[gcc r11-5454] libstdc++: Define (and use) _GLIBCXX_HAVE_ATOMIC_WAIT
Jonathan Wakely
redi@gcc.gnu.org
Thu Nov 26 23:56:02 GMT 2020
https://gcc.gnu.org/g:61c71a62453e4f2def5d94bdb2b293fcec463c14
commit r11-5454-g61c71a62453e4f2def5d94bdb2b293fcec463c14
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Nov 26 22:23:11 2020 +0000
libstdc++: Define (and use) _GLIBCXX_HAVE_ATOMIC_WAIT
In order to simplify the preprocessor checks for whether __atomic_wait
is available, this commit does:
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
The original was wrong anyway, as it should have used 'defined' to check
_GLIBCXX_HAVE_LINUX_FUTEX (for consistency with how that's used
elsewhere).
The new macro is defined in <bits/atomic_wait.h> when the file is
defines __atomic_wait and related facilities. All other code that
depends on those features can just check the one macro.
libstdc++-v3/ChangeLog:
* include/bits/atomic_wait.h (_GLIBCXX_HAVE_ATOMIC_WAIT):
Define.
* include/bits/atomic_base.h: Check _GLIBCXX_HAVE_ATOMIC_WAIT.
* include/bits/atomic_timed_wait.h: Likewise.
* include/bits/semaphore_base.h: Likewise.
* include/std/atomic: Likewise.
* include/std/latch: Likewise.
* include/std/semaphore: Likewise.
Diff:
---
libstdc++-v3/include/bits/atomic_base.h | 42 +++++++++------------
libstdc++-v3/include/bits/atomic_timed_wait.h | 7 ++--
libstdc++-v3/include/bits/atomic_wait.h | 4 +-
libstdc++-v3/include/bits/semaphore_base.h | 5 +--
libstdc++-v3/include/std/atomic | 54 +++++++++++++--------------
libstdc++-v3/include/std/latch | 4 +-
libstdc++-v3/include/std/semaphore | 6 +--
7 files changed, 57 insertions(+), 65 deletions(-)
diff --git a/libstdc++-v3/include/bits/atomic_base.h b/libstdc++-v3/include/bits/atomic_base.h
index d7db8612889..d0d962d3047 100644
--- a/libstdc++-v3/include/bits/atomic_base.h
+++ b/libstdc++-v3/include/bits/atomic_base.h
@@ -230,7 +230,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __v == __GCC_ATOMIC_TEST_AND_SET_TRUEVAL;
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(bool __old,
memory_order __m = memory_order_seq_cst) const noexcept
@@ -253,7 +253,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ std::__atomic_notify(&_M_i, true); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
#endif // C++20
_GLIBCXX_ALWAYS_INLINE void
@@ -604,8 +604,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(__int_type __old,
memory_order __m = memory_order_seq_cst) const noexcept
@@ -628,8 +627,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ std::__atomic_notify(&_M_i, true); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
-#endif // C++2a
+#endif // C++20 && HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE __int_type
fetch_add(__int_type __i,
@@ -900,8 +898,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
int(__m1), int(__m2));
}
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(__pointer_type __old,
memory_order __m = memory_order_seq_cst) noexcept
@@ -924,8 +921,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ std::__atomic_notify(&_M_p, true); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
-#endif // C++2a
+#endif // C++20 && HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE __pointer_type
fetch_add(ptrdiff_t __d,
@@ -1015,8 +1011,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
int(__success), int(__failure));
}
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
template<typename _Tp>
_GLIBCXX_ALWAYS_INLINE void
wait(const _Tp* __ptr, _Val<_Tp> __old,
@@ -1041,8 +1036,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ std::__atomic_notify(__ptr, true); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
-#endif // C++2a
+#endif // C++20 && HAVE_ATOMIC_WAIT
template<typename _Tp>
_GLIBCXX_ALWAYS_INLINE _Tp
@@ -1297,7 +1291,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__order));
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
{ __atomic_impl::wait(&_M_fp, __old, __m); }
@@ -1315,7 +1309,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_impl::notify_all(&_M_fp); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
value_type
fetch_add(value_type __i,
@@ -1454,7 +1448,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__order));
