[Mesa-dev] [PATCH] mesa: silence coverity warning in _mesa_get_attachment()

[Jose Fonseca]

Given this sort of warning will pop-up all over the place, it would be nice to educate coverity without introducing any behaviour change or making logic statements unnecessarily more complex.

For example, I wonder if adding:

  assert(ctx->Const.MaxColorAttachments <= Elements(fb->Attachment));

would be enough for coverity to realize this should never happen. This is more self-documenting -- our assumptions are clearly stated as such --, without changing behavior or making code more complex.

Jose

----- Original Message -----
> The warning is kind of bogus since the i >=
> ctx->Const.MaxColorAttachments
> will prevent out of bounds array accesses, but it's easily silenced.
> 
> See http://bugs.freedesktop.org/show_bug.cgi?id=53426
> ---
>  src/mesa/main/fbobject.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/src/mesa/main/fbobject.c b/src/mesa/main/fbobject.c
> index aa8ba18..556426c 100644
> --- a/src/mesa/main/fbobject.c
> +++ b/src/mesa/main/fbobject.c
> @@ -215,8 +215,9 @@ _mesa_get_attachment(struct gl_context *ctx,
> struct gl_framebuffer *fb,
>         * hardware is used.
>         */
>        i = attachment - GL_COLOR_ATTACHMENT0_EXT;
> -      if (i >= ctx->Const.MaxColorAttachments
> -	  || (i > 0 && ctx->API == API_OPENGLES)) {
> +      if (i >= ctx->Const.MaxColorAttachments ||
> +          i >= Elements(fb->Attachment) ||
> +	  (i > 0 && ctx->API == API_OPENGLES)) {
>  	 return NULL;
>        }
>        return &fb->Attachment[BUFFER_COLOR0 + i];
> --
> 1.7.3.4
> 
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