Index: lib/Basic/FileManager.cpp
===================================================================
--- lib/Basic/FileManager.cpp
+++ lib/Basic/FileManager.cpp
@@ -316,9 +316,16 @@
   UFE.File = std::move(F);
   UFE.IsValid = true;
 
-  SmallString<128> RealPathName;
-  if (!FS->getRealPath(InterndFileName, RealPathName))
-    UFE.RealPathName = RealPathName.str();
+  if (UFE.File) {
+    if (auto Path = UFE.File->getName()) {
+      llvm::SmallString<128> AbsPath(*Path);
+      // This is not the same as `real_path()` system call, which also resolves
+      // symlinks.
+      makeAbsolutePath(AbsPath);
+      llvm::sys::path::remove_dots(AbsPath, /*remove_dot_dot=*/true);
+      UFE.RealPathName = AbsPath.str();
+    }
+  }
 
   return &UFE;
 }