2 files changed, 21 insertions, 3 deletions
diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index 43b203a334e..dc0f52f72b4 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -733,8 +733,12 @@ VFSFromYAML *VFSFromYAML::create(MemoryBuffer *Buffer,
 }
 
 ErrorOr<Entry *> VFSFromYAML::lookupPath(const Twine &Path_) {
-  SmallVector<char, 256> Storage;
-  StringRef Path = Path_.toNullTerminatedStringRef(Storage);
+  SmallString<256> Path;
+  Path_.toVector(Path);
+
+  // Handle relative paths
+  if (error_code EC = sys::fs::make_absolute(Path))
+    return EC;
 
   if (Path.empty())
     return error_code(errc::invalid_argument, system_category());
@@ -753,7 +757,10 @@ ErrorOr<Entry *> VFSFromYAML::lookupPath(const Twine &Path_) {
 ErrorOr<Entry *> VFSFromYAML::lookupPath(sys::path::const_iterator Start,
                                          sys::path::const_iterator End,
                                          Entry *From) {
-  // FIXME: handle . and ..
+  if (Start->equals("."))
+    ++Start;
+
+  // FIXME: handle ..
   if (CaseSensitive ? !Start->equals(From->getName())
                     : !Start->equals_lower(From->getName()))
     // failure to match
diff --git a/clang/test/VFS/relative-path.c b/clang/test/VFS/relative-path.c
new file mode 100644
index 00000000000..e7101fb3a82
--- /dev/null
+++ b/clang/test/VFS/relative-path.c
@@ -0,0 +1,11 @@
+// RUN: mkdir -p %t
+// RUN: cd %t
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+// RUN: %clang_cc1 -Werror -I . -ivfsoverlay %t.yaml -fsyntax-only %s
+// REQUIRES: shell
+
+#include "not_real.h"
+
+void foo() {
+  bar();
+}