[clang] [PAC] Add support for __ptrauth type qualifier (PR #100830)

[Aaron Ballman via cfe-commits]

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@@ -8395,6 +8410,68 @@ static void HandleNeonVectorTypeAttr(QualType &CurType, const ParsedAttr &Attr,
   CurType = S.Context.getVectorType(CurType, numElts, VecKind);
 }
 
+/// Handle the __ptrauth qualifier.
+static void HandlePtrAuthQualifier(ASTContext &Ctx, QualType &T,
+                                   const ParsedAttr &Attr, Sema &S) {
+  if (Attr.getNumArgs() < 1 || Attr.getNumArgs() > 3) {
+    S.Diag(Attr.getLoc(), diag::err_ptrauth_qualifier_bad_arg_count);
+    Attr.setInvalid();
+    return;
+  }
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AaronBallman wrote:

I think this should be handled in parser rather than Sema; then it for sure won't result in oddities with SFINAE. CC @erichkeane @cor3ntin 

https://github.com/llvm/llvm-project/pull/100830