clang,openMP和CMake

Question

我使用cmake构建一个简单的openMP代码时遇到问题.

我已经安装了clang-omp,我可以编译程序 clang-omp -fopenmp filename.c

我已经尝试了很多制作CMakeLists.txt文件,没有结果!在我包含的文件中:

FIND_PACKAGE( OpenMP REQUIRED)
if(OPENMP_FOUND)
message("OPENMP FOUND")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
endif()

我试过告诉CMake通过调用来使用该编译器

CC=clang-omp CXX=clang-omp++ cmake 

没有.

两种情况的结果如下

-- Try OpenMP C flag = [-fopenmp=libomp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [ ]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-fopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [/openmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-Qopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-openmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-xopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [+Oopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-qsmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP C flag = [-mp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-fopenmp=libomp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [ ]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-fopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [/openmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-Qopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-openmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-xopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [+Oopenmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-qsmp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
-- Try OpenMP CXX flag = [-mp]
-- Performing Test OpenMP_FLAG_DETECTED
-- Performing Test OpenMP_FLAG_DETECTED - Failed
CMake Error at /Applications/CMake.app/Contents/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find OpenMP (missing: OpenMP_C_FLAGS OpenMP_CXX_FLAGS)
Call Stack (most recent call first):
  /Applications/CMake.app/Contents/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  /Applications/CMake.app/Contents/share/cmake-3.5/Modules/FindOpenMP.cmake:234 (find_package_handle_standard_args)
  CMakeLists.txt:4 (FIND_PACKAGE)

Answer 1

添加非系统 clang（对我来说，LLVM 4.0）的问题是您必须添加 include 和 lib 目录。 llvm-config在我的例子中正确地选择了它们，但 CMake 没有使用它们。

假设你PATH没问题，并且你已经设置CC好CXX了，你需要添加：

export C_INCLUDE_PATH=$(llvm-config --includedir)
export CPLUS_INCLUDE_PATH=$(llvm-config --includedir)
export LIBRARY_PATH=$(llvm-config --libdir)

如果你更喜欢 Lmod，这个.lua文件应该可以做到：

help([[
This is the module file for the llvm and clang compiler.
]])

local version = "4.0"

whatis("Name: LLVM")
whatis("Version: " .. version)
whatis("Keywords: System, Compiler")
whatis("URL: http://www.llvm.org/")
whatis("Description: LLVM compiler family")

family("compiler")

local prefix = "/work/llvm"

prepend_path("PATH", pathJoin(prefix, "bin"))
setenv("CC",  pathJoin(prefix, "bin/clang"))
setenv("CXX", pathJoin(prefix, "bin/clang++"))
setenv("C_INCLUDE_PATH", pathJoin(prefix, "include"))
setenv("CPLUS_INCLUDE_PATH", pathJoin(prefix, "include"))
setenv("LIBRARY_PATH", pathJoin(prefix, "lib"))
prepend_path("DYLD_LIBRARY_PATH", pathJoin(prefix, "lib"))

（这是针对 Mac 的，改为DYLD针对LDLinux 的）

这与 CMake 配合得很好，它会拾取-fopenmp. 手动编译也只需要一个标志。