[libcxx] r348138 - [libcxx] Implement P0318: unwrap_ref_decay and unwrap_reference
Louis Dionne
ldionne at apple.com
Mon Dec 3 06:03:27 PST 2018
Author: ldionne
Date: Mon Dec 3 06:03:27 2018
New Revision: 348138
URL: http://llvm.org/viewvc/llvm-project?rev=348138&view=rev
Log:
[libcxx] Implement P0318: unwrap_ref_decay and unwrap_reference
Summary:
This was voted into C++20 in San Diego. Note that there was a revision
D0318R2 which did include unwrap_reference_t, but we mistakingly voted
P0318R1 into the C++20 Working Draft (which does not include
unwrap_reference_t). This patch implements D0318R2, which is what
we'll end up with in the Working Draft once this mistake has been
fixed.
Reviewers: EricWF, mclow.lists
Subscribers: christof, dexonsmith, libcxx-commits
Differential Revision: https://reviews.llvm.org/D54485
Added:
libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
Modified:
libcxx/trunk/include/functional
libcxx/trunk/include/tuple
libcxx/trunk/include/utility
libcxx/trunk/www/cxx2a_status.html
Modified: libcxx/trunk/include/functional
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/functional?rev=348138&r1=348137&r2=348138&view=diff
==============================================================================
--- libcxx/trunk/include/functional (original)
+++ libcxx/trunk/include/functional Mon Dec 3 06:03:27 2018
@@ -68,6 +68,11 @@ template <class T> reference_wrapper<con
template <class T> void cref(const T&& t) = delete;
template <class T> reference_wrapper<const T> cref(reference_wrapper<T> t) noexcept;
+template <class T> struct unwrap_reference; // since C++20
+template <class T> struct unwrap_ref_decay : unwrap_reference<decay_t<T>> { }; // since C++20
+template <class T> using unwrap_reference_t = typename unwrap_reference<T>::type; // since C++20
+template <class T> using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type; // since C++20
+
template <class T> // <class T=void> in C++14
struct plus : binary_function<T, T, T>
{
@@ -2527,6 +2532,14 @@ private:
#endif // _LIBCPP_STD_VER > 14
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
+
+template <class _Tp>
+using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
+#endif // > C++17
+
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_FUNCTIONAL
Modified: libcxx/trunk/include/tuple
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/tuple?rev=348138&r1=348137&r2=348138&view=diff
==============================================================================
--- libcxx/trunk/include/tuple (original)
+++ libcxx/trunk/include/tuple Mon Dec 3 06:03:27 2018
@@ -1078,30 +1078,12 @@ namespace {
_LIBCPP_INLINE_VAR constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
}
-template <class _Tp>
-struct __make_tuple_return_impl
-{
- typedef _Tp type;
-};
-
-template <class _Tp>
-struct __make_tuple_return_impl<reference_wrapper<_Tp> >
-{
- typedef _Tp& type;
-};
-
-template <class _Tp>
-struct __make_tuple_return
-{
- typedef typename __make_tuple_return_impl<typename decay<_Tp>::type>::type type;
-};
-
template <class... _Tp>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-tuple<typename __make_tuple_return<_Tp>::type...>
+tuple<typename __unwrap_ref_decay<_Tp>::type...>
make_tuple(_Tp&&... __t)
{
- return tuple<typename __make_tuple_return<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
+ return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
}
template <class... _Tp>
Modified: libcxx/trunk/include/utility
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/utility?rev=348138&r1=348137&r2=348138&view=diff
==============================================================================
--- libcxx/trunk/include/utility (original)
+++ libcxx/trunk/include/utility Mon Dec 3 06:03:27 2018
@@ -616,32 +616,37 @@ swap(pair<_T1, _T2>& __x, pair<_T1, _T2>
__x.swap(__y);
}
-#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+struct __unwrap_reference { typedef _Tp type; };
template <class _Tp>
-struct __make_pair_return_impl
-{
- typedef _Tp type;
-};
+struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _Tp& type; };
+#if _LIBCPP_STD_VER > 17
template <class _Tp>
-struct __make_pair_return_impl<reference_wrapper<_Tp>>
-{
- typedef _Tp& type;
-};
+struct unwrap_reference : __unwrap_reference<_Tp> { };
template <class _Tp>
-struct __make_pair_return
-{
- typedef typename __make_pair_return_impl<typename decay<_Tp>::type>::type type;
-};
+struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
+#endif // > C++17
+
+template <class _Tp>
+struct __unwrap_ref_decay
+#if _LIBCPP_STD_VER > 17
+ : unwrap_ref_decay<_Tp>
+#else
+ : __unwrap_reference<typename decay<_Tp>::type>
+#endif
+{ };
+
+#ifndef _LIBCPP_CXX03_LANG
template <class _T1, class _T2>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
+pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
