1 files changed, 11 insertions, 4 deletions
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 29cdcd7df1d..859e8ba18bd 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2750,15 +2750,22 @@ void BuryPointer(const void *Ptr) {
 IntrusiveRefCntPtr<vfs::FileSystem>
 createVFSFromCompilerInvocation(const CompilerInvocation &CI,
                                 DiagnosticsEngine &Diags) {
+  return createVFSFromCompilerInvocation(CI, Diags, vfs::getRealFileSystem());
+}
+
+IntrusiveRefCntPtr<vfs::FileSystem>
+createVFSFromCompilerInvocation(const CompilerInvocation &CI,
+                                DiagnosticsEngine &Diags,
+                                IntrusiveRefCntPtr<vfs::FileSystem> BaseFS) {
   if (CI.getHeaderSearchOpts().VFSOverlayFiles.empty())
-    return vfs::getRealFileSystem();
+    return BaseFS;
 
-  IntrusiveRefCntPtr<vfs::OverlayFileSystem>
-    Overlay(new vfs::OverlayFileSystem(vfs::getRealFileSystem()));
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> Overlay(
+      new vfs::OverlayFileSystem(BaseFS));
   // earlier vfs files are on the bottom
   for (const std::string &File : CI.getHeaderSearchOpts().VFSOverlayFiles) {
     llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Buffer =
-        llvm::MemoryBuffer::getFile(File);
+        BaseFS->getBufferForFile(File);
     if (!Buffer) {
       Diags.Report(diag::err_missing_vfs_overlay_file) << File;
       return IntrusiveRefCntPtr<vfs::FileSystem>();