use rustc_abi::TyAbiInterface;

use crate::callconv::{ArgAbi, FnAbi};
use crate::spec::{Env, HasTargetSpec, Os};

fn classify_ret<Ty>(ret: &mut ArgAbi<'_, Ty>) {
    if ret.layout.is_aggregate() {
        ret.make_indirect();
    } else {
        ret.extend_integer_width_to(32);
    }
}

fn classify_arg<'a, Ty, C: HasTargetSpec>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
where
    Ty: TyAbiInterface<'a, C> + Copy,
{
    if arg.is_ignore() {
        // powerpc-unknown-linux-{gnu,musl,uclibc} doesn't ignore ZSTs.
        if cx.target_spec().os == Os::Linux
            && matches!(cx.target_spec().env, Env::Gnu | Env::Musl | Env::Uclibc)
            && arg.layout.is_zst()
        {
            arg.make_indirect_from_ignore();
        }
        return;
    }
    if arg.layout.pass_indirectly_in_non_rustic_abis(cx) || arg.layout.is_aggregate() {
        arg.make_indirect();
    } else {
        arg.extend_integer_width_to(32);
    }
}

pub(crate) fn compute_abi_info<'a, Ty, C: HasTargetSpec>(cx: &C, fn_abi: &mut FnAbi<'a, Ty>)
where
    Ty: TyAbiInterface<'a, C> + Copy,
{
    if !fn_abi.ret.is_ignore() {
        classify_ret(&mut fn_abi.ret);
    }

    for arg in fn_abi.args.iter_mut() {
        classify_arg(cx, arg);
    }
}