Merge llvm-project release/17.x llvmorg-17.0.0-rc4-10-g0176e8729ea4

This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-17.0.0-rc4-10-g0176e8729ea4.

PR:		273753
MFC after:	1 month

13 files changed, 842 insertions, 106 deletions

diff --git a/contrib/llvm-project/libcxx/include/__algorithm/pstl_sort.h b/contrib/llvm-project/libcxx/include/__algorithm/pstl_sort.h
index 81514953f24b..75c77ed40527 100644
--- a/contrib/llvm-project/libcxx/include/__algorithm/pstl_sort.h
+++ b/contrib/llvm-project/libcxx/include/__algorithm/pstl_sort.h
@@ -17,6 +17,7 @@
 #include <__type_traits/is_execution_policy.h>
 #include <__type_traits/remove_cvref.h>
 #include <__utility/forward.h>
+#include <__utility/move.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/contrib/llvm-project/libcxx/include/__config b/contrib/llvm-project/libcxx/include/__config
index 9759d3b9e8e0..43f8a20031ff 100644
--- a/contrib/llvm-project/libcxx/include/__config
+++ b/contrib/llvm-project/libcxx/include/__config
@@ -208,19 +208,16 @@
 
 // HARDENING {
 
-// TODO(hardening): remove this in LLVM 18.
-// This is for backward compatibility -- make enabling `_LIBCPP_ENABLE_ASSERTIONS` (which predates hardening modes)
-// equivalent to setting the hardened mode.
-#  ifdef _LIBCPP_ENABLE_ASSERTIONS
-#    warning "_LIBCPP_ENABLE_ASSERTIONS is deprecated, please use _LIBCPP_ENABLE_HARDENED_MODE instead."
-#    if _LIBCPP_ENABLE_ASSERTIONS != 0 && _LIBCPP_ENABLE_ASSERTIONS != 1
-#      error "_LIBCPP_ENABLE_ASSERTIONS must be set to 0 or 1"
-#    endif
-#    if _LIBCPP_ENABLE_ASSERTIONS
-#      define _LIBCPP_ENABLE_HARDENED_MODE 1
-#    endif
+#  ifndef _LIBCPP_ENABLE_ASSERTIONS
+#    define _LIBCPP_ENABLE_ASSERTIONS _LIBCPP_ENABLE_ASSERTIONS_DEFAULT
+#  endif
+#  if _LIBCPP_ENABLE_ASSERTIONS != 0 && _LIBCPP_ENABLE_ASSERTIONS != 1
+#    error "_LIBCPP_ENABLE_ASSERTIONS must be set to 0 or 1"
 #  endif
 
+// NOTE: These modes are experimental and are not stable yet in LLVM 17. Please refrain from using them and use the
+// documented libc++ "safe" mode instead.
+//
 // Enables the hardened mode which consists of all checks intended to be used in production. Hardened mode prioritizes
 // security-critical checks that can be done with relatively little overhead in constant time. Mutually exclusive with
 // `_LIBCPP_ENABLE_DEBUG_MODE`.
@@ -275,6 +272,11 @@
 #    error "Only one of _LIBCPP_ENABLE_HARDENED_MODE and _LIBCPP_ENABLE_DEBUG_MODE can be enabled."
 #  endif
 
+#  if _LIBCPP_ENABLE_ASSERTIONS && (_LIBCPP_ENABLE_HARDENED_MODE || _LIBCPP_ENABLE_DEBUG_MODE)
+#    error                                                                                                             \
+        "_LIBCPP_ENABLE_ASSERTIONS is mutually exclusive with _LIBCPP_ENABLE_HARDENED_MODE and _LIBCPP_ENABLE_DEBUG_MODE."
+#  endif
+
 // Hardened mode checks.
 
 // clang-format off
@@ -303,6 +305,18 @@
 #    define _LIBCPP_ASSERT_INTERNAL(expression, message)                  _LIBCPP_ASSERT(expression, message)
 #    define _LIBCPP_ASSERT_UNCATEGORIZED(expression, message)             _LIBCPP_ASSERT(expression, message)
 
+// Safe mode checks.
+
+#  elif _LIBCPP_ENABLE_ASSERTIONS
+
+// All checks enabled.
+#    define _LIBCPP_ASSERT_VALID_INPUT_RANGE(expression, message)         _LIBCPP_ASSERT(expression, message)
+#    define _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(expression, message)      _LIBCPP_ASSERT(expression, message)
+#    define _LIBCPP_ASSERT_NON_OVERLAPPING_RANGES(expression, message)    _LIBCPP_ASSERT(expression, message)
+#    define _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(expression, message)      _LIBCPP_ASSERT(expression, message)
+#    define _LIBCPP_ASSERT_INTERNAL(expression, message)                  _LIBCPP_ASSERT(expression, message)
+#    define _LIBCPP_ASSERT_UNCATEGORIZED(expression, message)             _LIBCPP_ASSERT(expression, message)
+
 // Disable all checks if hardening is not enabled.
 
 #  else
diff --git a/contrib/llvm-project/libcxx/include/__format/format_functions.h b/contrib/llvm-project/libcxx/include/__format/format_functions.h
index 27ec0a295f4f..bb62c1ce10c1 100644
--- a/contrib/llvm-project/libcxx/include/__format/format_functions.h
+++ b/contrib/llvm-project/libcxx/include/__format/format_functions.h
@@ -245,6 +245,9 @@ __handle_replacement_field(_Iterator __begin, _Iterator __end,
   using _CharT = iter_value_t<_Iterator>;
   __format::__parse_number_result __r = __format::__parse_arg_id(__begin, __end, __parse_ctx);
 
+  if (__r.__last == __end)
+    std::__throw_format_error("The argument index should end with a ':' or a '}'");
+
   bool __parse = *__r.__last == _CharT(':');
   switch (*__r.__last) {
   case _CharT(':'):
diff --git a/contrib/llvm-project/libcxx/include/__locale_dir/locale_base_api/locale_guard.h b/contrib/llvm-project/libcxx/include/__locale_dir/locale_base_api/locale_guard.h
index 0e2e91af7d19..5946ed698e0f 100644
--- a/contrib/llvm-project/libcxx/include/__locale_dir/locale_base_api/locale_guard.h
+++ b/contrib/llvm-project/libcxx/include/__locale_dir/locale_base_api/locale_guard.h
@@ -10,6 +10,7 @@
 #define _LIBCPP___LOCALE_LOCALE_BASE_API_LOCALE_GUARD_H
 
 #include <__config>
+#include <__locale> // for locale_t
 #include <clocale>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/contrib/llvm-project/libcxx/include/__mdspan/extents.h b/contrib/llvm-project/libcxx/include/__mdspan/extents.h
index 42355678d60c..a510220d4096 100644
--- a/contrib/llvm-project/libcxx/include/__mdspan/extents.h
+++ b/contrib/llvm-project/libcxx/include/__mdspan/extents.h
@@ -171,11 +171,14 @@ public:
       _TStatic __static_val = _StaticValues::__get(__i);
       if (__static_val == _DynTag) {
         __dyn_vals_[_DynamicIdxMap::__get(__i)] = __values[__i];
-      }
-      // Precondition check
-      else
-        _LIBCPP_ASSERT_UNCATEGORIZED(__values[__i] == static_cast<_TDynamic>(__static_val),
-                                     "extents construction: mismatch of provided arguments with static extents.");
+      } else
+        // Not catching this could lead to out of bounds errors later
+        // e.g. using my_mdspan_t = mdspan<int, extents<int, 10>>; my_mdspan_t = m(new int[5], 5);
+        // Right-hand-side construction looks ok with allocation and size matching,
+        // but since (potentially elsewhere defined) my_mdspan_t has static size m now thinks its range is 10 not 5
+        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+            __values[__i] == static_cast<_TDynamic>(__static_val),
+            "extents construction: mismatch of provided arguments with static extents.");
     }
   }
 
