[libcxx-commits] [libcxx] [libc++] Refactor the predicate taking variant of `__cxx_atomic_wait` (PR #80596)
Jan Kokemüller via libcxx-commits
libcxx-commits at lists.llvm.org
Sun Feb 18 03:55:20 PST 2024
https://github.com/jiixyj updated https://github.com/llvm/llvm-project/pull/80596
>From 8e34214922538e43c0fff242b200db922974f275 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 4 Feb 2024 13:43:19 +0100
Subject: [PATCH 1/7] refactor the predicate taking variant of
'__cxx_atomic_wait'
---
libcxx/include/__atomic/atomic_sync.h | 101 +++++++++++++++++---------
libcxx/include/latch | 11 ++-
libcxx/include/semaphore | 17 +----
libcxx/src/atomic.cpp | 1 +
4 files changed, 80 insertions(+), 50 deletions(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index e1994ddde86c19..1eca545afb99ff 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -43,15 +43,53 @@ __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void
__libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
-template <class _Atp, class _BackoffTest>
+template <class _Atp, class _Poll>
+struct __libcpp_atomic_wait_poll_impl {
+ _Atp* __a_;
+ _Poll __poll_;
+ memory_order __order_;
+
+ _LIBCPP_AVAILABILITY_SYNC
+ _LIBCPP_HIDE_FROM_ABI bool operator()() const {
+ auto __current_val = __cxx_atomic_load(__a_, __order_);
+ return __poll_(__current_val);
+ }
+};
+
+template <class _Atp, class _Poll>
struct __libcpp_atomic_wait_backoff_impl {
_Atp* __a_;
- _BackoffTest __backoff_test_;
+ _Poll __poll_;
+ memory_order __order_;
+
+ _LIBCPP_AVAILABILITY_SYNC
+ _LIBCPP_HIDE_FROM_ABI bool
+ __poll_or_get_monitor(__cxx_atomic_contention_t const volatile*, __cxx_contention_t& __monitor) const {
+ // In case the atomic can be waited on directly, the monitor value is just
+ // the value of the atomic.
+ // `__poll_` takes the current value of the atomic as an in-out argument
+ // to potentially modify it. After it returns, `__monitor` has a value
+ // which can be safely waited on by `std::__libcpp_atomic_wait` without any
+ // ABA style issues.
+ __monitor = __cxx_atomic_load(__a_, __order_);
+ return __poll_(__monitor);
+ }
+
+ _LIBCPP_AVAILABILITY_SYNC
+ _LIBCPP_HIDE_FROM_ABI bool __poll_or_get_monitor(void const volatile*, __cxx_contention_t& __monitor) const {
+ // In case we must wait on an atomic from the pool, the monitor comes from
+ // `std::__libcpp_atomic_monitor`.
+ // Only then we may read from `__a_`. This is the "event count" pattern.
+ __monitor = std::__libcpp_atomic_monitor(__a_);
+ auto __current_val = __cxx_atomic_load(__a_, __order_);
+ return __poll_(__current_val);
+ }
+
_LIBCPP_AVAILABILITY_SYNC
_LIBCPP_HIDE_FROM_ABI bool operator()(chrono::nanoseconds __elapsed) const {
if (__elapsed > chrono::microseconds(64)) {
- auto __monitor = std::__libcpp_atomic_monitor(__a_);
- if (__backoff_test_(__monitor))
+ __cxx_contention_t __monitor;
+ if (__poll_or_get_monitor(__a_, __monitor))
return true;
std::__libcpp_atomic_wait(__a_, __monitor);
} else if (__elapsed > chrono::microseconds(4))
@@ -62,26 +100,20 @@ struct __libcpp_atomic_wait_backoff_impl {
}
};
-template <class _Atp, class _Poll, class _BackoffTest>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool
-__cxx_atomic_wait(_Atp* __a, _Poll&& __poll, _BackoffTest&& __backoff_test) {
- __libcpp_atomic_wait_backoff_impl<_Atp, __decay_t<_BackoffTest> > __backoff_fn = {__a, __backoff_test};
- return std::__libcpp_thread_poll_with_backoff(__poll, __backoff_fn);
-}
-
-template <class _Poll>
-struct __libcpp_atomic_wait_poll_as_backoff_test {
- _Poll __poll_;
-
- _LIBCPP_AVAILABILITY_SYNC
- _LIBCPP_HIDE_FROM_ABI bool operator()(__cxx_contention_t&) const { return __poll_(); }
-};
-
+// The semantics of this function are similar to `atomic`'s
+// `.wait(T old, std::memory_order order)`, but instead of having a hardcoded
+// predicate (is the loaded value unequal to `old`?), the predicate function is
+// specified as an argument. The loaded value is given as an in-out argument to
+// the predicate. If the predicate function returns `true`,
+// `_cxx_atomic_wait_fn` will return. If the predicate function returns
+// `false`, it must set the argument to its current understanding of the atomic
+// value. The predicate function must not return `false` spuriously.