make_pair(_T1&& __t1, _T2&& __t2)
{
- return pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
+ return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
}
Added: libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp?rev=348138&view=auto
==============================================================================
--- libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp (added)
+++ libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp Mon Dec 3 06:03:27 2018
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <functional>
+//
+// template <class T>
+// struct unwrap_ref_decay;
+//
+// template <class T>
+// using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type;
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <functional>
+#include <type_traits>
+
+
+template <typename T, typename Result>
+void check() {
+ static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, Result>);
+ static_assert(std::is_same_v<typename std::unwrap_ref_decay<T>::type, std::unwrap_ref_decay_t<T>>);
+}
+
+struct T { };
+
+int main() {
+ check<T, T>();
+ check<T&, T>();
+ check<T const, T>();
+ check<T const&, T>();
+ check<T*, T*>();
+ check<T const*, T const*>();
+ check<T[3], T*>();
+ check<T const [3], T const*>();
+ check<T (), T (*)()>();
+ check<T (int) const, T (int) const>();
+ check<T (int) &, T (int) &>();
+ check<T (int) &&, T (int) &&>();
+
+ check<std::reference_wrapper<T>, T&>();
+ check<std::reference_wrapper<T>&, T&>();
+ check<std::reference_wrapper<T const>, T const&>();
+ check<std::reference_wrapper<T const>&, T const&>();
+ check<std::reference_wrapper<T*>, T*&>();
+ check<std::reference_wrapper<T*>&, T*&>();
+ check<std::reference_wrapper<T const*>, T const*&>();
+ check<std::reference_wrapper<T const*>&, T const*&>();
+ check<std::reference_wrapper<T[3]>, T (&)[3]>();
+ check<std::reference_wrapper<T[3]>&, T (&)[3]>();
+ check<std::reference_wrapper<T ()>, T (&)()>();
+ check<std::reference_wrapper<T ()>&, T (&)()>();
+}
Added: libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp?rev=348138&view=auto
==============================================================================
--- libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp (added)
+++ libcxx/trunk/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp Mon Dec 3 06:03:27 2018
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <functional>
+//
+// template <class T>
+// struct unwrap_reference;
+//
+// template <class T>
+// using unwrap_reference_t = typename unwrap_reference<T>::type;
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+#include <functional>
+#include <type_traits>
+
+
+template <typename T, typename Expected>
+void check_equal() {
+ static_assert(std::is_same_v<typename std::unwrap_reference<T>::type, Expected>);
+ static_assert(std::is_same_v<typename std::unwrap_reference<T>::type, std::unwrap_reference_t<T>>);
+}
+
+template <typename T>
+void check() {
+ check_equal<T, T>();
+ check_equal<T&, T&>();
+ check_equal<T const, T const>();
+ check_equal<T const&, T const&>();
+
+ check_equal<std::reference_wrapper<T>, T&>();
+ check_equal<std::reference_wrapper<T const>, T const&>();
+}
+
+struct T { };
+
+int main() {
+ check<T>();
+ check<int>();
+ check<float>();
+
+ check<T*>();
+ check<int*>();
+ check<float*>();
+}
Modified: libcxx/trunk/www/cxx2a_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx2a_status.html?rev=348138&r1=348137&r2=348138&view=diff
==============================================================================
--- libcxx/trunk/www/cxx2a_status.html (original)
+++ libcxx/trunk/www/cxx2a_status.html Mon Dec 3 06:03:27 2018
@@ -108,7 +108,7 @@
<tr><td><a href="https://wg21.link/P1120R0">P1120R0</a></td><td>CWG</td><td>Consistency improvements for <=> and other comparison operators</td><td>Rapperswil</td><td></td><td></td></tr>
<tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
- <tr><td><a href="https://wg21.link/P0318R1">P0318R1</a></td><td>LWG</td><td>unwrap_ref_decay and unwrap_reference</td><td>San Diego</td><td><i> </i></td><td></td></tr>
+ <tr><td><a href="https://wg21.link/P0318R1">P0318R1</a></td><td>LWG</td><td>unwrap_ref_decay and unwrap_reference</td><td>San Diego</td><td>Complete</td><td>8.0</td></tr>
<tr><td><a href="https://wg21.link/P0356R5">P0356R5</a></td><td>LWG</td><td>Simplified partial function application</td><td>San Diego</td><td><i> </i></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0357R3">P0357R3</a></td><td>LWG</td><td>reference_wrapper for incomplete types</td><td>San Diego</td><td><i> </i></td><td></td></tr>
<tr><td><a href="https://wg21.link/P0482R6">P0482R6</a></td><td>CWG</td><td>char8_t: A type for UTF-8 characters and strings</td><td>San Diego</td><td><i> </i></td><td></td></tr>
More information about the libcxx-commits
mailing list