@@ -187,11 +190,14 @@ public:
       _TStatic __static_val = _StaticValues::__get(__i);
       if (__static_val == _DynTag) {
         __dyn_vals_[_DynamicIdxMap::__get(__i)] = static_cast<_TDynamic>(__vals[__i]);
-      }
-      // Precondition check
-      else
-        _LIBCPP_ASSERT_UNCATEGORIZED(static_cast<_TDynamic>(__vals[__i]) == static_cast<_TDynamic>(__static_val),
-                                     "extents construction: mismatch of provided arguments with static extents.");
+      } else
+        // Not catching this could lead to out of bounds errors later
+        // e.g. using my_mdspan_t = mdspan<int, extents<int, 10>>; my_mdspan_t = m(new int[N], span<int,1>(&N));
+        // Right-hand-side construction looks ok with allocation and size matching,
+        // but since (potentially elsewhere defined) my_mdspan_t has static size m now thinks its range is 10 not N
+        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+            static_cast<_TDynamic>(__vals[__i]) == static_cast<_TDynamic>(__static_val),
+            "extents construction: mismatch of provided arguments with static extents.");
     }
   }
 
@@ -310,28 +316,37 @@ public:
              (sizeof...(_OtherIndexTypes) == __rank_ || sizeof...(_OtherIndexTypes) == __rank_dynamic_))
   _LIBCPP_HIDE_FROM_ABI constexpr explicit extents(_OtherIndexTypes... __dynvals) noexcept
       : __vals_(static_cast<index_type>(__dynvals)...) {
-    _LIBCPP_ASSERT_UNCATEGORIZED(__mdspan_detail::__are_representable_as<index_type>(__dynvals...),
-                                 "extents ctor: arguments must be representable as index_type and nonnegative");
+    // Not catching this could lead to out of bounds errors later
+    // e.g. mdspan m(ptr, dextents<char, 1>(200u)); leads to an extent of -56 on m
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__mdspan_detail::__are_representable_as<index_type>(__dynvals...),
+                                        "extents ctor: arguments must be representable as index_type and nonnegative");
   }
 
   template <class _OtherIndexType, size_t _Size>
-    requires(is_convertible_v<_OtherIndexType, index_type> && is_nothrow_constructible_v<index_type, _OtherIndexType> &&
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&> &&
              (_Size == __rank_ || _Size == __rank_dynamic_))
   explicit(_Size != __rank_dynamic_)
       _LIBCPP_HIDE_FROM_ABI constexpr extents(const array<_OtherIndexType, _Size>& __exts) noexcept
       : __vals_(span(__exts)) {
-    _LIBCPP_ASSERT_UNCATEGORIZED(__mdspan_detail::__are_representable_as<index_type>(span(__exts)),
-                                 "extents ctor: arguments must be representable as index_type and nonnegative");
+    // Not catching this could lead to out of bounds errors later
+    // e.g. mdspan m(ptr, dextents<char, 1>(array<unsigned,1>(200))); leads to an extent of -56 on m
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__mdspan_detail::__are_representable_as<index_type>(span(__exts)),
+                                        "extents ctor: arguments must be representable as index_type and nonnegative");
   }
 
   template <class _OtherIndexType, size_t _Size>
-    requires(is_convertible_v<_OtherIndexType, index_type> && is_nothrow_constructible_v<index_type, _OtherIndexType> &&
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&> &&
              (_Size == __rank_ || _Size == __rank_dynamic_))
   explicit(_Size != __rank_dynamic_)
       _LIBCPP_HIDE_FROM_ABI constexpr extents(const span<_OtherIndexType, _Size>& __exts) noexcept
       : __vals_(__exts) {
-    _LIBCPP_ASSERT_UNCATEGORIZED(__mdspan_detail::__are_representable_as<index_type>(__exts),
-                                 "extents ctor: arguments must be representable as index_type and nonnegative");
+    // Not catching this could lead to out of bounds errors later
+    // e.g. array a{200u}; mdspan<int, dextents<char,1>> m(ptr, extents(span<unsigned,1>(a))); leads to an extent of -56
+    // on m
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__mdspan_detail::__are_representable_as<index_type>(__exts),
+                                        "extents ctor: arguments must be representable as index_type and nonnegative");
   }
 
 private:
@@ -380,10 +395,16 @@ public:
       for (size_t __r = 0; __r < rank(); __r++) {
         if constexpr (static_cast<make_unsigned_t<index_type>>(numeric_limits<index_type>::max()) <
                       static_cast<make_unsigned_t<_OtherIndexType>>(numeric_limits<_OtherIndexType>::max())) {
-          _LIBCPP_ASSERT_UNCATEGORIZED(__mdspan_detail::__is_representable_as<index_type>(__other.extent(__r)),
-                                       "extents ctor: arguments must be representable as index_type and nonnegative");
+          // Not catching this could lead to out of bounds errors later
+          // e.g. dextents<char,1>> e(dextents<unsigned,1>(200)) leads to an extent of -56 on e
+          _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+              __mdspan_detail::__is_representable_as<index_type>(__other.extent(__r)),
+              "extents ctor: arguments must be representable as index_type and nonnegative");
         }
-        _LIBCPP_ASSERT_UNCATEGORIZED(
+        // Not catching this could lead to out of bounds errors later
+        // e.g. mdspan<int, extents<int, 10>> m = mdspan<int, dextents<int, 1>>(new int[5], 5);
+        // Right-hand-side construction was ok, but m now thinks its range is 10 not 5
+        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
             (_Values::__static_value(__r) == dynamic_extent) ||
                 (static_cast<index_type>(__other.extent(__r)) == static_cast<index_type>(_Values::__static_value(__r))),
             "extents construction: mismatch of provided arguments with static extents.");
diff --git a/contrib/llvm-project/libcxx/include/__mdspan/layout_left.h b/contrib/llvm-project/libcxx/include/__mdspan/layout_left.h
index e81e0d10b595..7503dcf77d13 100644
--- a/contrib/llvm-project/libcxx/include/__mdspan/layout_left.h
+++ b/contrib/llvm-project/libcxx/include/__mdspan/layout_left.h
@@ -75,8 +75,11 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr mapping() noexcept               = default;
   _LIBCPP_HIDE_FROM_ABI constexpr mapping(const mapping&) noexcept = default;
   _LIBCPP_HIDE_FROM_ABI constexpr mapping(const extents_type& __ext) noexcept : __extents_(__ext) {
-    _LIBCPP_ASSERT(__required_span_size_is_representable(__ext),
-                   "layout_left::mapping extents ctor: product of extents must be representable as index_type.");
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // mapping<dextents<char, 2>> map(dextents<char, 2>(40,40)); map(10, 3) == -126
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        __required_span_size_is_representable(__ext),
+        "layout_left::mapping extents ctor: product of extents must be representable as index_type.");
   }
 
