| Message ID | 20211104183322.2123606-1-jwakely@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [committed] libstdc++: Optimize std::tuple_element and std::tuple_size_v | expand |
On Thu, Nov 4, 2021 at 2:34 PM Jonathan Wakely via Libstdc++ <libstdc++@gcc.gnu.org> wrote: > > Tested powerpc64le-linux, committed to trunk. > > > This reduces the number of class template instantiations needed for code > using tuples, by reusing _Nth_type in tuple_element and specializing > tuple_size_v for tuple, pair and array (and const-qualified versions of > them). > > Also define the _Nth_type primary template as a complete type (but with > no nested 'type' member). This avoids "invalid use of incomplete type" > errors for out-of-range specializations of tuple_element. Those errors > would probably be confusing and unhelpful for users. We already have > a user-friendly static assert in tuple_element itself. > > Also ensure that tuple_size_v is available whenever tuple_size is (as > proposed by LWG 3387). We already do that for tuple_element_t. > > libstdc++-v3/ChangeLog: > > * include/bits/stl_pair.h (tuple_size_v): Define partial > specializations for std::pair. > * include/bits/utility.h (_Nth_type): Move definition here > and define primary template. > (tuple_size_v): Move definition here. > * include/std/array (tuple_size_v): Define partial > specializations for std::array. > * include/std/tuple (tuple_size_v): Move primary template to > <bits/utility.h>. Define partial specializations for > std::tuple. > (tuple_element): Change definition to use _Nth_type. > * include/std/variant (_Nth_type): Move to <bits/utility.h>. > (variant_alternative, variant): Adjust qualification of > _Nth_type. > * testsuite/20_util/tuple/element_access/get_neg.cc: Prune > additional errors from _Nth_type. > --- > libstdc++-v3/include/bits/stl_pair.h | 8 +++ > libstdc++-v3/include/bits/utility.h | 51 +++++++++++++++- > libstdc++-v3/include/std/array | 8 +++ > libstdc++-v3/include/std/tuple | 39 +++++-------- > libstdc++-v3/include/std/variant | 58 ++----------------- > .../20_util/tuple/element_access/get_neg.cc | 1 + > 6 files changed, 84 insertions(+), 81 deletions(-) > > diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h > index 5b400daf97f..6081e0c7fe9 100644 > --- a/libstdc++-v3/include/bits/stl_pair.h > +++ b/libstdc++-v3/include/bits/stl_pair.h > @@ -771,6 +771,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > struct tuple_element<1, pair<_Tp1, _Tp2>> > { typedef _Tp2 type; }; > > +#if __cplusplus >= 201703L > + template<typename _Tp1, typename _Tp2> > + inline constexpr size_t tuple_size_v<pair<_Tp1, _Tp2>> = 2; > + > + template<typename _Tp1, typename _Tp2> > + inline constexpr size_t tuple_size_v<const pair<_Tp1, _Tp2>> = 2; > +#endif > + > /// @cond undocumented > template<size_t _Int> > struct __pair_get; > diff --git a/libstdc++-v3/include/bits/utility.h b/libstdc++-v3/include/bits/utility.h > index fce52a4530d..c9ffa008217 100644 > --- a/libstdc++-v3/include/bits/utility.h > +++ b/libstdc++-v3/include/bits/utility.h > @@ -70,6 +70,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>> > : public tuple_size<_Tp> { }; > > +#if __cplusplus >= 201703L > + template<typename _Tp> > + inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; > +#endif > + > /// Gives the type of the ith element of a given tuple type. > template<size_t __i, typename _Tp> > struct tuple_element; > @@ -97,8 +102,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > }; > > #if __cplusplus >= 201402L > -// The standard says this macro and alias template should be in <tuple> > -// but we define them here, to be available in <utility> and <array> too. > +// The standard says this macro and alias template should be in <tuple> but we > +// we define them here, to be available in <array>, <utility> and <ranges> too. > +// _GLIBCXX_RESOLVE_LIB_DEFECTS > +// 3378. tuple_size_v/tuple_element_t should be available when > +// tuple_size/tuple_element are > #define __cpp_lib_tuple_element_t 201402L > > template<size_t __i, typename _Tp> > @@ -195,6 +203,45 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > #endif // C++17 > #endif // C++14 > > + template<size_t _Np, typename... _Types> > + struct _Nth_type > + { }; > + > + template<typename _Tp0, typename... _Rest> > + struct _Nth_type<0, _Tp0, _Rest...