swiftcinvokes sub-commands, so you shouldn't run
swiftccommand itself. You can add the
swiftcto see the underlying sub-commands. Pick the correct sub-command, then run
lldb -- <command>.
Usually, we want the first command, so run something like:
lldb -- `swiftc file.swift | head -n 1`
--one-line rto run immediately after loading, without having to set breakopints - great for debugging crashes