template <class _Atp, class _Poll>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool __cxx_atomic_wait(_Atp* __a, _Poll&& __poll) {
- __libcpp_atomic_wait_backoff_impl<_Atp, __libcpp_atomic_wait_poll_as_backoff_test<_Poll&> > __backoff_fn = {
- __a, {__poll}};
- return std::__libcpp_thread_poll_with_backoff(__poll, __backoff_fn);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void
+__cxx_atomic_wait_fn(_Atp* __a, _Poll&& __poll, memory_order __order) {
+ __libcpp_atomic_wait_poll_impl<_Atp, __decay_t<_Poll> > __poll_fn = {__a, __poll, __order};
+ __libcpp_atomic_wait_backoff_impl<_Atp, __decay_t<_Poll> > __backoff_fn = {__a, __poll, __order};
+ (void)std::__libcpp_thread_poll_with_backoff(__poll_fn, __backoff_fn);
}
#else // _LIBCPP_HAS_NO_THREADS
@@ -90,9 +122,10 @@ template <class _Tp>
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) {}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) {}
-template <class _Atp, class _Fn>
-_LIBCPP_HIDE_FROM_ABI bool __cxx_atomic_wait(_Atp*, _Fn&& __test_fn) {
- return std::__libcpp_thread_poll_with_backoff(__test_fn, __spinning_backoff_policy());
+template <class _Atp, class _Poll>
+_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_wait_fn(_Atp*, _Poll&& __poll, memory_order __order) {
+ __libcpp_atomic_wait_poll_impl<_Atp, __decay_t<_Poll> > __poll_fn = {__a, __poll, __order};
+ (void)std::__libcpp_thread_poll_with_backoff(__poll_fn, __spinning_backoff_policy());
}
#endif // _LIBCPP_HAS_NO_THREADS
@@ -102,21 +135,19 @@ _LIBCPP_HIDE_FROM_ABI bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp c
return std::memcmp(std::addressof(__lhs), std::addressof(__rhs), sizeof(_Tp)) == 0;
}
-template <class _Atp, class _Tp>
-struct __cxx_atomic_wait_test_fn_impl {
- _Atp* __a;
+template <class _Tp>
+struct __cxx_atomic_wait_poll_fn_impl {
_Tp __val;
- memory_order __order;
- _LIBCPP_HIDE_FROM_ABI bool operator()() const {
- return !std::__cxx_nonatomic_compare_equal(std::__cxx_atomic_load(__a, __order), __val);
+ _LIBCPP_HIDE_FROM_ABI bool operator()(_Tp& __current_val) const {
+ return !std::__cxx_nonatomic_compare_equal(__current_val, __val);
}
};
template <class _Atp, class _Tp>
-_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void
__cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order) {
- __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
- return std::__cxx_atomic_wait(__a, __test_fn);
+ __cxx_atomic_wait_poll_fn_impl<_Tp> __poll_fn = {__val};
+ std::__cxx_atomic_wait_fn(__a, __poll_fn, __order);
}
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/latch b/libcxx/include/latch
index ad7b35579913b3..45c1b5c91e6cd7 100644
--- a/libcxx/include/latch
+++ b/libcxx/include/latch
@@ -97,9 +97,13 @@ public:
if (__old == __update)
__a_.notify_all();
}
- inline _LIBCPP_HIDE_FROM_ABI bool try_wait() const noexcept { return 0 == __a_.load(memory_order_acquire); }
+ inline _LIBCPP_HIDE_FROM_ABI bool try_wait() const noexcept {
+ auto __value = __a_.load(memory_order_acquire);
+ return try_wait_impl(__value);
+ }
inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void wait() const {
- __cxx_atomic_wait(&__a_.__a_, [this]() -> bool { return try_wait(); });
+ __cxx_atomic_wait_fn(
+ &__a_.__a_, [this](ptrdiff_t& __value) -> bool { return try_wait_impl(__value); }, memory_order_acquire);
}
inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void arrive_and_wait(ptrdiff_t __update = 1) {
_LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(__update >= 0, "latch::arrive_and_wait called with a negative value");
@@ -108,6 +112,9 @@ public:
count_down(__update);
wait();
}
+
+private:
+ inline _LIBCPP_HIDE_FROM_ABI bool try_wait_impl(ptrdiff_t& __value) const noexcept { return __value == 0; }
};
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/semaphore b/libcxx/include/semaphore
