From: Patrick Palka <ppalka@redhat.com>
To: Ken Matsui <kmatsui@gcc.gnu.org>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Define _GLIBCXX_HAS_BUILTIN_TRAIT
Date: Wed, 19 Jul 2023 14:48:16 -0400 (EDT) [thread overview]
Message-ID: <645412ed-82dd-fe17-d25a-68bbe0ccf8ac@idea> (raw)
In-Reply-To: <20230718223233.15328-1-kmatsui@gcc.gnu.org>
On Tue, 18 Jul 2023, Ken Matsui via Libstdc++ wrote:
> This patch defines _GLIBCXX_HAS_BUILTIN_TRAIT, which will be used as a
> flag to toggle built-in traits in the type_traits header. Through this
> macro function and _GLIBCXX_NO_BUILTIN_TRAITS macro, we can switch the
> use of built-in traits without needing to modify the source code.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/c++config (_GLIBCXX_HAS_BUILTIN_TRAIT): Define.
The ChangeLog entry should also mention the change to _GLIBCXX_HAS_BUILTIN,
e.g.
(_GLIBCXX_HAS_BUILTIN): Keep defined.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
> libstdc++-v3/include/bits/c++config | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
> index dd47f274d5f..de13f61db71 100644
> --- a/libstdc++-v3/include/bits/c++config
> +++ b/libstdc++-v3/include/bits/c++config
> @@ -854,7 +854,11 @@ namespace __gnu_cxx
> # define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
> #endif
>
> -#undef _GLIBCXX_HAS_BUILTIN
> +// Returns true if _GLIBCXX_NO_BUILTIN_TRAITS is not defined and the compiler
> +// has a corresponding built-in type trait. _GLIBCXX_NO_BUILTIN_TRAITS is
> +// defined to disable the use of built-in traits.
> +#define _GLIBCXX_HAS_BUILTIN_TRAIT(BT) \
> + (!defined(_GLIBCXX_NO_BUILTIN_TRAITS) && _GLIBCXX_HAS_BUILTIN(BT))
Since we don't expect _GLIBCXX_NO_BUILTIN_TRAITS to get
defined/undefined in the middle of preprocessing, perhaps we should
factor out the _GLIBCXX_NO_BUILTIN_TRAITS test from the macro function
and instead conditionally define the macro function to 0 according
_GLIBCXX_NO_BUILTIN_TRAITS?
>
> // Mark code that should be ignored by the compiler, but seen by Doxygen.
> #define _GLIBCXX_DOXYGEN_ONLY(X)
> --
> 2.41.0
>
>
next prev parent reply other threads:[~2023-07-19 18:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 22:32 Ken Matsui
2023-07-19 18:48 ` Patrick Palka [this message]
2023-07-19 19:31 ` Ken Matsui
2023-08-08 20:22 ` Jonathan Wakely
2023-07-19 19:32 ` [PATCH v2] " Ken Matsui
2023-07-20 16:05 ` Patrick Palka
2023-07-28 3:57 ` [PATCH v3 1/2] " Ken Matsui
2023-07-28 3:57 ` [PATCH v3 2/2] libstdc++: Use _GLIBCXX_HAS_BUILTIN_TRAIT Ken Matsui
2023-08-01 17:24 ` Patrick Palka
2023-08-08 20:23 ` [PATCH v2] libstdc++: Define _GLIBCXX_HAS_BUILTIN_TRAIT Jonathan Wakely
2023-08-31 12:32 ` Ken Matsui
2023-09-11 14:50 ` Jonathan Wakely
2023-09-11 14:58 ` Ken Matsui
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