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build: Enable C++11 build, require C++11 compiler

Implements #6211.
tags/v0.15.1
Wladimir J. van der Laan 4 years ago
parent
commit
67969af09f
2 changed files with 560 additions and 0 deletions
  1. 558
    0
      build-aux/m4/ax_cxx_compile_stdcxx.m4
  2. 2
    0
      configure.ac

+ 558
- 0
build-aux/m4/ax_cxx_compile_stdcxx.m4 View File

@@ -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

]])

+ 2
- 0
configure.ac View File

@@ -55,6 +55,8 @@ case $host in
lt_cv_deplibs_check_method="pass_all"
;;
esac
dnl Require C++11 compiler (no GNU extensions)
AX_CXX_COMPILE_STDCXX([11], [noext], [mandatory])
dnl Libtool init checks.
LT_INIT([pic-only])


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