[Mesa-dev] [PATCH v3 22/32] glsl: allow bindless samplers/images to be l-values

[Nicolai Hähnle]

On 02.05.2017 22:53, Samuel Pitoiset wrote:
> From section 4.1.7 of the ARB_bindless_texture spec:
>
>    "Samplers can be used as l-values, so can be assigned into and
>    used as "out" and "inout" function parameters."
>
> From section 4.1.X of the ARB_bindless_texture spec:
>
>    "Images can be used as l-values, so can be assigned into and
>     used as "out" and "inout" function parameters."
>
> v3: - update spec comment formatting
>     - keep the read_only check
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/compiler/glsl/ir.cpp | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/src/compiler/glsl/ir.cpp b/src/compiler/glsl/ir.cpp
> index 538da8b28f..7b95c19723 100644
> --- a/src/compiler/glsl/ir.cpp
> +++ b/src/compiler/glsl/ir.cpp
> @@ -1447,6 +1447,20 @@ ir_dereference::is_lvalue(const struct _mesa_glsl_parse_state *state) const
>     if ((var == NULL) || var->data.read_only)
>        return false;
>
> +   /* From section 4.1.7 of the ARB_bindless_texture spec:
> +    *
> +    * "Samplers can be used as l-values, so can be assigned into and used as
> +    *  "out" and "inout" function parameters."
> +    *
> +    * From section 4.1.X of the ARB_bindless_texture spec:
> +    *
> +    * "Images can be used as l-values, so can be assigned into and used as
> +    *  "out" and "inout" function parameters."
> +    */
> +   if (state && state->has_bindless() &&
> +       (this->type->contains_sampler() || this->type->contains_image()))
> +      return true;

Have you considered inverting the logic for the default-parameter case? I.e.

   if ((!state || state->has_bindless()) &&
       (this->type->contains_sampler() || this->type->contains_image()))

Then you could skip the previous patch. I'd prefer that because it also 
covers that assertion in opt_function_inlining.

Cheers,
Nicolai


> +
>     /* From section 4.1.7 of the GLSL 4.40 spec:
>      *
>      *   "Opaque variables cannot be treated as l-values; hence cannot
>


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