   template <class _OtherExtents>
@@ -84,7 +87,9 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherExtents, extents_type>)
       mapping(const mapping<_OtherExtents>& __other) noexcept
       : __extents_(__other.extents()) {
-    _LIBCPP_ASSERT(
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // mapping<dextents<char, 2>> map(mapping<dextents<int, 2>>(dextents<int, 2>(40,40))); map(10, 3) == -126
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
         __mdspan_detail::__is_representable_as<index_type>(__other.required_span_size()),
         "layout_left::mapping converting ctor: other.required_span_size() must be representable as index_type.");
   }
@@ -94,7 +99,13 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherExtents, extents_type>)
       mapping(const layout_right::mapping<_OtherExtents>& __other) noexcept
       : __extents_(__other.extents()) {
-    _LIBCPP_ASSERT(
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // Note: since this is constraint to rank 1, extents itself would catch the invalid conversion first
+    //       and thus this assertion should never be triggered, but keeping it here for consistency
+    // layout_left::mapping<dextents<char, 1>> map(
+    //           layout_right::mapping<dextents<unsigned, 1>>(dextents<unsigned, 1>(200))); map.extents().extent(0) ==
+    //           -56
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
         __mdspan_detail::__is_representable_as<index_type>(__other.required_span_size()),
         "layout_left::mapping converting ctor: other.required_span_size() must be representable as index_type.");
   }
@@ -122,6 +133,10 @@ public:
     requires((sizeof...(_Indices) == extents_type::rank()) && (is_convertible_v<_Indices, index_type> && ...) &&
              (is_nothrow_constructible_v<index_type, _Indices> && ...))
   _LIBCPP_HIDE_FROM_ABI constexpr index_type operator()(_Indices... __idx) const noexcept {
+    // Mappings are generally meant to be used for accessing allocations and are meant to guarantee to never
+    // return a value exceeding required_span_size(), which is used to know how large an allocation one needs
+    // Thus, this is a canonical point in multi-dimensional data structures to make invalid element access checks
+    // However, mdspan does check this on its own, so for now we avoid double checking in hardened mode
     _LIBCPP_ASSERT(__mdspan_detail::__is_multidimensional_index_in(__extents_, __idx...),
                    "layout_left::mapping: out of bounds indexing");
     array<index_type, extents_type::rank()> __idx_a{static_cast<index_type>(__idx)...};
@@ -144,9 +159,12 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr index_type stride(rank_type __r) const noexcept
     requires(extents_type::rank() > 0)
   {
-    _LIBCPP_ASSERT(__r < extents_type::rank(), "layout_left::mapping::stride(): invalid rank index");
+    // While it would be caught by extents itself too, using a too large __r
+    // is functionally an out of bounds access on the stored information needed to compute strides
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        __r < extents_type::rank(), "layout_left::mapping::stride(): invalid rank index");
     index_type __s = 1;
-    for (rank_type __i = extents_type::rank() - 1; __i > __r; __i--)
+    for (rank_type __i = 0; __i < __r; __i++)
       __s *= __extents_.extent(__i);
     return __s;
   }
@@ -159,7 +177,7 @@ public:
   }
 
 private:
-  extents_type __extents_{}; // exposition only
+  _LIBCPP_NO_UNIQUE_ADDRESS extents_type __extents_{};
 };
 
 #endif // _LIBCPP_STD_VER >= 23
diff --git a/contrib/llvm-project/libcxx/include/__mdspan/layout_right.h b/contrib/llvm-project/libcxx/include/__mdspan/layout_right.h
index a8a91b86c714..3d814554a1be 100644
--- a/contrib/llvm-project/libcxx/include/__mdspan/layout_right.h
+++ b/contrib/llvm-project/libcxx/include/__mdspan/layout_right.h
@@ -74,8 +74,11 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr mapping() noexcept               = default;
   _LIBCPP_HIDE_FROM_ABI constexpr mapping(const mapping&) noexcept = default;
   _LIBCPP_HIDE_FROM_ABI constexpr mapping(const extents_type& __ext) noexcept : __extents_(__ext) {
-    _LIBCPP_ASSERT(__required_span_size_is_representable(__ext),
-                   "layout_right::mapping extents ctor: product of extents must be representable as index_type.");
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // mapping<dextents<char, 2>> map(dextents<char, 2>(40,40)); map(3, 10) == -126
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        __required_span_size_is_representable(__ext),
+        "layout_right::mapping extents ctor: product of extents must be representable as index_type.");
   }
 
   template <class _OtherExtents>
@@ -83,7 +86,9 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherExtents, extents_type>)
       mapping(const mapping<_OtherExtents>& __other) noexcept
       : __extents_(__other.extents()) {
-    _LIBCPP_ASSERT(
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // mapping<dextents<char, 2>> map(mapping<dextents<int, 2>>(dextents<int, 2>(40,40))); map(3, 10) == -126
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
         __mdspan_detail::__is_representable_as<index_type>(__other.required_span_size()),
         "layout_right::mapping converting ctor: other.required_span_size() must be representable as index_type.");
   }
@@ -93,7 +98,13 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr explicit(!is_convertible_v<_OtherExtents, extents_type>)
       mapping(const layout_left::mapping<_OtherExtents>& __other) noexcept
       : __extents_(__other.extents()) {
-    _LIBCPP_ASSERT(
+    // not catching this could lead to out-of-bounds access later when used inside mdspan
+    // Note: since this is constraint to rank 1, extents itself would catch the invalid conversion first
+    //       and thus this assertion should never be triggered, but keeping it here for consistency
+    // layout_right::mapping<dextents<char, 1>> map(
+    //           layout_left::mapping<dextents<unsigned, 1>>(dextents<unsigned, 1>(200))); map.extents().extent(0) ==
+    //           -56
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
         __mdspan_detail::__is_representable_as<index_type>(__other.required_span_size()),
         "layout_right::mapping converting ctor: other.required_span_size() must be representable as index_type.");
   }
@@ -121,6 +132,10 @@ public:
     requires((sizeof...(_Indices) == extents_type::rank()) && (is_convertible_v<_Indices, index_type> && ...) &&
              (is_nothrow_constructible_v<index_type, _Indices> && ...))
   _LIBCPP_HIDE_FROM_ABI constexpr index_type operator()(_Indices... __idx) const noexcept {
+    // Mappings are generally meant to be used for accessing allocations and are meant to guarantee to never
+    // return a value exceeding required_span_size(), which is used to know how large an allocation one needs
+    // Thus, this is a canonical point in multi-dimensional data structures to make invalid element access checks
+    // However, mdspan does check this on its own, so for now we avoid double checking in hardened mode
     _LIBCPP_ASSERT(__mdspan_detail::__is_multidimensional_index_in(__extents_, __idx...),
                    "layout_right::mapping: out of bounds indexing");
     return [&]<size_t... _Pos>(index_sequence<_Pos...>) {
@@ -141,7 +156,10 @@ public:
   _LIBCPP_HIDE_FROM_ABI constexpr index_type stride(rank_type __r) const noexcept
     requires(extents_type::rank() > 0)
   {
-    _LIBCPP_ASSERT(__r < extents_type::rank(), "layout_right::mapping::stride(): invalid rank index");
+    // While it would be caught by extents itself too, using a too large __r
+    // is functionally an out of bounds access on the stored information needed to compute strides
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+        __r < extents_type::rank(), "layout_right::mapping::stride(): invalid rank index");
     index_type __s = 1;
     for (rank_type __i = extents_type::rank() - 1; __i > __r; __i--)
       __s *= __extents_.extent(__i);
@@ -156,7 +174,7 @@ public:
   }
 
 private:
-  extents_type __extents_{}; // exposition only
+  _LIBCPP_NO_UNIQUE_ADDRESS extents_type __extents_{};
 };
 
