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[libc++] Simplify the implementation of __tuple_leaf
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8 files changed

+146
-154
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8 files changed

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-154
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‎libcxx/include/CMakeLists.txt‎

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@@ -863,6 +863,7 @@ set(files
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__utility/as_lvalue.h
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__utility/auto_cast.h
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__utility/cmp.h
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__utility/conditional_no_unique_address.h
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__utility/convert_to_integral.h
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__utility/declval.h
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__utility/empty.h

‎libcxx/include/__expected/expected.h‎

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@@ -40,6 +40,7 @@
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#include <__type_traits/remove_cv.h>
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#include <__type_traits/remove_cvref.h>
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#include <__utility/as_const.h>
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#include <__utility/conditional_no_unique_address.h>
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#include <__utility/exception_guard.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
@@ -81,55 +82,6 @@ _LIBCPP_HIDE_FROM_ABI void __throw_bad_expected_access(_Arg&& __arg) {
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# endif
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}
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// If parameter type `_Tp` of `__conditional_no_unique_address` is neither
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// copyable nor movable, a constructor with this tag is provided. For that
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// constructor, the user has to provide a function and arguments. The function
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// must return an object of type `_Tp`. When the function is invoked by the
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// constructor, guaranteed copy elision kicks in and the `_Tp` is constructed
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// in place.
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struct __conditional_no_unique_address_invoke_tag {};
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// This class implements an object with `[[no_unique_address]]` conditionally applied to it,
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// based on the value of `_NoUnique`.
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//
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// A member of this class must always have `[[no_unique_address]]` applied to
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// it. Otherwise, the `[[no_unique_address]]` in the "`_NoUnique == true`" case
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// would not have any effect. In the `false` case, the `__v` is not
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// `[[no_unique_address]]`, so nullifies the effects of the "outer"
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// `[[no_unique_address]]` regarding data layout.
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//
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// If we had a language feature, this class would basically be replaced by `[[no_unique_address(condition)]]`.
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template <bool _NoUnique, class _Tp>
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struct __conditional_no_unique_address;
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template <class _Tp>
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struct __conditional_no_unique_address<true, _Tp> {
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template <class... _Args>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit __conditional_no_unique_address(in_place_t, _Args&&... __args)
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: __v(std::forward<_Args>(__args)...) {}
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template <class _Func, class... _Args>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit __conditional_no_unique_address(
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__conditional_no_unique_address_invoke_tag, _Func&& __f, _Args&&... __args)
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: __v(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
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_LIBCPP_NO_UNIQUE_ADDRESS _Tp __v;
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};
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template <class _Tp>
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struct __conditional_no_unique_address<false, _Tp> {
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template <class... _Args>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit __conditional_no_unique_address(in_place_t, _Args&&... __args)
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: __v(std::forward<_Args>(__args)...) {}
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template <class _Func, class... _Args>
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_LIBCPP_HIDE_FROM_ABI constexpr explicit __conditional_no_unique_address(
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__conditional_no_unique_address_invoke_tag, _Func&& __f, _Args&&... __args)
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: __v(std::invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
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_Tp __v;
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};
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// This function returns whether the type `_Second` can be stuffed into the tail padding
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// of the `_First` type if both of them are given `[[no_unique_address]]`.
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template <class _First, class _Second>

‎libcxx/include/__utility/conditional_no_unique_address.h‎

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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___UTILITY_CONDITIONAL_NO_UNIQUE_ADDRESS_H
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#define _LIBCPP___UTILITY_CONDITIONAL_NO_UNIQUE_ADDRESS_H
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#include <__config>
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#include <__type_traits/invoke.h>
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#include <__type_traits/is_swappable.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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// If parameter type `_Tp` of `__conditional_no_unique_address` is neither
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// copyable nor movable, a constructor with this tag is provided. For that
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// constructor, the user has to provide a function and arguments. The function
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// must return an object of type `_Tp`. When the function is invoked by the
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// constructor, guaranteed copy elision kicks in and the `_Tp` is constructed
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// in place.
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struct __conditional_no_unique_address_invoke_tag {};
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// This class implements an object with `[[no_unique_address]]` conditionally applied to it,
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// based on the value of `_NoUnique`.
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//
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// A member of this class must always have `[[no_unique_address]]` applied to
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// it. Otherwise, the `[[no_unique_address]]` in the "`_NoUnique == true`" case
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// would not have any effect. In the `false` case, the `__v` is not
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// `[[no_unique_address]]`, so nullifies the effects of the "outer"
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// `[[no_unique_address]]` regarding data layout.
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//
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// If we had a language feature, this class would basically be replaced by `[[no_unique_address(condition)]]`.
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template <bool _NoUnique, class _Tp>
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struct __conditional_no_unique_address;
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template <class _Tp>
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struct __conditional_no_unique_address<true, _Tp> {
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template <class... _Args>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __conditional_no_unique_address(__in_place_t, _Args&&... __args)
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: __v(std::forward<_Args>(__args)...) {}
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template <class _Func, class... _Args>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __conditional_no_unique_address(
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__conditional_no_unique_address_invoke_tag, _Func&& __f, _Args&&... __args)
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: __v(std::__invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
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_LIBCPP_NO_UNIQUE_ADDRESS _Tp __v;
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};
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template <class _Tp>
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struct __conditional_no_unique_address<false, _Tp> {
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template <class... _Args>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __conditional_no_unique_address(__in_place_t, _Args&&... __args)
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: __v(std::forward<_Args>(__args)...) {}
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template <class _Func, class... _Args>
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_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit __conditional_no_unique_address(
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__conditional_no_unique_address_invoke_tag, _Func&& __f, _Args&&... __args)
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: __v(std::__invoke(std::forward<_Func>(__f), std::forward<_Args>(__args)...)) {}
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_Tp __v;
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};
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template <bool _NoUnique, class _Tp>
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void swap(__conditional_no_unique_address<_NoUnique, _Tp>& __lhs,
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__conditional_no_unique_address<_NoUnique, _Tp>& __rhs) _NOEXCEPT_(__is_swappable_v<_Tp>) {
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using std::swap;
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swap(__lhs.__v, __rhs.__v);
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___UTILITY_CONDITIONAL_NO_UNIQUE_ADDRESS_H

