Re: [PATCH v2] docs/misra: document gcc-specific behavior with shifting signed integers

[Julien Grall <julien@xxxxxxx>]

Hi Stefano,

On 22/08/2023 02:02, Stefano Stabellini wrote:
> From: Stefano Stabellini <stefano.stabellini@xxxxxxx>
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
> ---
> v2:
> - split << and >>
> - do not use the word "shift" instead of << or >>
> ---
>   docs/misra/C-language-toolchain.rst | 9 +++++++++
>   1 file changed, 9 insertions(+)
>
> diff --git a/docs/misra/C-language-toolchain.rst 
> b/docs/misra/C-language-toolchain.rst
> index 785aed1eaf..4c4942a113 100644
> --- a/docs/misra/C-language-toolchain.rst
> +++ b/docs/misra/C-language-toolchain.rst
> @@ -200,6 +200,15 @@ The table columns are as follows:
>        - ARM64, X86_64
>        - See Section "6.29 Designated Initializers" of GCC_MANUAL
>   
> +   * - Signed << compiler-defined behavior
> +     - All architectures
> +     - See Section "4.5 Integers" of GCC_MANUAL. As an extension to the
> +       C language, GCC does not use the latitude given in C99 and C11
> +       only to treat certain aspects of signed << as undefined.
> +
> +   * - Signed >> acts on negative numbers by sign extension
> +     - All architectures
> +     - See Section "4.5 Integers" of GCC_MANUAL.
I noticed that all this document is referring to GCC. But we also 
support CLang. Did you confirm that CLang abide with this behavior?
Cheers,

--
Julien Grall