[libcxx-commits] [libcxx] [libc++] Simplify the std::pair constructor overload set (PR #81448)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Feb 12 00:09:06 PST 2024
https://github.com/philnik777 created https://github.com/llvm/llvm-project/pull/81448
This depends on enabling extensions in the implementation.
>From 01068019c4a928e8190491a6b7dbed1dfda3e9b8 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Fri, 26 Jan 2024 12:11:12 +0100
Subject: [PATCH] [libc++] Simplify the std::pair constructor overload set
---
libcxx/include/__utility/pair.h | 101 ++++++++++----------------------
1 file changed, 30 insertions(+), 71 deletions(-)
diff --git a/libcxx/include/__utility/pair.h b/libcxx/include/__utility/pair.h
index 577e23198812b4..6469faee0c3835 100644
--- a/libcxx/include/__utility/pair.h
+++ b/libcxx/include/__utility/pair.h
@@ -120,14 +120,13 @@ struct _LIBCPP_TEMPLATE_VIS pair
#else
struct _CheckArgs {
template <int&...>
- static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_explicit_default() {
- return is_default_constructible<_T1>::value && is_default_constructible<_T2>::value &&
- !__enable_implicit_default<>();
+ static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_implicit_default() {
+ return __is_implicitly_default_constructible<_T1>::value && __is_implicitly_default_constructible<_T2>::value;
}
template <int&...>
- static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_implicit_default() {
- return __is_implicitly_default_constructible<_T1>::value && __is_implicitly_default_constructible<_T2>::value;
+ static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_default() {
+ return is_default_constructible<_T1>::value && is_default_constructible<_T2>::value;
}
template <class _U1, class _U2>
@@ -139,41 +138,22 @@ struct _LIBCPP_TEMPLATE_VIS pair
static _LIBCPP_HIDE_FROM_ABI constexpr bool __is_implicit() {
return is_convertible<_U1, first_type>::value && is_convertible<_U2, second_type>::value;
}
-
- template <class _U1, class _U2>
- static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_explicit() {
- return __is_pair_constructible<_U1, _U2>() && !__is_implicit<_U1, _U2>();
- }
-
- template <class _U1, class _U2>
- static _LIBCPP_HIDE_FROM_ABI constexpr bool __enable_implicit() {
- return __is_pair_constructible<_U1, _U2>() && __is_implicit<_U1, _U2>();
- }
};
template <bool _MaybeEnable>
using _CheckArgsDep _LIBCPP_NODEBUG =
typename conditional< _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
- template <bool _Dummy = true, __enable_if_t<_CheckArgsDep<_Dummy>::__enable_explicit_default(), int> = 0>
- explicit _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair() _NOEXCEPT_(
- is_nothrow_default_constructible<first_type>::value&& is_nothrow_default_constructible<second_type>::value)
- : first(), second() {}
-
- template <bool _Dummy = true, __enable_if_t<_CheckArgsDep<_Dummy>::__enable_implicit_default(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR pair() _NOEXCEPT_(
+ template <bool _Dummy = true, __enable_if_t<_CheckArgsDep<_Dummy>::__enable_default(), int> = 0>
+ explicit(!_CheckArgsDep<_Dummy>::__enable_implicit_default()) _LIBCPP_HIDE_FROM_ABI
+ _LIBCPP_CONSTEXPR pair() _NOEXCEPT_(
is_nothrow_default_constructible<first_type>::value&& is_nothrow_default_constructible<second_type>::value)
: first(), second() {}
- template <bool _Dummy = true,
- __enable_if_t<_CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit pair(_T1 const& __t1, _T2 const& __t2)
- _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value&& is_nothrow_copy_constructible<second_type>::value)
- : first(__t1), second(__t2) {}
-
- template <bool _Dummy = true,
- __enable_if_t<_CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair(_T1 const& __t1, _T2 const& __t2)
+ template <bool _Dummy = true,
+ __enable_if_t<_CheckArgsDep<_Dummy>::template __is_pair_constructible<_T1 const&, _T2 const&>(), int> = 0>
+ _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
+ !_CheckArgsDep<_Dummy>::template __is_implicit<_T1 const&, _T2 const&>()) pair(_T1 const& __t1, _T2 const& __t2)
_NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value&& is_nothrow_copy_constructible<second_type>::value)
