Replace __make_tuple_indices implementation with superior implementation.

The previous __make_tuple_indices implementation caused O(N) instantiations
and was pretty inefficient. The C++14 __make_integer_sequence implementation
is much better, since it either uses a builtin to generate the sequence or
a very nice Log8(N) implementation provided by richard smith.

This patch moves the __make_integer_sequence implementation into __tuple
and uses it to implement __make_tuple_indices.

Since libc++ can't expose the name 'integer_sequence' in C++11 this patch
also introduces a dummy type '__integer_sequence' which is used when generating
the sequence. One the sequence is generated '__integer_sequence' can be
converted into the required type; either '__tuple_indices' or 'integer_sequence'.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@274286 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier 2016-06-30 22:34:43 +00:00
parent 1a93312404
commit a3ccd96ede
2 changed files with 81 additions and 77 deletions

View File

@ -68,6 +68,80 @@ template <class _Tp> struct __tuple_like<const volatile _Tp> : public __tuple_li
// tuple specializations
#if !defined(_LIBCPP_HAS_NO_VARIADICS)
template <size_t...> struct __tuple_indices {};
template <class _IdxType, _IdxType... _Values>
struct __integer_sequence {
template <template <class _OIdxType, _OIdxType...> class _ToIndexSeq, class _ToIndexType>
using __convert = _ToIndexSeq<_ToIndexType, _Values...>;
template <size_t _Sp>
using __to_tuple_indices = __tuple_indices<(_Values + _Sp)...>;
};
#if !__has_builtin(__make_integer_seq) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
namespace __detail {
template<typename _Tp, size_t ..._Extra> struct __repeat;
template<typename _Tp, _Tp ..._Np, size_t ..._Extra> struct __repeat<__integer_sequence<_Tp, _Np...>, _Extra...> {
typedef __integer_sequence<_Tp,
_Np...,
sizeof...(_Np) + _Np...,
2 * sizeof...(_Np) + _Np...,
3 * sizeof...(_Np) + _Np...,
4 * sizeof...(_Np) + _Np...,
5 * sizeof...(_Np) + _Np...,
6 * sizeof...(_Np) + _Np...,
7 * sizeof...(_Np) + _Np...,
_Extra...> type;
};
template<size_t _Np> struct __parity;
template<size_t _Np> struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
template<> struct __make<0> { typedef __integer_sequence<size_t> type; };
template<> struct __make<1> { typedef __integer_sequence<size_t, 0> type; };
template<> struct __make<2> { typedef __integer_sequence<size_t, 0, 1> type; };
template<> struct __make<3> { typedef __integer_sequence<size_t, 0, 1, 2> type; };
template<> struct __make<4> { typedef __integer_sequence<size_t, 0, 1, 2, 3> type; };
template<> struct __make<5> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
template<> struct __make<6> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
template<> struct __make<7> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
} // namespace detail
#endif // !__has_builtin(__make_integer_seq) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
#if __has_builtin(__make_integer_seq)
template <size_t _Ep, size_t _Sp>
using __make_indices_imp =
typename __make_integer_seq<__integer_sequence, size_t, _Ep - _Sp>::template
__to_tuple_indices<_Sp>;
#else
template <size_t _Ep, size_t _Sp>
using __make_indices_imp =
typename __detail::__make<_Ep - _Sp>::type::template __to_tuple_indices<_Sp>;
#endif
template <size_t _Ep, size_t _Sp = 0>
struct __make_tuple_indices
{
static_assert(_Sp <= _Ep, "__make_tuple_indices input error");
typedef __make_indices_imp<_Ep, _Sp> type;
};
template <class ..._Tp> class _LIBCPP_TYPE_VIS_ONLY tuple;
template <class... _Tp> struct __tuple_like<tuple<_Tp...> > : true_type {};
@ -149,31 +223,6 @@ get(const array<_Tp, _Size>&&) _NOEXCEPT;
#if !defined(_LIBCPP_HAS_NO_VARIADICS)
// __make_tuple_indices
template <size_t...> struct __tuple_indices {};
template <size_t _Sp, class _IntTuple, size_t _Ep>
struct __make_indices_imp;
template <size_t _Sp, size_t ..._Indices, size_t _Ep>
struct __make_indices_imp<_Sp, __tuple_indices<_Indices...>, _Ep>
{
typedef typename __make_indices_imp<_Sp+1, __tuple_indices<_Indices..., _Sp>, _Ep>::type type;
};
template <size_t _Ep, size_t ..._Indices>
struct __make_indices_imp<_Ep, __tuple_indices<_Indices...>, _Ep>
{
typedef __tuple_indices<_Indices...> type;
};
template <size_t _Ep, size_t _Sp = 0>
struct __make_tuple_indices
{
static_assert(_Sp <= _Ep, "__make_tuple_indices input error");
typedef typename __make_indices_imp<_Sp, __tuple_indices<>, _Ep>::type type;
};
// __tuple_types

View File

@ -741,63 +741,15 @@ template<size_t... _Ip>
#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
template <class _Tp, _Tp _Ep>
struct __make_integer_sequence
{
typedef __make_integer_seq<integer_sequence, _Tp, _Ep> type;
};
using __make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
#else
namespace __detail {
template<typename _Tp, size_t ..._Extra> struct __repeat;
template<typename _Tp, _Tp ..._Np, size_t ..._Extra> struct __repeat<integer_sequence<_Tp, _Np...>, _Extra...> {
typedef integer_sequence<_Tp,
_Np...,
sizeof...(_Np) + _Np...,
2 * sizeof...(_Np) + _Np...,
3 * sizeof...(_Np) + _Np...,
4 * sizeof...(_Np) + _Np...,
5 * sizeof...(_Np) + _Np...,
6 * sizeof...(_Np) + _Np...,
7 * sizeof...(_Np) + _Np...,
_Extra...> type;
};
template<size_t _Np> struct __parity;
template<size_t _Np> struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
template<> struct __make<0> { typedef integer_sequence<size_t> type; };
template<> struct __make<1> { typedef integer_sequence<size_t, 0> type; };
template<> struct __make<2> { typedef integer_sequence<size_t, 0, 1> type; };
template<> struct __make<3> { typedef integer_sequence<size_t, 0, 1, 2> type; };
template<> struct __make<4> { typedef integer_sequence<size_t, 0, 1, 2, 3> type; };
template<> struct __make<5> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
template<> struct __make<6> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
template<> struct __make<7> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
template<typename _Tp, typename _Up> struct __convert {
template<typename> struct __result;
template<_Tp ..._Np> struct __result<integer_sequence<_Tp, _Np...> > { typedef integer_sequence<_Up, _Np...> type; };
};
template<typename _Tp> struct __convert<_Tp, _Tp> { template<typename _Up> struct __result { typedef _Up type; }; };
}
template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
typename __detail::__convert<size_t, _Tp>::template __result<typename __detail::__make<_Np>::type>::type;
typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
template <class _Tp, _Tp _Ep>
struct __make_integer_sequence
struct __make_integer_sequence_checked
{
static_assert(is_integral<_Tp>::value,
"std::make_integer_sequence can only be instantiated with an integral type" );
@ -807,10 +759,13 @@ struct __make_integer_sequence
typedef __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
};
template <class _Tp, _Tp _Ep>
using __make_integer_sequence = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
#endif
template<class _Tp, _Tp _Np>
using make_integer_sequence = typename __make_integer_sequence<_Tp, _Np>::type;
using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
template<size_t _Np>
using make_index_sequence = make_integer_sequence<size_t, _Np>;