[Mesa-dev] [RFC PATCH 10/12] glsl: add AoA support for an inteface with unsized array members

[Ilia Mirkin]

On Sat, Mar 21, 2015 at 5:49 AM, Timothy Arceri <t_arceri at yahoo.com.au> wrote:
> Add support for setting the max access of an unsized member
> of an interface array of arrays.
>
> For example ifc[j][k].foo[i] where foo is unsized.
> ---
>  src/glsl/ast_array_index.cpp | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/src/glsl/ast_array_index.cpp b/src/glsl/ast_array_index.cpp
> index ecef651..481bba8 100644
> --- a/src/glsl/ast_array_index.cpp
> +++ b/src/glsl/ast_array_index.cpp
> @@ -64,21 +64,29 @@ update_max_array_access(ir_rvalue *ir, int idx, YYLTYPE *loc,
>        }
>     } else if (ir_dereference_record *deref_record =
>                ir->as_dereference_record()) {
> -      /* There are two possibilities we need to consider:
> +      /* There are three possibilities we need to consider:
>         *
>         * - Accessing an element of an array that is a member of a named
>         *   interface block (e.g. ifc.foo[i])
>         *
>         * - Accessing an element of an array that is a member of a named
>         *   interface block array (e.g. ifc[j].foo[i]).
> +       *
> +       * - Accessing an element of an array that is a member of a named
> +       *   interface block array of arrays (e.g. ifc[j][k].foo[i]).
>         */
>        ir_dereference_variable *deref_var =
>           deref_record->record->as_dereference_variable();
>        if (deref_var == NULL) {
> -         if (ir_dereference_array *deref_array =
> -             deref_record->record->as_dereference_array()) {
> -            deref_var = deref_array->array->as_dereference_variable();
> +         ir_dereference_array *deref_array =
> +            deref_record->record->as_dereference_array();
> +         ir_dereference_array *deref_array_prev = NULL;
> +         while (deref_array != NULL) {
> +            deref_array_prev = deref_array;
> +            deref_array = deref_array->array->as_dereference_array();
>           }
> +         if (deref_array_prev != NULL)
> +            deref_var = deref_array_prev->array->as_dereference_variable();

Hm... what will this variable be? An interface, or a
dereference_array? I'm guessing the latter, but the code below wants
the deref_var->var to be an interface. Is that still going to work?
(Don't know the code well enough... so just asking the question.)

Also can you just do ->array->as_dereference_array() /
->as_dereference_variable() like that and expect it to work? I'd think
only one of those would ever return non-null, but you end up doing
both on the value pointed at by deref_array_prev->array...

>        }
>
>        if (deref_var != NULL) {
> --
> 2.1.0
>
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