compiler/rustc_target/src/abi/call/s390x.rs

// FIXME: The assumes we're using the non-vector ABI, i.e., compiling
// for a pre-z13 machine or using -mno-vx.

use crate::abi::call::{ArgAbi, FnAbi, Reg};
use crate::abi::{HasDataLayout, TyAbiInterface};

fn classify_ret<Ty>(ret: &mut ArgAbi<'_, Ty>) {
    if !ret.layout.is_aggregate() && ret.layout.size.bits() <= 64 {
        ret.extend_integer_width_to(64);
    } else {
        ret.make_indirect();
    }
}

fn classify_arg<'a, Ty, C>(cx: &C, arg: &mut ArgAbi<'a, Ty>)
where
    Ty: TyAbiInterface<'a, C> + Copy,
    C: HasDataLayout,
{
    if !arg.layout.is_aggregate() && arg.layout.size.bits() <= 64 {
        arg.extend_integer_width_to(64);
        return;
    }

    if arg.layout.is_single_fp_element(cx) {
        match arg.layout.size.bytes() {
            4 => arg.cast_to(Reg::f32()),
            8 => arg.cast_to(Reg::f64()),
            _ => arg.make_indirect(),
        }
    } else {
        match arg.layout.size.bytes() {
            1 => arg.cast_to(Reg::i8()),
            2 => arg.cast_to(Reg::i16()),
            4 => arg.cast_to(Reg::i32()),
            8 => arg.cast_to(Reg::i64()),
            _ => arg.make_indirect(),
        }
    }
}

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

    for arg in &mut fn_abi.args {
        if arg.is_ignore() {
            continue;
        }
        classify_arg(cx, arg);
    }
}