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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 16 Jun 2020 15:09:33 +0200
Message-ID: <CANiq72kH3mw3yRpyjrCNxKMXtRmx8a_Yto_bOct2O0OZ_UMyuA@mail.gmail.com>
Subject: Re: [PATCH] compiler_attributes.h: Support no_sanitize_undefined
 check with GCC 4
To:     Marco Elver <elver@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        kernel test robot <lkp@intel.com>, kbuild-all@lists.01.org,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi Marco,

On Tue, Jun 16, 2020 at 1:15 AM Marco Elver <elver@google.com> wrote:
>
> UBSAN is supported since GCC 4.9, which unfortunately did not yet have
> __has_attribute(). To work around, the __GCC4_has_attribute workaround
> requires defining which compiler version supports the given attribute.
>
> In the case of no_sanitize_undefined, it is the first version that
> supports UBSAN, which is GCC 4.9.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Marco Elver <elver@google.com>
> ---

I am happy to see the `__GCC4_has_attribute` workaround is useful
outside the file, too (originally the list was meant to be used inside
the file itself, but I see it is good to reuse it).

Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

Cheers,
Miguel