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

[Akira Hatanaka via cfe-commits]

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@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -triple arm64-apple-ios -fsyntax-only -verify -fptrauth-intrinsics -std=c++11 %s
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -fsyntax-only -verify -fptrauth-intrinsics -std=c++11 %s
+
+template <typename T> struct G {
+  T __ptrauth(0,0,1234) test;
+  // expected-error at -1 2 {{type '__ptrauth(0,0,1234) T' is already __ptrauth-qualified}}
+};
+
+template <typename T> struct Indirect {
+  G<T> layers;
+  // expected-note at -1{{in instantiation of template class 'G<void *__ptrauth(0,0,1235)>' requested here}}
+  // expected-note at -2{{in instantiation of template class 'G<void *__ptrauth(0,0,1234)>' requested here}}
+};
+
+void f3() {
+  Indirect<void* __ptrauth(0,0,1234)> one;
+  // expected-note at -1{{in instantiation of template class 'Indirect<void *__ptrauth(0,0,1234)>' requested here}}
+  Indirect<void* __ptrauth(0,0,1235)> two;
+  // expected-note at -1{{in instantiation of template class 'Indirect<void *__ptrauth(0,0,1235)>' requested here}}
+  Indirect<void*> three;
+}
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ahatanak wrote:

> > This isn't possible as template parameters cannot be passed to __ptrauth
> 
> Why? Also, missing test coverage then.

AFAIK, there is no inherent reason why `__ptrauth` cannot take template parameters, but we haven't implemented support for it yet.

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