From: René Scharfe <l.s.r@web.de>
Date: Tue, 12 Nov 2019 18:37:23 GMT
Subject: Re: coccinelle: adjustments for array.cocci?
Message-ID: <5189f847-1af1-f050-6c72-576a977f6f12@web.de>
In-Reply-To: <50c77cdc-2b2d-16c8-b413-5eb6a2bae749@web.de>

Am 12.11.19 um 16:08 schrieb Markus Elfring:
> Hello,
>
> I would like to comment implementation details from
> the commit 177fbab747da4f58cb2a8ce010b3515c86dd67c9 ("coccinelle: use COPY_ARRAY for copying arrays").
>
>
> Do you find the following code variant (for the semantic patch language) also useful?
>
>  memcpy(
> (       ptr, E, n *
> -       sizeof(*(ptr))
> +       sizeof(T)
> |       arr, E, n *
> -       sizeof(*(arr))
> +       sizeof(T)
> |       E, ptr, n *
> -       sizeof(*(ptr))
> +       sizeof(T)
> |       E, arr, n *
> -       sizeof(*(arr))
> +       sizeof(T)
> )
>        )

This reduces duplication in the semantic patch, which is nice.  I think
I tried something like that at the time, but found that it failed to
produce some of the cases in 921d49be86 ("use COPY_ARRAY for copying
arrays", 2019-06-15) for some reason.

> How do you think about the following SmPL code variant?
>
> -memcpy
> +COPY_ARRAY
>        (
> (       dst_ptr
> |       dst_arr
> )
>        ,
> (       src_ptr
> |       src_arr
> )
>        ,
> -       (n) * sizeof(T)
> +       n
>        )

This eliminates duplication in the semantic patch, which is good.  It
messes up the indentation of n in some of the cases in 921d49be86 ("use
COPY_ARRAY for copying arrays", 2019-06-15), though.  Hmm, but that can
be cured by duplicating the comma:

   - , (n) * sizeof(T)
   + , n

René