From 9c996882b0ed279ca314d995f2eb1d538b94e3f8 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Fri, 20 Jan 2023 04:57:26 +0200 Subject: [PATCH] libcxx: Implement atomic::wait/notify using _umtx_op(2) for 64bit arches Only 64bit architectures can be supported this way, because libcxx defines __cxx_contention_t to be int64_t for FreeBSD, and 32bit arches do not have a kind of UMTX_OP_WAIT_INT64_PRIVATE operation. LLVM review: https://reviews.llvm.org/D142134 Tested by: emaste Reviewed by: dim, emaste, markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D38132 --- contrib/llvm-project/libcxx/src/atomic.cpp | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/contrib/llvm-project/libcxx/src/atomic.cpp b/contrib/llvm-project/libcxx/src/atomic.cpp index 250d33e98b02..e7496fa43666 100644 --- a/contrib/llvm-project/libcxx/src/atomic.cpp +++ b/contrib/llvm-project/libcxx/src/atomic.cpp @@ -26,6 +26,11 @@ # define SYS_futex SYS_futex_time64 #endif +#elif defined(__FreeBSD__) + +#include +#include + #else // <- Add other operating systems here // Baseline needs no new headers @@ -72,6 +77,22 @@ static void __libcpp_platform_wake_by_address(__cxx_atomic_contention_t const vo const_cast<__cxx_atomic_contention_t*>(__ptr), 0); } +#elif defined(__FreeBSD__) && defined(__LP64__) + +static void __libcpp_platform_wait_on_address(__cxx_atomic_contention_t const volatile* __ptr, + __cxx_contention_t __val) +{ + _umtx_op(const_cast<__cxx_atomic_contention_t*>(__ptr), + UMTX_OP_WAIT, __val, NULL, NULL); +} + +static void __libcpp_platform_wake_by_address(__cxx_atomic_contention_t const volatile* __ptr, + bool __notify_one) +{ + _umtx_op(const_cast<__cxx_atomic_contention_t*>(__ptr), + UMTX_OP_WAKE, __notify_one ? 1 : INT_MAX, NULL, NULL); +} + #else // <- Add other operating systems here // Baseline is just a timed backoff