Don't let test/Driver/no-canonical-prefixes.c form a symlink cycle the second time it runs.

[thakis]

Summary

The test makes %t.fake a symlink to %t.real by running ln -sf %t.real %t.fake. If %t.fake already is a symlink to %t.real when this runs (e.g. if the test has run before), then this effectively becomes ln -sf %t.real %t.real, symlinking the directory to itself. At least on my mac, this leads to the directory containing itself.

As fix, just remove %t.fake before creating the symlink. To clean up build dirs on bots, also remove %t.real for a while.

[rnk]

lgtm

[thakis]

r334972, thanks!

test/Driver/no-canonical-prefixes.c

 // Due to ln -sf:
 // REQUIRES: shell
+// RUN: rm -rf %t.real
 // RUN: mkdir -p %t.real
 // RUN: cd %t.real
 // RUN: ln -sf %clang test-clang
 // RUN: cd ..
+// Important to remove %t.fake: If it already is a symlink to %t.real when
+// `ln -sf %t.real %t.fake` runs, then that would symlink %t.real to itself,
+// forming a cycle.
+// RUN: rm -rf %t.fake
 // RUN: ln -sf %t.real %t.fake
 // RUN: cd %t.fake
 // RUN: ./test-clang -v -S %s 2>&1 | FileCheck --check-prefix=CANONICAL %s
 // RUN: ./test-clang -v -S %s -no-canonical-prefixes 2>&1 | FileCheck --check-prefix=NON-CANONICAL %s
 //
 // FIXME: This should really be '.real'.
 // CANONICAL: InstalledDir: {{.*}}.fake
 // CANONICAL: {{[/|\\]*}}clang{{.*}}" -cc1
 //
 // NON-CANONICAL: InstalledDir: .{{$}}
 // NON-CANONICAL: test-clang" -cc1