Everything is in the title. -S (do not assemble) is not supported by the frontend yet.
When -S is passed:
- do not call the link command ad the end (driver.compileOnly = true)
- the generated file (relo) ends with .s and not with .o
- do not remove it
I have also added it in the help displayed by -h.
I don't really know what to test in the associated unit test, since the generated assembly code depends on the backed compiler we are using...