[libcxx-commits] [libcxxabi] libcxxabi: declare __gnu_unwind_frame in cxa_personality (PR #189787)

[Khem Raj via libcxx-commits]

https://github.com/kraj updated https://github.com/llvm/llvm-project/pull/189787

>From e9d3306622c7fc8d5789367274823387052c0d1e Mon Sep 17 00:00:00 2001
From: Khem Raj <khem.raj at oss.qualcomm.com>
Date: Tue, 31 Mar 2026 19:33:29 -0700
Subject: [PATCH] libcxxabi: declare __gnu_unwind_frame in cxa_personality

ARM EHABI builds of libcxxabi fail with clang-22+ because
cxa_personality.cpp calls __gnu_unwind_frame without a visible
declaration, triggering:

  error: use of undeclared identifier '__gnu_unwind_frame'

Add an extern "C" forward declaration before the EHABI unwind helper
so the source compiles correctly.

Signed-off-by: Khem Raj <khem.raj at oss.qualcomm.com>
---
 libcxxabi/src/cxa_personality.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libcxxabi/src/cxa_personality.cpp b/libcxxabi/src/cxa_personality.cpp
index 35f4e38077248..6599f89740113 100644
--- a/libcxxabi/src/cxa_personality.cpp
+++ b/libcxxabi/src/cxa_personality.cpp
@@ -1116,6 +1116,8 @@ __gxx_personality_seh0(PEXCEPTION_RECORD ms_exc, void *this_frame,
 
 #else
 
+extern "C" _Unwind_Reason_Code __gnu_unwind_frame(_Unwind_Exception*, _Unwind_Context*);
+
 // Helper function to unwind one frame.
 // ARM EHABI 7.3 and 7.4: If the personality function returns _URC_CONTINUE_UNWIND, the
 // personality routine should update the virtual register set (VRS) according to the