message: Fix crash if function is empty
diff: @@ -279,6 +279,9 @@ impl BBFunction {
  }
  fn build_cfg(&mut self, label_map: FxHashMap<String, usize>) -> Result<(), InterpError> {
  + if self.blocks.is_empty() {
  + return Ok(());
  + }
  let last_idx = self.blocks.len() - 1;
  for (i, block) in self.blocks.iter_mut().enumerate() {
  // If we're before the last block
  