Intel oneAPI dpcpp compiler with google test

Question

I'm kinda new to the world of Intel's HPC toolchain and I'm facing some troubles making even simple DPC++ application to work when gtest is used as a testing framework

This is the CMakeLists "structure" I'm following

cmake_minimum_required(VERSION 3.14)
project(foo)

set(CMAKE_CXX_COMPILER "dpcpp")

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 -O3 -fsycl")

# add executables 
# target linked libraries 
# ...

option(ENABLE_TESTS ON)
if(ENABLE_TESTS)
  FetchContent_Declare(
    googletest
    GIT_REPOSITORY https://github.com/google/googletest.git
    GIT_TAG release-1.11.0
  )
  set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
  FetchContent_MakeAvailable(googletest)

  add_subdirectory(tests)
endif()

If I remove the last block, it compiles and runs as expected, otherwise I get the following error:

CMake Error at build/_deps/googletest-src/CMakeLists.txt:10 (project):
  The CMAKE_CXX_COMPILER:

    dpcpp

  is not a full path and was not found in the PATH.

  Tell CMake where to find the compiler by setting either the environment
  variable "CXX" or the CMake cache entry CMAKE_CXX_COMPILER to the full path
  to the compiler, or to the compiler name if it is in the PATH.


-- Configuring incomplete, errors occurred!
See also "/home/u141905/foo/build/CMakeFiles/CMakeOutput.log".
See also "/home/u141905/foo/build/CMakeFiles/CMakeError.log".
You have changed variables that require your cache to be deleted.
Configure will be re-run and you may have to reset some variables.
The following variables have changed:
CMAKE_CXX_COMPILER= /usr/bin/c++

-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.
make: *** [Makefile:2: all] Error 1

Please notice that dpcpp is correctly set, in fact I'm using Intel's devcloud platform. Setting CXXto the output of whereis dpcpp produces the same error. The only "workaround" (I doubt it is one though) I found is using clang++ instead (the version from Intel's llvm). Any help or suggestion is much appreciated, thanks in advance!

EDIT: after some more attempts, I noticed that if I set CMAKE_CXX_COMPILER just after fetching gtest, everything works fine. Anyway I don't understand why this happens and how can be properly fixed.

Answer 1

Did you run the source /opt/intel/oneapi/setvars.sh intel64 script? I.e. is dpcpp on your path before running cmake?

Answer 2

Use the path for dpcpp binary for setting the CMAKE_CXX_COMPILER instead of using"set(CMAKE_CXX_COMPILER "dpcpp")". After adding the path("/opt/intel/oneapi/compiler/2022.0.1/linux/bin/dpcpp") to the CMAKE_CXX_COMPILER, you can run the program successfully.

Please find the below CMakeLists.txt for setting the CMAKE_CXX_COMPILER:

project(foo)
set(CMAKE_CXX_COMPILER "/opt/intel/oneapi/compiler/2022.0.1/linux/bin/dpcpp")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 -O3 -fsycl")
# add executables
# target linked libraries
# ...
set(ENABLE_TESTS ON)
include(FetchContent)
if(ENABLE_TESTS)
 FetchContent_Declare(
  googletest
  GIT_REPOSITORY https://github.com/google/googletest.git
  GIT_TAG release-1.11.0
 )
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
FetchContent_MakeAvailable(googletest)
add_subdirectory(tests)
endif()

Thanks & Regards, Hemanth