Function control_index

winch/codegen/src/codegen/mod.rs:2558–2562

Returns the index of the [`ControlStackFrame`] for the given depth.

(depth: u32, control_length: usize)

/// Returns the index of the [`ControlStackFrame`] for the given
/// depth.
pub fn control_index(depth: u32, control_length: usize) -> Result<usize> {
    (control_length - 1)
        .checked_sub(depth as usize)
        .ok_or_else(|| format_err!(CodeGenError::control_frame_expected()))
}