index 5235d720bf6fee..27e5951e7d982e 100644
--- a/libcxx/include/semaphore
+++ b/libcxx/include/semaphore
@@ -100,17 +100,8 @@ public:
}
}
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void acquire() {
- auto const __poll_fn = [this]() -> bool {
- auto __old = __a_.load(memory_order_relaxed);
- return (__old != 0) && __a_.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed);
- };
- auto const __backoff_test = [this](__cxx_contention_t& __monitor) -> bool {
- ptrdiff_t __old = __monitor;
- bool __r = __try_acquire_impl(__old);
- __monitor = static_cast<__cxx_contention_t>(__old);
- return __r;
- };
- __cxx_atomic_wait(&__a_.__a_, __poll_fn, __backoff_test);
+ __cxx_atomic_wait_fn(
+ &__a_.__a_, [this](ptrdiff_t& __old) { return __try_acquire_impl(__old); }, memory_order_relaxed);
}
template <class _Rep, class _Period>
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool
@@ -121,7 +112,7 @@ public:
return std::__libcpp_thread_poll_with_backoff(__poll_fn, __libcpp_timed_backoff_policy(), __rel_time);
}
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI bool try_acquire() {
- auto __old = __a_.load(memory_order_acquire);
+ auto __old = __a_.load(memory_order_relaxed);
return __try_acquire_impl(__old);
}
@@ -130,7 +121,7 @@ private:
while (true) {
if (__old == 0)
return false;
- if (__a_.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
+ if (__a_.compare_exchange_weak(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
return true;
}
}
diff --git a/libcxx/src/atomic.cpp b/libcxx/src/atomic.cpp
index 2f0389ae6974a6..2b67685c8a0a10 100644
--- a/libcxx/src/atomic.cpp
+++ b/libcxx/src/atomic.cpp
@@ -178,6 +178,7 @@ _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t
_LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile* __location) {
__libcpp_contention_notify(&__libcpp_contention_state(__location)->__contention_state, __location, false);
}
+// This function is never used, but still exported for ABI compatibility.
_LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t
__libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile* __location) {
return __libcpp_contention_monitor_for_wait(&__libcpp_contention_state(__location)->__contention_state, __location);
>From ce27d09d95b3d6f5ec7d08f4522fe75def06aa64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 4 Feb 2024 14:39:47 +0100
Subject: [PATCH 2/7] remove unneeded include of '__atomic/contention_t.h'
---
libcxx/include/semaphore | 1 -
1 file changed, 1 deletion(-)
diff --git a/libcxx/include/semaphore b/libcxx/include/semaphore
index 27e5951e7d982e..ae5af24e99e327 100644
--- a/libcxx/include/semaphore
+++ b/libcxx/include/semaphore
@@ -54,7 +54,6 @@ using binary_semaphore = counting_semaphore<1>;
#include <__assert> // all public C++ headers provide the assertion handler
#include <__atomic/atomic_base.h>
#include <__atomic/atomic_sync.h>
-#include <__atomic/contention_t.h>
#include <__atomic/memory_order.h>
#include <__availability>
#include <__chrono/time_point.h>
>From 6f39049ec50093d22db3c99432276346d3a8cec0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 4 Feb 2024 15:01:14 +0100
Subject: [PATCH 3/7] try to fix CI error
---
libcxx/include/__atomic/atomic_sync.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index 1eca545afb99ff..78bdd88cf0b8fa 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -51,7 +51,7 @@ struct __libcpp_atomic_wait_poll_impl {
_LIBCPP_AVAILABILITY_SYNC
_LIBCPP_HIDE_FROM_ABI bool operator()() const {
- auto __current_val = __cxx_atomic_load(__a_, __order_);
+ auto __current_val = std::__cxx_atomic_load(__a_, __order_);
return __poll_(__current_val);
}
};
@@ -71,7 +71,7 @@ struct __libcpp_atomic_wait_backoff_impl {
// to potentially modify it. After it returns, `__monitor` has a value
// which can be safely waited on by `std::__libcpp_atomic_wait` without any
// ABA style issues.