> > + { using type = _Tp0; }; > + > + template<typename _Tp0, typename _Tp1, typename... _Rest> > + struct _Nth_type<1, _Tp0, _Tp1, _Rest...> > + { using type = _Tp1; }; > + > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > + struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...> > + { using type = _Tp2; }; > + > + template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2, > + typename... _Rest> > +#if __cpp_concepts > + requires (_Np >= 3) > +#endif > + struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...> > + : _Nth_type<_Np - 3, _Rest...> > + { }; > + > +#if ! __cpp_concepts // Need additional specializations to avoid ambiguities. > + template<typename _Tp0, typename _Tp1, typename... _Rest> > + struct _Nth_type<0, _Tp0, _Tp1, _Rest...> > + { using type = _Tp0; }; > + > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > + struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...> > + { using type = _Tp0; }; > + > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > + struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...> > + { using type = _Tp1; }; > +#endif > + > _GLIBCXX_END_NAMESPACE_VERSION > } // namespace > > diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array > index 3e12d35157c..413f8e2be01 100644 > --- a/libstdc++-v3/include/std/array > +++ b/libstdc++-v3/include/std/array > @@ -481,6 +481,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > using type = _Tp; > }; > > +#if __cplusplus >= 201703L > + template<typename _Tp, size_t _Nm> > + inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm; > + > + template<typename _Tp, size_t _Nm> > + inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm; > +#endif > + > template<typename _Tp, size_t _Nm> > struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type > { }; > diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple > index aaee0b8826a..b82cdf12569 100644 > --- a/libstdc++-v3/include/std/tuple > +++ b/libstdc++-v3/include/std/tuple > @@ -1344,36 +1344,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > struct tuple_size<tuple<_Elements...>> > : public integral_constant<size_t, sizeof...(_Elements)> { }; > > -#if __cplusplus > 201402L > - template <typename _Tp> > - inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; > +#if __cplusplus >= 201703L > + template<typename... _Types> > + inline constexpr size_t tuple_size_v<tuple<_Types>> Missing ... after _Types? > + = sizeof...(_Types); > + > + template<typename... _Types> > + inline constexpr size_t tuple_size_v<const tuple<_Types>> Same here. (I guess now's a good time to fix PR100652!) > + = sizeof...(_Types); > #endif > > - /** > - * Recursive case for tuple_element: strip off the first element in > - * the tuple and retrieve the (i-1)th element of the remaining tuple. > - */ > - template<size_t __i, typename _Head, typename... _Tail> > - struct tuple_element<__i, tuple<_Head, _Tail...> > > - : tuple_element<__i - 1, tuple<_Tail...> > { }; > - > - /** > - * Basis case for tuple_element: The first element is the one we're seeking. > - */ > - template<typename _Head, typename... _Tail> > - struct tuple_element<0, tuple<_Head, _Tail...> > > + /// Trait to get the Ith element type from a tuple. > + template<size_t __i, typename... _Types> > + struct tuple_element<__i, tuple<_Types...