The (old) driver handles -print-target-info commands by building a subset of the command line and directly invoking the frontend. This bypasses mechanisms like -v and -###, which is undesirable from a debugging standpoint. It would be helpful if these things worked with this command.
Somewhat separately, this design also requires the driver to have complete knowledge of which flags influence the target and search paths, which is a bit brittle. There might be a better way to architect this; for instance, we might be able to treat the target info as a potential output of the compiler and perform normal processing in the driver before invoking the frontend to print the information.