--- /dev/null
+# Copyright 1999-2020 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=7
+
+PYTHON_COMPAT=( python3_{6,7,8} )
+inherit cmake-multilib linux-info llvm.org multiprocessing python-any-r1
+
+DESCRIPTION="OpenMP runtime library for LLVM/clang compiler"
+HOMEPAGE="https://openmp.llvm.org"
+LLVM_COMPONENTS=( openmp )
+llvm.org_set_globals
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="0"
+KEYWORDS=""
+IUSE="cuda hwloc kernel_linux offload ompt test"
+# CUDA works only with the x86_64 ABI
+REQUIRED_USE="offload? ( cuda? ( abi_x86_64 ) )"
+RESTRICT="!test? ( test )"
+
+RDEPEND="
+ hwloc? ( sys-apps/hwloc:0=[${MULTILIB_USEDEP}] )
+ offload? (
+ virtual/libelf:=[${MULTILIB_USEDEP}]
+ dev-libs/libffi:=[${MULTILIB_USEDEP}]
+ cuda? ( dev-util/nvidia-cuda-toolkit:= )
+ )"
+# tests:
+# - dev-python/lit provides the test runner
+# - sys-devel/llvm provide test utils (e.g. FileCheck)
+# - sys-devel/clang provides the compiler to run tests
+DEPEND="${RDEPEND}"
+BDEPEND="dev-lang/perl
+ offload? ( virtual/pkgconfig[${MULTILIB_USEDEP}] )
+ test? (
+ $(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]')
+ >=sys-devel/clang-6
+ )"
+
+# least intrusive of all
+CMAKE_BUILD_TYPE=RelWithDebInfo
+
+python_check_deps() {
+ has_version "dev-python/lit[${PYTHON_USEDEP}]"
+}
+
+kernel_pds_check() {
+ if use kernel_linux && kernel_is -lt 4 15 && kernel_is -ge 4 13; then
+ local CONFIG_CHECK="~!SCHED_PDS"
+ local ERROR_SCHED_PDS="\
+PDS scheduler versions >= 0.98c < 0.98i (e.g. used in kernels >= 4.13-pf11
+< 4.14-pf9) do not implement sched_yield() call which may result in horrible
+performance problems with libomp. If you are using one of the specified
+kernel versions, you may want to disable the PDS scheduler."
+
+ check_extra_config
+ fi
+}
+
+pkg_pretend() {
+ kernel_pds_check
+}
+
+pkg_setup() {
+ use test && python-any-r1_pkg_setup
+}
+
+multilib_src_configure() {
+ local libdir="$(get_libdir)"
+ local mycmakeargs=(
+ -DOPENMP_LIBDIR_SUFFIX="${libdir#lib}"
+
+ -DLIBOMP_USE_HWLOC=$(usex hwloc)
+ -DLIBOMP_OMPT_SUPPORT=$(usex ompt)
+
+ -DOPENMP_ENABLE_LIBOMPTARGET=$(usex offload)
+
+ # do not install libgomp.so & libiomp5.so aliases
+ -DLIBOMP_INSTALL_ALIASES=OFF
+ # disable unnecessary hack copying stuff back to srcdir
+ -DLIBOMP_COPY_EXPORTS=OFF
+ )
+ use offload && mycmakeargs+=(
+ # this is non-fatal and libomp checks for CUDA conditionally
+ # to ABI, so we can just ignore passing the wrong value
+ # on non-amd64 ABIs
+ -DCMAKE_DISABLE_FIND_PACKAGE_CUDA=$(usex !cuda)
+ )
+ use test && mycmakeargs+=(
+ # this project does not use standard LLVM cmake macros
+ -DOPENMP_LLVM_LIT_EXECUTABLE="${EPREFIX}/usr/bin/lit"
+ -DOPENMP_LIT_ARGS="-vv;-j;${LIT_JOBS:-$(makeopts_jobs "${MAKEOPTS}" "$(get_nproc)")}"
+
+ -DOPENMP_TEST_C_COMPILER="$(type -P "${CHOST}-clang")"
+ -DOPENMP_TEST_CXX_COMPILER="$(type -P "${CHOST}-clang++")"
+ )
+ cmake-utils_src_configure
+}
+
+multilib_src_test() {
+ # respect TMPDIR!
+ local -x LIT_PRESERVES_TMP=1
+
+ cmake-utils_src_make check-libomp
+}