>> > { > - typedef _Head type; > - }; > + static_assert(__i < sizeof...(_Types), "tuple index must be in range"); > > - /** > - * Error case for tuple_element: invalid index. > - */ > - template<size_t __i> > - struct tuple_element<__i, tuple<>> > - { > - static_assert(__i < tuple_size<tuple<>>::value, > - "tuple index must be in range"); > + using type = typename _Nth_type<__i, _Types...>::type; > }; > > template<size_t __i, typename _Head, typename... _Tail> > diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant > index c4c307b7bb2..993ce3dba91 100644 > --- a/libstdc++-v3/include/std/variant > +++ b/libstdc++-v3/include/std/variant > @@ -54,51 +54,6 @@ namespace std _GLIBCXX_VISIBILITY(default) > { > _GLIBCXX_BEGIN_NAMESPACE_VERSION > > -namespace __detail > -{ > -namespace __variant > -{ > - template<size_t _Np, typename... _Types> > - struct _Nth_type; > - > - template<typename _Tp0, typename... _Rest> > - struct _Nth_type<0, _Tp0, _Rest...> > - { using type = _Tp0; }; > - > - template<typename _Tp0, typename _Tp1, typename... _Rest> > - struct _Nth_type<1, _Tp0, _Tp1, _Rest...> > - { using type = _Tp1; }; > - > - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > - struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...> > - { using type = _Tp2; }; > - > - template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2, > - typename... _Rest> > -#if __cpp_concepts > - requires (_Np >= 3) > -#endif > - struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...> > - : _Nth_type<_Np - 3, _Rest...> > - { }; > - > -#if ! __cpp_concepts // Need additional specializations to avoid ambiguities. > - template<typename _Tp0, typename _Tp1, typename... _Rest> > - struct _Nth_type<0, _Tp0, _Tp1, _Rest...> > - { using type = _Tp0; }; > - > - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > - struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...> > - { using type = _Tp0; }; > - > - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> > - struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...> > - { using type = _Tp1; }; > -#endif > - > -} // namespace __variant > -} // namespace __detail > - > #if __cplusplus >= 202002L && __cpp_concepts > // P2231R1 constexpr needs constexpr unions and constrained destructors. > # define __cpp_lib_variant 202106L > @@ -145,8 +100,7 @@ namespace __variant > { > static_assert(_Np < sizeof...(_Types)); > > - using type > - = typename __detail::__variant::_Nth_type<_Np, _Types...>::type; > + using type = typename _Nth_type<_Np, _Types...>::type; > }; > > template<size_t _Np, typename _Variant> > @@ -1442,8 +1396,7 @@ namespace __variant > = __detail::__variant::__accepted_index<_Tp, variant>::value; > > template<size_t _Np, typename = enable_if_t<(_Np < sizeof...(_Types))>> > - using __to_type > - = typename __detail::__variant::_Nth_type<_Np, _Types...>::type; > + using __to_type = typename _Nth_type<_Np, _Types...>::type; > > template<typename _Tp, typename = enable_if_t<__not_self<_Tp>>> > using __accepted_type = __to_type<__accepted_index<_Tp>>; > @@ -1580,7 +1533,7 @@ namespace __variant > emplace(_Args&&... __args) > { > namespace __variant = std::__detail::__variant; > - using type = typename __variant::_Nth_type<_Np, _Types...>::type; > + using type = typename _Nth_type<_Np, _Types...>::type; > // Provide the strong exception-safety guarantee when possible, > // to avoid becoming valueless. > if constexpr (is_nothrow_constructible_v<type, _Args...>) > @@ -1620,7 +1573,7 @@ namespace __variant > emplace(initializer_list<_Up> __il, _Args&&... __args) > { > namespace __variant = std::__detail::__variant; > - using type = typename __variant::_Nth_type<_Np, _Types...>::type; > + using type = typename _Nth_type<_Np, _Types...