[MXNET-859] Add a clang-tidy stage to CI

Jenkinsfile

@@ -183,6 +183,16 @@ core_logic: {
         }
       }
     },
+    'CPU: Clang Tidy': {
+      node(NODE_LINUX_CPU) {
+        ws('workspace/build-cpu-clang50') {
+          timeout(time: max_time, unit: 'MINUTES') {
+            utils.init_git()
+            utils.docker_run('ubuntu_cpu', 'build_ubuntu_cpu_clang_tidy', false)
+          }
+        }
+      }
+    },
     'CPU: Clang 3.9 MKLDNN': {
       node(NODE_LINUX_CPU) {
         ws('workspace/build-cpu-mkldnn-clang39') {

ci/docker/install/ubuntu_clang.sh

@@ -26,6 +26,11 @@ wget -O - http://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - && \
     apt-add-repository "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-3.9 main" && \
     apt-add-repository "deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-6.0 main" && \
     apt-get update && \
-    apt-get install -y clang-3.9 clang-6.0 && \
+    apt-get install -y clang-3.9 clang-6.0 clang-tidy-6.0 && \
     clang-3.9 --version && \
     clang-6.0 --version
+
+# Use llvm's master version of run-clang-tidy.py.  This version has mostly minor updates, but
+# importantly will properly return a non-zero exit code when an error is reported in clang-tidy.
+# Please remove the below if we install a clang version higher than 6.0.
+wget https://raw.githubusercontent.com/llvm-mirror/clang-tools-extra/7654135f0cbd155c285fd2a37d87e27e4fff3071/clang-tidy/tool/run-clang-tidy.py -O /usr/lib/llvm-6.0/share/clang/run-clang-tidy.py

ci/docker/runtime_functions.sh

@@ -365,6 +365,32 @@ build_ubuntu_cpu_clang60() {
         -j$(nproc)
 }
 
+build_ubuntu_cpu_clang_tidy() {
+    set -ex
+
+    export CXX=clang++-6.0
+    export CC=clang-6.0
+    export CLANG_TIDY=/usr/lib/llvm-6.0/share/clang/run-clang-tidy.py
+
+    pushd .
+    cd /work/build
+    cmake \
+        -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+        -DCMAKE_C_COMPILER_LAUNCHER=ccache \
+        -DUSE_CUDA=OFF \
+        -DUSE_MKL_IF_AVAILABLE=OFF \
+        -DUSE_OPENCV=ON \
+        -DCMAKE_BUILD_TYPE=Debug \
+        -G Ninja \
+        -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
+        /work/mxnet
+
+    ninja -v
+    cd /work/mxnet
+    $CLANG_TIDY -p /work/build -j $(nproc) -clang-tidy-binary clang-tidy-6.0 /work/mxnet/src
+    popd
+}
+
 build_ubuntu_cpu_clang39_mkldnn() {
     set -ex