Author: ericwf
Date: Thu Jun 30 17:34:43 2016
New Revision: 274286
URL: http://llvm.org/viewvc/llvm-project?rev=274286&view=rev
Log:
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'.
Modified:
libcxx/trunk/include/__tuple
libcxx/trunk/include/utility
Modified: libcxx/trunk/include/__tuple
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__tuple?rev=274286&r1=274285&r2=274286&view=diff
==============================================================================
--- libcxx/trunk/include/__tuple (original)
+++ libcxx/trunk/include/__tuple Thu Jun 30 17:34:43 2016
@@ -68,6 +68,80 @@ template <class _Tp> struct __tuple_like
// 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
Modified: libcxx/trunk/include/utility
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/utility?rev=274286&r1=274285&r2=274286&view=diff
==============================================================================
--- libcxx/trunk/include/utility (original)
+++ libcxx/trunk/include/utility Thu Jun 30 17:34:43 2016
@@ -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>;
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