Enabling ccache on github builds for Ubuntu

.github/workflows/native-ubuntu.yml

@@ -15,6 +15,8 @@ jobs:
           - name: "full-marian"
             os: ubuntu-latest
             gcc: 8
+            force_recache: false
+            ccache_cmd: "bash ${GITHUB_WORKSPACE}/scripts/ci/compiler-hash.sh %compiler%"
             cpu: 'ON'
             gpu: 'OFF'
             test_tags: ""
@@ -24,10 +26,14 @@ jobs:
               USE_WASM_COMPATIBLE_SOURCE: "OFF"
               COMPILE_SERVER: "OFF"
               COMPILE_EXAMPLES: "OFF"
+              CMAKE_C_COMPILER_LAUNCHER: "ccache"
+              CMAKE_CXX_COMPILER_LAUNCHER: "ccache"
 
           - name: "minimal-marian"
             os: ubuntu-latest
             gcc: 8
+            force_recache: false
+            ccache_cmd: "bash ${GITHUB_WORKSPACE}/scripts/ci/compiler-hash.sh %compiler%"
             cpu: 'ON'
             gpu: 'OFF'
             test_tags: "'#wasm'"
@@ -37,6 +43,42 @@ jobs:
               USE_WASM_COMPATIBLE_SOURCE: "ON"
               COMPILE_SERVER: "OFF"
               COMPILE_EXAMPLES: "OFF"
+              CMAKE_C_COMPILER_LAUNCHER: "ccache"
+              CMAKE_CXX_COMPILER_LAUNCHER: "ccache"
+
+          - name: "full-marian-force-recache"
+            os: ubuntu-latest
+            gcc: 8
+            force_recache: true
+            ccache_cmd: "bash ${GITHUB_WORKSPACE}/scripts/ci/compiler-hash.sh %compiler%"
+            cpu: 'ON'
+            gpu: 'OFF'
+            test_tags: ""
+            cmake: 
+              CMAKE_BUILD_TYPE: "Release"
+              COMPILE_TESTS: "ON"
+              USE_WASM_COMPATIBLE_SOURCE: "OFF"
+              COMPILE_SERVER: "OFF"
+              COMPILE_EXAMPLES: "OFF"
+              CMAKE_C_COMPILER_LAUNCHER: "ccache"
+              CMAKE_CXX_COMPILER_LAUNCHER: "ccache"
+
+          - name: "minimal-marian-force-recache"
+            os: ubuntu-latest
+            gcc: 8
+            force_recache: true
+            ccache_cmd: "bash ${GITHUB_WORKSPACE}/scripts/ci/compiler-hash.sh %compiler%"
+            cpu: 'ON'
+            gpu: 'OFF'
+            test_tags: "'#wasm'"
+            cmake:
+              CMAKE_BUILD_TYPE: "Release"
+              COMPILE_TESTS: "OFF" # Minimal marian has no sqlite support and COMPILE_TEST=ON fails.
+              USE_WASM_COMPATIBLE_SOURCE: "ON"
+              COMPILE_SERVER: "OFF"
+              COMPILE_EXAMPLES: "OFF"
+              CMAKE_C_COMPILER_LAUNCHER: "ccache"
+              CMAKE_CXX_COMPILER_LAUNCHER: "ccache"
 
 
     runs-on: ${{ matrix.os }}
@@ -57,7 +99,7 @@ jobs:
         sudo apt-get update 
         sudo apt-get install -y \
             libgoogle-perftools-dev libprotobuf-dev protobuf-compiler  \
-            libboost-all-dev g++-${{ matrix.gcc }} 
+            libboost-all-dev g++-${{ matrix.gcc }} ccache
 
     # https://software.intel.com/content/www/us/en/develop/articles/installing-intel-free-libs-and-python-apt-repo.html
     - name: Install MKL
@@ -68,24 +110,67 @@ jobs:
         sudo apt-get install -y --no-install-recommends intel-mkl-64bit-2020.0-088
       if: matrix.cmake.USE_WASM_COMPATIBLE_SOURCE == 'OFF'
 
