Index: cfe-6.0.0rc1.src/lib/Driver/Driver.cpp
===================================================================
--- cfe-6.0.0rc1.src.orig/lib/Driver/Driver.cpp
+++ cfe-6.0.0rc1.src/lib/Driver/Driver.cpp
@@ -115,7 +115,7 @@ Driver::Driver(StringRef ClangExecutable
   // Dir is bin/ or lib/, depending on where BinaryPath is.
   std::string Dir = std::string(llvm::sys::path::parent_path(BinaryPath));
 
-  SmallString<128> P(Dir);
+  SmallString<128> P((Dir != "") ? Dir : "/usr/bin/");
   if (CustomResourceDir != "") {
     llvm::sys::path::append(P, CustomResourceDir);
   } else {