Update libcxx to 2 Apr 2024 239236b8c2154aa49e98bc7ed774a7d2712edf50

```
[libc++] Remove pair dependency (#85621)
[libc++] Simplify the implementation of <stddef.h> (#86843)
Update the "Current Status" section of the website to be current. (#84507)
[libc++] Optimize the two range overload of mismatch (#86853)
[libc++] Refactor __tuple_like and __pair_like (#85206)
[libc++][test] Improves src include paths. (#86864)
[libc++] Document guidelines for applying [[nodiscard]] (#84000)
[libc++] Optimize the std::mismatch tail (#83440)
[libc++] Remove <queue> and <stack> includes from <format> (#85520)
[libc++] Switch FreeBSD to C++26 (#86658)
[libc++] Fix one case in saturate_cast.pass.cpp for 64-bit on z/OS (#86724)
[libc++][test] Remove tests that testing std::variant<T&> (#84222)
[libc++] <experimental/simd> Reduce types for template parameter U in tests (#83781)
[libc++] Switch FreeBSD CI job to Clang 17 (#86320)
[libc++][CI] Updates the documentation. (#85264)
[libc++][format] Adds ABI tags to inline constexpr variables. (#86293)
[libc++][test] Fix race condition in condition_variable_any tests (#84788)
[libc++] Vectorize mismatch (#73255)
[libc++] Don't push and pop extensions diagnostics when using clang modules (#85917)
[libc++][ranges] use `static operator()` for C++23 ranges (#86052)
[libc++] Implement LWG3528 (`make_from_tuple` can perform (the equivalent of) a C-style cast) (#85263)
[libc++] Remove macros for keeping std::allocator members and void specialization after C++20 (#85806)
[libc++] Deprecates std::errc constants. (#80542)
[libcxx] [cmake] Fix cmake_path(ABSOLUTE_PATH) for empty CMAKE_INSTALL_PREFIX
[libc++][CI] Reenables the module tests. (#85799)
[libc++][ranges] remove `__workaround_52970` (#85683)
[libc++][ranges] LWG3715: `view_interface::empty` is overconstrained (#85004)
[libcxx] [modules] Fix relative paths with absolute LIBCXX_INSTALL_MODULES_DIR (#85756)
[libc++][format] Fixes nested concept evaluation. (#85548)
[libc++][CMake] Removes LIBCXX_ENABLE_CLANG_TIDY. (#85262)
[libc++] Remove __unconstrained_reverse_iterator (#85582)
[libc++] Simplify the implementation of remove_reference (#85207)
[libcxx][test] Create feature host-can-create-symlinks (#82204)
[libc++] Use __is_scoped_enum for the implementation of is_scoped_enum if it's available (#85580)
[libc++] Add missing hide-from-ABI annotations on virtual functions (#85439)
[libc++] Optimize ranges::fill{,_n} for vector<bool>::iterator (#84642)
[libc++] Add <locale> include in <chrono> (#85521)
[libc++] Remove <locale> includes from <format> (#85478)
[libc++] P2602R2 Poison Pills are Too Toxic (#74534)
[libc++] Fixes run-buildbot-container. (#84644)
[libc++] Add [[nodiscard]] to static numeric limit functions (#83748)
 Rework Modules CMake to be (more) idiomatic. (#84936)
[libc++] Enables TZDB tests. (#82108)
[libc++] Remove a few includes from <__functional/hash.h> (#83254)
[libc++] Implements filebuf unbuffered. (#76629)
[libc++][CI] Updates the version number of the latest release.
[libc++] Remove <tuple> include from <__format/concepts.h> (#80214)
[runtimes] Prefer -fvisibility-global-new-delete=force-hidden (#84917)
[libc++] Fix tests on musl (#85085)
[libc++] Remove _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT (#83928)
[libcxx] Fix incorrect type in the has-1024-bit-atomics feature test (#84904)
[libc++] Improves UB handling in ios_base destructor. (#76525)
[libc++][CI] Installs tzdata package in Docker. (#84643)
[libc++][TZDB] Fixes parsing interleaved rules. (#84808)
[libc++][hardening] Check bounds on arithmetic in __bounded_iter (#78876)
[libc++][hardening] Add iterator validity checks on unordered containers (#80230)
[libc++][hardening] Reclassify string_view(ptr, len)'s size assertion (#79297)
[libc++] Re-enable the clang_modules_include test for Objective-C++ (#66801)
[libc++] Remove XFAIL for SIMD in optimized build (#84767)
[libcxx] Update 128-bit-atomics feature test (#83841)
[libc++] Only forward-declare ABI-functions in exception_ptr.h if they are meant to be used (#84707)
[libc++][test] Don't include `test_format_context.h` in `parse.pass.cpp` (#83734)
[libc++] Add missing include in test (#84579)
[libc++] Remove <tuple> from <variant> (#83183)
[RFC][libc++] Reworks clang-tidy selection. (#81362)
[libc++] Remove <array> include from <span> (#83742)
[libc++][format] Updates LWG3462 status. (#80550)
[libc++][format] Update LWG3701 status. (#80545)
[libc++][test] Fix MSVC warning C4127 in `array.cons/initialization.pass.cpp` (#79793)
[libc++] Simplify the std::pair constructor overload set (#81448)
[libc++] Allow the use of extensions in the implementation (#79532)
[libc++] Don't build against libcxxrt by default on FreeBSD (#84484)
Actually disable the module generation tests.
[libc++] Disable module_std and module_std_compat tests
[libc++] Enable availability based on the compiler instead of __has_extension (#84065)
[libc++] Fixes time formatter test output for Linux on PowerPC (#75526)
[libc++] Remove unused includes from __type_traits/is_convertible.h (#83747)
```
commit_hash:171258d93ab92f516dfb1789300677a164e63219