 #endif // _LIBCPP_STD_VER >= 23
diff --git a/contrib/llvm-project/libcxx/include/__mdspan/mdspan.h b/contrib/llvm-project/libcxx/include/__mdspan/mdspan.h
new file mode 100644
index 000000000000..58f3b9cf1b18
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__mdspan/mdspan.h
@@ -0,0 +1,308 @@
+// -*- 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
+//
+//                        Kokkos v. 4.0
+//       Copyright (2022) National Technology & Engineering
+//               Solutions of Sandia, LLC (NTESS).
+//
+// Under the terms of Contract DE-NA0003525 with NTESS,
+// the U.S. Government retains certain rights in this software.
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MDSPAN_MDSPAN_H
+#define _LIBCPP___MDSPAN_MDSPAN_H
+
+#include <__assert>
+#include <__config>
+#include <__fwd/mdspan.h>
+#include <__mdspan/default_accessor.h>
+#include <__mdspan/extents.h>
+#include <__type_traits/extent.h>
+#include <__type_traits/is_abstract.h>
+#include <__type_traits/is_array.h>
+#include <__type_traits/is_constructible.h>
+#include <__type_traits/is_convertible.h>
+#include <__type_traits/is_default_constructible.h>
+#include <__type_traits/is_nothrow_constructible.h>
+#include <__type_traits/is_pointer.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/rank.h>
+#include <__type_traits/remove_all_extents.h>
+#include <__type_traits/remove_cv.h>
+#include <__type_traits/remove_pointer.h>
+#include <__type_traits/remove_reference.h>
+#include <__utility/integer_sequence.h>
+#include <array>
+#include <cinttypes>
+#include <cstddef>
+#include <limits>
+#include <span>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 23
+
+// Helper for lightweight test checking that one did pass a layout policy as LayoutPolicy template argument
+namespace __mdspan_detail {
+template <class _Layout, class _Extents>
+concept __has_invalid_mapping = !requires { typename _Layout::template mapping<_Extents>; };
+} // namespace __mdspan_detail
+
+template <class _ElementType,
+          class _Extents,
+          class _LayoutPolicy   = layout_right,
+          class _AccessorPolicy = default_accessor<_ElementType> >
+class mdspan {
+private:
+  static_assert(__mdspan_detail::__is_extents_v<_Extents>,
+                "mdspan: Extents template parameter must be a specialization of extents.");
+  static_assert(!is_array_v<_ElementType>, "mdspan: ElementType template parameter may not be an array type");
+  static_assert(!is_abstract_v<_ElementType>, "mdspan: ElementType template parameter may not be an abstract class");
+  static_assert(is_same_v<_ElementType, typename _AccessorPolicy::element_type>,
+                "mdspan: ElementType template parameter must match AccessorPolicy::element_type");
+  static_assert(!__mdspan_detail::__has_invalid_mapping<_LayoutPolicy, _Extents>,
+                "mdspan: LayoutPolicy template parameter is invalid. A common mistake is to pass a layout mapping "
+                "instead of a layout policy");
+
+public:
+  using extents_type     = _Extents;
+  using layout_type      = _LayoutPolicy;
+  using accessor_type    = _AccessorPolicy;
+  using mapping_type     = typename layout_type::template mapping<extents_type>;
+  using element_type     = _ElementType;
+  using value_type       = remove_cv_t<element_type>;
+  using index_type       = typename extents_type::index_type;
+  using size_type        = typename extents_type::size_type;
+  using rank_type        = typename extents_type::rank_type;
+  using data_handle_type = typename accessor_type::data_handle_type;
+  using reference        = typename accessor_type::reference;
+
+  _LIBCPP_HIDE_FROM_ABI static constexpr rank_type rank() noexcept { return extents_type::rank(); }
+  _LIBCPP_HIDE_FROM_ABI static constexpr rank_type rank_dynamic() noexcept { return extents_type::rank_dynamic(); }
+  _LIBCPP_HIDE_FROM_ABI static constexpr size_t static_extent(rank_type __r) noexcept {
+    return extents_type::static_extent(__r);
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr index_type extent(rank_type __r) const noexcept {
+    return __map_.extents().extent(__r);
+  };
+
+public:
+  //--------------------------------------------------------------------------------
+  // [mdspan.mdspan.cons], mdspan constructors, assignment, and destructor
+
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan()
+    requires((extents_type::rank_dynamic() > 0) && is_default_constructible_v<data_handle_type> &&
+             is_default_constructible_v<mapping_type> && is_default_constructible_v<accessor_type>)
+  = default;
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan(const mdspan&) = default;
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan(mdspan&&)      = default;
+
+  template <class... _OtherIndexTypes>
+    requires((is_convertible_v<_OtherIndexTypes, index_type> && ...) &&
+             (is_nothrow_constructible_v<index_type, _OtherIndexTypes> && ...) &&
+             ((sizeof...(_OtherIndexTypes) == rank()) || (sizeof...(_OtherIndexTypes) == rank_dynamic())) &&
+             is_constructible_v<mapping_type, extents_type> && is_default_constructible_v<accessor_type>)
+  _LIBCPP_HIDE_FROM_ABI explicit constexpr mdspan(data_handle_type __p, _OtherIndexTypes... __exts)
+      : __ptr_(std::move(__p)), __map_(extents_type(static_cast<index_type>(std::move(__exts))...)), __acc_{} {}
+
+  template <class _OtherIndexType, size_t _Size>
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&> &&
+             ((_Size == rank()) || (_Size == rank_dynamic())) && is_constructible_v<mapping_type, extents_type> &&
+             is_default_constructible_v<accessor_type>)
+  explicit(_Size != rank_dynamic())
+      _LIBCPP_HIDE_FROM_ABI constexpr mdspan(data_handle_type __p, const array<_OtherIndexType, _Size>& __exts)
+      : __ptr_(std::move(__p)), __map_(extents_type(__exts)), __acc_{} {}
+
+  template <class _OtherIndexType, size_t _Size>
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&> &&
+             ((_Size == rank()) || (_Size == rank_dynamic())) && is_constructible_v<mapping_type, extents_type> &&
+             is_default_constructible_v<accessor_type>)
+  explicit(_Size != rank_dynamic())
+      _LIBCPP_HIDE_FROM_ABI constexpr mdspan(data_handle_type __p, span<_OtherIndexType, _Size> __exts)
+      : __ptr_(std::move(__p)), __map_(extents_type(__exts)), __acc_{} {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan(data_handle_type __p, const extents_type& __exts)
+    requires(is_default_constructible_v<accessor_type> && is_constructible_v<mapping_type, const extents_type&>)
+      : __ptr_(std::move(__p)), __map_(__exts), __acc_{} {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan(data_handle_type __p, const mapping_type& __m)
+    requires(is_default_constructible_v<accessor_type>)
+      : __ptr_(std::move(__p)), __map_(__m), __acc_{} {}
+
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan(data_handle_type __p, const mapping_type& __m, const accessor_type& __a)
+      : __ptr_(std::move(__p)), __map_(__m), __acc_(__a) {}
+
+  template <class _OtherElementType, class _OtherExtents, class _OtherLayoutPolicy, class _OtherAccessor>
+    requires(is_constructible_v<mapping_type, const typename _OtherLayoutPolicy::template mapping<_OtherExtents>&> &&
+             is_constructible_v<accessor_type, const _OtherAccessor&>)
+  explicit(!is_convertible_v<const typename _OtherLayoutPolicy::template mapping<_OtherExtents>&, mapping_type> ||
+           !is_convertible_v<const _OtherAccessor&, accessor_type>)
+      _LIBCPP_HIDE_FROM_ABI constexpr mdspan(
+          const mdspan<_OtherElementType, _OtherExtents, _OtherLayoutPolicy, _OtherAccessor>& __other)
+      : __ptr_(__other.__ptr_), __map_(__other.__map_), __acc_(__other.__acc_) {
+    static_assert(is_constructible_v<data_handle_type, const typename _OtherAccessor::data_handle_type&>,
+                  "mdspan: incompatible data_handle_type for mdspan construction");
+    static_assert(
+        is_constructible_v<extents_type, _OtherExtents>, "mdspan: incompatible extents for mdspan construction");
+
+    // The following precondition is part of the standard, but is unlikely to be triggered.
+    // The extents constructor checks this and the mapping must be storing the extents, since
+    // its extents() function returns a const reference to extents_type.
+    // The only way this can be triggered is if the mapping conversion constructor would for example
+    // always construct its extents() only from the dynamic extents, instead of from the other extents.
+    if constexpr (rank() > 0) {
+      for (size_t __r = 0; __r < rank(); __r++) {
+        // Not catching this could lead to out of bounds errors later
+        // e.g. mdspan<int, dextents<char,1>, non_checking_layout> m =
+        //        mdspan<int, dextents<unsigned, 1>, non_checking_layout>(ptr, 200); leads to an extent of -56 on m
+        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
+            (static_extent(__r) == dynamic_extent) ||
+                (static_cast<index_type>(__other.extent(__r)) == static_cast<index_type>(static_extent(__r))),
+            "mdspan: conversion mismatch of source dynamic extents with static extents");
+      }
+    }
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan& operator=(const mdspan&) = default;
+  _LIBCPP_HIDE_FROM_ABI constexpr mdspan& operator=(mdspan&&)      = default;
+
+  //--------------------------------------------------------------------------------
+  // [mdspan.mdspan.members], members
+
+  template <class... _OtherIndexTypes>
+    requires((is_convertible_v<_OtherIndexTypes, index_type> && ...) &&
+             (is_nothrow_constructible_v<index_type, _OtherIndexTypes> && ...) &&
+             (sizeof...(_OtherIndexTypes) == rank()))
+  _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](_OtherIndexTypes... __indices) const {
+    // Note the standard layouts would also check this, but user provided ones may not, so we
+    // check the precondition here
+    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__mdspan_detail::__is_multidimensional_index_in(extents(), __indices...),
+                                        "mdspan: operator[] out of bounds access");
+    return __acc_.access(__ptr_, __map_(static_cast<index_type>(std::move(__indices))...));
+  }
+
+  template <class _OtherIndexType>
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&>)
+  _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](const array< _OtherIndexType, rank()>& __indices) const {
+    return __acc_.access(__ptr_, [&]<size_t... _Idxs>(index_sequence<_Idxs...>) {
+      return __map_(__indices[_Idxs]...);
+    }(make_index_sequence<rank()>()));
+  }
+
+  template <class _OtherIndexType>
+    requires(is_convertible_v<const _OtherIndexType&, index_type> &&
+             is_nothrow_constructible_v<index_type, const _OtherIndexType&>)
+  _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](span<_OtherIndexType, rank()> __indices) const {
+    return __acc_.access(__ptr_, [&]<size_t... _Idxs>(index_sequence<_Idxs...>) {
