[ubsan] Add helpers to decide when null/vptr checks are required. NFC.

llvm-svn: 314750
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index ade60f2..45244df 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -2356,6 +2356,12 @@
     TCK_NonnullAssign
   };
 
+  /// Determine whether the pointer type check \p TCK permits null pointers.
+  static bool isNullPointerAllowed(TypeCheckKind TCK);
+
+  /// Determine whether the pointer type check \p TCK requires a vptr check.
+  static bool isVptrCheckRequired(TypeCheckKind TCK, QualType Ty);
+
   /// \brief Whether any type-checking sanitizers are enabled. If \c false,
   /// calls to EmitTypeCheck can be skipped.
   bool sanitizePerformTypeCheck() const;