1 files changed, 67 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__algorithm/comp_ref_type.h b/contrib/llvm-project/libcxx/include/__algorithm/comp_ref_type.h
new file mode 100644
index 000000000000..aa9350c38caa
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__algorithm/comp_ref_type.h
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// 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___ALGORITHM_COMP_REF_TYPE_H
+#define _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
+
+#include <__assert>
+#include <__config>
+#include <__utility/declval.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare>
+struct __debug_less {
+  _Compare& __comp_;
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI __debug_less(_Compare& __c) : __comp_(__c) {}
+
+  template <class _Tp, class _Up>
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool operator()(const _Tp& __x, const _Up& __y) {
+    bool __r = __comp_(__x, __y);
+    if (__r)
+      __do_compare_assert(0, __y, __x);
+    return __r;
+  }
+
+  template <class _Tp, class _Up>
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool operator()(_Tp& __x, _Up& __y) {
+    bool __r = __comp_(__x, __y);
+    if (__r)
+      __do_compare_assert(0, __y, __x);
+    return __r;
+  }
+
+  template <class _LHS, class _RHS>
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 inline _LIBCPP_HIDE_FROM_ABI decltype((void)std::declval<_Compare&>()(
+      std::declval<_LHS&>(), std::declval<_RHS&>()))
+  __do_compare_assert(int, _LHS& __l, _RHS& __r) {
+    _LIBCPP_ASSERT_SEMANTIC_REQUIREMENT(!__comp_(__l, __r), "Comparator does not induce a strict weak ordering");
+    (void)__l;
+    (void)__r;
+  }
+
+  template <class _LHS, class _RHS>
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 inline _LIBCPP_HIDE_FROM_ABI void __do_compare_assert(long, _LHS&, _RHS&) {}
+};
+
+// Pass the comparator by lvalue reference. Or in the debug mode, using a debugging wrapper that stores a reference.
+#if _LIBCPP_HARDENING_MODE == _LIBCPP_HARDENING_MODE_DEBUG
+template <class _Comp>
+using __comp_ref_type = __debug_less<_Comp>;
+#else
+template <class _Comp>
+using __comp_ref_type = _Comp&;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COMP_REF_TYPE_H