[8/8] libstdc++: Do not define lock-free atomic aliases if not fully lock-free [PR114103]
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Commit Message
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(-)
Comments
On Tue, 27 Feb 2024 at 11:49, Jonathan Wakely <jwakely@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
>
Ooops, I forgot to add --no-numbered so these were eight unrelated
patches, not PATCH 1/8 .. PATCH 8/8. Sorry for any confusion.
On Tue, 27 Feb 2024 at 14:33, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Tue, 27 Feb 2024 at 11:49, Jonathan Wakely <jwakely@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
> >
@@ -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";
};
};
@@ -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
@@ -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