[libcxx-commits] [libcxx] 38812f4 - [libc++] [P1614] Implement std::compare_three_way_result.
Arthur O'Dwyer via libcxx-commits
libcxx-commits at lists.llvm.org
Wed Aug 18 07:02:30 PDT 2021
Author: Arthur O'Dwyer
Date: 2021-08-18T10:01:24-04:00
New Revision: 38812f4ac122df2cef7754d7afda8c9a08695a03
URL: https://github.com/llvm/llvm-project/commit/38812f4ac122df2cef7754d7afda8c9a08695a03
DIFF: https://github.com/llvm/llvm-project/commit/38812f4ac122df2cef7754d7afda8c9a08695a03.diff
LOG: [libc++] [P1614] Implement std::compare_three_way_result.
Differential Revision: https://reviews.llvm.org/D103581
Added:
libcxx/include/__compare/compare_three_way_result.h
libcxx/test/libcxx/diagnostics/detail.headers/compare/compare_three_way_result.module.verify.cpp
libcxx/test/std/language.support/cmp/cmp.result/compare_three_way_result.compile.pass.cpp
Modified:
libcxx/include/CMakeLists.txt
libcxx/include/compare
libcxx/include/module.modulemap
Removed:
################################################################################
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index f30580e5e8aa5..62f5eea1216ca 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -98,6 +98,7 @@ set(files
__bsd_locale_defaults.h
__bsd_locale_fallbacks.h
__compare/common_comparison_category.h
+ __compare/compare_three_way_result.h
__compare/ordering.h
__concepts/arithmetic.h
__concepts/assignable.h
diff --git a/libcxx/include/__compare/compare_three_way_result.h b/libcxx/include/__compare/compare_three_way_result.h
new file mode 100644
index 0000000000000..14908c6bbc1bb
--- /dev/null
+++ b/libcxx/include/__compare/compare_three_way_result.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
+#define _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template<class, class, class>
+struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result { };
+
+template<class _Tp, class _Up>
+struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result<_Tp, _Up, decltype(
+ declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>(), void()
+)> {
+ using type = decltype(declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>());
+};
+
+template<class _Tp, class _Up = _Tp>
+struct _LIBCPP_TEMPLATE_VIS compare_three_way_result : __compare_three_way_result<_Tp, _Up, void> { };
+
+template<class _Tp, class _Up = _Tp>
+using compare_three_way_result_t = typename compare_three_way_result<_Tp, _Up>::type;
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
diff --git a/libcxx/include/compare b/libcxx/include/compare
index 4683078188ed9..f6814542a0c3c 100644
--- a/libcxx/include/compare
+++ b/libcxx/include/compare
@@ -35,6 +35,12 @@ namespace std {
template<class... Ts>
using common_comparison_category_t = typename common_comparison_category<Ts...>::type;
+ // [cmp.result], result of three-way comparison
+ template<class T, class U = T> struct compare_three_way_result;
+
+ template<class T, class U = T>
+ using compare_three_way_result_t = typename compare_three_way_result<T, U>::type;
+
// [cmp.alg], comparison algorithms
template<class T> constexpr strong_ordering strong_order(const T& a, const T& b);
template<class T> constexpr weak_ordering weak_order(const T& a, const T& b);
@@ -121,6 +127,7 @@ namespace std {
*/
#include <__compare/common_comparison_category.h>
+#include <__compare/compare_three_way_result.h>
#include <__compare/ordering.h>
#include <__config>
#include <type_traits>
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index f9955a3cd0c3b..98ba8d38c71a3 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -361,6 +361,7 @@ module std [system] {
module __compare {
module common_comparison_category { private header "__compare/common_comparison_category.h" }
+ module compare_three_way_result { private header "__compare/compare_three_way_result.h" }
module ordering { private header "__compare/ordering.h" }
}
}
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/compare/compare_three_way_result.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/compare/compare_three_way_result.module.verify.cpp
new file mode 100644
index 0000000000000..f9e705d331cfd
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/compare/compare_three_way_result.module.verify.cpp
@@ -0,0 +1,16 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__compare/compare_three_way_result.h'}}
+#include <__compare/compare_three_way_result.h>
diff --git a/libcxx/test/std/language.support/cmp/cmp.result/compare_three_way_result.compile.pass.cpp b/libcxx/test/std/language.support/cmp/cmp.result/compare_three_way_result.compile.pass.cpp
new file mode 100644
index 0000000000000..4ad764fd65186
--- /dev/null
+++ b/libcxx/test/std/language.support/cmp/cmp.result/compare_three_way_result.compile.pass.cpp
@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <compare>
+
+// template<class T, class U = T> struct compare_three_way_result;
+// template<class T, class U = T>
+// using compare_three_way_result_t = typename compare_three_way_result<T, U>::type;
+
+#include <compare>
+
+#include "test_macros.h"
+
+template<class T>
+concept has_no_nested_type = !requires { typename T::type; };
+
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<int>, std::strong_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<float>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<unsigned>, std::strong_ordering);
+
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<int, int>, std::strong_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<int, float>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<float, int>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<float, float>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<float, unsigned>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<unsigned, float>, std::partial_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<unsigned, unsigned>, std::strong_ordering);
+
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const int&>, std::strong_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const int&, int>, std::strong_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const int*>, std::strong_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const int*, int*>, std::strong_ordering);
+
+static_assert(has_no_nested_type<std::compare_three_way_result<void>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<void, void>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<int, void>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<int, int*>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<int, unsigned>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<unsigned, int>>);
+
+struct A {
+ float operator<=>(const A&) const; // a non-comparison-category type is OK
+};
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<A>, float);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<A, A>, float);
+
+struct B {
+ using T = int(&)();
+ T operator<=>(const B&) const; // no decay takes place either
+};
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<B>, int(&)());
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<B, B>, int(&)());
+
+struct C {
+ std::strong_ordering operator<=>(C&); // C isn't const-comparable
+};
+static_assert(has_no_nested_type<std::compare_three_way_result<C>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<C&>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<C&&>>);
+
+static_assert(has_no_nested_type<std::compare_three_way_result<C, C>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<C&, C&>>);
+static_assert(has_no_nested_type<std::compare_three_way_result<C&&, C&&>>);
+
+struct D {
+ std::strong_ordering operator<=>(D&) &;
+ std::strong_ordering operator<=>(D&&) &&;
+ std::weak_ordering operator<=>(const D&) const&; // comparison is always done by const&
+ std::strong_ordering operator<=>(const D&&) const&&;
+};
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D&&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const D&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const D&&>, std::weak_ordering);
+
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D, D>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D&, D&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<D&&, D&&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const D&, const D&>, std::weak_ordering);
+ASSERT_SAME_TYPE(std::compare_three_way_result_t<const D&&, const D&&>, std::weak_ordering);
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