[clang] [clang] Guard identifier reads in pragma handlers (PR #230927)

[Yihan Wang via cfe-commits]

================
@@ -101,17 +101,23 @@ void PragmaNamespace::RemovePragmaHandler(PragmaHandler *Handler) {
   Handlers.erase(I);
 }
 
+// Names may be C++ operator keywords, which have punctuator token kinds.
+static IdentifierInfo *getPragmaIdentifierInfo(const Token &Tok) {
+  if (Tok.isAnnotation() || Tok.is(tok::raw_identifier))
----------------
yronglin wrote:

This might be missing if early return without any diagnostic:
```
if (!Handler) {
  PP.Diag(Tok, diag::warn_pragma_ignored);
  return;
}
```

Without an IdentifierInfo, clang cannot find a suitable handler for the pragma directive.  Please correct me if I have missed any other scenarios.

https://github.com/llvm/llvm-project/pull/230927