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

[Brian Paul]

Actually, in this particular case, the assertion would have to be:

  assert(BUFFER_COLOR0 + ctx->Const.MaxColorAttachments <= 
Elements(fb->Attachment));

I'm not sure that Coverity will figure this out.

-Brian

On 08/16/2012 12:57 PM, Brian Paul wrote:
> Yeah, this could happen a lot.
>
> Vinson, can you try the assertion that Jose suggests below?
>
> -Brian
>
> On 08/16/2012 11:51 AM, Jose Fonseca wrote:
>> 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
>>>
>>> _______________________________________________
>>> mesa-dev mailing list
>>> mesa-dev at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>>
>
>