[Mesa-dev] [PATCH] glsl: Make #pragma STDGL invariant(all) only modify outputs.

[Iago Toral]

Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>

On Tue, 2017-11-07 at 01:52 -0800, Kenneth Graunke wrote:
> According to the GLSL ES 3.20, GLSL 4.50, and GLSL 1.20 specs:
> 
>    "To force all output variables to be invariant, use the pragma
> 
>        #pragma STDGL invariant(all)
> 
>     before all declarations in a shader."
> 
> Notably, this is only supposed to affect output
> variables.  Furthermore,
> 
>    "Only variables output from a shader can be candidates for
> invariance."
> 
> It looks like this has been wrong since we first supported the pragma
> in
> 2011 (commit 86b4398cd158024f6be9fa830554a11c2a7ebe0c).
> 
> Fixes dEQP-
> GLES2.functional.shaders.preprocessor.pragmas.pragma_fragment
> ---
>  src/compiler/glsl/ast_to_hir.cpp | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/src/compiler/glsl/ast_to_hir.cpp
> b/src/compiler/glsl/ast_to_hir.cpp
> index 441404f86d3..98af6bb7239 100644
> --- a/src/compiler/glsl/ast_to_hir.cpp
> +++ b/src/compiler/glsl/ast_to_hir.cpp
> @@ -4086,12 +4086,11 @@ apply_type_qualifier_to_variable(const struct
> ast_type_qualifier *qual,
>        case MESA_SHADER_TESS_CTRL:
>        case MESA_SHADER_TESS_EVAL:
>        case MESA_SHADER_GEOMETRY:
> -         if ((var->data.mode == ir_var_shader_in)
> -             || (var->data.mode == ir_var_shader_out))
> +         if (var->data.mode == ir_var_shader_out)
>              var->data.invariant = true;
>           break;
>        case MESA_SHADER_FRAGMENT:
> -         if (var->data.mode == ir_var_shader_in)
> +         if (var->data.mode == ir_var_shader_out)
>              var->data.invariant = true;
>           break;
>        case MESA_SHADER_COMPUTE: