[clang] [Clang][AArch64] Command-line options for A-profile's Sign Return Address Hardening (PR #176171)

[Anatoly Trosinenko via cfe-commits]

================
@@ -1541,6 +1551,12 @@ class TargetInfo : public TransferrableTargetInfo,
     return false;
   }
 
+  /// Validate the Return Address Signing Hardening specification
+  virtual std::optional<LangOptions::SignReturnAddressHardeningKind>
+  validateSignReturnAddressHardening(StringRef Spec) const {
+    return std::nullopt;
+  }
----------------
atrosinenko wrote:

[nit] All other "validateSomething" methods in this class return `bool`. Maybe something like "parse" would be better?

https://github.com/llvm/llvm-project/pull/176171