2 = [a = lambda1(x)](){ return a; };
return lambda2();
}
}
namespace test_digit_seperators
{
constexpr auto ten_million = 100'000'000;
static_assert(ten_million == 100000000, "");
}
namespace test_return_type_deduction
{
auto f(int& x) { return x; }
decltype(auto) g(int& x) { return x; }
template < typename T1, typename T2 >
struct is_same
{
static constexpr auto value = false;
};
template < typename T >
struct is_same<T, T>
{
static constexpr auto value = true;
};
int
test()
{
auto x = 0;
static_assert(is_same<int, decltype(f(x))>::value, "");
static_assert(is_same<int&, decltype(g(x))>::value, "");
return x;
}
}
} // namespace cxx14
#endif // __cplusplus >= 201402L
]])

1303
configure vendored

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@ -631,6 +631,7 @@ dnl global compile options
dnl ---------------------------------------------------------------------------
WX_ARG_DISABLE(shared, [ --disable-shared create static library instead of shared], wxUSE_SHARED)
WX_ARG_ENABLE(cxx11, [ --enable-cxx11 use C++11 compiler], wxUSE_CXX11)
WX_ARG_ENABLE(stl, [ --enable-stl use standard C++ classes for everything], wxUSE_STL)
if test "$wxUSE_STL" = "yes"; then
DEFAULT_wxUSE_STD_CONTAINERS=yes
@ -1060,6 +1061,12 @@ if test "$CXX" = "g++" -a "$GXX" != "yes"; then
AC_MSG_ERROR([C++ compiler is needed to build wxWidgets])
fi
if test "$wxUSE_CXX11" = "yes"; then
dnl We still continue even if C++11 support is not available, would it be
dnl better to stop with an error in this case?
AX_CXX_COMPILE_STDCXX(11,,optional)
fi
dnl ar command
dnl defines AR with the appropriate command
dnl
@ -1224,6 +1231,12 @@ if test "x$wxUSE_MACOSX_VERSION_MIN" != "x"; then
retest_macosx_linking=yes
fi
if test "$HAVE_CXX11" = "1" ; then
dnl We also need to use libc++ standard library instead of libstdc++ for
dnl C++11 support.
CXX="$CXX -stdlib=libc++"
fi
dnl If either an SDK or a version option was added, make sure that we can
dnl still compile and link both C and C++. If we didn't do this, then most
dnl of the remaining tests would fail.
@ -1966,7 +1979,18 @@ if test "$wxUSE_STL" = "yes"; then
fi
fi
AC_CHECK_HEADERS([type_traits tr1/type_traits], break)
dnl Check for type_traits header if necessary: we know that it's always present
dnl in C++11 mode. Also notice that it's important to pass AC_INCLUDES_DEFAULT()
dnl as the last argument because otherwise autoconf would perform the check
dnl using both the compiler and the preprocessor and the latter could fail if
dnl the preprocessor is not in C++11 mode, resulting in a warning when running
dnl configure, while providing this argument allows to skip the preprocessor
dnl check.
if test "$HAVE_CXX11" != "1" ; then
AC_CHECK_HEADERS([type_traits tr1/type_traits], break, [], [AC_INCLUDES_DEFAULT()])
else
AC_DEFINE(HAVE_TYPE_TRAITS)
fi
dnl check for atomic operations builtins for wx/atomic.h:
WX_ATOMIC_BUILTINS

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@ -81,6 +81,7 @@ Unix:
- Fix bug in wxExecute() if child exited too quickly (Kevin B. McCarty).
- Add --disable-sys-libs configure option.
- Add --enable-cxx11 configure option.
All (GUI):