lkml.org 
[lkml]   [2016]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: coccinelle: generalized removal of unnecessary pointer casts?


On Mon, 14 Mar 2016, Joe Perches wrote:

> I wrote a little cocci script to remove unnecessary
> casts for memset and memcpy (below) and tested it on
> linux kernel's drivers/staging/ directory.
>
> For instance, when dst and src are already pointers:
>
> - memcpy((u8 *)dst, (u8 *)src, r8712_get_wlan_bssid_ex_sz(src));
> + memcpy(dst, src, r8712_get_wlan_bssid_ex_sz(src));
>
> It works ok, (it doesn't remove unnecessary parentheses
> around the pointers) but it makes me wonder if there's a
> generalized spatch mechanism to remove casts when an
> arbitrary function takes a void * in any argument
> position and a call to that function uses a cast of a
> pointer to any pointer type for that argument.
>
> $ cat remove_mem_casts.cocci 
> @@
> type t;
> t *p;
> type v;
> expression e1;
> expression e2;
> @@
>
> - memset((v*)p, e1, e2)
> + memset(p, e1, e2)
>
> @@
> type t;
> t *p;
> type v;
> expression e1;
> expression e2;
> @@
>
> - memcpy((v*)p, e1, e2)
> + memcpy(p, e1, e2)
>
> @@
> type t;
> t *p;
> type v;
> expression e1;
> expression e2;
> @@
>
> - memcpy(e1, (v*)p, e2)
> + memcpy(e1, p, e2)
>
> @@
> type t1;
> type t2;
> t1 *p1;
> t2 *p2;
> type v1;
> type v2;
> expression e1;
> @@
>
> - memcpy((v1*)p1, (v2*)p2, e1)
> + memcpy(p1, p2, e1)

This should do everything:

@@
identifier f;
expression *e;
type T;
@@

f(...,
- (T *)(
e
- )
,...)

@@
identifier f;
expression *e;
type T;
@@

f(...,
- (T *)
e
,...)

julia
\
 
 \ /
  Last update: 2016-03-14 22:21    [W:0.446 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site