>::type; > // Provide the strong exception-safety guarantee when possible, > // to avoid becoming valueless. > if constexpr (is_nothrow_constructible_v<type, > @@ -1803,8 +1756,7 @@ namespace __variant > constexpr size_t __max = 11; // "These go to eleven." > > // The type of the first variant in the pack. > - using _V0 > - = typename __detail::__variant::_Nth_type<0, _Variants...>::type; > + using _V0 = typename _Nth_type<0, _Variants...>::type; > // The number of alternatives in that first variant. > constexpr auto __n = variant_size_v<remove_reference_t<_V0>>; > > diff --git a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc > index 225bb6245a6..113a7fd62de 100644 > --- a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc > +++ b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc > @@ -60,3 +60,4 @@ test03() > } > > // { dg-error "tuple index must be in range" "" { target *-*-* } 0 } > +// { dg-prune-output "no type named 'type' in .*_Nth_type" } > -- > 2.31.1 >
On Fri, 5 Nov 2021 at 21:19, Patrick Palka <ppalka@redhat.com> wrote: > On Thu, Nov 4, 2021 at 2:34 PM Jonathan Wakely via Libstdc++ > <libstdc++@gcc.gnu.org> wrote: > > > > Tested powerpc64le-linux, committed to trunk. > > > > > > This reduces the number of class template instantiations needed for code > > using tuples, by reusing _Nth_type in tuple_element and specializing > > tuple_size_v for tuple, pair and array (and const-qualified versions of > > them). > > > > Also define the _Nth_type primary template as a complete type (but with > > no nested 'type' member). This avoids "invalid use of incomplete type" > > errors for out-of-range specializations of tuple_element. Those errors > > would probably be confusing and unhelpful for users. We already have > > a user-friendly static assert in tuple_element itself. > > > > Also ensure that tuple_size_v is available whenever tuple_size is (as > > proposed by LWG 3387). We already do that for tuple_element_t. > > > > libstdc++-v3/ChangeLog: > > > > * include/bits/stl_pair.h (tuple_size_v): Define partial > > specializations for std::pair. > > * include/bits/utility.h (_Nth_type): Move definition here > > and define primary template. > > (tuple_size_v): Move definition here. > > * include/std/array (tuple_size_v): Define partial > > specializations for std::array. > > * include/std/tuple (tuple_size_v): Move primary template to > > <bits/utility.h>. Define partial specializations for > > std::tuple. > > (tuple_element): Change definition to use _Nth_type. > > * include/std/variant (_Nth_type): Move to <bits/utility.h>. > > (variant_alternative, variant): Adjust qualification of > > _Nth_type. > > * testsuite/20_util/tuple/element_access/get_neg.cc: Prune > > additional errors from _Nth_type. > > --- > > libstdc++-v3/include/bits/stl_pair.h | 8 +++ > > libstdc++-v3/include/bits/utility.h | 51 +++++++++++++++- > > libstdc++-v3/include/std/array | 8 +++ > > libstdc++-v3/include/std/tuple | 39 +++++-------- > > libstdc++-v3/include/std/variant | 58 ++----------------- > > .../20_util/tuple/element_access/get_neg.cc | 1 + > > 6 files changed, 84 insertions(+), 81 deletions(-) > > > > diff --git a/libstdc++-v3/include/bits/stl_pair.h > b/libstdc++-v3/include/bits/stl_pair.h > > index 5b400daf97f..6081e0c7fe9 100644 > > --- a/libstdc++-v3/include/bits/stl_pair.h > > +++ b/libstdc++-v3/include/bits/stl_pair.h > > @@ -771,6 +771,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > struct tuple_element<1, pair<_Tp1, _Tp2>> > > { typedef _Tp2 type; }; > > > > +#if __cplusplus >= 201703L > > + template<typename _Tp1, typename _Tp2> > > + inline constexpr size_t tuple_size_v<pair<_Tp1, _Tp2>> = 2; > > + > > + template<typename _Tp1, typename _Tp2> > > + inline constexpr size_t tuple_size_v<const