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

[Timothy Arceri]

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.

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