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
{ __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1472,7 +1466,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_impl::notify_all(_M_ptr); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
private:
_Tp* _M_ptr;
@@ -1569,7 +1563,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__order));
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
{ __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1587,7 +1581,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_impl::notify_all(_M_ptr); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
value_type
fetch_add(value_type __i,
@@ -1744,7 +1738,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__order));
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(_Fp __old, memory_order __m = memory_order_seq_cst) const noexcept
{ __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1762,7 +1756,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_impl::notify_all(_M_ptr); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
value_type
fetch_add(value_type __i,
@@ -1873,7 +1867,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__order));
}
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE void
wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
{ __atomic_impl::wait(_M_ptr, __old, __m); }
@@ -1891,7 +1885,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ __atomic_impl::notify_all(_M_ptr); }
// TODO add const volatile overload
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
_GLIBCXX_ALWAYS_INLINE value_type
fetch_add(difference_type __d,
diff --git a/libstdc++-v3/include/bits/atomic_timed_wait.h b/libstdc++-v3/include/bits/atomic_timed_wait.h
index 1c91c858ce7..f3a07a36722 100644
--- a/libstdc++-v3/include/bits/atomic_timed_wait.h
+++ b/libstdc++-v3/include/bits/atomic_timed_wait.h
@@ -32,10 +32,9 @@
#pragma GCC system_header
-#include <bits/c++config.h>
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
-#include <bits/functional_hash.h>
#include <bits/atomic_wait.h>
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
+#include <bits/functional_hash.h>
#include <chrono>
@@ -293,5 +292,5 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
#endif // _GLIBCXX_ATOMIC_TIMED_WAIT_H
diff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h
index 3aaaa9aaec3..a59ed8cb418 100644
--- a/libstdc++-v3/include/bits/atomic_wait.h
+++ b/libstdc++-v3/include/bits/atomic_wait.h
@@ -33,7 +33,7 @@
#pragma GCC system_header
#include <bits/c++config.h>
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#if defined _GLIBCXX_HAS_GTHREADS || defined _GLIBCXX_HAVE_LINUX_FUTEX
#include <bits/functional_hash.h>
#include <bits/gthr.h>
#include <ext/numeric_traits.h>
@@ -50,6 +50,8 @@
# include <bits/std_mutex.h> // std::mutex, std::__condvar
#endif
+// Other headers use this to check for the facilities defined in this header.
+#define _GLIBCXX_HAVE_ATOMIC_WAIT 1
namespace std _GLIBCXX_VISIBILITY(default)
{
diff --git a/libstdc++-v3/include/bits/semaphore_base.h b/libstdc++-v3/include/bits/semaphore_base.h
index 56333bbbfef..f2984236e03 100644
--- a/libstdc++-v3/include/bits/semaphore_base.h
+++ b/libstdc++-v3/include/bits/semaphore_base.h
@@ -32,9 +32,8 @@
#pragma GCC system_header
-#include <bits/c++config.h>
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
#include <bits/atomic_base.h>
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
#include <bits/atomic_timed_wait.h>
#include <ext/numeric_traits.h>
@@ -298,5 +297,5 @@ template<ptrdiff_t __least_max_value>
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
#endif // _GLIBCXX_SEMAPHORE_BASE_H
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index fe4de244f85..664af023d77 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -164,21 +164,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
memory_order __m = memory_order_seq_cst) volatile noexcept
{ return _M_base.compare_exchange_strong(__i1, __i2, __m); }
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
- void wait(bool __old, memory_order __m = memory_order_seq_cst) const
- noexcept
+#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+ void