‎libcxx/include/__utility/in_place.h‎

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@@ -59,6 +59,14 @@ using __is_inplace_index = __is_inplace_index_imp<__remove_cvref_t<_Tp>>;
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#endif // _LIBCPP_STD_VER >= 17
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struct __in_place_t {
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explicit __in_place_t() = default;
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#if _LIBCPP_STD_VER >= 17
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_LIBCPP_HIDE_FROM_ABI constexpr __in_place_t(in_place_t) {}
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#endif
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};
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inline const __in_place_t __in_place;
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___UTILITY_IN_PLACE_H

‎libcxx/include/module.modulemap‎

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@@ -1988,36 +1988,37 @@ module std [system] {
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}
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module utility {
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module as_const { header "__utility/as_const.h" }
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module as_lvalue { header "__utility/as_lvalue.h" }
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module auto_cast {
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module as_const { header "__utility/as_const.h" }
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module as_lvalue { header "__utility/as_lvalue.h" }
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module auto_cast {
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header "__utility/auto_cast.h"
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export std_core.type_traits.decay // the macro expansion uses that trait
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}
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module cmp { header "__utility/cmp.h" }
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module convert_to_integral { header "__utility/convert_to_integral.h" }
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module exception_guard { header "__utility/exception_guard.h" }
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module exchange { header "__utility/exchange.h" }
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module forward_like { header "__utility/forward_like.h" }
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module cmp { header "__utility/cmp.h" }
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module conditional_no_unique_address { header "__utility/conditional_no_unique_address.h" }
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module convert_to_integral { header "__utility/convert_to_integral.h" }
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module exception_guard { header "__utility/exception_guard.h" }
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module exchange { header "__utility/exchange.h" }
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module forward_like { header "__utility/forward_like.h" }
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module in_place {
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header "__utility/in_place.h"
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export std_core.type_traits.integral_constant
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}
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module integer_sequence { header "__utility/integer_sequence.h" }
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module is_pointer_in_range { header "__utility/is_pointer_in_range.h" }
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module is_valid_range { header "__utility/is_valid_range.h" }
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module move { header "__utility/move.h" }
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module no_destroy { header "__utility/no_destroy.h" }
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module pair { header "__utility/pair.h" }
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module piecewise_construct { header "__utility/piecewise_construct.h" }
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module priority_tag { header "__utility/priority_tag.h" }
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module private_constructor_tag { header "__utility/private_constructor_tag.h" }
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module rel_ops { header "__utility/rel_ops.h" }
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module scope_guard { header "__utility/scope_guard.h" }
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module small_buffer { header "__utility/small_buffer.h" }
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module swap { header "__utility/swap.h" }
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module to_underlying { header "__utility/to_underlying.h" }
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module unreachable { header "__utility/unreachable.h" }
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module integer_sequence { header "__utility/integer_sequence.h" }
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module is_pointer_in_range { header "__utility/is_pointer_in_range.h" }
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module is_valid_range { header "__utility/is_valid_range.h" }
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module move { header "__utility/move.h" }
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module no_destroy { header "__utility/no_destroy.h" }
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module pair { header "__utility/pair.h" }
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module piecewise_construct { header "__utility/piecewise_construct.h" }
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module priority_tag { header "__utility/priority_tag.h" }
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module private_constructor_tag { header "__utility/private_constructor_tag.h" }
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module rel_ops { header "__utility/rel_ops.h" }
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module scope_guard { header "__utility/scope_guard.h" }
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module small_buffer { header "__utility/small_buffer.h" }
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module swap { header "__utility/swap.h" }
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module to_underlying { header "__utility/to_underlying.h" }
2021+
module unreachable { header "__utility/unreachable.h" }
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header "utility"
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export *

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