[tarantool-patches] Re: [PATCH] Fix libgomp linking for static build

[Alexander Turenko <alexander.turenko@tarantool.org>]

Hi!

The patch looks good to me. Two comments about formatting are below.

Checked static + dynamic build locally (on Gentoo) with gcc and checked
dynamic build locally with clang. It works.

I think we should file an issue re adding Linux/clang target into CI.

WBR, Alexander Turenko.

On Fri, Sep 07, 2018 at 12:17:33PM +0300, Kirill Yukhin wrote:
> Since addition of -fopenmp to compiler also means
> addition of -lgomp to the link stage, pass -fno-openmp
> to the linking stage in case of static build. In that
> case OMP functions are statically linked into libmisc.
> 
> Also, emit error if trying to perform static build using
> clang.
> ---
> Branch: https://github.com/tarantool/tarantool/commits/kyukhin/gh-xxxx-fix-gomp-in-static-build
> Issue: n/a
> 
>  cmake/compiler.cmake | 5 ++++-
>  src/CMakeLists.txt   | 7 +++++++
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/cmake/compiler.cmake b/cmake/compiler.cmake
> index b3a0702..5b323c7 100644
> --- a/cmake/compiler.cmake
> +++ b/cmake/compiler.cmake
> @@ -33,6 +33,10 @@ if (CMAKE_COMPILER_IS_GNUCC)
>                 Your GCC version is ${CMAKE_CXX_COMPILER_VERSION}, please update
>                         ")
>         endif()
> +else()
> +     if (BUILD_STATIC)
> +               message(FATAL_ERROR "Static build is supported for GCC only")

Double indent.

> +     endif()
>  endif()
>  
>  #
> @@ -284,7 +288,6 @@ if (HAVE_OPENMP)
>      add_compile_flags("C;CXX" "-fopenmp")
>  endif()
>  
> -
>  if (CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNUCC)
>      set(HAVE_BUILTIN_CTZ 1)
>      set(HAVE_BUILTIN_CTZLL 1)
> diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
> index ebda098..aa39d8b 100644
> --- a/src/CMakeLists.txt
> +++ b/src/CMakeLists.txt
> @@ -277,6 +277,13 @@ if(BUILD_STATIC)
>          endif()
>      endforeach(libstatic)
>      string(REPLACE ";" " " EXPORT_LIST "${EXPORT_LIST}")
> +
> +    if (HAVE_OPENMP)
> +        # Link libgomp explicitly to make it static. Avoid linking
> +        # against DSO version of libgomp, which implied by -fopenmp
> +        set (common_libraries ${common_libraries} "libgomp.a")
> +        set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -fno-openmp")
> +    endif ()

endif () -> endif()

>  endif()
>  
>  # Exports syntax is toolchain-dependent, preprocessing is necessary
> -- 
> 2.16.2
>