diff --git a/clang/lib/Basic/VirtualFileSystem.cpp b/clang/lib/Basic/VirtualFileSystem.cpp
index 84684a4..1727b7d 100644
--- a/clang/lib/Basic/VirtualFileSystem.cpp
+++ b/clang/lib/Basic/VirtualFileSystem.cpp
@@ -139,6 +139,11 @@
   return llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
 }
 
+std::error_code FileSystem::getRealPath(const Twine &Path,
+                                        SmallVectorImpl<char> &Output) const {
+  return errc::operation_not_permitted;
+}
+
 bool FileSystem::exists(const Twine &Path) {
   auto Status = status(Path);
   return Status && Status->exists();
@@ -236,6 +241,8 @@
 
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
+  std::error_code getRealPath(const Twine &Path,
+                              SmallVectorImpl<char> &Output) const override;
 };
 
 } // namespace
@@ -274,6 +281,12 @@
   return llvm::sys::fs::set_current_path(Path);
 }
 
+std::error_code
+RealFileSystem::getRealPath(const Twine &Path,
+                            SmallVectorImpl<char> &Output) const {
+  return llvm::sys::fs::real_path(Path, Output);
+}
+
 IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
   static IntrusiveRefCntPtr<FileSystem> FS = new RealFileSystem();
   return FS;