1 files changed, 7 insertions, 0 deletions
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 61fe26c9222..0e9b0c0ebe3 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -194,9 +194,14 @@ CompilerInstance::createDiagnostics(DiagnosticOptions *Opts,
   return Diags;
 }
 
+void CompilerInstance::createVirtualFileSystem() {
+  VirtualFileSystem = vfs::getRealFileSystem();
+}
+
 // File Manager
 
 void CompilerInstance::createFileManager() {
+  assert(hasVirtualFileSystem() && "expected virtual file system");
   FileMgr = new FileManager(getFileSystemOpts());
 }
 
@@ -867,6 +872,8 @@ static void compileModule(CompilerInstance &ImportingInstance,
                                    ImportingInstance.getDiagnosticClient()),
                              /*ShouldOwnClient=*/true);
 
+  Instance.setVirtualFileSystem(&ImportingInstance.getVirtualFileSystem());
+
   // Note that this module is part of the module build stack, so that we
   // can detect cycles in the module graph.
   Instance.createFileManager(); // FIXME: Adopt file manager from importer?