Merge pull request FloopCZ#201 from Youw/require_cuda_option

add option REQUIRE_CUDA

Author: FloopCZ

tensorflow_cc/CMakeLists.txt

@@ -9,6 +9,7 @@ project(
 # If enabled, bazel has to be installed.
 option(TENSORFLOW_SHARED "Build shared library (required for GPU support)." OFF)
 option(ALLOW_CUDA "When building the shared library, try to find and use CUDA." ON)
+option(REQUIRE_CUDA "When building the shared library, make sure to find and use CUDA (implies ALLOW_CUDA)." OFF)
 option(TENSORFLOW_STATIC "Build static library." ON)
 set(TENSORFLOW_TAG "v1.15.0" CACHE STRING "The tensorflow release tag to be checked out (default v1.15.0).")
 option(SYSTEM_PROTOBUF "Use system protobuf instead of static protobuf from contrib/makefile." OFF)

tensorflow_cc/cmake/build_tensorflow.sh.in

@@ -33,7 +33,25 @@ export PYTHON_BIN_PATH=${PYTHON_BIN_PATH:-"$(which python3)"}
 export PYTHON_LIB_PATH="$($PYTHON_BIN_PATH -c 'import site; print(site.getsitepackages()[0])')"
 
 # check if cuda support requested and supported
-if [ "@ALLOW_CUDA@" = "ON" ] && hash nvcc 2>/dev/null; then
+cuda_available=false
+if hash nvcc 2>/dev/null; then
+   cuda_available=true
+fi
+
+cuda_allowed=false
+if [ "@ALLOW_CUDA@" = "ON" ]; then
+    cuda_allowed=true
+fi
+
+if [ "@REQUIRE_CUDA@" = "ON" ];  then
+    cuda_allowed=true
+    if [ "$cuda_available" != true ]; then
+        echo "CUDA support is required but not available in the system (nvcc not found)"
+        exit 1
+    fi
+fi
+
+if [ "$cuda_allowed" == true ] && [ "$cuda_available" == true ]; then
     echo "CUDA support enabled"
     cuda_config_opts="--config=cuda"
     export TF_NEED_CUDA=1