Reapply "[clang] Remove intrusive reference count from `DiagnosticOptions` (#139584)"

This reverts commit e2a885537f11f8d9ced1c80c2c90069ab5adeb1d. Build failures were fixed right away and reverting the original commit without the fixes breaks the build again.

1 files changed, 9 insertions, 5 deletions

diff --git a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
index d0b855f..99212b8 100644
--- a/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
+++ b/clang/lib/Frontend/CreateInvocationFromCommandLine.cpp
@@ -31,11 +31,15 @@ std::unique_ptr<CompilerInvocation>
 clang::createInvocation(ArrayRef<const char *> ArgList,
                         CreateInvocationOptions Opts) {
   assert(!ArgList.empty());
-  auto Diags = Opts.Diags
-                   ? std::move(Opts.Diags)
-                   : CompilerInstance::createDiagnostics(
-                         Opts.VFS ? *Opts.VFS : *llvm::vfs::getRealFileSystem(),
-                         new DiagnosticOptions);
+  std::optional<DiagnosticOptions> LocalDiagOpts;
+  IntrusiveRefCntPtr<DiagnosticsEngine> Diags;
+  if (Opts.Diags) {
+    Diags = std::move(Opts.Diags);
+  } else {
+    LocalDiagOpts.emplace();
+    Diags = CompilerInstance::createDiagnostics(
+        Opts.VFS ? *Opts.VFS : *llvm::vfs::getRealFileSystem(), *LocalDiagOpts);
+  }
 
   SmallVector<const char *, 16> Args(ArgList);