Add 'is_callable' and 'is_nothrow_callable' traits and cleanup INVOKE.

The primary purpose of this patch is to add the 'is_callable' traits.
Since 'is_nothrow_callable' required making 'INVOKE' conditionally noexcept
I also took this oppertunity to implement a constexpr version of INVOKE.
This fixes 'std::experimental::apply' which required constexpr 'INVOKE support'.

This patch will be followed up with some cleanup. Primarly removing most
of "__member_function_traits" since it's no longer used by INVOKE (in C++11 at least).

llvm-svn: 266836

1 files changed, 3 insertions, 81 deletions

diff --git a/libcxx/include/__functional_base b/libcxx/include/__functional_base
index 3274842dc93..feb587f7b55 100644
--- a/libcxx/include/__functional_base
+++ b/libcxx/include/__functional_base
@@ -306,97 +306,19 @@ struct __weak_result_type<_Rp (_Cp::*)(_A1, _A2, _A3...) const volatile>
 
 #endif // _LIBCPP_HAS_NO_VARIADICS
 
-// __invoke
+#ifndef _LIBCPP_CXX03_LANG
 
-#ifndef _LIBCPP_HAS_NO_VARIADICS
-
-// bullets 1 and 2
-
-template <class _Fp, class _A0, class ..._Args,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
-    -> decltype((_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...))
-{
-    return (_VSTD::forward<_A0>(__a0).*__f)(_VSTD::forward<_Args>(__args)...);
-}
-
-
-template <class _Fp, class _A0, class ..._Args,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
-    -> decltype((__a0.get().*__f)(_VSTD::forward<_Args>(__args)...))
-{
-    return (__a0.get().*__f)(_VSTD::forward<_Args>(__args)...);
-}
-
-template <class _Fp, class _A0, class ..._Args,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
-    -> decltype(((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...))
-{
-    return ((*_VSTD::forward<_A0>(__a0)).*__f)(_VSTD::forward<_Args>(__args)...);
-}
-
-// bullets 3 and 4
-
-template <class _Fp, class _A0,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0)
-    -> decltype(_VSTD::forward<_A0>(__a0).*__f)
-{
-    return _VSTD::forward<_A0>(__a0).*__f;
-}
-
-
-template <class _Fp, class _A0,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0)
-    -> decltype(__a0.get().*__f)
-{
-    return __a0.get().*__f;
-}
-
-template <class _Fp, class _A0,
-            class>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _A0&& __a0)
-    -> decltype((*_VSTD::forward<_A0>(__a0)).*__f)
-{
-    return (*_VSTD::forward<_A0>(__a0)).*__f;
-}
-
-// bullet 5
-
-template <class _Fp, class ..._Args>
-inline _LIBCPP_INLINE_VISIBILITY
-auto
-__invoke(_Fp&& __f, _Args&& ...__args)
-    -> decltype(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
-{
-    return _VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...);
-}
 template <class _Tp, class ..._Args>
 struct __invoke_return
 {
     typedef decltype(__invoke(_VSTD::declval<_Tp>(), _VSTD::declval<_Args>()...)) type;
 };
 
-#else // _LIBCPP_HAS_NO_VARIADICS
+#else // defined(_LIBCPP_CXX03_LANG)
 
 #include <__functional_base_03>
 
-#endif  // _LIBCPP_HAS_NO_VARIADICS
+#endif  // !defined(_LIBCPP_CXX03_LANG)
 
 
 template <class _Ret>