+      return __map_(__indices[_Idxs]...);
+    }(make_index_sequence<rank()>()));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr size_type size() const noexcept {
+    // Could leave this as only checked in debug mode: semantically size() is never
+    // guaranteed to be related to any accessible range
+    _LIBCPP_ASSERT_UNCATEGORIZED(
+        false == ([&]<size_t... _Idxs>(index_sequence<_Idxs...>) {
+          size_type __prod = 1;
+          return (__builtin_mul_overflow(__prod, extent(_Idxs), &__prod) || ... || false);
+        }(make_index_sequence<rank()>())),
+        "mdspan: size() is not representable as size_type");
+    return [&]<size_t... _Idxs>(index_sequence<_Idxs...>) {
+      return ((static_cast<size_type>(__map_.extents().extent(_Idxs))) * ... * size_type(1));
+    }(make_index_sequence<rank()>());
+  }
+
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const noexcept {
+    return [&]<size_t... _Idxs>(index_sequence<_Idxs...>) {
+      return (rank() > 0) && ((__map_.extents().extent(_Idxs) == index_type(0)) || ... || false);
+    }(make_index_sequence<rank()>());
+  }
+
+  _LIBCPP_HIDE_FROM_ABI friend constexpr void swap(mdspan& __x, mdspan& __y) noexcept {
+    swap(__x.__ptr_, __y.__ptr_);
+    swap(__x.__map_, __y.__map_);
+    swap(__x.__acc_, __y.__acc_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr const extents_type& extents() const noexcept { return __map_.extents(); };
+  _LIBCPP_HIDE_FROM_ABI constexpr const data_handle_type& data_handle() const noexcept { return __ptr_; };
+  _LIBCPP_HIDE_FROM_ABI constexpr const mapping_type& mapping() const noexcept { return __map_; };
+  _LIBCPP_HIDE_FROM_ABI constexpr const accessor_type& accessor() const noexcept { return __acc_; };
+
+  _LIBCPP_HIDE_FROM_ABI static constexpr bool is_always_unique() { return mapping_type::is_always_unique(); };
+  _LIBCPP_HIDE_FROM_ABI static constexpr bool is_always_exhaustive() { return mapping_type::is_always_exhaustive(); };
+  _LIBCPP_HIDE_FROM_ABI static constexpr bool is_always_strided() { return mapping_type::is_always_strided(); };
+
+  _LIBCPP_HIDE_FROM_ABI constexpr bool is_unique() const { return __map_.is_unique(); };
+  _LIBCPP_HIDE_FROM_ABI constexpr bool is_exhaustive() const { return __map_.is_exhaustive(); };
+  _LIBCPP_HIDE_FROM_ABI constexpr bool is_strided() const { return __map_.is_strided(); };
+  _LIBCPP_HIDE_FROM_ABI constexpr index_type stride(rank_type __r) const { return __map_.stride(__r); };
+
+private:
+  _LIBCPP_NO_UNIQUE_ADDRESS data_handle_type __ptr_{};
+  _LIBCPP_NO_UNIQUE_ADDRESS mapping_type __map_{};
+  _LIBCPP_NO_UNIQUE_ADDRESS accessor_type __acc_{};
+
+  template <class, class, class, class>
+  friend class mdspan;
+};
+
+template <class _ElementType, class... _OtherIndexTypes>
+  requires((is_convertible_v<_OtherIndexTypes, size_t> && ...) && (sizeof...(_OtherIndexTypes) > 0))
+explicit mdspan(_ElementType*, _OtherIndexTypes...)
+    -> mdspan<_ElementType, dextents<size_t, sizeof...(_OtherIndexTypes)>>;
+
+template <class _Pointer>
+  requires(is_pointer_v<remove_reference_t<_Pointer>>)
+mdspan(_Pointer&&) -> mdspan<remove_pointer_t<remove_reference_t<_Pointer>>, extents<size_t>>;
+
+template <class _CArray>
+  requires(is_array_v<_CArray> && (rank_v<_CArray> == 1))
+mdspan(_CArray&) -> mdspan<remove_all_extents_t<_CArray>, extents<size_t, extent_v<_CArray, 0>>>;
+
+template <class _ElementType, class _OtherIndexType, size_t _Size>
+mdspan(_ElementType*, const array<_OtherIndexType, _Size>&) -> mdspan<_ElementType, dextents<size_t, _Size>>;
+
+template <class _ElementType, class _OtherIndexType, size_t _Size>
+mdspan(_ElementType*, span<_OtherIndexType, _Size>) -> mdspan<_ElementType, dextents<size_t, _Size>>;
+
+// This one is necessary because all the constructors take `data_handle_type`s, not
+// `_ElementType*`s, and `data_handle_type` is taken from `accessor_type::data_handle_type`, which
+// seems to throw off automatic deduction guides.
+template <class _ElementType, class _OtherIndexType, size_t... _ExtentsPack>
+mdspan(_ElementType*, const extents<_OtherIndexType, _ExtentsPack...>&)
+    -> mdspan<_ElementType, extents<_OtherIndexType, _ExtentsPack...>>;
+
+template <class _ElementType, class _MappingType>
+mdspan(_ElementType*, const _MappingType&)
+    -> mdspan<_ElementType, typename _MappingType::extents_type, typename _MappingType::layout_type>;
+
+template <class _MappingType, class _AccessorType>
+mdspan(const typename _AccessorType::data_handle_type, const _MappingType&, const _AccessorType&)
+    -> mdspan<typename _AccessorType::element_type,
+              typename _MappingType::extents_type,
+              typename _MappingType::layout_type,
+              _AccessorType>;
+
+#endif // _LIBCPP_STD_VER >= 23
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___MDSPAN_MDSPAN_H
diff --git a/contrib/llvm-project/libcxx/include/__std_clang_module b/contrib/llvm-project/libcxx/include/__std_clang_module
new file mode 100644
index 000000000000..4d02336d30b0
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__std_clang_module
@@ -0,0 +1,226 @@
+// -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+// WARNING, this entire header is generated by
+// utils/generate_std_clang_module_header.py
+// DO NOT MODIFY!
+
+// This header should not be directly included, it's exclusively to import all
+// of the libc++ public clang modules for the `std` clang module to export. In
+// other words, it's to facilitate `@import std;` in Objective-C++ and `import std`
+// in Swift to expose all of the libc++ interfaces. This is generally not
+// recommended, however there are some clients that need to import all of libc++
+// without knowing what "all" is.
+#if !__building_module(std)
+#  error "Do not include this header directly, include individual headers instead"
+#endif
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#include <algorithm>
+#include <any>
+#include <array>
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+#  include <atomic>
+#endif
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <barrier>
+#endif
+#include <bit>
+#include <bitset>
+#include <cassert>
+#include <ccomplex>
+#include <cctype>
+#include <cerrno>
+#include <cfenv>
+#include <cfloat>
+#include <charconv>
+#include <chrono>
+#include <cinttypes>
+#include <ciso646>
+#include <climits>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <clocale>
+#endif
+#include <cmath>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <codecvt>
+#endif
+#include <compare>
+#include <complex.h>
+#include <complex>
+#include <concepts>
+#include <condition_variable>
+#include <coroutine>
+#include <csetjmp>
+#include <csignal>
+#include <cstdarg>
+#include <cstdbool>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <ctgmath>
+#include <ctime>
+#include <ctype.h>
+#include <cuchar>
+#if !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#  include <cwchar>
+#endif
+#if !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#  include <cwctype>
+#endif
+#include <deque>
+#include <errno.h>
+#include <exception>
+#include <execution>
+#include <expected>
+#include <experimental/deque>
+#include <experimental/forward_list>
+#include <experimental/iterator>
+#include <experimental/list>
+#include <experimental/map>
+#include <experimental/memory_resource>
+#include <experimental/propagate_const>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <experimental/regex>
+#endif
+#include <experimental/set>
+#include <experimental/simd>
+#include <experimental/string>
+#include <experimental/type_traits>
+#include <experimental/unordered_map>
+#include <experimental/unordered_set>
+#include <experimental/utility>
+#include <experimental/vector>
+#include <fenv.h>
+#include <filesystem>
+#include <float.h>
+#include <format>
+#include <forward_list>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <fstream>
+#endif
+#include <functional>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <future>
+#endif
+#include <initializer_list>
+#include <inttypes.h>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <iomanip>
+#endif
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <ios>
+#endif
+#include <iosfwd>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <iostream>
+#endif
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <istream>
+#endif
+#include <iterator>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <latch>
+#endif
+#include <limits.h>
+#include <limits>
+#include <list>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <locale.h>
+#endif
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <locale>
+#endif
+#include <map>
+#include <math.h>
+#include <mdspan>
+#include <memory>
+#include <memory_resource>
+#include <mutex>
+#include <new>
+#include <numbers>
+#include <numeric>
+#include <optional>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <ostream>
+#endif
+#include <print>
+#include <queue>
+#include <random>
+#include <ranges>
+#include <ratio>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <regex>
+#endif
+#include <scoped_allocator>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <semaphore>
+#endif
+#include <set>
+#include <setjmp.h>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <shared_mutex>
+#endif
+#include <source_location>
+#include <span>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <sstream>
+#endif
+#include <stack>
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+#  include <stdatomic.h>
+#endif
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdexcept>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <stop_token>
+#endif
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <streambuf>
+#endif
+#include <string.h>
+#include <string>
+#include <string_view>
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#  include <strstream>
+#endif
+#include <system_error>
+#include <tgmath.h>
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#  include <thread>
+#endif
+#include <tuple>
+#include <type_traits>
+#include <typeindex>
+#include <typeinfo>
+#include <uchar.h>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+#include <valarray>
+#include <variant>
+#include <vector>
+#include <version>
+#if !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#  include <wchar.h>
+#endif
+#if !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#  include <wctype.h>
+#endif
diff --git a/contrib/llvm-project/libcxx/include/__type_traits/is_nothrow_constructible.h b/contrib/llvm-project/libcxx/include/__type_traits/is_nothrow_constructible.h
index d4686d89fd96..4949062433b7 100644
--- a/contrib/llvm-project/libcxx/include/__type_traits/is_nothrow_constructible.h
+++ b/contrib/llvm-project/libcxx/include/__type_traits/is_nothrow_constructible.h
@@ -22,7 +22,8 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if __has_builtin(__is_nothrow_constructible)
+// GCC is disabled due to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106611
+#if __has_builtin(__is_nothrow_constructible) && !defined(_LIBCPP_COMPILER_GCC)
 
