From 02ca07484cd0b0fa8f7148e77555d07cf4363eb7 Mon Sep 17 00:00:00 2001
From: "Herman S." <429230+has207@users.noreply.github.com>
Date: Fri, 27 Mar 2026 14:54:15 +0900
Subject: [PATCH] [Build] Ensure clang/lld are pinned to the correct version

---
 .github/workflows/Linux_x86.yml | 15 +++++++++++----
 CMakeLists.txt                  | 11 ++++++++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/Linux_x86.yml b/.github/workflows/Linux_x86.yml
index 91aea1ecd..e6c12302f 100644
--- a/.github/workflows/Linux_x86.yml
+++ b/.github/workflows/Linux_x86.yml
@@ -35,11 +35,18 @@ jobs:
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           sudo apt-add-repository "deb http://apt.llvm.org/${{ env.UBUNTU_BASE }}/ llvm-toolchain-${{ env.UBUNTU_BASE }}-${{ env.LLVM_VERSION }} main"
           sudo apt-get -y update
-          sudo apt-get -y install mesa-vulkan-drivers valgrind libc++-dev libc++abi-dev libgtk-3-dev libsdl2-dev libvulkan-dev libx11-xcb-dev clang-${{ env.LLVM_VERSION }} lld-${{ env.LLVM_VERSION }} ninja-build cmake spirv-tools
+          sudo apt-get -y install mesa-vulkan-drivers valgrind libc++-dev libc++abi-dev libgtk-3-dev libsdl2-dev libvulkan-dev libx11-xcb-dev clang-${{ env.LLVM_VERSION }} lld-${{ env.LLVM_VERSION }} ninja-build cmake spirv-tools libfuse2
+
+          # Pin LLVM tools to the correct version so system ar/ranlib/lld
+          # don't use the older LLVM 17 gold plugin with clang-20 LTO bitcode
+          sudo update-alternatives --install /usr/bin/clang      clang      /usr/bin/clang-${{ env.LLVM_VERSION }}      200
+          sudo update-alternatives --install /usr/bin/clang++    clang++    /usr/bin/clang++-${{ env.LLVM_VERSION }}    200
+          sudo update-alternatives --install /usr/bin/lld        lld        /usr/bin/lld-${{ env.LLVM_VERSION }}        200
+          sudo update-alternatives --install /usr/bin/ld.lld     ld.lld     /usr/bin/ld.lld-${{ env.LLVM_VERSION }}     200
+          sudo update-alternatives --install /usr/bin/llvm-ar    llvm-ar    /usr/bin/llvm-ar-${{ env.LLVM_VERSION }}    200
+          sudo update-alternatives --install /usr/bin/llvm-ranlib llvm-ranlib /usr/bin/llvm-ranlib-${{ env.LLVM_VERSION }} 200
+          sudo update-alternatives --install /usr/bin/llvm-nm    llvm-nm    /usr/bin/llvm-nm-${{ env.LLVM_VERSION }}    200
 
-          # Pin clang to the correct version
-          sudo update-alternatives --install /usr/bin/clang   clang   /usr/bin/clang-${{ env.LLVM_VERSION }}   200
-          sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-${{ env.LLVM_VERSION }} 200
       - name: Install Vulkan SDK
         run: |
           # Install Vulkan SDK
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 115ffab45..7bd84ceef 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -283,10 +283,19 @@ else()
     $<$<CONFIG:Release>:_NO_DEBUG_HEAP=1>
   )
   add_compile_options($<$<CONFIG:Release>:-O3>)
-  # Link-time optimization (use lld to avoid system linker LTO plugin version mismatch)
+  # Link-time optimization (use lld and llvm-ar/ranlib to avoid system
+  # linker/archiver LTO plugin version mismatch with clang's bitcode)
   add_compile_options($<$<CONFIG:Release>:-flto=thin>)
   add_link_options($<$<CONFIG:Release>:-flto=thin>)
   add_link_options($<$<CONFIG:Release>:-fuse-ld=lld>)
+  find_program(LLVM_AR NAMES llvm-ar)
+  find_program(LLVM_RANLIB NAMES llvm-ranlib)
+  if(LLVM_AR)
+    set(CMAKE_AR "${LLVM_AR}" CACHE FILEPATH "" FORCE)
+  endif()
+  if(LLVM_RANLIB)
+    set(CMAKE_RANLIB "${LLVM_RANLIB}" CACHE FILEPATH "" FORCE)
+  endif()
   # No symbols in release on non-Windows
   string(REPLACE "-g" "" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
   string(REPLACE "-g" "" CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")