[libcxx-commits] [libcxx] f97cc6b - [libc++] Clean up `_LIBCPP_HAS_NO_PLATFORM_WAIT` macro

[Joe Loser via libcxx-commits]

Author: Joe Loser
Date: 2022-09-15T09:45:21-06:00
New Revision: f97cc6b7120255c3e81017c1a4052012cbe0a004

URL: https://github.com/llvm/llvm-project/commit/f97cc6b7120255c3e81017c1a4052012cbe0a004
DIFF: https://github.com/llvm/llvm-project/commit/f97cc6b7120255c3e81017c1a4052012cbe0a004.diff

LOG: [libc++] Clean up `_LIBCPP_HAS_NO_PLATFORM_WAIT` macro

As the comment suggests, `_LIBCPP_HAS_NO_PLATFORM_WAIT` is not documented or
defined anywhere internally in the build system. It's a direct define in terms
of `_LIBCPP_HAS_NO_THREADS`. So, remove `_LIBCPP_HAS_NO_PLATFORM_WAIT` and use
`_LIBCPP_HAS_NO_THREADS` instead to control the desired behavior.

Differential Revision: https://reviews.llvm.org/D132715

Added: 
    

Modified: 
    libcxx/include/atomic

Removed: 
    


################################################################################
diff  --git a/libcxx/include/atomic b/libcxx/include/atomic
index 1c27fa804e419..4775022f7503a 100644
--- a/libcxx/include/atomic
+++ b/libcxx/include/atomic
@@ -1459,17 +1459,7 @@ struct __cxx_atomic_impl : public _Base {
 
 using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
 
-#if defined(_LIBCPP_HAS_NO_THREADS)
-#   define _LIBCPP_HAS_NO_PLATFORM_WAIT
-#endif
-
-// TODO:
-// _LIBCPP_HAS_NO_PLATFORM_WAIT is currently a "dead" macro, in the sense that
-// it is not tied anywhere into the build system or even documented. We should
-// clean it up because it is technically never defined except when threads are
-// disabled. We should clean it up in its own changeset in case we break "bad"
-// users.
-#ifndef _LIBCPP_HAS_NO_PLATFORM_WAIT
+#ifndef _LIBCPP_HAS_NO_THREADS
 
 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
 _LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
@@ -1511,7 +1501,7 @@ _LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
     return __libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
 }
 
-#else // _LIBCPP_HAS_NO_PLATFORM_WAIT
+#else // _LIBCPP_HAS_NO_THREADS
 
 template <class _Tp>
 _LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
@@ -1520,15 +1510,10 @@ _LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> co
 template <class _Atp, class _Fn>
 _LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
 {
-#if defined(_LIBCPP_HAS_NO_THREADS)
-    using _Policy = __spinning_backoff_policy;
-#else
-    using _Policy = __libcpp_timed_backoff_policy;
-#endif
-    return __libcpp_thread_poll_with_backoff(__test_fn, _Policy());
+    return __libcpp_thread_poll_with_backoff(__test_fn, __spinning_backoff_policy());
 }
 
-#endif // _LIBCPP_HAS_NO_PLATFORM_WAIT
+#endif // _LIBCPP_HAS_NO_THREADS
 
 template <class _Atp, class _Tp>
 struct __cxx_atomic_wait_test_fn_impl {