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

[Ilia Mirkin]

On Sun, Mar 22, 2015 at 2:09 AM, Timothy Arceri <t_arceri at yahoo.com.au> wrote:
> On Sat, 2015-03-21 at 19:57 -0400, Ilia Mirkin wrote:
>> 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.)
>
> We are going from the inside out like this:
>
> ifc[j][k]
> ifc[j]
> ifc
>
> So we should end up at the interface which is where the max_array_access
> information is stored.
>
>>
>> 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...
>>
>
> Yeah the last deref_array->array->as_dereference_array() call is
> expected to return null which is how we know that there are no more
> arrays and its time to exit the loop and call as_dereference_variable()

Duh, of course. My bad :)

>
>> >        }
>> >
>> >        if (deref_var != NULL) {
>> > --
>> > 2.1.0
>> >
>> > _______________________________________________
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>> > mesa-dev at lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
>