使用OpenMP构建LLVM/Clang时与OpenMP和C++相关的错误

Question

我正在尝试从Fedora25上的源代码编译LLVM、Clang、OpenMP (来自LLVM项目)和libc++ (libcxx)。默认的GCC 6.3被用来构建它们。我发布

cmake ../llvm -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="X86"

一切似乎都很顺利，直到我

-- Performing Test LIBOMPTARGET_HAVE_STD_CPP11_FLAG
-- Performing Test LIBOMPTARGET_HAVE_STD_CPP11_FLAG - Success
-- Performing Test LIBOMPTARGET_HAVE_WERROR_FLAG
-- Performing Test LIBOMPTARGET_HAVE_WERROR_FLAG - Success
-- Could NOT find LIBOMPTARGET_DEP_LIBELF (missing:  LIBOMPTARGET_DEP_LIBELF_LIBRARIES LIBOMPTARGET_DEP_LIBELF_INCLUDE_DIRS) 
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.29.1") 
-- Could NOT find LIBOMPTARGET_DEP_LIBFFI (missing:  LIBOMPTARGET_DEP_LIBFFI_LIBRARIES LIBOMPTARGET_DEP_LIBFFI_INCLUDE_DIRS) 
-- LIBOMPTARGET: Building offloading runtime library libomptarget.
-- LIBOMPTARGET: Not building aarch64 offloading plugin: machine not found in the system.
-- LIBOMPTARGET: Not building CUDA offloading plugin: libelf dependency not found.
-- LIBOMPTARGET: Not building PPC64 offloading plugin: machine not found in the system.
-- LIBOMPTARGET: Not building PPC64le offloading plugin: machine not found in the system.
-- LIBOMPTARGET: Not building x86_64 offloading plugin: libelf dependency not found.
-- Found Z3: /usr/lib64/libz3.so (found suitable version "4.5.0 - 64 bit - build hashcode d57a2a6dce92", minimum required is "4.5") 
-- Looking for sys/resource.h
-- Looking for sys/resource.h - found
-- Clang version: 5.0.0
-- Performing Test CXX_SUPPORTS_NO_NESTED_ANON_TYPES_FLAG
-- Performing Test CXX_SUPPORTS_NO_NESTED_ANON_TYPES_FLAG - Failed
-- Configuring done
-- Generating done

似乎有两个错误-1个与OpenMP相关(与LIBOMPTARGET_DEP_LIBELF和LIBOMPTARGET_DEP_LIBFFI相关)，1个与C++ (CXX_SUPPORTS_NO_NESTED_ANON_TYPES_FLAG - Failed)相关。我真的不知道它们是什么意思，但我希望至少能够在多核CPU上使用OpenMP，而且我肯定希望能够编译C++源文件。那么，我应该对这些错误有多担心呢？如果它们很重要，有什么建议吗？

更新:当我尝试以某种方式构建它时，在libcxx中得到了几个未定义的引用。

Answer 1

对于与OpenMP相关的错误，我认为您需要在系统上安装libelf和libffi。