[llvm-branch-commits] [libcxx] release/21.x: [libc++][AIX] Fixup problems with ABI list checking (#155643) (PR #156502)

[Tobias Hieta via llvm-branch-commits]

https://github.com/tru updated https://github.com/llvm/llvm-project/pull/156502

>From 7a077a1b312b66055643e05d88795c5b1f329874 Mon Sep 17 00:00:00 2001
From: David Tenty <daltenty at ibm.com>
Date: Wed, 27 Aug 2025 18:28:26 -0400
Subject: [PATCH] [libc++][AIX] Fixup problems with ABI list checking (#155643)

There are some problems with our ABI list checking exposed by recent
compiler/cmake upgrades.

- For symcheck, there are typos in how XCOFF magic are defined, we
intended the second two digits to be a hex value, but our syntax doesn't
say that. Thus this will never match a valid XCOFF file.
- AIX triples can have version numbers. Those need to be discarded when
looking for an libc++ ABI list, like we do for other targets.

(cherry picked from commit b8456e2a9698aa927d7b3f9c38213f3219aa0498)
---
 libcxx/lib/abi/CMakeLists.txt         | 3 +++
 libcxx/utils/libcxx/sym_check/util.py | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/libcxx/lib/abi/CMakeLists.txt b/libcxx/lib/abi/CMakeLists.txt
index 7c08bd06c50b2..8f277aad2dcd5 100644
--- a/libcxx/lib/abi/CMakeLists.txt
+++ b/libcxx/lib/abi/CMakeLists.txt
@@ -16,6 +16,9 @@ function(cxx_abi_list_identifier result triple abi_library abi_version unstable
   elseif("${triple}" MATCHES "freebsd")
     # Ignore the major and minor versions of freebsd targets.
     string(REGEX REPLACE "freebsd[0-9]+\\.[0-9]+" "freebsd" triple "${triple}")
+  elseif("${triple}" MATCHES "aix")
+    # Ignore the V.R.M.F version string of aix targets.
+    string(REGEX REPLACE "aix[0-9]+\\.[0-9]+\\.[0-9]+\\.[0-9]+" "aix" triple "${triple}")
   endif()
   list(APPEND abi_properties "${triple}")
   list(APPEND abi_properties "${abi_library}")
diff --git a/libcxx/utils/libcxx/sym_check/util.py b/libcxx/utils/libcxx/sym_check/util.py
index fc7ba4244ab5a..dbc886f29ddea 100644
--- a/libcxx/utils/libcxx/sym_check/util.py
+++ b/libcxx/utils/libcxx/sym_check/util.py
@@ -95,7 +95,7 @@ def is_xcoff_or_big_ar(filename):
     with open(filename, "rb") as f:
         magic_bytes = f.read(7)
     return (
-        magic_bytes[:4] in [b"\x01DF", b"\x01F7"]  # XCOFF32  # XCOFF64
+        magic_bytes[:2] in [b"\x01\xDF", b"\x01\xF7"]  # XCOFF32  # XCOFF64
         or magic_bytes == b"<bigaf>"
     )