[libcxx-commits] [libcxx] [libc++] Allows any types of size 4 and 8 to use native platform ulock_wait (PR #161086)

[Louis Dionne via libcxx-commits]

================
@@ -70,42 +77,97 @@ __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*) _NOEXCEPT;
 _LIBCPP_EXPORTED_FROM_ABI void
 __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t) _NOEXCEPT;
 
+// new dylib interface
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t
+__libcpp_atomic_monitor_global(void const volatile* __address) _NOEXCEPT;
+
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+__libcpp_atomic_wait_global_table(void const volatile* __address, __cxx_contention_t __monitor_value) _NOEXCEPT;
+
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+__libcpp_atomic_notify_one_global_table(void const volatile*) _NOEXCEPT;
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+__libcpp_atomic_notify_all_global_table(void const volatile*) _NOEXCEPT;
+
+template <std::size_t _Size>
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+
+__libcpp_atomic_wait_native(void const volatile* __address, void const* __old_value) _NOEXCEPT;
+template <std::size_t _Size>
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+__libcpp_atomic_notify_one_native(const volatile void*) _NOEXCEPT;
+
+template <std::size_t _Size>
+_LIBCPP_AVAILABILITY_NEW_SYNC _LIBCPP_EXPORTED_FROM_ABI void
+__libcpp_atomic_notify_all_native(const volatile void*) _NOEXCEPT;
+
+// concepts defines the types are supported natively by the platform's wait
+
+#    if defined(_LIBCPP_ABI_ATOMIC_WAIT_NATIVE_BY_SIZE)
+
+#      ifdef __linux__
+
+#        define _LIBCPP_ATOMIC_WAIT_SIZES_LIST(_APPLY) _APPLY(4)
+
+#      elif defined(__APPLE__)
+
+#        define _LIBCPP_ATOMIC_WAIT_SIZES_LIST(_APPLY)                                                                 \
+          _APPLY(4)                                                                                                    \
+          _APPLY(8)
+
+#      elif defined(__FreeBSD__) && __SIZEOF_LONG__ == 8
+
+#        define _LIBCPP_ATOMIC_WAIT_SIZES_LIST(_APPLY) _APPLY(8)
+
+#      else
+
+#        define _LIBCPP_ATOMIC_WAIT_SIZES_LIST(_APPLY) _APPLY(sizeof(__cxx_contention_t))
----------------
ldionne wrote:

Could we/should we also refactor the selection of `__cxx_contention_t` in this patch? The selection of that type seems a bit arbitrary to me and it's not even clear to me that it makes sense on all platforms.

https://github.com/llvm/llvm-project/pull/161086