[Path] Fix bug in make_absolute logic

This fixes a bug for making path with a //net style root absolute. I
discovered the bug while writing a test case for the VFS, which uses
these paths because they're both legal absolute paths on Windows and
Unix.

Differential revision: https://reviews.llvm.org/D65675

llvm-svn: 368053

1 files changed, 13 insertions, 4 deletions

diff --git a/llvm/unittests/Support/Path.cpp b/llvm/unittests/Support/Path.cpp
index 5e0581c945b..1802b0031ad 100644
--- a/llvm/unittests/Support/Path.cpp
+++ b/llvm/unittests/Support/Path.cpp
@@ -185,10 +185,19 @@ TEST(Support, Path) {
     path::native(*i, temp_store);
   }
 
-  SmallString<32> Relative("foo.cpp");
-  sys::fs::make_absolute("/root", Relative);
-  Relative[5] = '/'; // Fix up windows paths.
-  ASSERT_EQ("/root/foo.cpp", Relative);
+  {
+    SmallString<32> Relative("foo.cpp");
+    sys::fs::make_absolute("/root", Relative);
+    Relative[5] = '/'; // Fix up windows paths.
+    ASSERT_EQ("/root/foo.cpp", Relative);
+  }
+
+  {
+    SmallString<32> Relative("foo.cpp");
+    sys::fs::make_absolute("//root", Relative);
+    Relative[6] = '/'; // Fix up windows paths.
+    ASSERT_EQ("//root/foo.cpp", Relative);
+  }
 }
 
 TEST(Support, FilenameParent) {