Generate code coverage report with llvm-cov (#469)

.github/workflows/coverage.yml

@@ -0,0 +1,42 @@
+name: Coverage
+
+on: [pull_request, push]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  coverage:
+    name: "Coverage"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      # TODO: Remove this once clang 15 is default; clang 14 had a stdlib bug
+      - name: Install clang 15
+        run: |
+          sudo apt-get update -q
+          sudo apt-get install llvm-15-dev libc++-15-dev
+          sudo update-alternatives --install \
+            /usr/bin/clang clang /usr/bin/clang-15 200
+          sudo update-alternatives --install \
+            /usr/bin/clang++ clang++ /usr/bin/clang++-15 200
+          sudo update-alternatives --install \
+            /usr/bin/llvm-cov llvm-cov /usr/bin/llvm-cov-15 200
+          sudo update-alternatives --install \
+            /usr/bin/llvm-profdata llvm-profdata /usr/bin/llvm-profdata-15 200
+
+      - run: ./tools/coverage-generate.sh SleipnirTest
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: Coverage report
+          path: ./build-coverage/coverage-line-by-line-SleipnirTest.html
+
+      - name: Write to job summary
+        run: |
+          echo '```bash' >> $GITHUB_STEP_SUMMARY
+          cat ./build-coverage/coverage-report-SleipnirTest.txt >> $GITHUB_STEP_SUMMARY
+          echo '' >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY

cmake/modules/SleipnirBuildTypes.cmake

@@ -99,5 +99,14 @@ if(NOT MSVC)
       "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}"
     )
 
+    sleipnir_add_build_type(
+      allowedBuildTypes
+      "Coverage"
+      "${CMAKE_C_FLAGS_RELWITHDEBINFO} -fprofile-instr-generate -fcoverage-mapping"
+      "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -fprofile-instr-generate -fcoverage-mapping"
+      "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}"
+      "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO}"
+    )
+
     sleipnir_check_build_type(allowedBuildTypes)
 endif()

tools/coverage-generate.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -e
+
+if [ $# -eq 0 ]; then
+  echo -e "Usage: coverage-generate.sh CMAKE_TARGET\nGenerates coverage of CMake target executable with llvm-cov."
+  exit 1
+fi
+
+# Build executable
+cmake -B build-coverage -S . -DCMAKE_BUILD_TYPE=Coverage -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+cmake --build build-coverage --target $1
+
+# Run executable and generate reports
+pushd build-coverage
+./$1
+llvm-profdata merge -sparse default.profraw -o default.profdata
+llvm-cov show -ignore-filename-regex=_deps/ ./$1 -instr-profile=default.profdata -format=html > coverage-line-by-line-$1.html
+llvm-cov report -ignore-filename-regex=_deps/ ./$1 -instr-profile=default.profdata > coverage-report-$1.txt
+popd