[v2] libstdc++: Define _GLIBCXX_HAS_BUILTIN_TRAIT
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Commit Message
This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
as a flag to toggle the use of built-in traits in the type_traits header
through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
source code.
libstdc++-v3/ChangeLog:
* include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
(_GLIBCXX_HAS_BUILTIN): Keep defined.
Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
libstdc++-v3/include/bits/c++config | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
Comments
On Wed, Jul 19, 2023 at 3:33 PM Ken Matsui via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
> as a flag to toggle the use of built-in traits in the type_traits header
> through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
> source code.
LGTM!
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> (_GLIBCXX_HAS_BUILTIN): Keep defined.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
> libstdc++-v3/include/bits/c++config | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
> index dd47f274d5f..984985d6fff 100644
> --- a/libstdc++-v3/include/bits/c++config
> +++ b/libstdc++-v3/include/bits/c++config
> @@ -854,7 +854,15 @@ namespace __gnu_cxx
> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
> #endif
>
> -#undef _GLIBCXX_HAS_BUILTIN
> +// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
> +// has a corresponding built-in type trait, 0 otherwise.
> +// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of built-in
> +// traits.
> +#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
> +#else
> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
> +#endif
>
> // Mark code that should be ignored by the compiler, but seen by Doxygen.
> #define _GLIBCXX_DOXYGEN_ONLY(X)
> --
> 2.41.0
>
On Wed, 19 Jul 2023 at 20:33, Ken Matsui via Libstdc++ <
libstdc++@gcc.gnu.org> wrote:
> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
> as a flag to toggle the use of built-in traits in the type_traits header
> through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
> source code.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> (_GLIBCXX_HAS_BUILTIN): Keep defined.
>
I think this would be a little better as:
* include/bits/c++config (_GLIBCXX_HAS_BUILTIN): Do not undef.
(_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
OK for trunk with that change, thanks.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
> libstdc++-v3/include/bits/c++config | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/include/bits/c++config
> b/libstdc++-v3/include/bits/c++config
> index dd47f274d5f..984985d6fff 100644
> --- a/libstdc++-v3/include/bits/c++config
> +++ b/libstdc++-v3/include/bits/c++config
> @@ -854,7 +854,15 @@ namespace __gnu_cxx
> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
> #endif
>
> -#undef _GLIBCXX_HAS_BUILTIN
> +// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
> +// has a corresponding built-in type trait, 0 otherwise.
> +// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of
> built-in
> +// traits.
> +#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
> +#else
> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
> +#endif
>
> // Mark code that should be ignored by the compiler, but seen by Doxygen.
> #define _GLIBCXX_DOXYGEN_ONLY(X)
> --
> 2.41.0
>
>
On Tue, Aug 8, 2023 at 1:23 PM Jonathan Wakely <jwakely@redhat.com> wrote:
>
>
>
> On Wed, 19 Jul 2023 at 20:33, Ken Matsui via Libstdc++ <libstdc++@gcc.gnu.org> wrote:
>>
>> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
>> as a flag to toggle the use of built-in traits in the type_traits header
>> through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
>> source code.
>>
>> libstdc++-v3/ChangeLog:
>>
>> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
>> (_GLIBCXX_HAS_BUILTIN): Keep defined.
>
>
> I think this would be a little better as:
>
> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN): Do not undef.
> (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
>
> OK for trunk with that change, thanks.
>
Thank you for your review! Patrick and I were discussing the naming
conventions for the macros _GLIBCXX_HAS_BUILTIN_TRAIT and
_GLIBCXX_NO_BUILTIN_TRAITS. It was brought to our attention that these
namings might be ambiguous, as there are implementations that have
corresponding built-ins but do not have fallback. Therefore, we
believe that using _GLIBCXX_USE_BUILTIN_TRAIT instead of
_GLIBCXX_HAS_BUILTIN_TRAIT would be more appropriate. Similarly, we
think that _GLIBCXX_AVOID_BUILTIN_TRAITS would be a better choice than
_GLIBCXX_NO_BUILTIN_TRAITS, as the latter implies that there are no
built-ins, when in fact it is meant to express that the use of
built-ins should be avoided when defining this macro. Could you please
let me know your thoughts on these updated namings?
