[Code Coverage] Add a tool to check test coverage of a patch

.github/workflows/patch-based-code-coverage.yml

@@ -0,0 +1,44 @@
+name: LLVM Code Coverage
+
+on:
+  push:
+    branches:
+      - test-format
+
+jobs:
+  code-coverage:
+    name: Generate Code Coverage Report
+    runs-on: self-hosted
+
+    steps:
+      - name: Checkout LLVM Repository
+        uses: actions/checkout@v1
+
+      - name: Install LLVM project build dependency
+        run: |
+          sudo apt-get install llvm
+          sudo apt-get install clang
+          sudo apt-get install lld
+          sudo apt-get install cmake
+          sudo apt-get install ninja-build
+          sudo apt-get install -y python3.11
+          pip install argparse unidiff
+
+      - name: Build LLVM project
+        run: |
+          mkdir build
+          cd build
+          cmake -G Ninja ../llvm -DLLVM_ENABLE_PROJECTS="clang" -DCMAKE_BUILD_TYPE=Release -DLLVM_USE_LINKER=lld -DCMAKE_C_COMPILER=/usr/local/bin/clang -DCMAKE_CXX_COMPILER=/usr/local/bin/clang++ -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_BUILD_TESTS=ON
+          ninja
+
+      - name: Run the patch-based code coverage tool
+        run: |
+          cp llvm/utils/git-check-coverage .
+          python3 git-check-coverage -b build bin/clang-format clang/test
+
+      - name: Archive code coverage artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: code-coverage-results
+          path: build/patch_coverage.log
+