pair<_Tp1, _Tp2>> = 2; > > +#endif > > + > > /// @cond undocumented > > template<size_t _Int> > > struct __pair_get; > > diff --git a/libstdc++-v3/include/bits/utility.h > b/libstdc++-v3/include/bits/utility.h > > index fce52a4530d..c9ffa008217 100644 > > --- a/libstdc++-v3/include/bits/utility.h > > +++ b/libstdc++-v3/include/bits/utility.h > > @@ -70,6 +70,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>> > > : public tuple_size<_Tp> { }; > > > > +#if __cplusplus >= 201703L > > + template<typename _Tp> > > + inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; > > +#endif > > + > > /// Gives the type of the ith element of a given tuple type. > > template<size_t __i, typename _Tp> > > struct tuple_element; > > @@ -97,8 +102,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > }; > > > > #if __cplusplus >= 201402L > > -// The standard says this macro and alias template should be in <tuple> > > -// but we define them here, to be available in <utility> and <array> > too. > > +// The standard says this macro and alias template should be in <tuple> > but we > > +// we define them here, to be available in <array>, <utility> and > <ranges> too. > > +// _GLIBCXX_RESOLVE_LIB_DEFECTS > > +// 3378. tuple_size_v/tuple_element_t should be available when > > +// tuple_size/tuple_element are > > #define __cpp_lib_tuple_element_t 201402L > > > > template<size_t __i, typename _Tp> > > @@ -195,6 +203,45 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > #endif // C++17 > > #endif // C++14 > > > > + template<size_t _Np, typename... _Types> > > + struct _Nth_type > > + { }; > > + > > + template<typename _Tp0, typename... _Rest> > > + struct _Nth_type<0, _Tp0, _Rest...> > > + { using type = _Tp0; }; > > + > > + template<typename _Tp0, typename _Tp1, typename... _Rest> > > + struct _Nth_type<1, _Tp0, _Tp1, _Rest...> > > + { using type = _Tp1; }; > > + > > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... > _Rest> > > + struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...> > > + { using type = _Tp2; }; > > + > > + template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2, > > + typename... _Rest> > > +#if __cpp_concepts > > + requires (_Np >= 3) > > +#endif > > + struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...> > > + : _Nth_type<_Np - 3, _Rest...> > > + { }; > > + > > +#if ! __cpp_concepts // Need additional specializations to avoid > ambiguities. > > + template<typename _Tp0, typename _Tp1, typename... _Rest> > > + struct _Nth_type<0, _Tp0, _Tp1, _Rest...> > > + { using type = _Tp0; }; > > + > > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... > _Rest> > > + struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...> > > + { using type = _Tp0; }; > > + > > + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... > _Rest> > > + struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...> > > + { using type = _Tp1; }; > > +#endif > > + > > _GLIBCXX_END_NAMESPACE_VERSION > > } // namespace > > > > diff --git a/libstdc++-v3/include/std/array > b/libstdc++-v3/include/std/array > > index 3e12d35157c..413f8e2be01 100644 > > --- a/libstdc++-v3/include/std/array > > +++ b/libstdc++-v3/include/std/array > > @@ -481,6 +481,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > using type = _Tp; > > }; > > > > +#if __cplusplus >= 201703L > > + template<typename _Tp, size_t _Nm> > > + inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm; > > + > > + template<typename _Tp, size_t _Nm> > > + inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm; > > +#endif > > + > > template<typename _Tp, size_t _Nm> > > struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type > > { }; > > diff --git a/libstdc++-v3/include/std/tuple > b/libstdc++-v3/include/std/tuple > > index aaee0b8826a..b82cdf12569 100644 > > --- a/libstdc++-v3/include/std/tuple > > +++ b/libstdc++-v3/include/std/tuple > > @@ -1344,36 +1344,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > > struct tuple_size<tuple<_Elements...