When enabling the early swift driver on Windows, these tests need to be
adjusted for the new driver name that is reported. Add an additional
spelling for the driver to accommodate that for the testsuite.
Unlike the frontend, the driver doesn't account for any VFS overlays set up
by the -vfsoverlay option when processing its input files. It also errors
if any of those input files don't exist on the file system. This makes it
impossible to use a file that only exists in the VFS as input to the driver,
even though the same file would be handled without issue by the frontend.
If the file doesn't exist even accounting for the VFS the frontend emits
a missing file diagnostic, so this change just suppresses the existence
check for inputs when a -vfsoverlay option is present.
Resolves rdar://problem/72485443
Build swift-frontend as the primary Swift binary, and have
swift/swiftc/etc. symlink over to it. This is a step toward allowing
swift-driver to replace the swift and swiftc binaries.
Today, the driver does not propagate the flag to the frontend
but also does not emit an error (silently consuming the flag
instead).
I'll open a similar PR for apple/swift-driver once this one is
merged, in case there are any issues that need to be worked out
first.
Fixes SR-12834.
