[Piglit] [PATCH 09/10] arb_enhanced_layouts: add another xfb_stride overflow test

[Timothy Arceri]

On 3/2/19 7:30 am, Andres Gomez wrote:
> On Sat, 2019-02-02 at 10:15 +1100, Timothy Arceri wrote:
>> On 2/2/19 4:55 am, Andres Gomez wrote:
>>> Additional check to address a bug in mesa in which a stride which
>>> is a divisor of the declared offset for an overflowing varying
>>> won't fail.
>>>
>>>   From the GL_ARB_enhanced_layouts spec:
>>>
>>>     " It is a compile-time or link-time error to have any *xfb_offset*
>>>       that overflows *xfb_stride*, whether stated on declarations before
>>>       or after the *xfb_stride*, or in different compilation units."
>>>
>>> Cc: Timothy Arceri <tarceri at itsqueeze.com>
>>> Signed-off-by: Andres Gomez <agomez at igalia.com>
>>> ---
>>>    .../xfb_stride/variable-stride-overflow2.vert | 28 +++++++++++++++++++
>>>    1 file changed, 28 insertions(+)
>>>    create mode 100644 tests/spec/arb_enhanced_layouts/compiler/transform-feedback-layout-qualifiers/xfb_stride/variable-stride-overflow2.vert
>>>
>>> diff --git a/tests/spec/arb_enhanced_layouts/compiler/transform-feedback-layout-qualifiers/xfb_stride/variable-stride-overflow2.vert b/tests/spec/arb_enhanced_layouts/compiler/transform-feedback-layout-qualifiers/xfb_stride/variable-stride-overflow2.vert
>>> new file mode 100644
>>> index 000000000..469c5e430
>>> --- /dev/null
>>> +++ b/tests/spec/arb_enhanced_layouts/compiler/transform-feedback-layout-qualifiers/xfb_stride/variable-stride-overflow2.vert
>>> @@ -0,0 +1,28 @@
>>> +// [config]
>>> +// expect_result: fail
>>> +// glsl_version: 1.40
>>> +// check_link: true
>>> +// require_extensions: GL_ARB_enhanced_layouts
>>> +// [end config]
>>> +//
>>> +// Additional check to address a bug in mesa in which a stride which
>>> +// is a divisor of the declared offset for an overflowing varying
>>> +// won't fail.
>>> +//
>>> +// From the GL_ARB_enhanced_layouts spec:
>>> +//
>>> +//    "It is a compile-time or link-time error to have any *xfb_offset*
>>> +//    that overflows *xfb_stride*, whether stated on declarations before or
>>> +//    after the *xfb_stride*, or in different compilation units."
>>> +
>>> +#version 140
>>> +#extension GL_ARB_enhanced_layouts: require
>>> +
>>> +layout(xfb_stride = 16) out vec4 var;
>>> +layout(xfb_offset = 16) out vec4 var2;
>>
>> This test looks wrong to me. This looks like it *should* compile.
>>
>> vec4 var uses bytes 0-15. So there is no issue with vec4 vec2 having an
>> offset of 16. Its been a long time since I worked on this but I think
>> this change is wrong. I see no reason this should fail compilation.
> 
> I believe I've answered now this in:
> https://lists.freedesktop.org/archives/mesa-dev/2019-February/214457.html

After rereading the spec I think you are right.

Reviewed-by: Timothy Arceri <tarceri at itsqueeze.com>

> 
>>
>>> +
>>> +void main()
>>> +{
>>> +  var = vec4(1.0);
>>> +  var2 = vec4(0.0);
>>> +}
>>>