>> > > : public integral_constant<size_t, sizeof...(_Elements)> { }; > > > > -#if __cplusplus > 201402L > > - template <typename _Tp> > > - inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; > > +#if __cplusplus >= 201703L > > + template<typename... _Types> > > + inline constexpr size_t tuple_size_v<tuple<_Types>> > > Missing ... after _Types? > > > + = sizeof...(_Types); > > + > > + template<typename... _Types> > > + inline constexpr size_t tuple_size_v<const tuple<_Types>> > > Same here. (I guess now's a good time to fix PR100652!) > > > Oops! Fixed by the attached patch, pushed to trunk. Thanks. commit 70d6f6e41f77269f7d293c6fbccf978680e68d2a Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Nov 5 21:40:58 2021 libstdc++: Fix pack expansions in tuple_size_v specializations libstdc++-v3/ChangeLog: * include/std/tuple (tuple_size_v): Fix pack expansion. diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple index 46173935b64..36dc05d97bc 100644 --- a/libstdc++-v3/include/std/tuple +++ b/libstdc++-v3/include/std/tuple @@ -1346,11 +1346,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #if __cplusplus >= 201703L template<typename... _Types> - inline constexpr size_t tuple_size_v<tuple<_Types>> + inline constexpr size_t tuple_size_v<tuple<_Types...>> = sizeof...(_Types); template<typename... _Types> - inline constexpr size_t tuple_size_v<const tuple<_Types>> + inline constexpr size_t tuple_size_v<const tuple<_Types...>> = sizeof...(_Types); #endif
diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h index 5b400daf97f..6081e0c7fe9 100644 --- a/libstdc++-v3/include/bits/stl_pair.h +++ b/libstdc++-v3/include/bits/stl_pair.h @@ -771,6 +771,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION struct tuple_element<1, pair<_Tp1, _Tp2>> { typedef _Tp2 type; }; +#if __cplusplus >= 201703L + template<typename _Tp1, typename _Tp2> + inline constexpr size_t tuple_size_v<pair<_Tp1, _Tp2>> = 2; + + template<typename _Tp1, typename _Tp2> + inline constexpr size_t tuple_size_v<const pair<_Tp1, _Tp2>> = 2; +#endif + /// @cond undocumented template<size_t _Int> struct __pair_get; diff --git a/libstdc++-v3/include/bits/utility.h b/libstdc++-v3/include/bits/utility.h index fce52a4530d..c9ffa008217 100644 --- a/libstdc++-v3/include/bits/utility.h +++ b/libstdc++-v3/include/bits/utility.h @@ -70,6 +70,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION struct tuple_size<const volatile __enable_if_has_tuple_size<_Tp>> : public tuple_size<_Tp> { }; +#if __cplusplus >= 201703L + template<typename _Tp> + inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; +#endif + /// Gives the type of the ith element of a given tuple type. template<size_t __i, typename _Tp> struct tuple_element; @@ -97,8 +102,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION }; #if __cplusplus >= 201402L -// The standard says this macro and alias template should be in <tuple> -// but we define them here, to be available in <utility> and <array> too. +// The standard says this macro and alias template should be in <tuple> but we +// we define them here, to be available in <array>, <utility> and <ranges> too. +// _GLIBCXX_RESOLVE_LIB_DEFECTS +// 3378. tuple_size_v/tuple_element_t should be available when +// tuple_size/tuple_element are #define __cpp_lib_tuple_element_t 201402L template<size_t __i, typename _Tp> @@ -195,6 +203,45 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION #endif // C++17 #endif // C++14 + template<size_t _Np, typename... _Types> + struct _Nth_type + { }; + + template<typename _Tp0, typename... _Rest> + struct _Nth_type<0, _Tp0, _Rest...