 template < class _Tp, class... _Args>
 struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
diff --git a/contrib/llvm-project/libcxx/include/mdspan b/contrib/llvm-project/libcxx/include/mdspan
index 701def50b40a..9082eb8bdb55 100644
--- a/contrib/llvm-project/libcxx/include/mdspan
+++ b/contrib/llvm-project/libcxx/include/mdspan
@@ -208,6 +208,135 @@ namespace std {
   };
 }
 
+// mdspan synopsis
+
+namespace std {
+  template<class ElementType, class Extents, class LayoutPolicy = layout_right,
+           class AccessorPolicy = default_accessor<ElementType>>
+  class mdspan {
+  public:
+    using extents_type = Extents;
+    using layout_type = LayoutPolicy;
+    using accessor_type = AccessorPolicy;
+    using mapping_type = typename layout_type::template mapping<extents_type>;
+    using element_type = ElementType;
+    using value_type = remove_cv_t<element_type>;
+    using index_type = typename extents_type::index_type;
+    using size_type = typename extents_type::size_type;
+    using rank_type = typename extents_type::rank_type;
+    using data_handle_type = typename accessor_type::data_handle_type;
+    using reference = typename accessor_type::reference;
+
+    static constexpr rank_type rank() noexcept { return extents_type::rank(); }
+    static constexpr rank_type rank_dynamic() noexcept { return extents_type::rank_dynamic(); }
+    static constexpr size_t static_extent(rank_type r) noexcept
+      { return extents_type::static_extent(r); }
+    constexpr index_type extent(rank_type r) const noexcept { return extents().extent(r); }
+
+    // [mdspan.mdspan.cons], constructors
+    constexpr mdspan();
+    constexpr mdspan(const mdspan& rhs) = default;
+    constexpr mdspan(mdspan&& rhs) = default;
+
+    template<class... OtherIndexTypes>
+      constexpr explicit mdspan(data_handle_type ptr, OtherIndexTypes... exts);
+    template<class OtherIndexType, size_t N>
+      constexpr explicit(N != rank_dynamic())
+        mdspan(data_handle_type p, span<OtherIndexType, N> exts);
+    template<class OtherIndexType, size_t N>
+      constexpr explicit(N != rank_dynamic())
+        mdspan(data_handle_type p, const array<OtherIndexType, N>& exts);
+    constexpr mdspan(data_handle_type p, const extents_type& ext);
+    constexpr mdspan(data_handle_type p, const mapping_type& m);
+    constexpr mdspan(data_handle_type p, const mapping_type& m, const accessor_type& a);
+
+    template<class OtherElementType, class OtherExtents,
+             class OtherLayoutPolicy, class OtherAccessorPolicy>
+      constexpr explicit(see below)
+        mdspan(const mdspan<OtherElementType, OtherExtents,
+                            OtherLayoutPolicy, OtherAccessorPolicy>& other);
+
+    constexpr mdspan& operator=(const mdspan& rhs) = default;
+    constexpr mdspan& operator=(mdspan&& rhs) = default;
+
+    // [mdspan.mdspan.members], members
+    template<class... OtherIndexTypes>
+      constexpr reference operator[](OtherIndexTypes... indices) const;
+    template<class OtherIndexType>
+      constexpr reference operator[](span<OtherIndexType, rank()> indices) const;
+    template<class OtherIndexType>
+      constexpr reference operator[](const array<OtherIndexType, rank()>& indices) const;
+
+    constexpr size_type size() const noexcept;
+    [[nodiscard]] constexpr bool empty() const noexcept;
+
+    friend constexpr void swap(mdspan& x, mdspan& y) noexcept;
+
+    constexpr const extents_type& extents() const noexcept { return map_.extents(); }
+    constexpr const data_handle_type& data_handle() const noexcept { return ptr_; }
+    constexpr const mapping_type& mapping() const noexcept { return map_; }
+    constexpr const accessor_type& accessor() const noexcept { return acc_; }
+
+    static constexpr bool is_always_unique()
+      { return mapping_type::is_always_unique(); }
+    static constexpr bool is_always_exhaustive()
+      { return mapping_type::is_always_exhaustive(); }
+    static constexpr bool is_always_strided()
+      { return mapping_type::is_always_strided(); }
+
+    constexpr bool is_unique() const
+      { return map_.is_unique(); }
+    constexpr bool is_exhaustive() const
+      { return map_.is_exhaustive(); }
+    constexpr bool is_strided() const
+      { return map_.is_strided(); }
+    constexpr index_type stride(rank_type r) const
+      { return map_.stride(r); }
+
+  private:
+    accessor_type acc_;         // exposition only
+    mapping_type map_;          // exposition only
+    data_handle_type ptr_;      // exposition only
+  };
+
+  template<class CArray>
+    requires(is_array_v<CArray> && rank_v<CArray> == 1)
+    mdspan(CArray&)
+      -> mdspan<remove_all_extents_t<CArray>, extents<size_t, extent_v<CArray, 0>>>;
+
+  template<class Pointer>
+    requires(is_pointer_v<remove_reference_t<Pointer>>)
+    mdspan(Pointer&&)
+      -> mdspan<remove_pointer_t<remove_reference_t<Pointer>>, extents<size_t>>;
+
+  template<class ElementType, class... Integrals>
+    requires((is_convertible_v<Integrals, size_t> && ...) && sizeof...(Integrals) > 0)
+    explicit mdspan(ElementType*, Integrals...)
+      -> mdspan<ElementType, dextents<size_t, sizeof...(Integrals)>>;
+
+  template<class ElementType, class OtherIndexType, size_t N>
+    mdspan(ElementType*, span<OtherIndexType, N>)
+      -> mdspan<ElementType, dextents<size_t, N>>;
+
+  template<class ElementType, class OtherIndexType, size_t N>
+    mdspan(ElementType*, const array<OtherIndexType, N>&)
+      -> mdspan<ElementType, dextents<size_t, N>>;
+
+  template<class ElementType, class IndexType, size_t... ExtentsPack>
+    mdspan(ElementType*, const extents<IndexType, ExtentsPack...>&)
+      -> mdspan<ElementType, extents<IndexType, ExtentsPack...>>;
+
+  template<class ElementType, class MappingType>
+    mdspan(ElementType*, const MappingType&)
+      -> mdspan<ElementType, typename MappingType::extents_type,
+                typename MappingType::layout_type>;
+
+  template<class MappingType, class AccessorType>
+    mdspan(const typename AccessorType::data_handle_type&, const MappingType&,
+           const AccessorType&)
+      -> mdspan<typename AccessorType::element_type, typename MappingType::extents_type,
+                typename MappingType::layout_type, AccessorType>;
+}
 */
 
