diff --git a/llvm/lib/Support/VirtualFileSystem.cpp b/llvm/lib/Support/VirtualFileSystem.cpp
--- a/llvm/lib/Support/VirtualFileSystem.cpp
+++ b/llvm/lib/Support/VirtualFileSystem.cpp
@@ -2017,7 +2017,10 @@
 
   if (!Entries.empty()) {
     const YAMLVFSEntry &Entry = Entries.front();
-    startDirectory(path::parent_path(Entry.VPath));
+    bool first_entry_is_directory = fs::is_directory(Entry.VPath);
+    StringRef Dir =
+        first_entry_is_directory ? Entry.VPath : path::parent_path(Entry.VPath);
+    startDirectory(Dir);
 
     StringRef RPath = Entry.RPath;
     if (UseOverlayRelative) {
@@ -2027,13 +2030,19 @@
       RPath = RPath.slice(OverlayDirLen, RPath.size());
     }
 
-    writeEntry(path::filename(Entry.VPath), RPath);
+    if (!first_entry_is_directory)
+      writeEntry(path::filename(Entry.VPath), RPath);
 
     for (const auto &Entry : Entries.slice(1)) {
-      StringRef Dir = path::parent_path(Entry.VPath);
-      if (Dir == DirStack.back())
-        OS << ",\n";
-      else {
+      StringRef Dir = fs::is_directory(Entry.VPath)
+                          ? Entry.VPath
+                          : path::parent_path(Entry.VPath);
+      if (Dir == DirStack.back()) {
+        if (!first_entry_is_directory) {
+          OS << ",\n";
+          first_entry_is_directory = false;
+        }
+      } else {
         while (!DirStack.empty() && !containedIn(DirStack.back(), Dir)) {
           OS << "\n";
           endDirectory();
diff --git a/llvm/unittests/Support/VirtualFileSystemTest.cpp b/llvm/unittests/Support/VirtualFileSystemTest.cpp
--- a/llvm/unittests/Support/VirtualFileSystemTest.cpp
+++ b/llvm/unittests/Support/VirtualFileSystemTest.cpp
@@ -2200,12 +2200,6 @@
   ScopedDir _g(TestDirectory + "/g");
   ScopedFile _h(TestDirectory + "/h", "");
 
-  // This test exposes a bug/shortcoming in the YAMLVFSWriter. Below we call
-  // addFileMapping for _a and _e, which causes _ab and _ef not to exists in
-  // the deserialized file system, because _a and _e got emitted as regular
-  // files. The counter example is _c, if we only call addFileMapping for _cd,
-  // things work as expected.
-
   vfs::YAMLVFSWriter VFSWriter;
   VFSWriter.addFileMapping(_a.Path, "//root/a");
   VFSWriter.addFileMapping(_ab.Path, "//root/a/b");
@@ -2236,11 +2230,11 @@
   ASSERT_TRUE(FS.get() != nullptr);
 
   EXPECT_TRUE(FS->exists(_a.Path));
-  EXPECT_FALSE(FS->exists(_ab.Path)); // FIXME: See explanation above.
+  EXPECT_TRUE(FS->exists(_ab.Path));
   EXPECT_TRUE(FS->exists(_c.Path));
   EXPECT_TRUE(FS->exists(_cd.Path));
   EXPECT_TRUE(FS->exists(_e.Path));
-  EXPECT_FALSE(FS->exists(_ef.Path)); // FIXME: See explanation above.
+  EXPECT_TRUE(FS->exists(_ef.Path));
   EXPECT_TRUE(FS->exists(_g.Path));
   EXPECT_TRUE(FS->exists(_h.Path));
 }