partial c++20 module support

.github/workflows/integration-tests.yml

@@ -293,6 +293,335 @@ jobs:
           ${SCCACHE_PATH} --show-stats
           ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
 
+  gcc:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      SCCACHE_GHA_ENABLED: "on"
+      SCCACHE_SERVER_UDS: "/home/runner/sccache.socket"
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Configure Cache Env
+        uses: actions/github-script@v8
+        with:
+          script: |
+            core.exportVariable('ACTIONS_RESULTS_URL', process.env.ACTIONS_RESULTS_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '')
+
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: Test C/C++
+        run: |
+          export CXX="${SCCACHE_PATH} g++"
+          $CXX -c `pwd`/tests/test_clang_multicall.c
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+      - name: Test Twice for Cache Read
+        run: |
+          export CXX="${SCCACHE_PATH} g++"
+          $CXX -c `pwd`/tests/test_clang_multicall.c
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+          ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
+
+      - name: Test ASM
+        run: |
+          export ASM="${SCCACHE_PATH} gcc"
+          $ASM -c `pwd`/tests/test_intel_asm.s
+
+      - name: Test ASM with preprocessor
+        run: |
+          export ASM="${SCCACHE_PATH} gcc"
+          $ASM -c `pwd`/tests/test_intel_asm_to_preproc.S
+
+  autotools:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      SCCACHE_GHA_ENABLED: "on"
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Configure Cache Env
+        uses: actions/github-script@v8
+        with:
+          script: |
+            core.exportVariable('ACTIONS_RESULTS_URL', process.env.ACTIONS_RESULTS_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '')
+
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: Install dependencies
+        shell: bash
+        run: |
+          ## Install dependencies
+          sudo apt-get update
+          sudo apt-get install autoconf automake libtool
+
+      - name: Test
+        run: |
+          cd `pwd`/tests/autotools/
+          autoreconf||true
+          automake --add-missing
+          ./configure CXX="${SCCACHE_PATH} g++"
+          make
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+      - name: Test Twice for Cache Read
+        run: |
+          cd `pwd`/tests/autotools/
+          make distclean
+          ./configure CXX="${SCCACHE_PATH} g++"
+          make
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+          ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
+
+  cmake:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      SCCACHE_GHA_ENABLED: "on"
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Configure Cache Env
+        uses: actions/github-script@v8
+        with:
+          script: |
+            core.exportVariable('ACTIONS_RESULTS_URL', process.env.ACTIONS_RESULTS_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '')
+
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: Install dependencies
+        shell: bash
+        run: |
+          ## Install dependencies
+          sudo apt-get update
+          sudo apt-get install cmake
+
+      - name: Test
+        run: |
+          cd `pwd`/tests/cmake/
+          mkdir build
+          cd build
+          cmake -DCMAKE_C_COMPILER_LAUNCHER=${SCCACHE_PATH} -DCMAKE_CXX_COMPILER_LAUNCHER=${SCCACHE_PATH} ..
+          make
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+      - name: Test Twice for Cache Read
+        run: |
+          cd `pwd`/tests/cmake/
+          rm -rf build
+          mkdir build
+          cd build
+          cmake -DCMAKE_C_COMPILER_LAUNCHER=${SCCACHE_PATH} -DCMAKE_CXX_COMPILER_LAUNCHER=${SCCACHE_PATH} ..
+          make
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+          ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
+
+  cmake-modules:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      SCCACHE_GHA_ENABLED: "on"
+      LLVM_VERSION: "19"
+
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Configure Cache Env
+        uses: actions/github-script@v8
+        with:
+          script: |
+            core.exportVariable('ACTIONS_RESULTS_URL', process.env.ACTIONS_RESULTS_URL || '');
+            core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '')
+
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: Install dependencies
+        shell: bash
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh "${LLVM_VERSION}"
+          sudo apt-get update
+          sudo apt-get install -y ninja-build
+          pip install cmake
+
+      - name: Test
+        run: |
+          cd `pwd`/tests/cmake-modules/
+          cmake -B build -G Ninja \
+            -DCMAKE_C_COMPILER=clang-${LLVM_VERSION} \
+            -DCMAKE_CXX_COMPILER=clang++-${LLVM_VERSION} \
+            -DCMAKE_C_COMPILER_LAUNCHER=${SCCACHE_PATH} \
+            -DCMAKE_CXX_COMPILER_LAUNCHER=${SCCACHE_PATH}
+          cmake --build build
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+      - name: Test Twice for Cache Read
+        run: |
+          cd `pwd`/tests/cmake-modules/
+          rm -rf build
+          cmake -B build -G Ninja \
+            -DCMAKE_C_COMPILER=clang-${LLVM_VERSION} \
+            -DCMAKE_CXX_COMPILER=clang++-${LLVM_VERSION} \
+            -DCMAKE_C_COMPILER_LAUNCHER=${SCCACHE_PATH} \
+            -DCMAKE_CXX_COMPILER_LAUNCHER=${SCCACHE_PATH}
+          cmake --build build
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+          ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
+
+  # Test sccache with modern LLVM-based code coverage
+  rust-test-coverage:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      RUSTC_WRAPPER: /home/runner/.cargo/bin/sccache
+      CARGO_INCREMENTAL: "0"
+      RUSTFLAGS: "-Cinstrument-coverage"
+      LLVM_PROFILE_FILE: "coverage-%p-%m.profraw"
+
+    steps:
+      - name: Clone repository
+        uses: actions/checkout@v5
+
+      - name: Install rust
+        uses: ./.github/actions/rust-toolchain
+        with:
+          toolchain: "stable"
+
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: "Coverage test #1"
+        run: cargo clean && cargo build
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+      - name: "Coverage test #2"
+        run: cargo clean && cargo build
+
+      - name: Output
+        run: |
+          ${SCCACHE_PATH} --show-stats
+
+          ${SCCACHE_PATH} --show-stats | grep -e "Cache hits\s*[1-9]"
+
+  zstd-compression-level:
+    runs-on: ubuntu-24.04
+    needs: build
+
+    env:
+      RUSTC_WRAPPER: /home/runner/.cargo/bin/sccache
+      SCCACHE_DIR:
+      CARGO_INCREMENTAL: "0"
+
+    steps:
+      - uses: actions/download-artifact@v5
+        with:
+          name: integration-tests
+          path: /home/runner/.cargo/bin/
+      - name: Chmod for binary
+        run: chmod +x ${SCCACHE_PATH}
+
+      - name: Clone repository
+        uses: actions/checkout@v5
+
+      - name: Install rust
+        uses: ./.github/actions/rust-toolchain
+        with:
+          toolchain: "stable"
+
+      - name: default-test-save
+        run: |
+          export SCCACHE_DIR=${PWD}/temp-test/zstd-level/default
+          cargo build
+      - name: default-stats-save
+        run: ${SCCACHE_PATH} --show-stats
+      - name: default-test-use
+        run: |
+          cargo clean && cargo build
+      - name: default-stats-use
+        run: ${SCCACHE_PATH} --show-stats
+      - name: lv10-test-save
+        run: |
+          export SCCACHE_DIR=${PWD}/temp-test/zstd-level/10
+          export SCCACHE_CACHE_ZSTD_LEVEL=10
+          ${SCCACHE_PATH} --stop-server > /dev/null
+          cargo clean
+          cargo build
+      - name: lv10-stats-save
+        run: ${SCCACHE_PATH} --show-stats
+      - name: lv10-test-use
+        run: |
+          cargo clean && cargo build
+      - name: lv10-stats-use
+        run: ${SCCACHE_PATH} --show-stats
+
   xcode:
     runs-on: macos-latest
     env:

