From 559dbe07ddec1fabc7d62148f2b91beba1cfd22f Mon Sep 17 00:00:00 2001
From: Dapeng Gao <31944689+dpgao@users.noreply.github.com>
Date: Wed, 12 Jun 2024 15:20:29 +0100
Subject: [PATCH] libunwind: Allow untagged pc under benchmark ABI

Under the benchmark ABI, when making a function call that never returns, the link register might contain an untagged capability generated by a previous function return (Recall that returning under the benchmark ABI involves clearing the LSB of the address, clearing the tag at the same time).
---
 libunwind/src/AddressSpace.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp
index 56e5de51e334..5ef584e7d3c1 100644
--- a/libunwind/src/AddressSpace.hpp
+++ b/libunwind/src/AddressSpace.hpp
@@ -247,7 +247,8 @@ class _LIBUNWIND_HIDDEN LocalAddressSpace {
     }
     bool isNull() const { return value == nullptr; }
     bool isValid() const {
-#ifdef __CHERI_PURE_CAPABILITY__
+#if defined(__CHERI_PURE_CAPABILITY__) &&                                      \
+    !defined(__ARM_MORELLO_PURECAP_BENCHMARK_ABI)
       return __builtin_cheri_tag_get(value);
 #else
       return !isNull();