Fix macOS build configuration

Author: AlexanderViand

.github/workflows/pytest-coverage.yml

@@ -33,28 +33,21 @@ jobs:
       with:
         submodules: recursive
 
-    - name: (MacOs only) Install GNU GCC.
+    - name: (MacOs only) Install build dependencies
       if: matrix.os == 'macos-latest'
       run: |
-        brew install gcc libomp
-
-    - name: (MacOs only) Set CC/CXX environment variables to GNU GCC 
-      if: matrix.os == 'macos-latest'
-      run: |
-
-        # Check GCC installation path. Brew installs GCC in /opt/homebrew/bin on Apple Silicon and /usr/local/bin on Intel.
-        if [[ $(uname -m) = "arm64" ]]; then BREW_GCC_PATH="/opt/homebrew/bin"; else BREW_GCC_PATH="/usr/local/bin"; fi
-        echo "GCC installed at $BREW_GCC_PATH"
-
-        # Set CC/CXX environment variables to GNU GCC
-        echo "CC=$BREW_GCC_PATH/$(ls $BREW_GCC_PATH | grep ^gcc-[0-9] | sort -V -r | head -n 1)" >> $GITHUB_ENV
-        echo "CXX=$BREW_GCC_PATH/$(ls $BREW_GCC_PATH | grep ^g++-[0-9] | sort -V -r | head -n 1)" >> $GITHUB_ENV
-        echo "CC=${{ env.CC }}"
-        echo "CXX=${{ env.CXX }}"
-        
-        # Set MACOSX_DEPLOYMENT_TARGET to avoid version mismatch warnings
+        # Install Homebrew LLVM toolchain with OpenMP support
+        brew install llvm libomp
+        if [[ $(uname -m) == "arm64" ]]; then BREW_PREFIX="/opt/homebrew"; else BREW_PREFIX="/usr/local"; fi
+        echo "PATH=$BREW_PREFIX/opt/llvm/bin:$PATH" >> $GITHUB_ENV
+        echo "CC=$BREW_PREFIX/opt/llvm/bin/clang" >> $GITHUB_ENV
+        echo "CXX=$BREW_PREFIX/opt/llvm/bin/clang++" >> $GITHUB_ENV
+        echo "LDFLAGS=-L$BREW_PREFIX/opt/libomp/lib" >> $GITHUB_ENV
+        echo "CPPFLAGS=-I$BREW_PREFIX/opt/libomp/include" >> $GITHUB_ENV
+        # Build only for the host architecture to avoid missing x86_64 libraries
+        echo "ARCHFLAGS=-arch $(uname -m)" >> $GITHUB_ENV
+        echo "CMAKE_OSX_ARCHITECTURES=$(uname -m)" >> $GITHUB_ENV
         echo "MACOSX_DEPLOYMENT_TARGET=$(sw_vers -productVersion)" >> $GITHUB_ENV
-        echo "MACOSX_DEPLOYMENT_TARGET=${{ env.MACOSX_DEPLOYMENT_TARGET }}"
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
@@ -70,13 +63,30 @@ jobs:
       run: python -m pip install --upgrade pip
 
     - name: Install package verbosely
+      env:
+        CC: ${{ env.CC }}
+        CXX: ${{ env.CXX }}
+        LDFLAGS: ${{ env.LDFLAGS }}
+        CPPFLAGS: ${{ env.CPPFLAGS }}
+        PATH: ${{ env.PATH }}
+        ARCHFLAGS: ${{ env.ARCHFLAGS }}
+        CMAKE_OSX_ARCHITECTURES: ${{ env.CMAKE_OSX_ARCHITECTURES }}
+        MACOSX_DEPLOYMENT_TARGET: ${{ env.MACOSX_DEPLOYMENT_TARGET }}
       run: |
-
-        touch .cov # Create a .cov file to trigger Cython compilation with coverage support 
+        touch .cov # Create a .cov file to trigger Cython compilation with coverage support
         ls
         python -m pip install -v -v .
 
     - name: Test with pytest
+      env:
+        CC: ${{ env.CC }}
+        CXX: ${{ env.CXX }}
+        LDFLAGS: ${{ env.LDFLAGS }}
+        CPPFLAGS: ${{ env.CPPFLAGS }}
+        PATH: ${{ env.PATH }}
+        ARCHFLAGS: ${{ env.ARCHFLAGS }}
+        CMAKE_OSX_ARCHITECTURES: ${{ env.CMAKE_OSX_ARCHITECTURES }}
+        MACOSX_DEPLOYMENT_TARGET: ${{ env.MACOSX_DEPLOYMENT_TARGET }}
       run: |
         python -m pip install cython==3.0.2 pytest-cov
         pytest --cov .

setup.py

@@ -400,10 +400,17 @@ def build_shared_lib(self, lib_name, build_info):
         lib_file = f"{get_lib_prefix()}{lib_name}{get_lib_suffix('shared')}"
 
         if platform_system == 'Darwin':
-            build_info['extra_link_args'].append(f"-Wl,-install_name,@loader_path/{lib_file}")
-            self.compiler.linker_so = ['-dynamiclib' if val=='-bundle' else val for val in self.compiler.linker_so]
+            orig_linker_so = self.compiler.linker_so
+            self.compiler.linker_so = [
+                '-dynamiclib' if val == '-bundle' else val
+                for val in orig_linker_so
+            ]
+            build_info['extra_link_args'].append(
+                f"-Wl,-install_name,@loader_path/{lib_file}"
+            )
+        
         self.compiler.link_shared_object(
-            objects,                     
+            objects,
             lib_file,
             output_dir          = self.build_clib,
             target_lang         = language,
@@ -412,6 +419,9 @@ def build_shared_lib(self, lib_name, build_info):
             extra_postargs      = build_info['extra_link_args'],
             build_temp          = self.build_temp,
         )
+
+        if platform_system == 'Darwin':
+            self.compiler.linker_so = orig_linker_so
         # Post build
         build_info.update({
             'built_lib_files': [str(Path(self.build_clib).absolute() / lib_file)]