+    - name: Generate ccache_vars
+      id: ccache_vars
+      shell: bash
+      run: |
+          echo "::set-output name=hash::$(${{ matrix.ccache_cmd }})"
+          echo "::set-output name=timestamp::$(date '+%Y-%m-%dT%H.%M.%S')"
+
+    - name: Setup ccache environment variables
+      run: | 
+        echo "CCACHE_COMPILERCHECK=${{ matrix.ccache_cmd }}" >> $GITHUB_ENV 
+        echo "CCACHE_BASE_DIR=${{ github.workspace }}" >> $GITHUB_ENV
+        echo "CCACHE_DIR=${{ github.workspace }}/.ccache" >> $GITHUB_ENV
+        echo "CCACHE_COMPRESS=true" >> $GITHUB_ENV
+        echo "CCACHE_COMPRESSLEVEL=6" >> $GITHUB_ENV
+        echo "CCACHE_MAXSIZE=2G" >> $GITHUB_ENV
+
+    - name: Setup ccache recache on
+      run: |
+        echo "CCACHE_RECACHE=" >> $GITHUB_ENV 
+      if: matrix.force_recache == true
+
+    - name: Cache-op for build-cache through ccache 
+      uses: actions/cache@v2
+      with:
+        path: ${{ env.CCACHE_DIR }}
+        key: ccache-${{ matrix.name }}-${{ steps.ccache_vars.outputs.hash }}-${{ github.ref }}-${{ steps.ccache_vars.outputs.timestamp }}
+        restore-keys: |
+           ccache-${{ matrix.name }}-${{ steps.ccache_vars.outputs.hash }}-${{ github.ref }}- 
+           ccache-${{ matrix.name }}-${{ steps.ccache_vars.outputs.hash }}- 
+           ccache-${{ matrix.name }}- 
+
+    - name: Cache stats before build
+      run: |
+          ccache -s
+          ccache -z
+
     # Boost is installed on GitHub-hosted runners in a non-standard location
     # https://github.com/actions/virtual-environments/issues/687#issuecomment-610471671
     - name: Configure CMake
       run: |
         mkdir -p build
         cd build
         CC=/usr/bin/gcc-${{ matrix.gcc }} CXX=/usr/bin/g++-${{ matrix.gcc }} CUDAHOSTCXX=/usr/bin/g++-${{ matrix.gcc }} \
-        cmake .. \
+        cmake -L .. \
           -DCMAKE_BUILD_TYPE=${{ matrix.cmake.CMAKE_BUILD_TYPE }}\
           -DCOMPILE_TESTS=${{ matrix.cmake.COMPILE_TESTS }}\
           -DCOMPILE_EXAMPLES=${{ matrix.cmake.COMPILE_EXAMPLES }} \
           -DCOMPILE_SERVER=${{ matrix.cmake.COMPILE_SERVER }} \
           -DUSE_WASM_COMPATIBLE_SOURCE=${{ matrix.cmake.USE_WASM_COMPATIBLE_SOURCE }} \
+          -DCMAKE_C_COMPILER_LAUNCHER=${{ matrix.cmake.CMAKE_C_COMPILER_LAUNCHER}} \
+          -DCMAKE_CXX_COMPILER_LAUNCHER=${{ matrix.cmake.CMAKE_CXX_COMPILER_LAUNCHER}} 
+
 
     - name: Compile bergamot-translator
       working-directory: build
       run: make -j2
 
+    - name: Cache stats after build
+      run: |
+          ccache -s
+
     - name: Run unit tests
       working-directory: build
       run: make test

scripts/ci/compiler-hash.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# Uses the command from https://stackoverflow.com/a/9355840/4565794.
+# -v displays the commands executed to run compilation. Of this cc1 additional
+#    flags which contain the flags triggered by -march=native is what we need.
+# -E stop after preprocessing stage.
+
+# Output on a linux machine with gcc-8 looks as follows:
+
+# $ gcc -march=native -E -v - </dev/null 2>&1 | grep cc1
+#       /usr/lib/gcc/x86_64-linux-gnu/8/cc1 -E -quiet -v -imultiarch x86_64-linux-gnu
+#       - -march=skylake-avx512 -mmmx -mno-3dnow -msse -msse2 -msse3 -mssse3
+#       -mno-sse4a -mcx16 -msahf -mmovbe -maes -mno-sha -mpclmul -mpopcnt -mabm
+#       -mno-lwp -mfma -mno-fma4 -mno-xop -mbmi -mno-sgx -mbmi2 -mno-pconfig
+#       -mno-wbnoinvd -mno-tbm -mavx -mavx2 -msse4.2 -msse4.1 -mlzcnt -mno-rtm
+#       -mno-hle -mrdrnd -mf16c -mfsgsbase -mrdseed -mprfchw -madx -mfxsr -mxsave
+#       -mxsaveopt -mavx512f -mno-avx512er -mavx512cd -mno-avx512pf -mno-prefetchwt1
+#       -mclflushopt -mxsavec -mxsaves -mavx512dq -mavx512bw -mavx512vl
+#       -mno-avx512ifma -mno-avx512vbmi -mno-avx5124fmaps -mno-avx5124vnniw -mclwb
+#       -mno-mwaitx -mno-clzero -mpku -mno-rdpid -mno-gfni -mno-shstk
+#       -mno-avx512vbmi2 -mavx512vnni -mno-vaes -mno-vpclmulqdq -mno-avx512bitalg
+#       -mno-movdiri -mno-movdir64b --param l1-cache-size=32 --param
+#       l1-cache-line-size=64 --param l2-cache-size=28160 -mtune=skylake-avx512
+#       -fstack-protector-strong -Wformat -Wformat-security
+
+# The sha256sum of the output is computed, and stripped to the first 8
+# characters for use in ccache and github cache store key. Can effectively be
+# considered as a hash of the compiler version and the flags activated by
+# -march=native.
+
+COMPILER=$1
+
+$COMPILER -march=native -E -v - < /dev/null 2>&1 | grep cc1 \
+    | sha256sum | cut -c1-8
+