[CMake] Using CMake to link C++ and CUDA Object file

[Quang Ha]

Thanks for your response, Robert. If I don't use find_package(CUDA), I run
into the following problem:

 fatal error: thrust/host_vector.h: No such file or directory

I guess this is needed if I am using Thrust/CUDA?

Thanks,
Quang

On Fri, 6 Jul 2018 at 06:38, Robert Maynard <robert.maynard at kitware.com>
wrote:

> if you are using the new first class cuda language, as seen by `project(MyTest
> LANGUAGES CXX CUDA)` you shouldn't use the old find cuda package or the
> associated cuda_add_library calls. When using the first class cuda
> language simply use add_library.
>
> The other difference I notice is that you makefile example is not building
> shared libraries but object files, so to the same in CMake you need to use
> 'add_library' with the OBJECT keyword not the SHARED keyword.
>
>
>
> On Fri, Jul 6, 2018 at 12:01 AM Quang Ha <quang.t.ha.20 at gmail.com> wrote:
>
>> Hi all,
>>
>> Following upon how to perform code linking between CUDA and C++ (here at
>> https://devblogs.nvidia.com/separate-compilation-linking-cuda-device-code/),
>> I have successfully come up with a Makefile that is currently working for
>> my test case:
>>
>> ##################################Makefile###############
>> ##################################
>> main_objects = main.o
>> host_objects = host.o
>> device_objects = device.o
>>
>> all: $(main_objects) $(host_objects) $(device_objects)
>>         g++ -O3 -fopenmp $(main_objects) $(host_objects)
>> $(device_objects) -L/usr/local/cuda/lib64 -lcudart -o main
>>
>> $(main_objects): $(main_objects:.o=.cpp)
>>         g++ -O3 -I/usr/local/cuda/include -c $< -o $@
>>
>> $(host_objects): $(host_objects:.o=.cpp)
>>         g++ -O3 -DTHRUST_HOST_SYSTEM=THRUST_HOST_SYSTEM_OMP -fopenmp -c
>> $< -o $@
>>
>> $(device_objects): $(device_objects:.o=.cu)
>>         nvcc -O3 -DTHRUST_DEVICE_SYSTEM=THRUST_DEVICE_SYSTEM_CUDA -c $<
>> -o $@
>>
>> clean:
>>         rm -f *.o main
>> ####################################################################
>> ##################################
>>
>> Now, I am trying to write a CMake for this, my current attempt is as
>> followed:
>>
>>
>> ##############################################CMakeLists.txt############################################
>> cmake_minimum_required(VERSION 3.8)
>> project(MyTest LANGUAGES CXX CUDA)
>>
>> # check requirements
>> find_package(CUDA REQUIRED)
>> find_package(OpenMP)
>>
>> if (CUDA_FOUND AND OPENMP_FOUND)
>>     # OpenMP
>>     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
>>     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
>>     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}
>> ${OpenMP_EXE_LINKER_FLAGS}")
>>
>>     # CUDA
>>     include_directories(${CUDA_INCLUDE_DIRS})
>>     set(ALL_CUDA_LIBS ${CUDA_LIBRARIES} ${CUDA_cusparse_LIBRARY}
>> ${CUDA_cublas_LIBRARY})
>>     set(LIBS ${LIBS} ${ALL_CUDA_LIBS})
>>     set(CUDA_SEPARABLE_COMPILATION OFF)
>>     set(CUDA_NVCC_FLAGS ${CUDA_NVCC_FLAGS};--maxrregcount 32)
>>
>>     set(OMP_SOURCES host.cpp)
>>     add_library(Host_OMP SHARED ${OMP_SOURCES})
>>     set_target_properties(Host_OMP PROPERTIES COMPILE_FLAGS
>> "-DTHRUST_HOST_SYSTEM=THRUST_HOST_SYSTEM_OMP")
>>     set(LIBS ${LIBS} ${Host_OMP})
>>
>>     set(CUDA_SOURCES device.cu)
>>     cuda_add_library(Device_CUDA SHARED ${CUDA_SOURCES})
>>     set_target_properties(Device_CUDA PROPERTIES COMPILE_FLAGS
>> "-DTHRUST_DEVICE_SYSTEM=THRUST_DEVICE_SYSTEM_CUDA")
>>     set_target_properties(Device_CUDA PROPERTIES
>> CUDA_SEPERABLE_COMPILATION ON)
>>     set(LIBS ${LIBS} ${Device_CUDA})
>>
>>     add_executable(main main.cpp)
>>     target_link_libraries(main ${LIBS})
>>
>> endif(CUDA_FOUND AND OPENMP_FOUND)
>> ####################################################################
>> ##################################
>>
>> It is still, unfortunately, not working. If I commented out the
>> add_executable line, the object code for Host_OMP and Device_CUDA is
>> compiled. I can then use the terminal and link them with main.cpp using gcc
>> and generate the executable - i.e. using the final command in the Makefile
>> above.
>>
>> What am I doing wrong here? It seems to be very fundamental, but I can't
>> seem to get it right...
>>
>> Any suggestions would be greatly appreciated!!
>>
>> Thanks,
>> Quang
>> --
>>
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