>
>>
>>
>> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
>> ---
>> libstdc++-v3/include/bits/c++config | 10 +++++++++-
>> 1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
>> index dd47f274d5f..984985d6fff 100644
>> --- a/libstdc++-v3/include/bits/c++config
>> +++ b/libstdc++-v3/include/bits/c++config
>> @@ -854,7 +854,15 @@ namespace __gnu_cxx
>> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
>> #endif
>>
>> -#undef _GLIBCXX_HAS_BUILTIN
>> +// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
>> +// has a corresponding built-in type trait, 0 otherwise.
>> +// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of built-in
>> +// traits.
>> +#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
>> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
>> +#else
>> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
>> +#endif
>>
>> // Mark code that should be ignored by the compiler, but seen by Doxygen.
>> #define _GLIBCXX_DOXYGEN_ONLY(X)
>> --
>> 2.41.0
>>
On Thu, 31 Aug 2023 at 13:33, Ken Matsui <kmatsui@cs.washington.edu> wrote:
>
> On Tue, Aug 8, 2023 at 1:23 PM Jonathan Wakely <jwakely@redhat.com> wrote:
> >
> >
> >
> > On Wed, 19 Jul 2023 at 20:33, Ken Matsui via Libstdc++ <libstdc++@gcc.gnu.org> wrote:
> >>
> >> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
> >> as a flag to toggle the use of built-in traits in the type_traits header
> >> through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
> >> source code.
> >>
> >> libstdc++-v3/ChangeLog:
> >>
> >> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> >> (_GLIBCXX_HAS_BUILTIN): Keep defined.
> >
> >
> > I think this would be a little better as:
> >
> > * include/bits/c++config (_GLIBCXX_HAS_BUILTIN): Do not undef.
> > (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> >
> > OK for trunk with that change, thanks.
> >
> Thank you for your review! Patrick and I were discussing the naming
> conventions for the macros _GLIBCXX_HAS_BUILTIN_TRAIT and
> _GLIBCXX_NO_BUILTIN_TRAITS. It was brought to our attention that these
> namings might be ambiguous, as there are implementations that have
> corresponding built-ins but do not have fallback. Therefore, we
> believe that using _GLIBCXX_USE_BUILTIN_TRAIT instead of
> _GLIBCXX_HAS_BUILTIN_TRAIT would be more appropriate. Similarly, we
> think that _GLIBCXX_AVOID_BUILTIN_TRAITS would be a better choice than
> _GLIBCXX_NO_BUILTIN_TRAITS, as the latter implies that there are no
> built-ins, when in fact it is meant to express that the use of
> built-ins should be avoided when defining this macro. Could you please
> let me know your thoughts on these updated namings?
Yes, I agree that makes sense. I think personally I'd go with
"DISABLE" instead of "AVOID", or even "DO_NOT_USE" (to mirror "USE" in
the macro for individual traits), but either is OK.
> >
> >>
> >>
> >> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> >> ---
> >> libstdc++-v3/include/bits/c++config | 10 +++++++++-
> >> 1 file changed, 9 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
> >> index dd47f274d5f..984985d6fff 100644
> >> --- a/libstdc++-v3/include/bits/c++config
> >> +++ b/libstdc++-v3/include/bits/c++config
> >> @@ -854,7 +854,15 @@ namespace __gnu_cxx
> >> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
> >> #endif
> >>
> >> -#undef _GLIBCXX_HAS_BUILTIN
> >> +// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
> >> +// has a corresponding built-in type trait, 0 otherwise.
> >> +// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of built-in
> >> +// traits.
> >> +#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
> >> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
> >> +#else
> >> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
> >> +#endif
> >>
> >> // Mark code that should be ignored by the compiler, but seen by Doxygen.
