Fix radeon kms compiled with clang.

[Michel Dänzer]

On Sam, 2013-11-30 at 17:38 +0100, Christiano F. Haesbaert wrote:
> This will prevent xorg from segfaulting at startup if compiled with
> clang, this was observed in bitrig (openbsd fork), as well as other
> systems, as it can be seen here: 
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=47160
> 
> This patch makes my radeon hd6770 work without problems in clang.
> 
> ps: I'm not subscribed to the list
> 
> From c0795485027baba0b8cff90f6d30fa008265469b Mon Sep 17 00:00:00 2001
> From: "Christiano F. Haesbaert" <haesbaert at haesbaert.org>
> Date: Sat, 30 Nov 2013 17:33:07 +0100
> Subject: [PATCH] Fix radeon kms on clang.
> 
> clang optimizations will consider this undefined behaviour due to
> uninitiliazed data. Xorg was segfaulting on startup with radeonkms on
> a HD6770, found out by fixing the clang warnings.
> ---
>  src/radeon_dri2.c | 2 +-
>  src/radeon_kms.c  | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git src/radeon_dri2.c src/radeon_dri2.c
> index 79d8f39..4498606 100644
> --- src/radeon_dri2.c
> +++ src/radeon_dri2.c
> @@ -576,7 +576,7 @@ static void
>  radeon_dri2_client_state_changed(CallbackListPtr *ClientStateCallback, pointer data, pointer calldata)
>  {
>      DRI2ClientEventsPtr pClientEventsPriv;
> -    DRI2FrameEventPtr ref;
> +    DRI2FrameEventPtr ref = NULL;
>      NewClientInfoRec *clientinfo = calldata;
>      ClientPtr pClient = clientinfo->client;
>      pClientEventsPriv = GetDRI2ClientEvents(pClient);
> diff --git src/radeon_kms.c src/radeon_kms.c
> index 44a0139..223d669 100644
> --- src/radeon_kms.c
> +++ src/radeon_kms.c
> @@ -270,7 +270,7 @@ static void
>  radeon_dirty_update(ScreenPtr screen)
>  {
>  	RegionPtr region;
> -	PixmapDirtyUpdatePtr ent;
> +	PixmapDirtyUpdatePtr ent = NULL;
>  
>  	if (xorg_list_is_empty(&screen->pixmap_dirty_list))
>  		return;

I think it would be better to address this in xorg_list_for_each_entry()
or in clang instead of working around it in users of
xorg_list_for_each_entry(). Have there been any efforts along those
lines?


Anyway, please make sure patches you submit have a Signed-off-by: tag.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer