diff --git a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
--- a/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
+++ b/clang/include/clang/Tooling/DependencyScanning/DependencyScanningWorker.h
@@ -66,7 +66,6 @@
                                   DependencyConsumer &Consumer);
 
 private:
-  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
   std::shared_ptr<PCHContainerOperations> PCHContainerOps;
   std::unique_ptr<ExcludedPreprocessorDirectiveSkipMapping> PPSkipMappings;
 
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -269,8 +269,6 @@
 DependencyScanningWorker::DependencyScanningWorker(
     DependencyScanningService &Service)
     : Format(Service.getFormat()) {
-  DiagOpts = new DiagnosticOptions();
-
   PCHContainerOps = std::make_shared<PCHContainerOperations>();
   PCHContainerOps->registerReader(
       std::make_unique<ObjectFilePCHContainerReader>());
@@ -290,16 +288,20 @@
     Files = new FileManager(FileSystemOptions(), RealFS);
 }
 
-static llvm::Error runWithDiags(
-    DiagnosticOptions *DiagOpts,
-    llvm::function_ref<bool(DiagnosticConsumer &DC)> BodyShouldSucceed) {
+static llvm::Error
+runWithDiags(DiagnosticOptions *DiagOpts,
+             llvm::function_ref<bool(DiagnosticConsumer &, DiagnosticOptions &)>
+                 BodyShouldSucceed) {
+  // Avoid serializing diagnostics.
+  DiagOpts->DiagnosticSerializationFile.clear();
+
   // Capture the emitted diagnostics and report them to the client
   // in the case of a failure.
   std::string DiagnosticOutput;
   llvm::raw_string_ostream DiagnosticsOS(DiagnosticOutput);
   TextDiagnosticPrinter DiagPrinter(DiagnosticsOS, DiagOpts);
 
-  if (BodyShouldSucceed(DiagPrinter))
+  if (BodyShouldSucceed(DiagPrinter, *DiagOpts))
     return llvm::Error::success();
   return llvm::make_error<llvm::StringError>(DiagnosticsOS.str(),
                                              llvm::inconvertibleErrorCode());
@@ -313,15 +315,22 @@
   llvm::IntrusiveRefCntPtr<FileManager> CurrentFiles =
       Files ? Files : new FileManager(FileSystemOptions(), RealFS);
 
-  return runWithDiags(DiagOpts.get(), [&](DiagnosticConsumer &DC) {
-    DependencyScanningAction Action(WorkingDirectory, Consumer, DepFS,
-                                    PPSkipMappings.get(), Format);
-    // Create an invocation that uses the underlying file system to ensure that
-    // any file system requests that are made by the driver do not go through
-    // the dependency scanning filesystem.
-    ToolInvocation Invocation(CommandLine, &Action, CurrentFiles.get(),
-                              PCHContainerOps);
-    Invocation.setDiagnosticConsumer(&DC);
-    return Invocation.run();
-  });
+  std::vector<const char *> CCommandLine(CommandLine.size(), nullptr);
+  llvm::transform(CommandLine, CCommandLine.begin(),
+                  [](const std::string &Str) { return Str.c_str(); });
+
+  return runWithDiags(
+      CreateAndPopulateDiagOpts(CCommandLine).release(),
+      [&](DiagnosticConsumer &DC, DiagnosticOptions &DiagOpts) {
+        DependencyScanningAction Action(WorkingDirectory, Consumer, DepFS,
+                                        PPSkipMappings.get(), Format);
+        // Create an invocation that uses the underlying file system to ensure
+        // that any file system requests that are made by the driver do not go
+        // through the dependency scanning filesystem.
+        ToolInvocation Invocation(CommandLine, &Action, CurrentFiles.get(),
+                                  PCHContainerOps);
+        Invocation.setDiagnosticConsumer(&DC);
+        Invocation.setDiagnosticOptions(&DiagOpts);
+        return Invocation.run();
+      });
 }