Method code_words

cranelift/codegen/src/isa/unwind/winarm64.rs:71–89

Calculate the number of words needed to encode the unwind codes.

(&self)

impl UnwindInfo {
    /// Calculate the number of words needed to encode the unwind codes.
    pub fn code_words(&self) -> u8 {
        let mut bytes = 0u16;
        for code in self.unwind_codes.iter() {
            let next_bytes = match code {
                UnwindCode::SaveFpLrPair { .. }
                | UnwindCode::AllocS { .. }
                | UnwindCode::PacSignLr
                | UnwindCode::SetFp => 1,
                UnwindCode::SaveReg { .. }
                | UnwindCode::SaveFReg { .. }
                | UnwindCode::AllocM { .. }
                | UnwindCode::AddFp { .. } => 2,
                UnwindCode::AllocL { .. } => 4,
            };
            bytes = bytes.checked_add(next_bytes).unwrap();
        }

        bytes.div_ceil(4).try_into().unwrap()
    }

    /// Emits the unwind information into the given mutable byte slice.
    ///