cmake : Link vulkan-shaders-gen with pthreads

[Patater]

When using CMake to build with Vulkan support, compiling vulkan-shaders-gen fails due to missing a CMakeLists.txt specification to link vulkan-shaders-gen with the threading library, resulting in the following error.

    [5/172] Linking CXX executable bin/vulkan-shaders-gen
    FAILED: bin/vulkan-shaders-gen
    : && /usr/bin/c++ ggml/src/vulkan-shaders/CMakeFiles/vulkan-shaders-gen.dir/vulkan-shaders-gen.cpp.o -o bin/vulkan-shaders-gen   && :
    ld: error: undefined symbol: pthread_create
    >>> referenced by vulkan-shaders-gen.cpp
    >>>               ggml/src/vulkan-shaders/CMakeFiles/vulkan-shaders-gen.dir/vulkan-shaders-gen.cpp.o:(std::__1::__libcpp_thread_create[abi:se180100](pthread**,
    >>>               void* (*)(void*), void*))
    c++: error: linker command failed with exit code 1 (use -v to see invocation)
    [6/172] Generating build details from Git
    -- Found Git: /usr/local/bin/git (found version "2.45.2")
    ninja: build stopped: subcommand failed.

Add the CMakeLists.txt specification to link vulkan-shaders-gen with the threading library and fix the above error.

Fixes #8834

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[0cc4m]

Is it a specific OS/distro/compiler setup that causes this? I have been using CMake to build Vulkan without issues on Linux.

I'll test this later. Thank you for the submission.

[Patater]

Is it a specific OS/distro/compiler setup that causes this? I have been using CMake to build Vulkan without issues on Linux.

Yes, this is an issue on FreeBSD with clang. Here's the version which led me to discover the missing dependency:

$ cc --version
FreeBSD clang version 18.1.5 (https://github.com/llvm/llvm-project.git llvmorg-18.1.5-0-g617a15a9eac9)
Target: x86_64-unknown-freebsd14.1
Thread model: posix
InstalledDir: /usr/bin

Other toolchains may include the threading library by default, but the robust thing to do is to be explicit about what we depend on. In this case, vulkan-shaders-gen requires threads, so we should tell CMake we require threads and let it take care of doing whatever necessary to build with the target toolchain.

[0cc4m]

You're right. Do you know if the same issue exists on FreeBSD with the Makefile?

[Patater]

Do you know if the same issue exists on FreeBSD with the Makefile?

The issue does not exist with the Makefile. The Makefile correctly uses -pthread during the build. As you can see, the vulkan-shaders-gen binary builds fine and runs as part of the build when we use make.

$ GGML_VULKAN=1 GGML_CURL=1 gmake -j
...
/usr/local/bin/ccache c++ -std=c++11 -fPIC -O3 -g -Wall -Wextra -Wpedantic -Wcast-qual -Wno-unused-function -Wmissing-declarations -Wmissing-noreturn -pthread -f
openmp  -march=native -mtune=native -Wunreachable-code-break -Wunreachable-code-return -Wmissing-prototypes -Wextra-semi -Iggml/include -Iggml/src -Iinclude -Isr
c -Icommon -D_XOPEN_SOURCE=600 -D__BSD_VISIBLE -DNDEBUG -DGGML_USE_OPENMP -DGGML_USE_LLAMAFILE -DGGML_USE_VULKAN  -o vulkan-shaders-gen -L/usr/local/lib -lvulkan
  ggml/src/vulkan-shaders/vulkan-shaders-gen.cpp
...
/usr/local/bin/ccache c++ -std=c++11 -fPIC -O3 -g -Wall -Wextra -Wpedantic -Wcast-qual -Wno-unused-function -Wmissing-declarations -Wmissing-noreturn -pthread -f
openmp  -march=native -mtune=native -Wunreachable-code-break -Wunreachable-code-return -Wmissing-prototypes -Wextra-semi -Iggml/include -Iggml/src -Iinclude -Isr
c -Icommon -D_XOPEN_SOURCE=600 -D__BSD_VISIBLE -DNDEBUG -DGGML_USE_OPENMP -DGGML_USE_LLAMAFILE -DGGML_USE_VULKAN  -c common/build-info.cpp -o common/build-info.o
/code/github.com/ggerganov/llama.cpp/vulkan-shaders-gen \                                                                                                        
        --glslc      glslc \                                                                                                                                     
        --input-dir  ggml/src/vulkan-shaders \                                                                                                                   
        --target-hpp ggml/src/ggml-vulkan-shaders.hpp \                                                                                                          
        --target-cpp ggml/src/ggml-vulkan-shaders.cpp                                                                                                            
ggml_vulkan: Generating and compiling shaders to SPIR-V
...

[0cc4m]

Thank you.