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| author | Jonathan Wakely <jwakely@redhat.com> | 2023-01-05 20:23:26 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2023-01-12 11:01:09 +0000 |
| commit | dc22cf461278ace754042d9388a62afb002dfa0e (patch) | |
| tree | 1e029a14a59f7b2bc3cceed2730fa15bc1088c96 | |
| parent | 2ce55247a8bf32985a96ed63a7a92d36746723dc (diff) | |
| download | gcc-dc22cf461278ace754042d9388a62afb002dfa0e.zip gcc-dc22cf461278ace754042d9388a62afb002dfa0e.tar.gz gcc-dc22cf461278ace754042d9388a62afb002dfa0e.tar.bz2 | |
libstdc++: Use lock-free type for __platform_wait_t
For non-futex targets the __platform_wait_t type is currently uint64_t,
but that requires a lock in libatomic for some 32-bit targets. We don't
really need a 64-bit type, so use unsigned long if that is lock-free,
and int otherwise. This should mean it's lock-free on a wider set of
targets.
libstdc++-v3/ChangeLog:
* include/bits/atomic_wait.h (__detail::__platform_wait_t):
Define as unsigned long if always lock-free, and unsigned int
otherwise.
| -rw-r--r-- | libstdc++-v3/include/bits/atomic_wait.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h index bd1ed56..1d7a034 100644 --- a/libstdc++-v3/include/bits/atomic_wait.h +++ b/libstdc++-v3/include/bits/atomic_wait.h @@ -64,7 +64,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // and __platform_notify() if there is a more efficient primitive supported // by the platform (e.g. __ulock_wait()/__ulock_wake()) which is better than // a mutex/condvar based wait. - using __platform_wait_t = uint64_t; +# if ATOMIC_LONG_LOCK_FREE == 2 + using __platform_wait_t = unsigned long; +# else + using __platform_wait_t = unsigned int; +# endif inline constexpr size_t __platform_wait_alignment = __alignof__(__platform_wait_t); #endif |