[llvm-branch-commits] [clang] release/22.x: [CMake][Release] Use llvm-bitcode-strip on Darwin for build with -ffat-lto-objects (#200764) (PR #201517)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/201517

Backport b8e768f6ae95343ac542b195265572ecd063fc2b

Requested by: @c-rhodes

>From 60c18c6aeaedc70e0c1c95be2e9397e788e3b142 Mon Sep 17 00:00:00 2001
From: Cullen Rhodes <cullen.rhodes at arm.com>
Date: Tue, 2 Jun 2026 06:45:33 +0100
Subject: [PATCH] [CMake][Release] Use llvm-bitcode-strip on Darwin for build
 with -ffat-lto-objects (#200764)

Building with --fat-lto-objects was added in #140381 (cff9ae7a15a5). On
macOS the tests are failing when building release binaries with many
"The file was not recognized as a valid object file" errors, e.g.:

  2026-01-16T12:54:26.0928880Z

/Users/runner/work/llvm-project/llvm-project/build/tools/clang/stage2-instrumented-bins/tools/clang/stage2-bins/_CPack_Packages/Darwin/TXZ/LLVM-22.1.0-rc1-macOS-ARM64/bin/llvm-strip:
  error:

'/Users/runner/work/llvm-project/llvm-project/build/tools/clang/stage2-instrumented-bins/tools/clang/stage2-bins/_CPack_Packages/Darwin/TXZ/LLVM-22.1.0-rc1-macOS-ARM64/lib/libLLVMAArch64AsmParser.a(AArch64AsmParser.cpp.o)':
  The file was not recognized as a valid object file

It's assuming bitcode is embedded in section .llvm.lto
(llvm/lib/Object/ObjectFile.cpp:80) but on MachO it's in
__LLVM,__bitcode (llvm/lib/Object/MachOObjectFile.cpp:2184)

llvm-bitcode-strip is a driver for the MachO bitcode_strip utility which
handles this. Use this instead.

Fixes #176398.

Assisted-by: codex
(cherry picked from commit b8e768f6ae95343ac542b195265572ecd063fc2b)
---
 .../caches/release_cpack_pre_build_strip_lto.cmake    | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/clang/cmake/caches/release_cpack_pre_build_strip_lto.cmake b/clang/cmake/caches/release_cpack_pre_build_strip_lto.cmake
index 743b64fe00f58..e7d8830515439 100644
--- a/clang/cmake/caches/release_cpack_pre_build_strip_lto.cmake
+++ b/clang/cmake/caches/release_cpack_pre_build_strip_lto.cmake
@@ -1,5 +1,14 @@
 file(GLOB files ${CPACK_TEMPORARY_INSTALL_DIRECTORY}/lib/*.a)
 
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+  set(strip_command
+    ${CPACK_TEMPORARY_INSTALL_DIRECTORY}/bin/llvm-bitcode-strip)
+  set(strip_args -r)
+else()
+  set(strip_command ${CPACK_TEMPORARY_INSTALL_DIRECTORY}/bin/llvm-strip)
+  set(strip_args --no-strip-all -R .llvm.lto)
+endif()
+
 foreach(file ${files})
-  execute_process(COMMAND ${CPACK_TEMPORARY_INSTALL_DIRECTORY}/bin/llvm-strip --no-strip-all -R .llvm.lto ${file})
+  execute_process(COMMAND ${strip_command} ${strip_args} ${file} -o ${file})
 endforeach()