[Mesa-dev] [PATCH shader-db] run: don't use alloca to avoid random crashes in the GLSL compiler

[Nicolai Hähnle]

On 07.12.2016 19:03, Ian Romanick wrote:
> On 12/07/2016 09:44 AM, Marek Olšák wrote:
>> On Wed, Dec 7, 2016 at 6:42 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>> What's wrong with feeding it stack memory?
>>
>> I don't really have an answer to that.
>
> Does valgrind provide any clues?  The usual problems are running out of
> stack (is that still a thing?) or buffer overrun.

The recursively called expression visitor in st_glsl_to_tgsi used to 
have several KB of stack use. We changed that to be much less, but a 
stack underflow still seems like a plausible reason if you have huge 
allocas.


>  I'm also curious why
> you allocate shader[i].length + 1000.  Did it also fail with just +1?

Yeah, that's a bit odd indeed.

Cheers,
Nicolai

>
>> Marek
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