[clang] [clang][ptrauth] add support for options parameter to __ptrauth (PR #136828)

[Oliver Hunt via cfe-commits]

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@@ -8374,20 +8376,212 @@ static void HandlePtrAuthQualifier(ASTContext &Ctx, QualType &T,
   IsInvalid |= !S.checkPointerAuthDiscriminatorArg(
       ExtraDiscriminatorArg, Sema::PADAK_ExtraDiscPtrAuth, ExtraDiscriminator);
 
-  if (IsInvalid) {
-    Attr.setInvalid();
-    return;
+  std::optional<PointerAuthenticationMode> AuthenticationMode = std::nullopt;
+  SourceRange AuthenticationModeRange;
+
+  if (AuthenticationOptionsArg && !AuthenticationOptionsArg->containsErrors()) {
+    std::string OptionsString;
+    bool IsInitialized = false;
+    const StringLiteral *OptionsStringLiteral =
+        dyn_cast<StringLiteral>(AuthenticationOptionsArg);
+    auto ReportEvaluationOfExpressionIfNeeded = [&]() {
+      if (OptionsStringLiteral || !IsInitialized)
+        return;
+      S.Diag(AuthenticationOptionsArg->getBeginLoc(),
+             diag::note_ptrauth_evaluating_options)
+          << OptionsString << AuthenticationOptionsArg->getSourceRange();
+    };
+    auto DiagnoseInvalidOptionsParameter = [&](llvm::StringRef Reason,
+                                               std::optional<char> InvalidCh,
+                                               auto Location) {
+      S.Diag(AuthenticationOptionsArg->getExprLoc(),
+             diag::err_ptrauth_invalid_option)
+          << AttrName << Reason << Location << !!InvalidCh
+          << (InvalidCh ? *InvalidCh : '\0');
+      Attr.setInvalid();
+      ReportEvaluationOfExpressionIfNeeded();
+    };
+    if (AuthenticationOptionsArg->isValueDependent() ||
+        AuthenticationOptionsArg->isTypeDependent()) {
+      DiagnoseInvalidOptionsParameter(
+          "is dependent", std::nullopt,
+          AuthenticationOptionsArg->getSourceRange());
+      return;
+    }
+    if (OptionsStringLiteral) {
+      if (OptionsStringLiteral->containsNonAsciiOrNull()) {
+        DiagnoseInvalidOptionsParameter(
+            "contains invalid characters", std::nullopt,
+            AuthenticationOptionsArg->getSourceRange());
+        return;
+      }
----------------
ojhunt wrote:

There are more than just those three strings, but adding the additional ones implies the ability to test them, which means pulling in the implementation of those options.

I went for this specific subset because PointerAuthQualifier already has the required functionality, and so this PR could be very close to just the parsing.

https://github.com/llvm/llvm-project/pull/136828