On Tue, 27 Feb 2024 at 11:49, Jonathan Wakely <jwak...@redhat.com> wrote:
>
> 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";
Maybe this should be > 1 instead of & 2 in case there are targets that
define it to 4 or something. I think those are only supposed to be
defined to 0, 1, or 2 though.
> };
> };
>
> 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
Similarly, this could be > 1 but again, I think == 2 is OK.
> 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
>
