From 246d8f179f0bb5b09fd1f6d7f3e215db09ae822b Mon Sep 17 00:00:00 2001
From: PVermeer <pim.vermeer@gmail.com>
Date: Sat, 11 Oct 2025 16:26:40 +0200
Subject: [PATCH] build(linux): explicitely set CC and CXX compilers (#4325)

---
 .github/workflows/ci-linux.yml |  2 +-
 scripts/linux_build.sh         | 63 +++++++++++++---------------------
 2 files changed, 24 insertions(+), 41 deletions(-)

diff --git a/.github/workflows/ci-linux.yml b/.github/workflows/ci-linux.yml
index 57723fe3..bbe1c952 100644
--- a/.github/workflows/ci-linux.yml
+++ b/.github/workflows/ci-linux.yml
@@ -186,7 +186,7 @@ jobs:
         working-directory: build
         run: |
           ${{ steps.python.outputs.python-path }} -m pip install gcovr
-          ${{ steps.python.outputs.python-path }} -m gcovr . -r ../src \
+          ${{ steps.python.outputs.python-path }} -m gcovr --gcov-executable "gcov-${GCC_VERSION}" . -r ../src \
             --exclude-noncode-lines \
             --exclude-throw-branches \
             --exclude-unreachable-branches \
diff --git a/scripts/linux_build.sh b/scripts/linux_build.sh
index 7128e093..2c10065f 100755
--- a/scripts/linux_build.sh
+++ b/scripts/linux_build.sh
@@ -23,15 +23,6 @@ sudo_cmd="sudo"
 ubuntu_test_repo=0
 step="all"
 
-# common variables
-gcc_alternative_files=(
-  "gcc"
-  "g++"
-  "gcov"
-  "gcc-ar"
-  "gcc-ranlib"
-)
-
 # Reusable function to detect nvcc path
 function detect_nvcc_path() {
   local nvcc_path=""
@@ -340,6 +331,11 @@ function install_cuda() {
     return
   fi
 
+  local cuda_override_arg=""
+  if [ "$distro" == "fedora" ]; then
+    cuda_override_arg="--override"
+  fi
+
   local cuda_prefix="https://developer.download.nvidia.com/compute/cuda/"
   local cuda_suffix=""
   if [ "$architecture" == "aarch64" ]; then
@@ -371,7 +367,7 @@ function install_cuda() {
   echo "cuda url: ${url}"
   wget "$url" --progress=bar:force:noscroll -q --show-progress -O "${build_dir}/cuda.run"
   chmod a+x "${build_dir}/cuda.run"
-  "${build_dir}/cuda.run" --silent --toolkit --toolkitpath="${build_dir}/cuda" --no-opengl-libs --no-man-page --no-drm
+  "${build_dir}/cuda.run" --silent --toolkit --toolkitpath="${build_dir}/cuda" --no-opengl-libs --no-man-page --no-drm "$cuda_override_arg"
   rm "${build_dir}/cuda.run"
 
   # run cuda patches
@@ -452,24 +448,8 @@ function run_step_deps() {
   source ~/.bashrc
 
   #set gcc version based on distros
-  if [ "$distro" == "arch" ]; then
-    export CC=gcc-14
-    export CXX=g++-14
-  elif [ "$distro" == "debian" ] || [ "$distro" == "ubuntu" ]; then
-    for file in "${gcc_alternative_files[@]}"; do
-      file_path="/etc/alternatives/$file"
-      if [ -e "$file_path" ]; then
-        ${sudo_cmd} mv "$file_path" "$file_path.bak"
-      fi
-    done
-
-    ${sudo_cmd} update-alternatives --install \
-      /usr/bin/gcc gcc /usr/bin/gcc-${gcc_version} 100 \
-      --slave /usr/bin/g++ g++ /usr/bin/g++-${gcc_version} \
-      --slave /usr/bin/gcov gcov /usr/bin/gcov-${gcc_version} \
-      --slave /usr/bin/gcc-ar gcc-ar /usr/bin/gcc-ar-${gcc_version} \
-      --slave /usr/bin/gcc-ranlib gcc-ranlib /usr/bin/gcc-ranlib-${gcc_version}
-  fi
+  export CC=gcc-${gcc_version}
+  export CXX=g++-${gcc_version}
 
   # compile cmake if the version is too low
   if ! check_version "cmake" "$cmake_min" "inf"; then
@@ -537,6 +517,10 @@ function run_step_cmake() {
     nvcc_path=$(detect_nvcc_path)
   fi
 
+  #set gcc version based on distros
+  export CC=gcc-${gcc_version}
+  export CXX=g++-${gcc_version}
+
   # prepare CMAKE args
   cmake_args=(
     "-B=build"
@@ -579,6 +563,7 @@ function run_step_cmake() {
     cmake_args+=("-DSUNSHINE_ENABLE_CUDA=ON")
     if [ -n "$nvcc_path" ]; then
       cmake_args+=("-DCMAKE_CUDA_COMPILER:PATH=$nvcc_path")
+      cmake_args+=("-DCMAKE_CUDA_HOST_COMPILER=gcc-${gcc_version}")
     fi
   else
     cmake_args+=("-DSUNSHINE_ENABLE_CUDA=OFF")
@@ -630,17 +615,6 @@ function run_step_cleanup() {
   echo "Running step: Cleanup"
 
   if [ "$skip_cleanup" == 0 ]; then
-    # Restore the original gcc alternatives
-    if [ "$distro" == "debian" ] || [ "$distro" == "ubuntu" ]; then
-      for file in "${gcc_alternative_files[@]}"; do
-        if [ -e "/etc/alternatives/$file.bak" ]; then
-          ${sudo_cmd} mv "/etc/alternatives/$file.bak" "/etc/alternatives/$file"
-        else
-          ${sudo_cmd} rm "/etc/alternatives/$file"
-        fi
-      done
-    fi
-
     # restore the math-vector.h file
     if [ "$architecture" == "aarch64" ] && [ -n "$math_vector_file" ]; then
       ${sudo_cmd} mv -f "$math_vector_file.bak" "$math_vector_file"
@@ -775,9 +749,18 @@ if [ "$architecture" != "x86_64" ] && [ "$architecture" != "aarch64" ]; then
   exit 1
 fi
 
+# export variables for github actions ci
+if [ -f "$GITHUB_ENV" ]; then
+  {
+    echo "CC=gcc-${gcc_version}"
+    echo "CXX=g++-${gcc_version}"
+    echo "GCC_VERSION=${gcc_version}"
+  } >> "$GITHUB_ENV"
+fi
+
 # get directory of this script
 script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-build_dir="$script_dir/../build"
+build_dir=$(readlink -f "$script_dir/../build")
 echo "Script Directory: $script_dir"
 echo "Build Directory: $build_dir"
 mkdir -p "$build_dir"