From: Matteo Bruni <matteo.mystral@gmail.com>
Subject: Re: [PATCH 1/5] d3dcompiler: Emit constructors as sequences of stores to a synthetic variable.
Message-Id: <CABvNrtNDnWs4YgcZS62uEBM6-O=akChGZZ3WEUc28g5WkoMecA@mail.gmail.com>
Date: Mon, 8 Jun 2020 16:06:30 +0200
In-Reply-To: <20200605221933.1861389-1-zfigura@codeweavers.com>
References: <20200605221933.1861389-1-zfigura@codeweavers.com>

On Sat, Jun 6, 2020 at 12:20 AM Zebediah Figura <z.figura12@gmail.com> wrote:
>
> @@ -2415,41 +2414,60 @@ postfix_expr:             primary_expr
>                                  }
>                                  $$ = append_binop($1, $3, &load->node);
>                              }
> -                          /* "var_modifiers" doesn't make sense in this case, but it's needed
> -                             in the grammar to avoid shift/reduce conflicts. */

BTW there are 3 of those comments in hlsl.y, all different from each
other... Good job me.

> +            if ($2->type == HLSL_CLASS_MATRIX)
> +                FIXME("Matrix constructors are not supported yet.\n");
> +
> +            sprintf(name, "<constructor-%x>", counter++);
> +            if (!(var = new_synthetic_var(name, $2, get_location(&@2))))
> +                YYABORT;
> +            for (i = 0; i < $4.args_count; ++i)
> +            {
> +                const struct hlsl_type *arg_type = $4.args[i]->data_type;
> +                unsigned int component_count = arg_type->dimx * arg_type->dimy;
> +
> +                if (!(assignment = new_assignment(var, NULL, $4.args[i],
> +                        ((1 << component_count) - 1) << writemask_offset, $4.args[i]->loc)))
> +                    YYABORT;
> +                writemask_offset += component_count;

Isn't this wrong for structs or arrays?

FWIW it seems it would be more easily extensible to matrix and other
types if you generate a "full" assignment with a swizzle on the lhs
and then delegate fixing it up to make_assignment() rather than
directly computing the writemask here.