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      1 //===-- sanitizer_ptrauth.h -------------------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 
      9 #ifndef SANITIZER_PTRAUTH_H
     10 #define SANITIZER_PTRAUTH_H
     11 
     12 #if __has_feature(ptrauth_calls)
     13 #include <ptrauth.h>
     14 #elif defined(__ARM_FEATURE_PAC_DEFAULT) && !defined(__APPLE__)
     15 inline unsigned long ptrauth_strip(void* __value, unsigned int __key) {
     16   // On the stack the link register is protected with Pointer
     17   // Authentication Code when compiled with -mbranch-protection.
     18   // Let's stripping the PAC unconditionally because xpaclri is in
     19   // the NOP space so will do nothing when it is not enabled or not available.
     20   unsigned long ret;
     21   asm volatile(
     22       "mov x30, %1\n\t"
     23       "hint #7\n\t"  // xpaclri
     24       "mov %0, x30\n\t"
     25       : "=r"(ret)
     26       : "r"(__value)
     27       : "x30");
     28   return ret;
     29 }
     30 #define ptrauth_auth_data(__value, __old_key, __old_data) __value
     31 #define ptrauth_string_discriminator(__string) ((int)0)
     32 #else
     33 // Copied from <ptrauth.h>
     34 #define ptrauth_strip(__value, __key) __value
     35 #define ptrauth_auth_data(__value, __old_key, __old_data) __value
     36 #define ptrauth_string_discriminator(__string) ((int)0)
     37 #endif
     38 
     39 #define STRIP_PAC_PC(pc) ((uptr)ptrauth_strip(pc, 0))
     40 
     41 #endif // SANITIZER_PTRAUTH_H
     42