[clang] [AArch64][PAC] Support ptrauth builtins and -fptrauth-intrinsics. (PR #65996)

[John McCall via cfe-commits]

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@@ -0,0 +1,167 @@
+/*===---- ptrauth.h - Pointer authentication -------------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+#ifndef __PTRAUTH_H
+#define __PTRAUTH_H
+
+typedef enum {
+  ptrauth_key_asia = 0,
+  ptrauth_key_asib = 1,
+  ptrauth_key_asda = 2,
+  ptrauth_key_asdb = 3,
+
+  /* A process-independent key which can be used to sign code pointers.
+     Signing and authenticating with this key is a no-op in processes
+     which disable ABI pointer authentication. */
+  ptrauth_key_process_independent_code = ptrauth_key_asia,
+
+  /* A process-specific key which can be used to sign code pointers.
+     Signing and authenticating with this key is enforced even in processes
+     which disable ABI pointer authentication. */
+  ptrauth_key_process_dependent_code = ptrauth_key_asib,
+
+  /* A process-independent key which can be used to sign data pointers.
+     Signing and authenticating with this key is a no-op in processes
+     which disable ABI pointer authentication. */
+  ptrauth_key_process_independent_data = ptrauth_key_asda,
+
+  /* A process-specific key which can be used to sign data pointers.
+     Signing and authenticating with this key is a no-op in processes
+     which disable ABI pointer authentication. */
+  ptrauth_key_process_dependent_data = ptrauth_key_asdb,
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rjmccall wrote:

I initially named and documented these expecting that these would be general semantic categories.  As time has gone on, we've really moved away from that — they're at best platform-specific, and some of them are already out-dated (arm64e doesn't really have any "process independent" keys).

https://github.com/llvm/llvm-project/pull/65996