Examples of how to compile swift and objective c together. Both in a single target/module, as well as modules depending on other mixed or single language targets. Going for full swiftc, clang and ld commands to repro what is Apple's official docs in Mix and Match Overview
There are shellscipts per import/mix case that I identified. Running the shell scripts will write the required files to a gen/ folder. The first positional argument for the bash script is how it should attempt to compile, options are manual, buck_static or buck_shared for libraries, buck_build for binaries.