> + { using type = _Tp0; }; + + template<typename _Tp0, typename _Tp1, typename... _Rest> + struct _Nth_type<1, _Tp0, _Tp1, _Rest...> + { using type = _Tp1; }; + + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> + struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...> + { using type = _Tp2; }; + + template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2, + typename... _Rest> +#if __cpp_concepts + requires (_Np >= 3) +#endif + struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...> + : _Nth_type<_Np - 3, _Rest...> + { }; + +#if ! __cpp_concepts // Need additional specializations to avoid ambiguities. + template<typename _Tp0, typename _Tp1, typename... _Rest> + struct _Nth_type<0, _Tp0, _Tp1, _Rest...> + { using type = _Tp0; }; + + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> + struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...> + { using type = _Tp0; }; + + template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> + struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...> + { using type = _Tp1; }; +#endif + _GLIBCXX_END_NAMESPACE_VERSION } // namespace diff --git a/libstdc++-v3/include/std/array b/libstdc++-v3/include/std/array index 3e12d35157c..413f8e2be01 100644 --- a/libstdc++-v3/include/std/array +++ b/libstdc++-v3/include/std/array @@ -481,6 +481,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION using type = _Tp; }; +#if __cplusplus >= 201703L + template<typename _Tp, size_t _Nm> + inline constexpr size_t tuple_size_v<array<_Tp, _Nm>> = _Nm; + + template<typename _Tp, size_t _Nm> + inline constexpr size_t tuple_size_v<const array<_Tp, _Nm>> = _Nm; +#endif + template<typename _Tp, size_t _Nm> struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type { }; diff --git a/libstdc++-v3/include/std/tuple b/libstdc++-v3/include/std/tuple index aaee0b8826a..b82cdf12569 100644 --- a/libstdc++-v3/include/std/tuple +++ b/libstdc++-v3/include/std/tuple @@ -1344,36 +1344,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION struct tuple_size<tuple<_Elements...>> : public integral_constant<size_t, sizeof...(_Elements)> { }; -#if __cplusplus > 201402L - template <typename _Tp> - inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value; +#if __cplusplus >= 201703L + template<typename... _Types> + inline constexpr size_t tuple_size_v<tuple<_Types>> + = sizeof...(_Types); + + template<typename... _Types> + inline constexpr size_t tuple_size_v<const tuple<_Types>> + = sizeof...(_Types); #endif - /** - * Recursive case for tuple_element: strip off the first element in - * the tuple and retrieve the (i-1)th element of the remaining tuple. - */ - template<size_t __i, typename _Head, typename... _Tail> - struct tuple_element<__i, tuple<_Head, _Tail...> > - : tuple_element<__i - 1, tuple<_Tail...> > { }; - - /** - * Basis case for tuple_element: The first element is the one we're seeking. - */ - template<typename _Head, typename... _Tail> - struct tuple_element<0, tuple<_Head, _Tail...> > + /// Trait to get the Ith element type from a tuple. + template<size_t __i, typename... _Types> + struct tuple_element<__i, tuple<_Types...>> { - typedef _Head type; - }; + static_assert(__i < sizeof...(_Types), "tuple index must be in range"); - /** - * Error case for tuple_element: invalid index. - */ - template<size_t __i> - struct tuple_element<__i, tuple<>> - { - static_assert(__i < tuple_size<tuple<>>::value, - "tuple index must be in range"); + using type = typename _Nth_type<__i, _Types...>::type; }; template<size_t __i, typename _Head, typename... _Tail> diff --git a/libstdc++-v3/include/std/variant b/libstdc++-v3/include/std/variant index c4c307b7bb2..993ce3dba91 100644 --- a/libstdc++-v3/include/std/variant +++ b/libstdc++-v3/include/std/variant @@ -54,51 +54,6 @@ namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION -namespace __detail -{ -namespace __variant -{ - template<size_t _Np, typename... _Types> - struct _Nth_type; - - template<typename _Tp0, typename... _Rest> - struct _Nth_type<0, _Tp0, _Rest...