Re: [PATCH v2 1/3] d3dcompiler: Store derefs as an offset to a variable.

[Matteo Bruni]

On Wed, May 20, 2020 at 3:18 AM Zebediah Figura <z.figura12(a)gmail.com> wrote:
> @@ -633,17 +660,21 @@ static struct hlsl_ir_deref *new_array_deref(struct hlsl_ir_node *array,
>          return NULL;
>      }
>
> -    if (!(array = get_var_deref(array)))
> -        return NULL;
> +    if (data_type->reg_size > 1)
> +    {

Doesn't this need to happen even for reg_size == 1 now that we're
using a scalar offset?
> +        struct hlsl_ir_constant *c;
> +        struct hlsl_ir_node *mul;
>
> -    if (!(deref = d3dcompiler_alloc(sizeof(*deref))))
> -        return NULL;
> +        if (!(c = new_uint_constant(data_type->reg_size * 4, loc)))
> +            return NULL;
> +        list_add_after(&index->entry, &c->node.entry);
> +        if (!(mul = new_binary_expr(HLSL_IR_BINOP_MUL, index, &c->node, loc)))
> +            return NULL;
> +        list_add_after(&c->node.entry, &mul->entry);
> +        index = mul;
> +    }
>
> -    init_node(&deref->node, HLSL_IR_DEREF, data_type, loc);
> -    deref->src.type = HLSL_IR_DEREF_ARRAY;
> -    deref->src.v.array.array = array;
> -    deref->src.v.array.index = index;
> -    return deref;
> +    return new_deref(array, index, data_type, loc);
>  }
>
> static void struct_var_initializer(struct list *list, struct hlsl_ir_var *var,
> @@ -1513,12 +1490,6 @@ struct hlsl_ir_node *make_assignment(struct hlsl_ir_node *lhs, enum parse_assign
>          lhs = lhs_inner;
>      }
>
> -    if (!validate_lhs_deref(lhs))
> -    {
> -        d3dcompiler_free(assign);
> -        return NULL;
> -    }
> -
>      TRACE("Creating proper assignment expression.\n");
>      if (writemask == BWRITERSP_WRITEMASK_ALL)
>          type = lhs->data_type;
> @@ -1562,26 +1533,12 @@ struct hlsl_ir_node *make_assignment(struct hlsl_ir_node *lhs, enum parse_assign
>          enum hlsl_ir_expr_op op = op_from_assignment(assign_op);
>          struct hlsl_ir_node *expr;
>
> -        if (assign->lhs.type != HLSL_IR_DEREF_VAR)
> -        {
> -            FIXME("LHS expression not supported in compound assignments yet.\n");
> -            assign->rhs = rhs;
> -        }
> -        else
> -        {
> -            TRACE("Adding an expression for the compound assignment.\n");
> -            expr = new_binary_expr(op, lhs, rhs, lhs->loc);
> -            list_add_after(&rhs->entry, &expr->entry);
> -            assign->rhs = expr;
> -        }
> -    }
> -    else
> -    {
> -        list_remove(&lhs->entry);
> -        /* Don't recursively free the deref; we just copied its members. */
> -        d3dcompiler_free(lhs);
> -        assign->rhs = rhs;
> +        TRACE("Adding an expression for the compound assignment.\n");
> +        expr = new_binary_expr(op, lhs, rhs, lhs->loc);
> +        list_add_after(&rhs->entry, &expr->entry);
> +        rhs = expr;
>      }
> +    assign->rhs = rhs;

I guess this is one of the cases where using a struct hlsl_deref for
both lvalues and rvalues comes in handy (to some degree).