 #ifndef _LIBCPP_MDSPAN
@@ -219,6 +348,7 @@ namespace std {
 #include <__mdspan/extents.h>
 #include <__mdspan/layout_left.h>
 #include <__mdspan/layout_right.h>
+#include <__mdspan/mdspan.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/contrib/llvm-project/libcxx/include/module.modulemap.in b/contrib/llvm-project/libcxx/include/module.modulemap.in
index 9ff8b67a6a20..37a9edcd7ece 100644
--- a/contrib/llvm-project/libcxx/include/module.modulemap.in
+++ b/contrib/llvm-project/libcxx/include/module.modulemap.in
@@ -16,7 +16,6 @@ module std_atomic [system] {
   export *
 }
 module std_barrier [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "barrier"
   export *
 }
@@ -37,7 +36,6 @@ module std_chrono [system] {
   export *
 }
 module std_codecvt [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "codecvt"
   export *
 }
@@ -78,7 +76,6 @@ module std_expected [system] {
   export *
 }
 module std_filesystem [system] {
-  @requires_LIBCXX_ENABLE_FILESYSTEM@
   header "filesystem"
   export *
 }
@@ -91,8 +88,6 @@ module std_forward_list [system] {
   export *
 }
 module std_fstream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
-  @requires_LIBCXX_ENABLE_FILESYSTEM@
   header "fstream"
   export *
 }
@@ -101,7 +96,6 @@ module std_functional [system] {
   export *
 }
 module std_future [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "future"
   export *
 }
@@ -110,12 +104,10 @@ module std_initializer_list [system] {
   export *
 }
 module std_iomanip [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "iomanip"
   export *
 }
 module std_ios [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "ios"
   export *
 }
@@ -124,12 +116,10 @@ module std_iosfwd [system] {
   export *
 }
 module std_iostream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "iostream"
   export *
 }
 module std_istream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "istream"
   export *
 }
@@ -138,7 +128,6 @@ module std_iterator [system] {
   export *
 }
 module std_latch [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "latch"
   export *
 }
@@ -151,7 +140,6 @@ module std_list [system] {
   export *
 }
 module std_locale [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "locale"
   export *
 }
@@ -192,7 +180,6 @@ module std_optional [system] {
   export *
 }
 module std_ostream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "ostream"
   export *
 }
@@ -217,7 +204,6 @@ module std_ratio [system] {
   export *
 }
 module std_regex [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "regex"
   export *
 }
@@ -226,7 +212,6 @@ module std_scoped_allocator [system] {
   export *
 }
 module std_semaphore [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "semaphore"
   export *
 }
@@ -235,7 +220,6 @@ module std_set [system] {
   export *
 }
 module std_shared_mutex [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "shared_mutex"
   export std_version
 }
@@ -250,7 +234,6 @@ module std_span [system] {
   export std_private_span_span_fwd
 }
 module std_sstream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "sstream"
   export *
 }
@@ -263,12 +246,10 @@ module std_stdexcept [system] {
   export *
 }
 module std_stop_token {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "stop_token"
   export *
 }
 module std_streambuf [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "streambuf"
   export *
 }
@@ -281,7 +262,6 @@ module std_string_view [system] {
   export *
 }
 module std_strstream [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "strstream"
   export *
 }
@@ -290,7 +270,6 @@ module std_system_error [system] {
   export *
 }
 module std_thread [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
   header "thread"
   export *
 }
@@ -377,7 +356,6 @@ module std_climits [system] {
   export *
 }
 module std_clocale [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "clocale"
   export *
 }
@@ -435,12 +413,10 @@ module std_cuchar [system] {
   export *
 }
 module std_cwchar [system] {
-  @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
   header "cwchar"
   export *
 }
 module std_cwctype [system] {
-  @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
   header "cwctype"
   export *
 }
@@ -477,7 +453,6 @@ module std_limits_h [system] {
   export *
 }
 module std_locale_h [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "locale.h"
   export *
 }
@@ -493,8 +468,6 @@ module std_setjmp_h [system] {
 // FIXME: <stdalign.h> is missing.
 // <stdarg.h> provided by compiler.
 module std_stdatomic_h [system] {
-  @requires_LIBCXX_ENABLE_THREADS@
-  requires cplusplus23
   header "stdatomic.h"
   export *
 }
@@ -536,21 +509,17 @@ module std_uchar_h [system] {
 }
 // <time.h> provided by C library.
 module std_wchar_h [system] {
-  @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
   // <wchar.h>'s __need_* macros require textual inclusion.
   textual header "wchar.h"
   export *
 }
 module std_wctype_h [system] {
-  @requires_LIBCXX_ENABLE_WIDE_CHARACTERS@
   header "wctype.h"
   export *
 }
 
 // Experimental C++ standard library interfaces
 module std_experimental [system] {
-  requires cplusplus11
-
   module deque {
     header "experimental/deque"
     export *
@@ -627,6 +596,13 @@ module std_experimental [system] {
   }
 }
 