5 files changed, 45 insertions, 25 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/src/include/tzdb/tzdb_list_private.h b/contrib/libs/cxxsupp/libcxx/src/include/tzdb/tzdb_list_private.h
index f43d7d8ea77..969b2b9f8a9 100644
--- a/contrib/libs/cxxsupp/libcxx/src/include/tzdb/tzdb_list_private.h
+++ b/contrib/libs/cxxsupp/libcxx/src/include/tzdb/tzdb_list_private.h
@@ -54,14 +54,14 @@ public:
 
   using const_iterator = tzdb_list::const_iterator;
 
-  const tzdb& front() const noexcept {
+  const tzdb& __front() const noexcept {
 #ifndef _LIBCPP_HAS_NO_THREADS
     shared_lock __lock{__mutex_};
 #endif
     return __tzdb_.front();
   }
 
-  const_iterator erase_after(const_iterator __p) {
+  const_iterator __erase_after(const_iterator __p) {
 #ifndef _LIBCPP_HAS_NO_THREADS
     unique_lock __lock{__mutex_};
 #endif
@@ -70,20 +70,17 @@ public:
     return __tzdb_.erase_after(__p);
   }
 
-  const_iterator begin() const noexcept {
+  const_iterator __begin() const noexcept {
 #ifndef _LIBCPP_HAS_NO_THREADS
     shared_lock __lock{__mutex_};
 #endif
     return __tzdb_.begin();
   }
-  const_iterator end() const noexcept {
+  const_iterator __end() const noexcept {
     //  forward_list<T>::end does not access the list, so no need to take a lock.
     return __tzdb_.end();
   }
 
-  const_iterator cbegin() const noexcept { return begin(); }
-  const_iterator cend() const noexcept { return end(); }
-
 private:
   // Loads the tzdbs
   // pre: The caller ensures the locking, if needed, is done.
diff --git a/contrib/libs/cxxsupp/libcxx/src/ios.cpp b/contrib/libs/cxxsupp/libcxx/src/ios.cpp
index d58827fa125..a727855c465 100644
--- a/contrib/libs/cxxsupp/libcxx/src/ios.cpp
+++ b/contrib/libs/cxxsupp/libcxx/src/ios.cpp
@@ -195,6 +195,10 @@ void ios_base::register_callback(event_callback fn, int index) {
 }
 
