[Mesa-dev] [PATCH] glsl/linker: fix bug when checking precision qualifier

[Tapani Pälli]

On 01/30/2018 09:50 AM, Samuel Iglesias Gonsálvez wrote:
> According to GLSL ES 3.2 spec, see table in 9.2.1 "Linked Shaders"
> section, the precision qualifier should match for uniform variables.
> This also applies to previous GLSL ES 3.x specs.
> 
> This 'if' checks the condition for uniform variables, while for UBOs
> it is checked in link_interface_blocks.cpp.
> 
> Fixes: b50b82b8a553
> ("glsl/es31: precision qualifier doesn't need to match in shader interface block members")
> 
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
> ---
>   src/compiler/glsl/linker.cpp | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
> index ce101935b01..050b2906f6b 100644
> --- a/src/compiler/glsl/linker.cpp
> +++ b/src/compiler/glsl/linker.cpp
> @@ -1134,15 +1134,11 @@ cross_validate_globals(struct gl_shader_program *prog,
>   
>               return;
>            }
> -         /* Only in GLSL ES 3.10, the precision qualifier should not match
> -          * between block members defined in matched block names within a
> -          * shader interface.
> -          *
> -          * In GLSL ES 3.00 and ES 3.20, precision qualifier for each block
> -          * member should match.
> +
> +         /* Check the precision qualifier matches for uniform variables. For UBOs,
> +          * it is checked in link_interface_blocks.cpp.

I think this change is correct. However this comment started to bother 
me, there was commit fc6d55952d08ea03d133c1178871b0d4d289a0cf that says 
"glsl/es: precision qualifier doesn't need to match in UBOs". Do we have 
precision qualifier matching for UBOs?


>             */
> -         if (prog->IsES && (prog->data->Version != 310 ||
> -                            !var->get_interface_type()) &&
> +         if (prog->IsES && !var->get_interface_type() &&
>                existing->data.precision != var->data.precision) {
>               if ((existing->data.used && var->data.used) || prog->data->Version >= 300) {
>                  linker_error(prog, "declarations for %s `%s` have "
>