[PAC] Define __builtin_ptrauth_type_discriminator (#100204)

The builtin computes the discriminator for a type, which can be used to
sign/authenticate function pointers and member function pointers.

If the type passed to the builtin is a C++ member function pointer type,
the result is the discriminator used to signed member function pointers
of that type. If the type is a function, function pointer, or function
reference type, the result is the discriminator used to sign functions
of that type. It is ill-formed to use this builtin with any other type.

A call to this function is an integer constant expression.

Co-Authored-By: John McCall rjmccall@apple.com

1 files changed, 7 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 45b9bbb..cf1196a 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -1489,14 +1489,18 @@ enum PointerAuthOpKind {
 };
 }
 
-static bool checkPointerAuthEnabled(Sema &S, Expr *E) {
-  if (S.getLangOpts().PointerAuthIntrinsics)
+bool Sema::checkPointerAuthEnabled(SourceLocation Loc, SourceRange Range) {
+  if (getLangOpts().PointerAuthIntrinsics)
     return false;
 
-  S.Diag(E->getExprLoc(), diag::err_ptrauth_disabled) << E->getSourceRange();
+  Diag(Loc, diag::err_ptrauth_disabled) << Range;
   return true;
 }
 
+static bool checkPointerAuthEnabled(Sema &S, Expr *E) {
+  return S.checkPointerAuthEnabled(E->getExprLoc(), E->getSourceRange());
+}
+
 static bool checkPointerAuthKey(Sema &S, Expr *&Arg) {
   // Convert it to type 'int'.
   if (convertArgumentToType(S, Arg, S.Context.IntTy))