- __monitor = __cxx_atomic_load(__a_, __order_);
+ __monitor = std::__cxx_atomic_load(__a_, __order_);
return __poll_(__monitor);
}
@@ -81,7 +81,7 @@ struct __libcpp_atomic_wait_backoff_impl {
// `std::__libcpp_atomic_monitor`.
// Only then we may read from `__a_`. This is the "event count" pattern.
__monitor = std::__libcpp_atomic_monitor(__a_);
- auto __current_val = __cxx_atomic_load(__a_, __order_);
+ auto __current_val = std::__cxx_atomic_load(__a_, __order_);
return __poll_(__current_val);
}
>From 08660014469b993eac4eef1dee6dfc93360443c4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 4 Feb 2024 17:01:38 +0100
Subject: [PATCH 4/7] CI
---
libcxx/include/__atomic/atomic_sync.h | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index 78bdd88cf0b8fa..8e17e3a58a1101 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -27,6 +27,19 @@
_LIBCPP_BEGIN_NAMESPACE_STD
+template <class _Atp, class _Poll>
+struct __libcpp_atomic_wait_poll_impl {
+ _Atp* __a_;
+ _Poll __poll_;
+ memory_order __order_;
+
+ _LIBCPP_AVAILABILITY_SYNC
+ _LIBCPP_HIDE_FROM_ABI bool operator()() const {
+ auto __current_val = std::__cxx_atomic_load(__a_, __order_);
+ return __poll_(__current_val);
+ }
+};
+
#ifndef _LIBCPP_HAS_NO_THREADS
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
@@ -43,19 +56,6 @@ __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void
__libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
-template <class _Atp, class _Poll>
-struct __libcpp_atomic_wait_poll_impl {
- _Atp* __a_;
- _Poll __poll_;
- memory_order __order_;
-
- _LIBCPP_AVAILABILITY_SYNC
- _LIBCPP_HIDE_FROM_ABI bool operator()() const {
- auto __current_val = std::__cxx_atomic_load(__a_, __order_);
- return __poll_(__current_val);
- }
-};
-
template <class _Atp, class _Poll>
struct __libcpp_atomic_wait_backoff_impl {
_Atp* __a_;
>From 55411621379b30a10d90a42724bb0b66668f5dbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 4 Feb 2024 18:34:10 +0100
Subject: [PATCH 5/7] CI
---
libcxx/include/__atomic/atomic_sync.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index 8e17e3a58a1101..47407fa20d3823 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -123,7 +123,7 @@ _LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) {}
template <class _Atp, class _Poll>
-_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_wait_fn(_Atp*, _Poll&& __poll, memory_order __order) {
+_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_wait_fn(_Atp* __a, _Poll&& __poll, memory_order __order) {
__libcpp_atomic_wait_poll_impl<_Atp, __decay_t<_Poll> > __poll_fn = {__a, __poll, __order};
(void)std::__libcpp_thread_poll_with_backoff(__poll_fn, __spinning_backoff_policy());
}
>From f151e17f36a96d439bd2ca4ab1f08d902a165f96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 18 Feb 2024 12:26:14 +0100
Subject: [PATCH 6/7] rename '_cxx_atomic_wait_fn' to
'__cxx_atomic_wait_unless'
---
libcxx/include/__atomic/atomic_sync.h | 8 ++++----
libcxx/include/latch | 2 +-
libcxx/include/semaphore | 2 +-
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index 47407fa20d3823..93b051debf3087 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -105,12 +105,12 @@ struct __libcpp_atomic_wait_backoff_impl {
// predicate (is the loaded value unequal to `old`?), the predicate function is
// specified as an argument. The loaded value is given as an in-out argument to
// the predicate. If the predicate function returns `true`,
-// `_cxx_atomic_wait_fn` will return. If the predicate function returns
+// `_cxx_atomic_wait_unless` will return. If the predicate function returns
// `false`, it must set the argument to its current understanding of the atomic
// value. The predicate function must not return `false` spuriously.
