Configure cmake to work with homebrew libraries instead system-provided libraries - cmake

Question

I find myself going against the grain configuring cmake paths with ccmake over and over again as with every change of for ex. compiler some of my library paths get lost.
In particular paths to (unlinked) lapack, lapacke, gsl get either lost or set to system defaults instead the ones I've installed with brew.
There has to be a way to tell cmake to "ignore" system libraries and instead look in homebrew paths (say. /opt/homebrew/lib, /opt/homebrew/include etc.).
I'd prefer not to link those libraries as this is not recommend and I'm not experienced in switching environments.
[EDIT] MRE:
git clone https://gitlab.physik.uni-muenchen.de/AG-Scrinzi/tRecX.git
cd tRecX
cmake . -DCMAKE_BUILD_TYPE=Parallel
make -j 8
I add the following to .bash_profile/.zshrc:
export LDFLAGS="-L/opt/homebrew/opt/lapack/lib -L/opt/homebrew/opt/lapack/lib"
export CPPFLAGS="-I/opt/homebrew/opt/lapack/include -I/opt/homebrew/opt/openblas/include"
export PKG_CONFIG_PATH="/opt/homebrew/opt/lapack/lib/pkgconfig /opt/homebrew/opt/openblas/lib/pkgconfig"
then I try:
cmake . -DCMAKE_PREFIX_PATH=/opt/homebrew -DCMAKE_FIND_FRAMEWORK=NEVER -DCMAKE_FIND_APPBUNDLE=NEVER -DCMAKE_FIND_USE_CMAKE_SYSTEM_PATH=FALSE -DCMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH=FALSE -DMPI_CXX_COMPILER=/opt/homebrew/bin/mpicxx -DMPI_C_COMPILER=/opt/homebrew/bin/mpicc -DCMAKE_CXX_COMPILER=/opt/homebrew/bin/g++-11 -DCMAKE_C_COMPILER=/opt/homebrew/bin/gcc-11

Answer 1

The most common solution is to just set CMAKE_PREFIX_PATH to /opt/homebrew. CMake will then look preferentially in /opt/homebrew for everything. Since you're on Apple, you might need to set CMAKE_FIND_FRAMEWORK and CMAKE_FIND_APPBUNDLE to LAST or NEVER, too.
You can skip the standard platform search paths by setting CMAKE_FIND_USE_CMAKE_SYSTEM_PATH to FALSE at the command line, in a preset, or in a toolchain file. You might also wish to disable looking at the PATH environment variable by setting CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH to FALSE.
Finally, if you're in a cross-compiling scenario or toolchain file, you can change the definition of the system directories by setting CMAKE_SYSROOT. Note that the sysroot will have to contain the language runtime libraries (e.g. glibc) and will be passed to the --sysroot flag (or equivalent). Just be aware of those effects, too.
All of this is documented here:
https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure
https://cmake.org/cmake/help/latest/variable/CMAKE_FIND_FRAMEWORK.html#variable:CMAKE_FIND_FRAMEWORK
https://cmake.org/cmake/help/latest/variable/CMAKE_FIND_APPBUNDLE.html#variable:CMAKE_FIND_APPBUNDLE
The following homebrew.cmake toolchain file worked for me:
set(HOMEBREW_PREFIX "/usr/local"
CACHE PATH "Path to Homebrew installation")
set(CMAKE_C_COMPILER "${HOMEBREW_PREFIX}/bin/gcc-11")
set(CMAKE_CXX_COMPILER "${HOMEBREW_PREFIX}/bin/g++-11")
set(CMAKE_PREFIX_PATH
"${HOMEBREW_PREFIX}"
# These libraries are keg-only and not loaded into
# the root prefix by default (to avoid clashes).
"${HOMEBREW_PREFIX}/opt/lapack"
"${HOMEBREW_PREFIX}/opt/openblas"
"${HOMEBREW_PREFIX}/opt/gcc/lib/gcc/11"
)
list(TRANSFORM CMAKE_PREFIX_PATH APPEND "/include"
OUTPUT_VARIABLE CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES)
set(CMAKE_C_STANDARD_INCLUDE_DIRECTORIES "${CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES}")
set(CMAKE_FIND_FRAMEWORK NEVER)
set(CMAKE_FIND_APPBUNDLE NEVER)
set(CMAKE_FIND_USE_CMAKE_SYSTEM_PATH FALSE)
set(CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH FALSE)
I built with the following commands:
$ ls
tRecX homebrew.cmake
$ cmake -G Ninja -S tRecX -B tRecX-build \
-DCMAKE_TOOLCHAIN_FILE=$PWD/homebrew.cmake \
-DCBLAS=/usr/local/opt/openblas/lib/libblas.dylib \
-DCMAKE_EXE_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_SHARED_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_BUILD_TYPE=Parallel
[ ... output clipped ... ]
Boost found -- full functionality
Build "Parallel" with C++ flags -D_USE_BOOST_ -O3 -pthread -D_USE_FFTW_, return to default by -UCMAKE_BUILD_TYPE
Compiler: /usr/local/bin/g++-11, change by -DCMAKE_CXX_COMPILER=[path_to_complier]
-- Linking to libraries Boost::system;Boost::filesystem;/usr/local/lib/libfftw3.dylib;/usr/local/opt/gcc/lib/gcc/11/libgfortran.dylib;alglib;/usr/local/lib/libarpack.dylib;Boost::system;Boost::filesystem;/usr/local/opt/lapack/lib/liblapacke.dylib;/usr/local/opt/openblas/lib/libblas.dylib;/usr/local/opt/lapack/lib/liblapack.dylib;/usr/local/opt/lapack/lib/libblas.dylib;m
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/alexreinking/Development/tRecX-build
$ cmake --build tRecX-build
I had to set CBLAS manually because libblas.dylib provides the OpenBLAS CBLAS interface, but the build system specifically looks for a library named libcblas. There's no other option in this case.
The code and build have issues with its linking model and dependencies. I was able to paper over these by setting -Wl,-undefined,dynamic_lookup. However, note that this will just defer linker errors to runtime and might impose a large startup cost.
If you can make commits to the project, I would store these settings in a preset, maybe name it homebrew-parallel or something:
-DCMAKE_TOOLCHAIN_FILE=$PWD/homebrew.cmake \
-DCBLAS=/usr/local/opt/openblas/lib/libblas.dylib \
-DCMAKE_EXE_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_SHARED_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_BUILD_TYPE=Parallel
Then you could just run cmake --preset=homebrew-parallel