+// Convenience method to get all of the above modules in a single import statement.
+// Importing only the needed modules is likely to be more performant.
+module std [system] {
+  header "__std_clang_module"
+  export *
+}
+
 // Implementation detail headers that are private to libc++. These modules
 // must not be directly imported.
 module std_private_assert            [system] {
@@ -650,7 +626,6 @@ module std_private_hash_table        [system] {
   export *
 }
 module std_private_locale            [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "__locale"
   export *
 }
@@ -819,6 +794,7 @@ module std_private_algorithm_pstl_generate                               [system
 module std_private_algorithm_pstl_is_partitioned                         [system] { header "__algorithm/pstl_is_partitioned.h" }
 module std_private_algorithm_pstl_merge                                  [system] { header "__algorithm/pstl_merge.h" }
 module std_private_algorithm_pstl_replace                                [system] { header "__algorithm/pstl_replace.h" }
+module std_private_algorithm_pstl_sort                                   [system] { header "__algorithm/pstl_sort.h" }
 module std_private_algorithm_pstl_stable_sort                            [system] {
   header "__algorithm/pstl_stable_sort.h"
   export std_private_functional_operations
@@ -1188,7 +1164,6 @@ module std_private_chrono_duration               [system] {
 }
 module std_private_chrono_file_clock             [system] { header "__chrono/file_clock.h" }
 module std_private_chrono_formatter              [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "__chrono/formatter.h"
 }
 module std_private_chrono_hh_mm_ss               [system] { header "__chrono/hh_mm_ss.h" }
@@ -1202,11 +1177,9 @@ module std_private_chrono_month                  [system] { header "__chrono/mon
 module std_private_chrono_month_weekday          [system] { header "__chrono/month_weekday.h" }
 module std_private_chrono_monthday               [system] { header "__chrono/monthday.h" }
 module std_private_chrono_ostream                [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "__chrono/ostream.h"
 }
 module std_private_chrono_parser_std_format_spec [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "__chrono/parser_std_format_spec.h"
 }
 module std_private_chrono_statically_widen       [system] { header "__chrono/statically_widen.h" }
@@ -1516,6 +1489,7 @@ module std_private_mdspan_extents          [system] {
 }
 module std_private_mdspan_layout_left      [system] { header "__mdspan/layout_left.h" }
 module std_private_mdspan_layout_right     [system] { header "__mdspan/layout_right.h" }
+module std_private_mdspan_mdspan           [system] { header "__mdspan/mdspan.h" }
 module std_private_mdspan_mdspan_fwd       [system] { header "__fwd/mdspan.h" }
 
 module std_private_memory_addressof                       [system] { header "__memory/addressof.h" }
@@ -1529,7 +1503,10 @@ module std_private_memory_allocator_destructor            [system] { header "__m
 module std_private_memory_allocator_traits                [system] { header "__memory/allocator_traits.h" }
 module std_private_memory_assume_aligned                  [system] { header "__memory/assume_aligned.h" }
 module std_private_memory_auto_ptr                        [system] { header "__memory/auto_ptr.h" }
-module std_private_memory_builtin_new_allocator           [system] { header "__memory/builtin_new_allocator.h" }
+module std_private_memory_builtin_new_allocator           [system] {
+  header "__memory/builtin_new_allocator.h"
+  export *
+}
 module std_private_memory_compressed_pair                 [system] { header "__memory/compressed_pair.h" }
 module std_private_memory_concepts                        [system] {
   header "__memory/concepts.h"
@@ -1636,9 +1613,15 @@ module std_private_random_piecewise_linear_distribution   [system] {
   export *
 }
 module std_private_random_poisson_distribution            [system] { header "__random/poisson_distribution.h" }
-module std_private_random_random_device                   [system] { header "__random/random_device.h" }
+module std_private_random_random_device                   [system] {
+  header "__random/random_device.h"
+  export *
+}
 module std_private_random_ranlux                          [system] { header "__random/ranlux.h" }
-module std_private_random_seed_seq                        [system] { header "__random/seed_seq.h" }
+module std_private_random_seed_seq                        [system] {
+  header "__random/seed_seq.h"
+  export *
+}
 module std_private_random_shuffle_order_engine            [system] { header "__random/shuffle_order_engine.h" }
 module std_private_random_student_t_distribution          [system] { header "__random/student_t_distribution.h" }
 module std_private_random_subtract_with_carry_engine      [system] { header "__random/subtract_with_carry_engine.h" }
@@ -1681,7 +1664,6 @@ module std_private_ranges_filter_view                [system] {
 module std_private_ranges_from_range                 [system] { header "__ranges/from_range.h" }
 module std_private_ranges_iota_view                  [system] { header "__ranges/iota_view.h" }
 module std_private_ranges_istream_view               [system] {
-  @requires_LIBCXX_ENABLE_LOCALIZATION@
   header "__ranges/istream_view.h"
 }
 module std_private_ranges_join_view                  [system] {
@@ -1748,7 +1730,10 @@ module std_private_stop_token_stop_token           [system] {
   export *
 }
 
-module std_private_string_char_traits           [system] { header "__string/char_traits.h" }
+module std_private_string_char_traits           [system] {
+  header "__string/char_traits.h"
+  export *
+}
 module std_private_string_constexpr_c_functions [system] {
   header "__string/constexpr_c_functions.h"
   export std_private_type_traits_is_equality_comparable
diff --git a/contrib/llvm-project/libcxx/include/sstream b/contrib/llvm-project/libcxx/include/sstream
index d7ad0213eb34..40930df24c6d 100644
--- a/contrib/llvm-project/libcxx/include/sstream
+++ b/contrib/llvm-project/libcxx/include/sstream
@@ -399,8 +399,12 @@ public:
     _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const & { return str(__str_.get_allocator()); }
 
     _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && {
+        string_type __result;
         const basic_string_view<_CharT, _Traits> __view = view();
-        string_type __result(std::move(__str_), __view.data() - __str_.data(), __view.size());
+        if (!__view.empty()) {
+            auto __pos = __view.data() - __str_.data();
+            __result.assign(std::move(__str_), __pos, __view.size());
+        }
         __str_.clear();
         __init_buf_ptrs();
         return __result;
@@ -415,7 +419,7 @@ public:
     }
 
     _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept;
-#endif
+#endif // _LIBCPP_STD_VER >= 20
 
     void str(const string_type& __s) {
         __str_ = __s;
@@ -900,20 +904,22 @@ public:
         return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
     }
 
-#if _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const & { return __sb_.str(); }
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)
+    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
+#else
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const & { return __sb_.str(); }
 
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && { return std::move(__sb_).str(); }
+#endif
+
+#if _LIBCPP_STD_VER >= 20
     template <class _SAlloc>
       requires __is_allocator<_SAlloc>::value
     _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {
         return __sb_.str(__sa);
     }
 
-    _LIBCPP_HIDE_FROM_ABI string_type str() && { return std::move(__sb_).str(); }
-
     _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept { return __sb_.view(); }
-#else // _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
 #endif // _LIBCPP_STD_VER >= 20
 
     _LIBCPP_HIDE_FROM_ABI void str(const string_type& __s) { __sb_.str(__s); }
@@ -1023,20 +1029,22 @@ public:
         return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
     }
 
-#if _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const & { return __sb_.str(); }
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)
+    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
+#else
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const & { return __sb_.str(); }
+
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && { return std::move(__sb_).str(); }
+#endif
 
+#if _LIBCPP_STD_VER >= 20
     template <class _SAlloc>
       requires __is_allocator<_SAlloc>::value
     _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {
         return __sb_.str(__sa);
     }
 
-    _LIBCPP_HIDE_FROM_ABI string_type str() && { return std::move(__sb_).str(); }
-
     _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept { return __sb_.view(); }
-#else // _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
 #endif // _LIBCPP_STD_VER >= 20
 
     _LIBCPP_HIDE_FROM_ABI void str(const string_type& __s) { __sb_.str(__s); }
@@ -1145,20 +1153,22 @@ public:
         return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
     }
 
-#if _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const & { return __sb_.str(); }
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_BUILDING_LIBRARY)
+    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
+#else
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() const & { return __sb_.str(); }
+
+    _LIBCPP_HIDE_FROM_ABI_SSTREAM string_type str() && { return std::move(__sb_).str(); }
+#endif
 
+#if _LIBCPP_STD_VER >= 20
     template <class _SAlloc>
       requires __is_allocator<_SAlloc>::value
     _LIBCPP_HIDE_FROM_ABI basic_string<char_type, traits_type, _SAlloc> str(const _SAlloc& __sa) const {
         return __sb_.str(__sa);
     }
 
-    _LIBCPP_HIDE_FROM_ABI string_type str() && { return std::move(__sb_).str(); }
-
     _LIBCPP_HIDE_FROM_ABI basic_string_view<char_type, traits_type> view() const noexcept { return __sb_.view(); }
-#else // _LIBCPP_STD_VER >= 20
-    _LIBCPP_HIDE_FROM_ABI string_type str() const { return __sb_.str(); }
 #endif // _LIBCPP_STD_VER >= 20
 
     _LIBCPP_HIDE_FROM_ABI void str(const string_type& __s) { __sb_.str(__s); }