Google Benchmark as a cmake dependency

Question

I'm trying to compile a google benchmark with a dependency on the Libtorch (Pytorch) library. I have installed Google Benchmark with make install so to my understanding i should be able to use find_package() to add both dependencies. Finally I add some compiler flags.

Here is my CMakeLists.txt:

cmake_minimum_required(VERSION 3.0 FATAL_ERROR)
project(learned_b VERSION 1.0)
add_executable(PROJECT_NAME learned_benchmark.cpp)

find_package(Torch REQUIRED)
find_package(benchmark REQUIRED)
target_link_libraries(PROJECT_NAME "${TORCH_LIBRARIES}")
target_include_directories(PROJECT_NAME PUBLIC "${benchmark_INCLUDE_DIRS}")
target_link_libraries(PROJECT_NAME "${benchmark_LIBRARIES}")

SET(GCC_LINK_FLAGS    "-isystem /Users/yhr/Programs/benchmark/include -lbenchmark -pthread")
SET(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} ${GCC_LINK_FLAGS}")
set_property(TARGET PROJECT_NAME PROPERTY CXX_STANDARD 11)

It should be noted that with and without the GCC_LINK_FLAGS, I always get a fatal error: 'benchmark/benchmark.h' file not found. My code was compiling and running when it only depended on Pytorch. Is it possible to use find_package with google benchmark? If not how can I go about this properly?

EDIT 1:

here are the commands I have run.

$ cd build
$ cmake -DCMAKE_PREFIX_PATH='/Users/yhr/Programs/libtorch;/Users/yhr/Programs/benchmark' ..
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter
 $ cd ..
 $ make VERBOSE=1
/usr/local/Cellar/cmake/3.15.4/bin/cmake -S/Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter -B/Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter --check-build-system CMakeFiles/Makefile.cmake 0
/usr/local/Cellar/cmake/3.15.4/bin/cmake -E cmake_progress_start /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter/CMakeFiles /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter/CMakeFiles/progress.marks
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/Makefile2 all
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/PROJECT_NAME.dir/build.make CMakeFiles/PROJECT_NAME.dir/depend
cd /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter && /usr/local/Cellar/cmake/3.15.4/bin/cmake -E cmake_depends "Unix Makefiles" /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter/CMakeFiles/PROJECT_NAME.dir/DependInfo.cmake --color=
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/PROJECT_NAME.dir/build.make CMakeFiles/PROJECT_NAME.dir/build
[ 50%] Building CXX object CMakeFiles/PROJECT_NAME.dir/learned_benchmark.cpp.o
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++  -DAT_PARALLEL_OPENMP=1 -D_THP_CORE -I/Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter -isystem /Users/yhr/programs/libtorch/include -isystem /Users/yhr/programs/libtorch/include/torch/csrc/api/include  -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -mmacosx-version-min=10.14   -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wno-write-strings -Wno-unknown-pragmas -Wno-missing-braces -std=gnu++11 -o CMakeFiles/PROJECT_NAME.dir/learned_benchmark.cpp.o -c /Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter/learned_benchmark.cpp
/Users/yhr/Programs/learnedbloomfilters/OpenBloomFilter/learned_benchmark.cpp:4:10: fatal error: 'benchmark/benchmark.h' file not found
#include <benchmark/benchmark.h>
         ^~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [CMakeFiles/PROJECT_NAME.dir/learned_benchmark.cpp.o] Error 1
make[1]: *** [CMakeFiles/PROJECT_NAME.dir/all] Error 2
make: *** [all] Error 2

Welcome to Stackoverflow! Can you please provide the CMake commands you used to run CMake, and the **full CMake output and build output** in your question post? — Kevin, Nov 11 '19 at 19:09
Did CMake even find `benchmark`? Can you provide the output of `message("benchmark_INCLUDE_DIRS: ${benchmark_INCLUDE_DIRS}")`? — Kevin, Nov 11 '19 at 19:12
thanks @squareskittles seems it didn't find benchmark. I thought the convention was the projectname_INCLUDE_DIRS but maybe that is not the case here. I'll try to play around with those — yhr, Nov 11 '19 at 19:19
maybe you can have a look at a small example I wrote [GitHub repo](https://github.com/vincent-picaud/Blog_CMake_GoogleBenchmark) which illustrates how to use cmake + goog benchmark. — Picaud Vincent, Nov 11 '19 at 19:23
That was the problem! For any other cmake noobs: you can use the script from this post at the top of your cmake to import it. https://github.com/google/benchmark/issues/188 — yhr, Nov 11 '19 at 19:25
@yhr this issue is closed because google benchmark is now exporting its configuration. I'd recommend it! It makes dependencies in CMake bearable. — Guillaume Racicot, Nov 11 '19 at 19:48

score 3 · Accepted Answer · answered Nov 11 '19 at 19:17

You use find_package correctly, but you misuse what it defines.

The find_package command don't export XY_LIBRARIES and XY_INCLUDE_DIRECTORIES when using exported packages. You'll notice it if you print the values of those variable.

Instead, modern CMake packages export targets. This is true for all projects that uses package exportation instead of find modules. To link to an imported target, you should use target_link_libraries:

target_link_libraries(PROJECT_NAME PRIVATE benchmark::benchmark)

This will add all necessary flags for all CPP insinde the PROJECT_NAME target to be able to use google benchmark.

You can drop flags variable (don't toutch CMAKE_CXX_FLAGS and link flags!) and use more robust constructs instead, like the target based target_link_libraries.

Google Benchmark as a cmake dependency

1 Answers1