fp_to_ra_offset

    const fp_to_ra_offset = off: {
        // On 32-bit PA-RISC, the return address sits in the middle-ish of the frame marker.
        if (native_arch == .hppa) break :off -5 * @sizeOf(usize);
        // On 64-bit PA-RISC, the frame marker was shrunk significantly; now there's just the return
        // address followed by the base pointer.
        if (native_arch == .hppa64) break :off -2 * @sizeOf(usize);
        // On LoongArch and RISC-V, the frame pointer points to the top of the saved register area,
        // in which the return address is the second word.
        if (native_arch.isLoongArch() or native_arch.isRISCV()) break :off -1 * @sizeOf(usize);
        // On OpenRISC, the return address is stored below the stack parameter area.
        if (native_arch == .or1k) break :off -1 * @sizeOf(usize);
        if (native_arch.isPowerPC64()) break :off 2 * @sizeOf(usize);
        // On s390x, r14 is the link register and we need to grab it from its customary slot in the
        // register save area (ELF ABI s390x Supplement §1.2.2.2).
        if (native_arch == .s390x) break :off 14 * @sizeOf(usize);
        // On SPARC, the frame pointer points to the save area which holds 16 slots for the local
        // and incoming registers. The return address (i7) is stored in its customary save slot.
        if (native_arch.isSPARC()) break :off 15 * @sizeOf(usize);
        break :off @sizeOf(usize);
    }