.gitignore

@@ -20,3 +20,4 @@ tests/**/Cargo.lock
 
 .direnv/
 result
+.vscode/settings.json

README.md

@@ -372,6 +372,22 @@ Known Caveats
 
 [More details on Rust caveats](/docs/Rust.md)
 
+### C++20 Modules
+
+sccache has partial support for C++20 named modules when using **Clang**. The following flags are supported:
+
+* `-fmodule-file=<path>` and `-fmodule-file=<name>=<path>` - importing precompiled module interfaces
+* `-fmodule-output=<path>` - generating module interface output alongside object files
+* `--precompile` - compiling module interface units
+* `-fmodules-reduced-bmi` - generating reduced BMI files
+
+The following module-related flags are **not supported** and will bypass the cache:
+
+* `-fmodules` and `-fcxx-modules` - Clang header modules (not C++20 named modules)
+* `-fprebuilt-implicit-modules` and `-fprebuilt-module-path` - implicit module discovery
+
+**GCC** and **MSVC** C++20 modules are not yet supported. Compilations using `-fmodules-ts` (GCC) or `/interface`, `/ifcOutput`, etc. (MSVC) will bypass the cache.
+
 ### User Agent
 
 * Requests sent to your storage option of choice will have a user agent header indicating the current sccache version, e.g. `sccache/0.8.2`.