Generate baseline coverage before running tests

.github/actions/coverage_epilogue/action.yml

@@ -10,18 +10,32 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: "Install lcov"
-      shell: bash
-      run: |
-        sudo apt-get update
-        sudo apt-get install -y lcov
-
     - name: Generate Coverage Report
       shell: bash
       run: |
-        lcov --capture --directory ${{ inputs.build-output-dir }} --output-file coverage.info --ignore-errors mismatch
-        lcov --remove coverage.info '/usr/*' '*/_deps/*' '*/include/bitlib/bit-algorithms/libpopcnt.h' '*/test/inc/*' '*/test/src/*' --output-file coverage.info
+        # Capture actual coverage data after tests
+        lcov --capture \
+             --directory "${{ inputs.build-output-dir }}" \
+             --output-file coverage.info \
+             --ignore-errors mismatch
+
+        # Combine with baseline
+        lcov --add-tracefile coverage.baseline \
+             --add-tracefile coverage.info\
+             --output-file coverage.info
+
+        # Clean the coverage report from system and external deps
+        lcov --remove coverage.info \
+             '/usr/*' \
+             '*/_deps/*' \
+             '*/include/bitlib/bit-algorithms/libpopcnt.h' \
+             '*/test/inc/*' \
+             '*/test/src/*' \
+             --output-file coverage.info
+
+        # Show a summary in the logs
         lcov --list coverage.info
+
         # Generate an HTML report
         genhtml coverage.info --output-directory out/coverage
 
@@ -31,6 +45,7 @@ runs:
         name: coverage-report
         path: |
           out/coverage
+          coverage.baseline
           coverage.info
 
     - name: Coveralls

.github/actions/coverage_prologue/action.yml

@@ -0,0 +1,24 @@
+name: "Coverage Prologue"
+description: "Installs lcov and generates the baseline coverage"
+inputs:
+  build-output-dir:
+    required: true
+    description: 'Build output directory'
+
+runs:
+  using: "composite"
+  steps:
+    - name: "Install lcov"
+      shell: bash
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y lcov
+
+    - name: "Initialize 0% coverage baseline"
+      shell: bash
+      run: |
+        lcov --capture --initial \
+             --base-directory "$GITHUB_WORKSPACE" \
+             --directory "${{ inputs.build-output-dir }}" \
+             --output-file coverage.baseline \
+             --ignore-errors mismatch

.github/workflows/cmake-multi-platform.yml

@@ -93,18 +93,23 @@ jobs:
       id: strings
       shell: bash
       run: |
-        echo "build-output-dir=${{ github.workspace }}/build" >> "$GITHUB_OUTPUT"
-
+        echo "build-output-dir=$(readlink -f "${{ github.workspace }}/../build")" >> "$GITHUB_OUTPUT"
+  
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
       # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
-      run: >
-        cmake -B ${{ steps.strings.outputs.build-output-dir }} -S ${{ github.workspace }}
-        --preset=${{ matrix.preset }}_${{ matrix.os }}_${{ matrix.compiler }}_${{ matrix.stdlib }}
-        -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }}
-        -DCMAKE_C_COMPILER=${{ matrix.c_compiler }}
+      run: |
+        # Configure
+        cmake -B ${{ steps.strings.outputs.build-output-dir }} -S ${{ github.workspace }} \
+        --preset=${{ matrix.preset }}_${{ matrix.os }}_${{ matrix.compiler }}_${{ matrix.stdlib }} \
+        -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }} \
+        -DCMAKE_C_COMPILER=${{ matrix.c_compiler }} \
         -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
 
+        # Delete any coverage files created from CMake probing
+        find ${{ github.workspace }} \( -name '*.gcno' -o -name '*.gcda' \) -delete
+        find ${{ steps.strings.outputs.build-output-dir }} \( -name '*.gcno' -o -name '*.gcda' \) -delete
+
     - name: Register Compiler Problem Matcher
       run: echo "::add-matcher::.github/problem_matchers/${{ matrix.compiler}}_problem_matcher.json"
 
@@ -115,6 +120,11 @@ jobs:
     - name: Unregister Compiler Problem Matcher
       run: echo "::remove-matcher owner=${{ matrix.compiler}}::"
 
+    - uses: ./.github/actions/coverage_prologue
+      if: matrix.preset == 'coverage'
+      with:
+        build-output-dir: ${{ steps.strings.outputs.build-output-dir }}
+
     - name: Test
       # Execute tests defined by the CMake configuration. Note that --build-config is needed because the default Windows generator is a multi-config generator (Visual Studio generator).
       # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail

CMakePresets.json

@@ -41,8 +41,8 @@
       "name": "gnu_base",
       "hidden": true,
       "cacheVariables": {
-        "CMAKE_C_FLAGS_DEBUG": "-DPOPCNT_NO_UNALIGNED -g3 -fno-omit-frame-pointer -fstack-protector-all -fsanitize=address -fsanitize=undefined -finstrument-functions -fno-inline",
-        "CMAKE_CXX_FLAGS_DEBUG": "-DPOPCNT_NO_UNALIGNED -g3 -fno-omit-frame-pointer -DPOPCNT_NO_UNALIGNED -fstack-protector-all -fsanitize=address -fsanitize=undefined -finstrument-functions -fno-inline",
+        "CMAKE_C_FLAGS_DEBUG": "-DPOPCNT_NO_UNALIGNED -g3 -fno-omit-frame-pointer -fstack-protector-all -fsanitize=address -fsanitize=undefined -finstrument-functions -fno-inline -fno-inline-small-functions -fno-default-inline",
+        "CMAKE_CXX_FLAGS_DEBUG": "-DPOPCNT_NO_UNALIGNED -g3 -fno-omit-frame-pointer -DPOPCNT_NO_UNALIGNED -fstack-protector-all -fsanitize=address -fsanitize=undefined -finstrument-functions -fno-inline -fno-inline-small-functions -fno-default-inline",
         "CMAKE_C_FLAGS_RELEASE": "-O3 -DNDEBUG -march=native",
         "CMAKE_CXX_FLAGS_RELEASE": "-O3 -DNDEBUG -march=native"
       }