duplicates:

• SR-4517 Teach the driver (and frontend?) to handle response files

Issue Description:

I spend a fair amount of time reducing test cases, and this sometimes involves reducing cmdline invocations to minimize the number of arguments.

In clang, I generally run:

$ cat run.sh
clang @$1 file.cpp

which makes reducing easier, through, e.g. delta. I tried to do the same with swift, but it turns out I can't find the swiftc equivalent:

bash-3.2$ ./run.sh blah.rsp
<unknown>:0: error: no such file or directory: '@blah.rsp'

@belkadan Jordan, do you happen to know if the driver supports such an option? And, if not, how hard would it be to implement (or desirable)?

Thanks!