[compiler-rt] [libcxxabi] [libunwind] [runtimes][PAC] Harden unwinding when possible (#138571) (PR #143230)

[Oliver Hunt via cfe-commits]

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@@ -1877,6 +1946,32 @@ inline Registers_arm64::Registers_arm64(const void *registers) {
   memcpy(_vectorHalfRegisters,
          static_cast<const uint8_t *>(registers) + sizeof(GPRs),
          sizeof(_vectorHalfRegisters));
+#if __has_feature(ptrauth_calls)
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ojhunt wrote:

- [ ] seems reasonable

https://github.com/llvm/llvm-project/pull/143230