[llvm-branch-commits] [libunwind] release/19.x: [libunwind][AIX] Fix the wrong traceback from signal handler (#101069) (PR #101182)

[Tobias Hieta via llvm-branch-commits]

https://github.com/tru updated https://github.com/llvm/llvm-project/pull/101182

>From 64699d328a39d3a2cc7c043768111794782ef9f0 Mon Sep 17 00:00:00 2001
From: Xing Xue <xingxue at outlook.com>
Date: Tue, 30 Jul 2024 06:28:59 -0400
Subject: [PATCH] [libunwind][AIX] Fix the wrong traceback from signal handler
 (#101069)

Patch [llvm#92291](https://github.com/llvm/llvm-project/pull/92291)
causes wrong traceback from a signal handler for AIX because the AIX
unwinder uses the traceback table at the end of each function instead of
FDE/CIE for unwinding. This patch adds a condition to exclude traceback
table based unwinding from the code added by the patch.

(cherry picked from commit d90fa612604b49dfc81c3f42c106fab7401322ec)
---
 libunwind/src/UnwindCursor.hpp             | 3 ++-
 libunwind/test/aix_signal_unwind.pass.sh.S | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/libunwind/src/UnwindCursor.hpp b/libunwind/src/UnwindCursor.hpp
index 2ec60e4c123d5..758557337899e 100644
--- a/libunwind/src/UnwindCursor.hpp
+++ b/libunwind/src/UnwindCursor.hpp
@@ -2589,7 +2589,8 @@ void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
     --pc;
 #endif
 
-#if !(defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32))
+#if !(defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)) &&            \
+    !defined(_LIBUNWIND_SUPPORT_TBTAB_UNWIND)
   // In case of this is frame of signal handler, the IP saved in the signal
   // handler points to first non-executed instruction, while FDE/CIE expects IP
   // to be after the first non-executed instruction.
diff --git a/libunwind/test/aix_signal_unwind.pass.sh.S b/libunwind/test/aix_signal_unwind.pass.sh.S
index 9ca18e9481f4f..a666577d095b1 100644
--- a/libunwind/test/aix_signal_unwind.pass.sh.S
+++ b/libunwind/test/aix_signal_unwind.pass.sh.S
@@ -10,7 +10,7 @@
 // a correct traceback when the function raising the signal does not save
 // the link register or does not store the stack back chain.
 
-// REQUIRES: target=powerpc{{(64)?}}-ibm-aix
+// REQUIRES: target=powerpc{{(64)?}}-ibm-aix{{.*}}
 
 // Test when the function raising the signal does not save the link register
 // RUN: %{cxx} -x c++ %s -o %t.exe -DCXX_CODE %{flags} %{compile_flags}