template <class _Atp, class _Poll>
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void
-__cxx_atomic_wait_fn(_Atp* __a, _Poll&& __poll, memory_order __order) {
+__cxx_atomic_wait_unless(_Atp* __a, _Poll&& __poll, memory_order __order) {
__libcpp_atomic_wait_poll_impl<_Atp, __decay_t<_Poll> > __poll_fn = {__a, __poll, __order};
__libcpp_atomic_wait_backoff_impl<_Atp, __decay_t<_Poll> > __backoff_fn = {__a, __poll, __order};
(void)std::__libcpp_thread_poll_with_backoff(__poll_fn, __backoff_fn);
@@ -123,7 +123,7 @@ _LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) {}
template <class _Atp, class _Poll>
-_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_wait_fn(_Atp* __a, _Poll&& __poll, memory_order __order) {
+_LIBCPP_HIDE_FROM_ABI void __cxx_atomic_wait_unless(_Atp* __a, _Poll&& __poll, memory_order __order) {
__libcpp_atomic_wait_poll_impl<_Atp, __decay_t<_Poll> > __poll_fn = {__a, __poll, __order};
(void)std::__libcpp_thread_poll_with_backoff(__poll_fn, __spinning_backoff_policy());
}
@@ -147,7 +147,7 @@ template <class _Atp, class _Tp>
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void
__cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order) {
__cxx_atomic_wait_poll_fn_impl<_Tp> __poll_fn = {__val};
- std::__cxx_atomic_wait_fn(__a, __poll_fn, __order);
+ std::__cxx_atomic_wait_unless(__a, __poll_fn, __order);
}
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/latch b/libcxx/include/latch
index 45c1b5c91e6cd7..dd389d296f5c11 100644
--- a/libcxx/include/latch
+++ b/libcxx/include/latch
@@ -102,7 +102,7 @@ public:
return try_wait_impl(__value);
}
inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void wait() const {
- __cxx_atomic_wait_fn(
+ __cxx_atomic_wait_unless(
&__a_.__a_, [this](ptrdiff_t& __value) -> bool { return try_wait_impl(__value); }, memory_order_acquire);
}
inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void arrive_and_wait(ptrdiff_t __update = 1) {
diff --git a/libcxx/include/semaphore b/libcxx/include/semaphore
index ae5af24e99e327..448b5fbd8c58cf 100644
--- a/libcxx/include/semaphore
+++ b/libcxx/include/semaphore
@@ -99,7 +99,7 @@ public:
}
}
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void acquire() {
- __cxx_atomic_wait_fn(
+ __cxx_atomic_wait_unless(
&__a_.__a_, [this](ptrdiff_t& __old) { return __try_acquire_impl(__old); }, memory_order_relaxed);
}
template <class _Rep, class _Period>
>From 2daeb53709423b7102238411452a575d442722ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kokem=C3=BCller?= <jan.kokemueller at gmail.com>
Date: Sun, 18 Feb 2024 12:46:43 +0100
Subject: [PATCH 7/7] rename '__cxx_atomic_wait_poll_fn_impl' to
'__atomic_compare_unequal_to'
---
libcxx/include/__atomic/atomic_sync.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libcxx/include/__atomic/atomic_sync.h b/libcxx/include/__atomic/atomic_sync.h
index 93b051debf3087..d07b35878493bc 100644
--- a/libcxx/include/__atomic/atomic_sync.h
+++ b/libcxx/include/__atomic/atomic_sync.h
@@ -136,7 +136,7 @@ _LIBCPP_HIDE_FROM_ABI bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp c
}
template <class _Tp>
-struct __cxx_atomic_wait_poll_fn_impl {
+struct __atomic_compare_unequal_to {
_Tp __val;
_LIBCPP_HIDE_FROM_ABI bool operator()(_Tp& __current_val) const {
return !std::__cxx_nonatomic_compare_equal(__current_val, __val);
@@ -146,7 +146,7 @@ struct __cxx_atomic_wait_poll_fn_impl {
template <class _Atp, class _Tp>
_LIBCPP_AVAILABILITY_SYNC _LIBCPP_HIDE_FROM_ABI void
__cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order) {
- __cxx_atomic_wait_poll_fn_impl<_Tp> __poll_fn = {__val};
+ __atomic_compare_unequal_to<_Tp> __poll_fn = {__val};
std::__cxx_atomic_wait_unless(__a, __poll_fn, __order);
}
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