+ wait(bool __old, memory_order __m = memory_order_seq_cst) const noexcept
{ _M_base.wait(__old, __m); }
// TODO add const volatile overload
- void notify_one() const noexcept
+ void
+ notify_one() const noexcept
{ _M_base.notify_one(); }
- void notify_all() const noexcept
+ void
+ notify_all() const noexcept
{ _M_base.notify_all(); }
-#endif // GTHREADS || LINUX_FUTEX
-#endif
+#endif // C++20 && HAVE_ATOMIC_WAIT
};
#if __cplusplus <= 201703L
@@ -380,9 +380,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return compare_exchange_strong(__e, __i, __m,
__cmpexch_failure_order(__m)); }
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
- void wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
+#if __cplusplus > 201703L && defined _GLIBCXX_HAVE_ATOMIC_WAIT
+ void
+ wait(_Tp __old, memory_order __m = memory_order_seq_cst) const noexcept
{
std::__atomic_wait(&_M_i, __old,
[__m, this, __old]
@@ -397,13 +397,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// TODO add const volatile overload
- void notify_one() const noexcept
+ void
+ notify_one() const noexcept
{ std::__atomic_notify(&_M_i, false); }
- void notify_all() const noexcept
+ void
+ notify_all() const noexcept
{ std::__atomic_notify(&_M_i, true); }
-#endif // GTHREADS || LINUX_FUTEX
-#endif // C++20
+#endif // C++20 && HAVE_ATOMIC_WAIT
};
#undef _GLIBCXX20_INIT
@@ -643,21 +644,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__cmpexch_failure_order(__m));
}
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
- void wait(__pointer_type __old,
- memory_order __m = memory_order_seq_cst) noexcept
+#if __cplusplus > 201703L && _GLIBCXX_HAVE_ATOMIC_WAIT
+ void
+ wait(__pointer_type __old, memory_order __m = memory_order_seq_cst) noexcept
{ _M_b.wait(__old, __m); }
// TODO add const volatile overload
- void notify_one() const noexcept
+ void
+ notify_one() const noexcept
{ _M_b.notify_one(); }
- void notify_all() const noexcept
+ void
+ notify_all() const noexcept
{ _M_b.notify_all(); }
-#endif // GTHREADS || LINUX_FUTEX
-#endif
+#endif // C++20 && HAVE_ATOMIC_WAIT
__pointer_type
fetch_add(ptrdiff_t __d,
memory_order __m = memory_order_seq_cst) noexcept
@@ -1411,8 +1412,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
-#if __cplusplus > 201703L
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#if __cplusplus > 201703L && _GLIBCXX_HAVE_ATOMIC_WAIT
template<typename _Tp>
inline void
atomic_wait(const atomic<_Tp>* __a,
@@ -1435,9 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline void
atomic_notify_all(atomic<_Tp>* __a) noexcept
{ __a->notify_all(); }
-
-#endif // GTHREADS || LINUX_FUTEX
-#endif // C++2a
+#endif // C++20 && HAVE_ATOMIC_WAIT
// Function templates for atomic_integral and atomic_pointer operations only.
// Some operations (and, or, xor) are only available for atomic integrals,
diff --git a/libstdc++-v3/include/std/latch b/libstdc++-v3/include/std/latch
index 3af295b4eb4..2684b72288f 100644
--- a/libstdc++-v3/include/std/latch
+++ b/libstdc++-v3/include/std/latch
@@ -36,7 +36,7 @@
#include <bits/atomic_base.h>
#include <ext/numeric_traits.h>
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -89,6 +89,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
};
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
#endif // __cplusplus > 201703L
#endif // _GLIBCXX_LATCH
diff --git a/libstdc++-v3/include/std/semaphore b/libstdc++-v3/include/std/semaphore
index f4b83ab6ae3..184c7c2867c 100644
--- a/libstdc++-v3/include/std/semaphore
+++ b/libstdc++-v3/include/std/semaphore
@@ -27,13 +27,13 @@
*/
#ifndef _GLIBCXX_SEMAPHORE
-#define _GLIBCXX_SEMAPHORE
+#define _GLIBCXX_SEMAPHORE 1
#pragma GCC system_header
#if __cplusplus > 201703L
#include <bits/semaphore_base.h>
-#if defined _GLIBCXX_HAS_GTHREADS || _GLIBCXX_HAVE_LINUX_FUTEX
+#ifdef _GLIBCXX_HAVE_ATOMIC_WAIT
#include <ext/numeric_traits.h>
namespace std _GLIBCXX_VISIBILITY(default)
@@ -90,6 +90,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using binary_semaphore = std::counting_semaphore<1>;
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
-#endif // GTHREADS || LINUX_FUTEX
+#endif // HAVE_ATOMIC_WAIT
#endif // C++20
#endif // _GLIBCXX_SEMAPHORE
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