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Subject: Re: [PATCH] coccinelle: misc: restrict patch mode in
 flexible_array.cocci
To:     Julia Lawall <julia.lawall@inria.fr>
Cc:     cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org
References: <20210308191215.1362498-1-efremov@linux.com>
From:   Denis Efremov <efremov@linux.com>
Message-ID: <212e0bf3-0807-e2f1-a6fc-23f9e03906b2@linux.com>
Date:   Wed, 24 Mar 2021 10:43:03 +0300
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Ping?

On 3/8/21 10:12 PM, Denis Efremov wrote:
> Skip patches generation for structs/unions with a single field.
> Changing a zero-length array to a flexible array member in a struct
> with no named members breaks the compilation. However, reporting
> such cases is still valuable, e.g. commit 637464c59e0b
> ("ACPI: NFIT: Fix flexible_array.cocci warnings").
> 
> Signed-off-by: Denis Efremov <efremov@linux.com>
> ---
>  scripts/coccinelle/misc/flexible_array.cocci | 23 ++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/coccinelle/misc/flexible_array.cocci b/scripts/coccinelle/misc/flexible_array.cocci
> index 947fbaff82a9..f427fd68ed2d 100644
> --- a/scripts/coccinelle/misc/flexible_array.cocci
> +++ b/scripts/coccinelle/misc/flexible_array.cocci
> @@ -51,21 +51,40 @@ position p : script:python() { relevant(p) };
>    };
>  )
>  
> +@only_field depends on patch@
> +identifier name, array;
> +type T;
> +position q;
> +@@
> +
> +(
> +  struct name {@q
> +    T array[0];
> +  };
> +|
> +  struct {@q
> +    T array[0];
> +  };
> +)
> +
>  @depends on patch@
>  identifier name, array;
>  type T;
>  position p : script:python() { relevant(p) };
> +// position @q with rule "only_field" simplifies
> +// handling of bitfields, arrays, etc.
> +position q != only_field.q;
>  @@
>  
>  (
> -  struct name {
> +  struct name {@q
>      ...
>      T array@p[
>  -       0
>      ];
>    };
>  |
> -  struct {
> +  struct {@q
>      ...
>      T array@p[
>  -       0
>