From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: [PATCH 8/8] libstdc++: Do not define lock-free atomic aliases if not fully lock-free [PR114103]
Date: Tue, 27 Feb 2024 11:42:05 +0000 [thread overview]
Message-ID: <20240227114528.1350601-8-jwakely@redhat.com> (raw)
Tested x86_64-linux. I think we should make this change, because
otherwise we define the typedefs for platforms with no lock-free
atomics, like hppa-hpux. Instead of lying, those typedefs should be
absent on that target.
-- >8 --
libstdc++-v3/ChangeLog:
PR libstdc++/114103
* include/bits/version.def (atomic_lock_free_type_aliases): Add
extra_cond to check for at least one always-lock-free type.
* include/bits/version.h: Regenerate.
* include/std/atomic (atomic_signed_lock_free)
(atomic_unsigned_lock_free): Only use always-lock-free types.
---
libstdc++-v3/include/bits/version.def | 1 +
libstdc++-v3/include/bits/version.h | 2 +-
libstdc++-v3/include/std/atomic | 6 +++---
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
index 502961eb269..d298420121b 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -739,6 +739,7 @@ ftms = {
values = {
v = 201907;
cxxmin = 20;
+ extra_cond = "(__GCC_ATOMIC_INT_LOCK_FREE | __GCC_ATOMIC_LONG_LOCK_FREE | __GCC_ATOMIC_CHAR_LOCK_FREE) & 2";
};
};
diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
index 7a6fbd35e2e..9107b45a484 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -819,7 +819,7 @@
#undef __glibcxx_want_atomic_float
#if !defined(__cpp_lib_atomic_lock_free_type_aliases)
-# if (__cplusplus >= 202002L)
+# if (__cplusplus >= 202002L) && ((__GCC_ATOMIC_INT_LOCK_FREE | __GCC_ATOMIC_LONG_LOCK_FREE | __GCC_ATOMIC_CHAR_LOCK_FREE) & 2)
# define __glibcxx_atomic_lock_free_type_aliases 201907L
# if defined(__glibcxx_want_all) || defined(__glibcxx_want_atomic_lock_free_type_aliases)
# define __cpp_lib_atomic_lock_free_type_aliases 201907L
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index 559f8370459..1462cf5ec23 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -1774,13 +1774,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= atomic<make_signed_t<__detail::__platform_wait_t>>;
using atomic_unsigned_lock_free
= atomic<make_unsigned_t<__detail::__platform_wait_t>>;
-# elif ATOMIC_INT_LOCK_FREE || !(ATOMIC_LONG_LOCK_FREE || ATOMIC_CHAR_LOCK_FREE)
+# elif ATOMIC_INT_LOCK_FREE == 2
using atomic_signed_lock_free = atomic<signed int>;
using atomic_unsigned_lock_free = atomic<unsigned int>;
-# elif ATOMIC_LONG_LOCK_FREE
+# elif ATOMIC_LONG_LOCK_FREE == 2
using atomic_signed_lock_free = atomic<signed long>;
using atomic_unsigned_lock_free = atomic<unsigned long>;
-# elif ATOMIC_CHAR_LOCK_FREE
+# elif ATOMIC_CHAR_LOCK_FREE == 2
using atomic_signed_lock_free = atomic<signed char>;
using atomic_unsigned_lock_free = atomic<unsigned char>;
# else
--
2.43.0
next reply other threads:[~2024-02-27 11:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-27 11:42 Jonathan Wakely [this message]
2024-02-27 14:33 ` Jonathan Wakely
2024-02-27 14:43 ` Jonathan Wakely
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