[clang] [PAC][clang] Define `PointerAuthQualifier` and `PointerAuthenticationMode` (PR #84384)

[Daniil Kovalev via cfe-commits]

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@@ -251,15 +423,16 @@ class Qualifiers {
   }
 
   // Deserialize qualifiers from an opaque representation.
-  static Qualifiers fromOpaqueValue(unsigned opaque) {
+  static Qualifiers fromOpaqueValue(uint64_t Opaque) {
     Qualifiers Qs;
-    Qs.Mask = opaque;
+    Qs.Mask = uint32_t(Opaque);
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kovdan01 wrote:

Thanks, I've used numeric limits stuff since it allows `constexpr` (while `maskTrailingOnes` is more flexible for arbitrary bit count but does not have `constexpr` variant as far as I can see). See df81082d6f0210b02e72a3237ab7c03715d23488


https://github.com/llvm/llvm-project/pull/84384