Index: clang-tidy/ClangTidy.cpp
===================================================================
--- clang-tidy/ClangTidy.cpp
+++ clang-tidy/ClangTidy.cpp
@@ -109,6 +109,8 @@
 
   void reportDiagnostic(const ClangTidyError &Error) {
     const ClangTidyMessage &Message = Error.Message;
+    Files.getVirtualFileSystem()->setCurrentWorkingDirectory(
+        Error.BuildDirectory);
     SourceLocation Loc = getLocation(Message.FilePath, Message.FileOffset);
     // Contains a pair for each attempted fix: location and whether the fix was
     // applied successfully.
Index: clang-tidy/ClangTidyDiagnosticConsumer.h
===================================================================
--- clang-tidy/ClangTidyDiagnosticConsumer.h
+++ clang-tidy/ClangTidyDiagnosticConsumer.h
@@ -57,8 +57,10 @@
     Error = DiagnosticsEngine::Error
   };
 
-  ClangTidyError(StringRef CheckName, Level DiagLevel, bool IsWarningAsError);
+  ClangTidyError(StringRef CheckName, Level DiagLevel, bool IsWarningAsError,
+                 const std::string &BuildDirectory);
 
+  std::string BuildDirectory;
   std::string CheckName;
   ClangTidyMessage Message;
   tooling::Replacements Fix;
Index: clang-tidy/ClangTidyDiagnosticConsumer.cpp
===================================================================
--- clang-tidy/ClangTidyDiagnosticConsumer.cpp
+++ clang-tidy/ClangTidyDiagnosticConsumer.cpp
@@ -116,9 +116,10 @@
 
 ClangTidyError::ClangTidyError(StringRef CheckName,
                                ClangTidyError::Level DiagLevel,
-                               bool IsWarningAsError)
-    : CheckName(CheckName), DiagLevel(DiagLevel),
-      IsWarningAsError(IsWarningAsError) {}
+                               bool IsWarningAsError,
+                               const std::string &BuildDirectory)
+    : BuildDirectory(BuildDirectory), CheckName(CheckName),
+      DiagLevel(DiagLevel), IsWarningAsError(IsWarningAsError) {}
 
 // Returns true if GlobList starts with the negative indicator ('-'), removes it
 // from the GlobList.
@@ -335,7 +336,12 @@
     bool IsWarningAsError =
         DiagLevel == DiagnosticsEngine::Warning &&
         Context.getWarningAsErrorFilter().contains(CheckName);
-    Errors.push_back(ClangTidyError(CheckName, Level, IsWarningAsError));
+    Errors.push_back(ClangTidyError(CheckName, Level, IsWarningAsError,
+                                    Info.getSourceManager()
+                                        .getFileManager()
+                                        .getVirtualFileSystem()
+                                        ->getCurrentWorkingDirectory()
+                                        .get()));
   }
 
   // FIXME: Provide correct LangOptions for each file.