: first(__t1), second(__t2) {}
@@ -185,23 +165,11 @@ struct _LIBCPP_TEMPLATE_VIS pair
class _U1,
class _U2,
# endif
- __enable_if_t<_CheckArgs::template __enable_explicit<_U1, _U2>(), int> = 0 >
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit pair(_U1&& __u1, _U2&& __u2)
- _NOEXCEPT_(is_nothrow_constructible<first_type, _U1>::value&& is_nothrow_constructible<second_type, _U2>::value)
- : first(std::forward<_U1>(__u1)), second(std::forward<_U2>(__u2)) {
- }
-
- template <
-# if _LIBCPP_STD_VER >= 23 // http://wg21.link/P1951
- class _U1 = _T1,
- class _U2 = _T2,
-# else
- class _U1,
- class _U2,
-# endif
- __enable_if_t<_CheckArgs::template __enable_implicit<_U1, _U2>(), int> = 0 >
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair(_U1&& __u1, _U2&& __u2)
- _NOEXCEPT_(is_nothrow_constructible<first_type, _U1>::value&& is_nothrow_constructible<second_type, _U2>::value)
+ __enable_if_t<_CheckArgs::template __is_pair_constructible<_U1, _U2>(), int> = 0 >
+ _LIBCPP_HIDE_FROM_ABI
+ _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(!_CheckArgs::template __is_implicit<_U1, _U2>()) pair(_U1&& __u1, _U2&& __u2)
+ _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
+ is_nothrow_constructible<second_type, _U2>::value))
: first(std::forward<_U1>(__u1)), second(std::forward<_U2>(__u2)) {
}
@@ -217,28 +185,19 @@ struct _LIBCPP_TEMPLATE_VIS pair
template <class _U1,
class _U2,
- __enable_if_t<_CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit pair(pair<_U1, _U2> const& __p)
- _NOEXCEPT_(is_nothrow_constructible<first_type, _U1 const&>::value&&
- is_nothrow_constructible<second_type, _U2 const&>::value)
- : first(__p.first), second(__p.second) {}
-
- template <class _U1,
- class _U2,
- __enable_if_t<_CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair(pair<_U1, _U2> const& __p)
- _NOEXCEPT_(is_nothrow_constructible<first_type, _U1 const&>::value&&
- is_nothrow_constructible<second_type, _U2 const&>::value)
+ __enable_if_t<_CheckArgs::template __is_pair_constructible<_U1 const&, _U2 const&>(), int> = 0>
+ _LIBCPP_HIDE_FROM_ABI
+ _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(!_CheckArgs::template __is_implicit<_U1 const&, _U2 const&>())
+ pair(pair<_U1, _U2> const& __p)
+ _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
+ is_nothrow_constructible<second_type, _U2 const&>::value))
: first(__p.first), second(__p.second) {}
- template <class _U1, class _U2, __enable_if_t<_CheckArgs::template __enable_explicit<_U1, _U2>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit pair(pair<_U1, _U2>&& __p) _NOEXCEPT_(
- is_nothrow_constructible<first_type, _U1&&>::value&& is_nothrow_constructible<second_type, _U2&&>::value)
- : first(std::forward<_U1>(__p.first)), second(std::forward<_U2>(__p.second)) {}
-
- template <class _U1, class _U2, __enable_if_t<_CheckArgs::template __enable_implicit<_U1, _U2>(), int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair(pair<_U1, _U2>&& __p) _NOEXCEPT_(
- is_nothrow_constructible<first_type, _U1&&>::value&& is_nothrow_constructible<second_type, _U2&&>::value)
+ template <class _U1, class _U2, __enable_if_t<_CheckArgs::template __is_pair_constructible<_U1, _U2>(), int> = 0>
+ _LIBCPP_HIDE_FROM_ABI
+ _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(!_CheckArgs::template __is_implicit<_U1, _U2>()) pair(pair<_U1, _U2>&& __p)
+ _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
+ is_nothrow_constructible<second_type, _U2&&>::value))
: first(std::forward<_U1>(__p.first)), second(std::forward<_U2>(__p.second)) {}
# if _LIBCPP_STD_VER >= 23
@@ -589,9 +548,9 @@ swap(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) noexcept(noexcept(__x
#endif
template <class _T1, class _T2>
-inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
- pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
- make_pair(_T1&& __t1, _T2&& __t2) {
+inline _LIBCPP_HIDE_FROM_ABI
+_LIBCPP_CONSTEXPR_SINCE_CXX14 pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
+make_pair(_T1&& __t1, _T2&& __t2) {
return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>(
std::forward<_T1>(__t1), std::forward<_T2>(__t2));
}
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