[Mesa-dev] [PATCH 06/10] glsl: invariant qualifier is not valid for shader inputs in GLSL ES 3.00

[Ian Romanick]

On 12/01/2014 05:04 AM, Eduardo Lima Mitev wrote:
> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> 
> GLSL ES 3.00 spec, chapter 4.6.1 "The Invariant Qualifier",
> 
>     Only variables output from a shader can be candidates for invariance. This
>     includes user-defined output variables and the built-in output variables.
>     As only outputs can be declared as invariant, an invariant output from one
>     shader stage will still match an input of a subsequent stage without the
>     input being declared as invariant.
> 
> This patch fixes the following dEQP tests:
> 
> dEQP-GLES3.functional.shaders.qualification_order.variables.valid.invariant_interp_storage_precision
> dEQP-GLES3.functional.shaders.qualification_order.variables.valid.invariant_interp_storage
> dEQP-GLES3.functional.shaders.qualification_order.variables.valid.invariant_storage_precision
> dEQP-GLES3.functional.shaders.qualification_order.variables.valid.invariant_storage
> dEQP-GLES3.functional.shaders.qualification_order.variables.invalid.invariant_interp_storage_precision_invariant_input
> dEQP-GLES3.functional.shaders.qualification_order.variables.invalid.invariant_interp_storage_invariant_input
> dEQP-GLES3.functional.shaders.qualification_order.variables.invalid.invariant_storage_precision_invariant_input
> dEQP-GLES3.functional.shaders.qualification_order.variables.invalid.invariant_storage_invariant_input
> 
> No piglit regressions observed.
> 
> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> ---
>  src/glsl/glsl_parser.yy    | 2 ++
>  src/glsl/link_varyings.cpp | 2 +-
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
> index 6160e26..55b3a7d 100644
> --- a/src/glsl/glsl_parser.yy
> +++ b/src/glsl/glsl_parser.yy
> @@ -1591,6 +1591,8 @@ type_qualifier:
>  
>        $$ = $2;
>        $$.flags.q.invariant = 1;
> +      if (state->es_shader && state->language_version >= 300 && $$.flags.q.in)
> +         _mesa_glsl_error(&@1, state, "invariant qualifiers cannot be used with shader inputs");

Since we already reject the invariant keyword for GLSL ES 1.00, I think
you can drop the '&& state->language_version >= 300' part.  I would also
add the spec quotation from the commit message here.

With those changes, this patch is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

>     }
>     | interpolation_qualifier type_qualifier
>     {
> diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
> index 1866ab2..1fe198a 100644
> --- a/src/glsl/link_varyings.cpp
> +++ b/src/glsl/link_varyings.cpp
> @@ -116,7 +116,7 @@ cross_validate_types_and_qualifiers(struct gl_shader_program *prog,
>        return;
>     }
>  
> -   if (input->data.invariant != output->data.invariant) {
> +   if (!prog->IsES && input->data.invariant != output->data.invariant) {
>        linker_error(prog,
>                     "%s shader output `%s' %s invariant qualifier, "
>                     "but %s shader input %s invariant qualifier\n",
>