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),
+      [&](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();
+      });
 }
diff --git a/clang/test/ClangScanDeps/Inputs/diagnostics/cdb.json.template b/clang/test/ClangScanDeps/Inputs/diagnostics/cdb.json.template
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/diagnostics/cdb.json.template
@@ -0,0 +1,7 @@
+[
+  {
+    "directory": "DIR",
+    "command": "clang -c DIR/tu.c -target i386-apple-ios14.0-simulator -Wno-error=invalid-ios-deployment-target -o DIR/tu.o",
+    "file": "DIR/tu.c"
+  }
+]
diff --git a/clang/test/ClangScanDeps/Inputs/diagnostics/tu.c b/clang/test/ClangScanDeps/Inputs/diagnostics/tu.c
new file mode 100644
diff --git a/clang/test/ClangScanDeps/diagnostics.c b/clang/test/ClangScanDeps/diagnostics.c
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/diagnostics.c
@@ -0,0 +1,8 @@
+// RUN: rm -rf %t && mkdir %t
+// RUN: cp %S/Inputs/diagnostics/* %t
+
+// RUN: sed "s|DIR|%/t|g" %S/Inputs/diagnostics/cdb.json.template > %t/cdb.json
+// RUN: clang-scan-deps -compilation-database %t/cdb.json -format experimental-full \
+// RUN:   -generate-modules-path-args -module-files-dir %t/build 2>&1 | FileCheck %s
+
+// CHECK-NOT: error: invalid iOS deployment version
diff --git a/clang/test/ClangScanDeps/strip_diag_serialize.cpp b/clang/test/ClangScanDeps/strip_diag_serialize.cpp
--- a/clang/test/ClangScanDeps/strip_diag_serialize.cpp
+++ b/clang/test/ClangScanDeps/strip_diag_serialize.cpp
@@ -1,6 +1,3 @@
-// FIXME: Make this pass again.
-// XFAIL: *
-
 // RUN: rm -rf %t.dir
 // RUN: rm -rf %t.cdb
 // RUN: mkdir -p %t.dir