> >> #define _GLIBCXX_DOXYGEN_ONLY(X)
> >> --
> >> 2.41.0
> >>
>
On Mon, Sep 11, 2023 at 7:51 AM Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Thu, 31 Aug 2023 at 13:33, Ken Matsui <kmatsui@cs.washington.edu> wrote:
> >
> > On Tue, Aug 8, 2023 at 1:23 PM Jonathan Wakely <jwakely@redhat.com> wrote:
> > >
> > >
> > >
> > > On Wed, 19 Jul 2023 at 20:33, Ken Matsui via Libstdc++ <libstdc++@gcc.gnu.org> wrote:
> > >>
> > >> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT macro, which will be used
> > >> as a flag to toggle the use of built-in traits in the type_traits header
> > >> through _GLIBCXX_NO_BUILTIN_TRAITS macro, without needing to modify the
> > >> source code.
> > >>
> > >> libstdc++-v3/ChangeLog:
> > >>
> > >> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> > >> (_GLIBCXX_HAS_BUILTIN): Keep defined.
> > >
> > >
> > > I think this would be a little better as:
> > >
> > > * include/bits/c++config (_GLIBCXX_HAS_BUILTIN): Do not undef.
> > > (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
> > >
> > > OK for trunk with that change, thanks.
> > >
> > Thank you for your review! Patrick and I were discussing the naming
> > conventions for the macros _GLIBCXX_HAS_BUILTIN_TRAIT and
> > _GLIBCXX_NO_BUILTIN_TRAITS. It was brought to our attention that these
> > namings might be ambiguous, as there are implementations that have
> > corresponding built-ins but do not have fallback. Therefore, we
> > believe that using _GLIBCXX_USE_BUILTIN_TRAIT instead of
> > _GLIBCXX_HAS_BUILTIN_TRAIT would be more appropriate. Similarly, we
> > think that _GLIBCXX_AVOID_BUILTIN_TRAITS would be a better choice than
> > _GLIBCXX_NO_BUILTIN_TRAITS, as the latter implies that there are no
> > built-ins, when in fact it is meant to express that the use of
> > built-ins should be avoided when defining this macro. Could you please
> > let me know your thoughts on these updated namings?
>
> Yes, I agree that makes sense. I think personally I'd go with
> "DISABLE" instead of "AVOID", or even "DO_NOT_USE" (to mirror "USE" in
> the macro for individual traits), but either is OK.
I like the idea of mirroring "USE", so I would choose "DO_NOT_USE".
Thank you for your response!
> > >
> > >>
> > >>
> > >> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > >> ---
> > >> libstdc++-v3/include/bits/c++config | 10 +++++++++-
> > >> 1 file changed, 9 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
> > >> index dd47f274d5f..984985d6fff 100644
> > >> --- a/libstdc++-v3/include/bits/c++config
> > >> +++ b/libstdc++-v3/include/bits/c++config
> > >> @@ -854,7 +854,15 @@ namespace __gnu_cxx
> > >> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
> > >> #endif
> > >>
> > >> -#undef _GLIBCXX_HAS_BUILTIN
> > >> +// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
> > >> +// has a corresponding built-in type trait, 0 otherwise.
> > >> +// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of built-in
> > >> +// traits.
> > >> +#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
> > >> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
> > >> +#else
> > >> +# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
> > >> +#endif
> > >>
> > >> // Mark code that should be ignored by the compiler, but seen by Doxygen.
> > >> #define _GLIBCXX_DOXYGEN_ONLY(X)
> > >> --
> > >> 2.41.0
> > >>
> >
>
@@ -854,7 +854,15 @@ namespace __gnu_cxx
# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
#endif
-#undef _GLIBCXX_HAS_BUILTIN
+// Returns 1 if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
+// has a corresponding built-in type trait, 0 otherwise.
+// _GLIBCXX_NO_BUILTIN_TRAITS can be defined to disable the use of built-in
+// traits.
+#ifndef _GLIBCXX_NO_BUILTIN_TRAITS
+# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) _GLIBCXX_HAS_BUILTIN(BT)
+#else
+# define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) 0
+#endif
// Mark code that should be ignored by the compiler, but seen by Doxygen.
#define _GLIBCXX_DOXYGEN_ONLY(X)