> - { using type = _Tp0; }; - - template<typename _Tp0, typename _Tp1, typename... _Rest> - struct _Nth_type<1, _Tp0, _Tp1, _Rest...> - { using type = _Tp1; }; - - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> - struct _Nth_type<2, _Tp0, _Tp1, _Tp2, _Rest...> - { using type = _Tp2; }; - - template<size_t _Np, typename _Tp0, typename _Tp1, typename _Tp2, - typename... _Rest> -#if __cpp_concepts - requires (_Np >= 3) -#endif - struct _Nth_type<_Np, _Tp0, _Tp1, _Tp2, _Rest...> - : _Nth_type<_Np - 3, _Rest...> - { }; - -#if ! __cpp_concepts // Need additional specializations to avoid ambiguities. - template<typename _Tp0, typename _Tp1, typename... _Rest> - struct _Nth_type<0, _Tp0, _Tp1, _Rest...> - { using type = _Tp0; }; - - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> - struct _Nth_type<0, _Tp0, _Tp1, _Tp2, _Rest...> - { using type = _Tp0; }; - - template<typename _Tp0, typename _Tp1, typename _Tp2, typename... _Rest> - struct _Nth_type<1, _Tp0, _Tp1, _Tp2, _Rest...> - { using type = _Tp1; }; -#endif - -} // namespace __variant -} // namespace __detail - #if __cplusplus >= 202002L && __cpp_concepts // P2231R1 constexpr needs constexpr unions and constrained destructors. # define __cpp_lib_variant 202106L @@ -145,8 +100,7 @@ namespace __variant { static_assert(_Np < sizeof...(_Types)); - using type - = typename __detail::__variant::_Nth_type<_Np, _Types...>::type; + using type = typename _Nth_type<_Np, _Types...>::type; }; template<size_t _Np, typename _Variant> @@ -1442,8 +1396,7 @@ namespace __variant = __detail::__variant::__accepted_index<_Tp, variant>::value; template<size_t _Np, typename = enable_if_t<(_Np < sizeof...(_Types))>> - using __to_type - = typename __detail::__variant::_Nth_type<_Np, _Types...>::type; + using __to_type = typename _Nth_type<_Np, _Types...>::type; template<typename _Tp, typename = enable_if_t<__not_self<_Tp>>> using __accepted_type = __to_type<__accepted_index<_Tp>>; @@ -1580,7 +1533,7 @@ namespace __variant emplace(_Args&&... __args) { namespace __variant = std::__detail::__variant; - using type = typename __variant::_Nth_type<_Np, _Types...>::type; + using type = typename _Nth_type<_Np, _Types...>::type; // Provide the strong exception-safety guarantee when possible, // to avoid becoming valueless. if constexpr (is_nothrow_constructible_v<type, _Args...>) @@ -1620,7 +1573,7 @@ namespace __variant emplace(initializer_list<_Up> __il, _Args&&... __args) { namespace __variant = std::__detail::__variant; - using type = typename __variant::_Nth_type<_Np, _Types...>::type; + using type = typename _Nth_type<_Np, _Types...>::type; // Provide the strong exception-safety guarantee when possible, // to avoid becoming valueless. if constexpr (is_nothrow_constructible_v<type, @@ -1803,8 +1756,7 @@ namespace __variant constexpr size_t __max = 11; // "These go to eleven." // The type of the first variant in the pack. - using _V0 - = typename __detail::__variant::_Nth_type<0, _Variants...>::type; + using _V0 = typename _Nth_type<0, _Variants...>::type; // The number of alternatives in that first variant. constexpr auto __n = variant_size_v<remove_reference_t<_V0>>; diff --git a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc index 225bb6245a6..113a7fd62de 100644 --- a/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc +++ b/libstdc++-v3/testsuite/20_util/tuple/element_access/get_neg.cc @@ -60,3 +60,4 @@ test03() } // { dg-error "tuple index must be in range" "" { target *-*-* } 0 } +// { dg-prune-output "no type named 'type' in .*_Nth_type" }