Index: lib/Tooling/Tooling.cpp
===================================================================
--- lib/Tooling/Tooling.cpp
+++ lib/Tooling/Tooling.cpp
@@ -411,15 +411,6 @@
   // This just needs to be some symbol in the binary.
   static int StaticSymbol;
 
-  std::string InitialDirectory;
-  if (llvm::ErrorOr<std::string> CWD =
-          OverlayFileSystem->getCurrentWorkingDirectory()) {
-    InitialDirectory = std::move(*CWD);
-  } else {
-    llvm::report_fatal_error("Cannot detect current path: " +
-                             Twine(CWD.getError().message()));
-  }
-
   // First insert all absolute paths into the in-memory VFS. These are global
   // for all compile commands.
   if (SeenWorkingDirectories.insert("/").second)
@@ -431,9 +422,14 @@
 
   bool ProcessingFailed = false;
   bool FileSkipped = false;
-  for (const auto &SourcePath : SourcePaths) {
-    std::string File(getAbsolutePath(SourcePath));
-
+  // Compute all absolute paths before we run any actions, as those will change
+  // the working directory.
+  std::vector<std::string> AbsolutePaths;
+  AbsolutePaths.reserve(SourcePaths.size());
+  for (const auto &SourcePath : SourcePaths)
+    AbsolutePaths.push_back(getAbsolutePath(SourcePath));
+
+  for (llvm::StringRef File : AbsolutePaths) {
     // Currently implementations of CompilationDatabase::getCompileCommands can
     // change the state of the file system (e.g.  prepare generated headers), so
     // this method needs to run right before we invoke the tool, as the next
@@ -498,11 +494,6 @@
         llvm::errs() << "Error while processing " << File << ".\n";
         ProcessingFailed = true;
       }
-      // Return to the initial directory to correctly resolve next file by
-      // relative path.
-      if (OverlayFileSystem->setCurrentWorkingDirectory(InitialDirectory.c_str()))
-        llvm::report_fatal_error("Cannot chdir into \"" +
-                                 Twine(InitialDirectory) + "\n!");
     }
   }
   return ProcessingFailed ? 1 : (FileSkipped ? 2 : 0);