 ios_base::~ios_base() {
+  // Avoid UB when not properly initialized. See ios_base::ios_base for
+  // more information.
+  if (!__loc_)
+    return;
   __call_callbacks(erase_event);
   locale& loc_storage = *reinterpret_cast<locale*>(&__loc_);
   loc_storage.~locale();
diff --git a/contrib/libs/cxxsupp/libcxx/src/random.cpp b/contrib/libs/cxxsupp/libcxx/src/random.cpp
index c7073c54da6..93590af310e 100644
--- a/contrib/libs/cxxsupp/libcxx/src/random.cpp
+++ b/contrib/libs/cxxsupp/libcxx/src/random.cpp
@@ -79,8 +79,10 @@ unsigned random_device::operator()() {
   char* p  = reinterpret_cast<char*>(&r);
   while (n > 0) {
     ssize_t s = read(__f_, p, n);
+    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     if (s == 0)
-      __throw_system_error(ENODATA, "random_device got EOF");
+      __throw_system_error(ENODATA, "random_device got EOF"); // TODO ENODATA -> ENOMSG
+    _LIBCPP_SUPPRESS_DEPRECATED_POP
     if (s == -1) {
       if (errno != EINTR)
         __throw_system_error(errno, "random_device got an unexpected error");
diff --git a/contrib/libs/cxxsupp/libcxx/src/tzdb.cpp b/contrib/libs/cxxsupp/libcxx/src/tzdb.cpp
index 2bb801e4869..0307f754caa 100644
--- a/contrib/libs/cxxsupp/libcxx/src/tzdb.cpp
+++ b/contrib/libs/cxxsupp/libcxx/src/tzdb.cpp
@@ -511,14 +511,33 @@ static string __parse_version(istream& __input) {
   return chrono::__parse_string(__input);
 }
 
+[[nodiscard]]
+static __tz::__rule& __create_entry(__tz::__rules_storage_type& __rules, const string& __name) {
+  auto __result = [&]() -> __tz::__rule& {
+    auto& __rule = __rules.emplace_back(__name, vector<__tz::__rule>{});
+    return __rule.second.emplace_back();
+  };
+
+  if (__rules.empty())
+    return __result();
+
+  // Typically rules are in contiguous order in the database.
+  // But there are exceptions, some rules are interleaved.
+  if (__rules.back().first == __name)
+    return __rules.back().second.emplace_back();
+
+  if (auto __it = ranges::find(__rules, __name, [](const auto& __r) { return __r.first; });
+      __it != ranges::end(__rules))
+    return __it->second.emplace_back();
+
+  return __result();
+}
+
 static void __parse_rule(tzdb& __tzdb, __tz::__rules_storage_type& __rules, istream& __input) {
   chrono::__skip_mandatory_whitespace(__input);
   string __name = chrono::__parse_string(__input);
 
-  if (__rules.empty() || __rules.back().first != __name)
-    __rules.emplace_back(__name, vector<__tz::__rule>{});
-
-  __tz::__rule& __rule = __rules.back().second.emplace_back();
+  __tz::__rule& __rule = __create_entry(__rules, __name);
 
   chrono::__skip_mandatory_whitespace(__input);
   __rule.__from = chrono::__parse_year(__input);
diff --git a/contrib/libs/cxxsupp/libcxx/src/tzdb_list.cpp b/contrib/libs/cxxsupp/libcxx/src/tzdb_list.cpp
index d3ee8b58f98..b99c30a9b9e 100644
--- a/contrib/libs/cxxsupp/libcxx/src/tzdb_list.cpp
+++ b/contrib/libs/cxxsupp/libcxx/src/tzdb_list.cpp
@@ -18,26 +18,24 @@ namespace chrono {
 
 _LIBCPP_EXPORTED_FROM_ABI tzdb_list::~tzdb_list() { delete __impl_; }
 
-_LIBCPP_NODISCARD_EXT _LIBCPP_EXPORTED_FROM_ABI const tzdb& tzdb_list::front() const noexcept {
-  return __impl_->front();
-}
+[[nodiscard]] _LIBCPP_EXPORTED_FROM_ABI const tzdb& tzdb_list::__front() const noexcept { return __impl_->__front(); }
 
-_LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::erase_after(const_iterator __p) {
-  return __impl_->erase_after(__p);
+_LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::__erase_after(const_iterator __p) {
+  return __impl_->__erase_after(__p);
 }
 
-_LIBCPP_NODISCARD_EXT _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::begin() const noexcept {
-  return __impl_->begin();
+[[nodiscard]] _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::__begin() const noexcept {
+  return __impl_->__begin();
 }
-_LIBCPP_NODISCARD_EXT _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::end() const noexcept {
-  return __impl_->end();
+[[nodiscard]] _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::__end() const noexcept {
+  return __impl_->__end();
 }
 
-_LIBCPP_NODISCARD_EXT _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::cbegin() const noexcept {
-  return __impl_->cbegin();
+[[nodiscard]] _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::__cbegin() const noexcept {
+  return __impl_->__begin();
 }
-_LIBCPP_NODISCARD_EXT _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::cend() const noexcept {
-  return __impl_->cend();
+[[nodiscard]] _LIBCPP_EXPORTED_FROM_ABI tzdb_list::const_iterator tzdb_list::__cend() const noexcept {
+  return __impl_->__end();
 }
 
 } // namespace chrono