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

[Brian Paul]

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
>>
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