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build: Update ax_cxx_compile_stdcxx macro

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* m4/ax_cxx_compile_stdcxx.m4: Replace with current version from the
autoconf archive.
--

This fixes the problem that the switch -std=c++11 was omitted if the
compiler supported C++11 features by default. This made gcc happily
compile C++14 code. Now C++11 is enforced by gcc.

GnuPG-bug-id: 6141
This commit is contained in:
Ingo Klöcker 2022-08-22 15:04:32 +02:00
parent 83176ad7d3
commit 73e96bfaa8
1 changed files with 487 additions and 36 deletions
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523
m4/ax_cxx_compile_stdcxx.m4
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@ -1,5 +1,5 @@
# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
# https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
# ===========================================================================
#
# SYNOPSIS
@ -10,13 +10,13 @@
#
# Check for baseline language coverage in the compiler for the specified
# version of the C++ standard. If necessary, add switches to CXX and
# CXXCPP to enable support. VERSION may be '11' (for the C++11 standard)
# or '14' (for the C++14 standard).
# CXXCPP to enable support. VERSION may be '11', '14', '17', or '20' for
# the respective C++ standard version.
#
# 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.
# preference for no added switch, and then for an extended mode.
#
# The third argument, if specified 'mandatory' or if left unspecified,
# indicates that baseline support for the specified C++ standard is
@ -33,21 +33,26 @@
# 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>
# Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
# Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
# Copyright (c) 2020 Jason Merrill <jason@redhat.com>
# Copyright (c) 2021 Jörn Heusipp <osmanx@problemloesungsmaschine.de>
#
# 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 4
#serial 15
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_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
[$1], [14], [ax_cxx_compile_alternatives="14 1y"],
[$1], [17], [ax_cxx_compile_alternatives="17 1z"],
[$1], [20], [ax_cxx_compile_alternatives="20"],
[m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
m4_if([$2], [], [],
[$2], [ext], [],
@ -59,18 +64,21 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
[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], [], [dnl
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
for alternative in ${ax_cxx_compile_alternatives}; do
switch="-std=gnu++${alternative}"
cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
$cachevar,
@ -82,7 +90,9 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
CXX="$ac_save_CXX"])
if eval test x\$$cachevar = xyes; then
CXX="$CXX $switch"
CXXCPP="$CXXCPP $switch"
if test -n "$CXXCPP" ; then
CXXCPP="$CXXCPP $switch"
fi
ac_success=yes
break
fi
@ -94,20 +104,27 @@ AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
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,
$cachevar,
[ac_save_CXX="$CXX"
CXX="$CXX $switch"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
[eval $cachevar=yes],
[eval $cachevar=no])
CXX="$ac_save_CXX"])
if eval test x\$$cachevar = xyes; then
CXX="$CXX $switch"
CXXCPP="$CXXCPP $switch"
ac_success=yes
for alternative in ${ax_cxx_compile_alternatives}; do
for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do
cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
$cachevar,
[ac_save_CXX="$CXX"
CXX="$CXX $switch"
AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
[eval $cachevar=yes],
[eval $cachevar=no])
CXX="$ac_save_CXX"])
if eval test x\$$cachevar = xyes; then
CXX="$CXX $switch"
if test -n "$CXXCPP" ; then
CXXCPP="$CXXCPP $switch"
fi
ac_success=yes
break
fi
done
if test x$ac_success = xyes; then
break
fi
done
@ -136,7 +153,6 @@ 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],
@ -144,6 +160,23 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
_AX_CXX_COMPILE_STDCXX_testbody_new_in_14
)
dnl Test body for checking C++17 support
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
_AX_CXX_COMPILE_STDCXX_testbody_new_in_14
_AX_CXX_COMPILE_STDCXX_testbody_new_in_17
)
dnl Test body for checking C++20 support
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20],
_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
_AX_CXX_COMPILE_STDCXX_testbody_new_in_14
_AX_CXX_COMPILE_STDCXX_testbody_new_in_17
_AX_CXX_COMPILE_STDCXX_testbody_new_in_20
)
dnl Tests for new features in C++11
@ -156,7 +189,11 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
#error "This is not a C++ compiler"
#elif __cplusplus < 201103L
// MSVC always sets __cplusplus to 199711L in older versions; newer versions
// only set it correctly if /Zc:__cplusplus is specified as well as a
// /std:c++NN switch:
// https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/
#elif __cplusplus < 201103L && !defined _MSC_VER
#error "This is not a C++11 compiler"
@ -181,11 +218,13 @@ namespace cxx11
struct Base
