[Mesa-dev] [PATCH 2/4] glsl/linker: fix location aliasing checks for interface variables

[Timothy Arceri]

On 20/10/17 08:45, Ilia Mirkin wrote:
> On Thu, Oct 19, 2017 at 5:35 PM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
>>
>>
>> On 20/10/17 08:27, Timothy Arceri wrote:
>>>
>>>
>>>
>>> On 20/10/17 08:19, Timothy Arceri wrote:
>>>>
>>>> On 20/10/17 04:21, Ilia Mirkin wrote:
>>>>>
>>>>> On Thu, Oct 19, 2017 at 12:45 PM, Ilia Mirkin <imirkin at alum.mit.edu>
>>>>> wrote:
>>>>>>
>>>>>> On Thu, Oct 19, 2017 at 12:40 PM, Iago Toral <itoral at igalia.com> wrote:
>>>>>>>
>>>>>>> On Thu, 2017-10-19 at 12:37 -0400, Ilia Mirkin wrote:
>>>>>>>>
>>>>>>>> Will this work with SSO shaders? Presumably the validation still has
>>>>>>>> to happen, but I don't think cross_validate_outputs_to_inputs() will
>>>>>>>> end up getting called.
>>>>>>>
>>>>>>>
>>>>>>> The piglit tests I mention use SSO so it seems to be working for this.
>>>>>>> See for example:
>>>>>>>
>>>>>>> tests/spec/arb_enhanced_layouts/linker/block-member-locations/named-
>>>>>>> block-member-location-overlap.shader_test
>>>>>>
>>>>>>
>>>>>> Ah great. I'm a little curious how, since I don't see how
>>>>>> cross_validate_outputs_to_inputs would get called for SSO shaders.
>>>>>> Perhaps I'm looking at old code.
>>>>>>
>>>>>> Oh - because that test doesn't test SSO. It's missing a "SSO ENABLED"
>>>>>> - can you try with that? It's just using a pipeline, but both shaders
>>>>>> are ending up in it.
>>>>>
>>>>>
>>>>> BTW, my solution to all this was
>>>>>
>>>>> https://patchwork.freedesktop.org/patch/175959/
>>>>>
>>>>> but Tim hated it, and I didn't have the time to properly respond.
>>>>
>>>>
>>>> Hate is a strong word, the problem is it duplicated some of the
>>>> checks/logic in cross_validate_outputs_to_inputs() unnecessarily. The checks
>>>> should be pulled into a helper/helpers that can also be used by SSO.
>>>
>>>
>>> Oh and your patch was also missing all the component checking logic which
>>> we also should be doing for SSO. Moving the checks into helpers will give us
>>> these check for free.
>>
>>
>> Thinking about it some more, I don't see how your patch works for SSO.
>>
>> The only place you can validate the SSO pipeline is via
>> _mesa_validate_program_pipeline() since we can't know what the other stages
>> will be at link time.
> 
> You don't need to validate the pipeline. You need to make sure each
> individual program links, and the code is called at glLinkShader()
> time, at which point it will fail the link if the interfaces have
> things they're not supposed to.
> 

Oh right, this is just for validating the outward facing interfaces of a 
SSO program. I think we have discussed this before :P