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

[Daniil Kovalev 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)
+  uint64_t pcRegister = 0;
+  memcpy(&pcRegister, ((uint8_t *)&_registers) + offsetof(GPRs, __pc),
+         sizeof(pcRegister));
+  setIP(pcRegister);
+  uint64_t fpRegister = 0;
+  memcpy(&fpRegister, ((uint8_t *)&_registers) + offsetof(GPRs, __fp),
+         sizeof(fpRegister));
+  setFP(fpRegister);
+#endif
+}
+
+inline Registers_arm64::Registers_arm64(const Registers_arm64 &other) {
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kovdan01 wrote:

I've just revealed that at least `operator=` is not dead code. It's called from `stepWithDwarf`. So yeah, you probably just need to add declarations.

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