{
virtual ~Base() {}
virtual void f() {}
};
struct Derived : public Base
{
virtual ~Derived() override {}
virtual void f() override {}
};
@ -445,7 +484,7 @@ m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
#error "This is not a C++ compiler"
#elif __cplusplus < 201402L
#elif __cplusplus < 201402L && !defined _MSC_VER
#error "This is not a C++14 compiler"
@ -514,7 +553,7 @@ namespace cxx14
}
namespace test_digit_seperators
namespace test_digit_separators
{
constexpr auto ten_million = 100'000'000;
@ -556,3 +595,415 @@ namespace cxx14
#endif // __cplusplus >= 201402L
]])
dnl Tests for new features in C++17
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
// If the compiler admits that it is not ready for C++17, why torture it?
// Hopefully, this will speed up the test.
#ifndef __cplusplus
#error "This is not a C++ compiler"
#elif __cplusplus < 201703L && !defined _MSC_VER
#error "This is not a C++17 compiler"
#else
#include <initializer_list>
#include <utility>
#include <type_traits>
namespace cxx17
{
namespace test_constexpr_lambdas
{
constexpr int foo = [](){return 42;}();
}
namespace test::nested_namespace::definitions
{
}
namespace test_fold_expression
{
template<typename... Args>
int multiply(Args... args)
{
return (args * ... * 1);
}
template<typename... Args>
bool all(Args... args)
{
return (args && ...);
}
}
namespace test_extended_static_assert
{
static_assert (true);
}
namespace test_auto_brace_init_list
{
auto foo = {5};
auto bar {5};
static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value);
static_assert(std::is_same<int, decltype(bar)>::value);
}
namespace test_typename_in_template_template_parameter
{
template<template<typename> typename X> struct D;
}
namespace test_fallthrough_nodiscard_maybe_unused_attributes
{
int f1()
{
return 42;
}
[[nodiscard]] int f2()
{
[[maybe_unused]] auto unused = f1();
switch (f1())
{
case 17:
f1();
[[fallthrough]];
case 42:
f1();
}
return f1();
}
}
namespace test_extended_aggregate_initialization
{
struct base1
{
int b1, b2 = 42;
};
struct base2
{
base2() {
b3 = 42;
}
int b3;
};
struct derived : base1, base2
{
int d;
};
derived d1 {{1, 2}, {}, 4}; // full initialization
derived d2 {{}, {}, 4}; // value-initialized bases
}
namespace test_general_range_based_for_loop
{
struct iter
{
int i;
int& operator* ()
{
return i;
}
const int& operator* () const
{
return i;
}
iter& operator++()
{
++i;
return *this;
}
};
struct sentinel
{
int i;
};
bool operator== (const iter& i, const sentinel& s)
{
return i.i == s.i;
}
bool operator!= (const iter& i, const sentinel& s)
{
return !(i == s);
}
struct range
{
iter begin() const
{
return {0};
}
sentinel end() const
{
return {5};
}
};
void f()
{
range r {};
for (auto i : r)
{
[[maybe_unused]] auto v = i;
}
}
}
namespace test_lambda_capture_asterisk_this_by_value
{
struct t
{
int i;
int foo()
{
return [*this]()
{
return i;
}();
}
};
}
namespace test_enum_class_construction
{
enum class byte : unsigned char
{};
byte foo {42};
}
namespace test_constexpr_if
{
template <bool cond>
int f ()
{
if constexpr(cond)
{
return 13;
}
else
{
return 42;
}
}
}
namespace test_selection_statement_with_initializer
{
int f()
{
return 13;
}
int f2()
{
if (auto i = f(); i > 0)
{
return 3;
}
switch (auto i = f(); i + 4)
{
case 17:
return 2;
default:
return 1;
}
}
}
namespace test_template_argument_deduction_for_class_templates
{
template <typename T1, typename T2>
struct pair
{
pair (T1 p1, T2 p2)
: m1 {p1},
m2 {p2}
{}
T1 m1;
T2 m2;
};
void f()
{
[[maybe_unused]] auto p = pair{13, 42u};
}
}
namespace test_non_type_auto_template_parameters
{
template <auto n>
struct B
{};
B<5> b1;
B<'a'> b2;
}
namespace test_structured_bindings
{
int arr[2] = { 1, 2 };
std::pair<int, int> pr = { 1, 2 };
auto f1() -> int(&)[2]
{
return arr;
}
auto f2() -> std::pair<int, int>&
{
return pr;
}
struct S
{
int x1 : 2;
volatile double y1;
};
S f3()
{
return {};
}
auto [ x1, y1 ] = f1();
auto& [ xr1, yr1 ] = f1();
auto [ x2, y2 ] = f2();
auto& [ xr2, yr2 ] = f2();
const auto [ x3, y3 ] = f3();
}
namespace test_exception_spec_type_system
{
struct Good {};
struct Bad {};
void g1() noexcept;
void g2();
template<typename T>
Bad
f(T*, T*);
template<typename T1, typename T2>
Good
f(T1*, T2*);
static_assert (std::is_same_v<Good, decltype(f(g1, g2))>);
}
namespace test_inline_variables
{
template<class T> void f(T)
{}
template<class T> inline T g(T)
{
return T{};
}
template<> inline void f<>(int)
{}
template<> int g<>(int)
{
return 5;
}
}
} // namespace cxx17
#endif // __cplusplus < 201703L && !defined _MSC_VER
]])
dnl Tests for new features in C++20
m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[
#ifndef __cplusplus
#error "This is not a C++ compiler"
#elif __cplusplus < 202002L && !defined _MSC_VER
#error "This is not a C++20 compiler"
#else
#include <version>
namespace cxx20
{
// As C++20 supports feature test macros in the standard, there is no
// immediate need to actually test for feature availability on the
// Autoconf side.
} // namespace cxx20
#endif // __cplusplus < 202002L && !defined _MSC_VER
]])