gentoo-locomotion/llvm-core/clang/clang-19.1.7.ebuild

# Copyright 1999-2025 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=8

PYTHON_COMPAT=( python3_{10..13} )

inherit cmake llvm.org llvm-utils multilib multilib-minimal
inherit prefix python-single-r1 toolchain-funcs
inherit flag-o-matic ninja-utils

DESCRIPTION="C language family frontend for LLVM"
HOMEPAGE="https://llvm.org/"

# MSVCSetupApi.h: MIT
# sorttable.js: MIT

LICENSE="Apache-2.0-with-LLVM-exceptions UoI-NCSA MIT"
SLOT="${LLVM_MAJOR}/${LLVM_SOABI}"
KEYWORDS="~amd64 ~arm ~arm64 ~loong ~ppc ~ppc64 ~riscv ~sparc ~x86 ~amd64-linux ~x64-macos"

IUSE="debug doc +extra ieee-long-double +pie static-analyzer test xml \
default-fortify-source-2 default-fortify-source-3 default-full-relro \
default-partial-relro default-ssp-buffer-size-4 \
default-stack-clash-protection cet hardened hardened-compat rocm ssp"
REQUIRED_USE="${PYTHON_REQUIRED_USE}
	amd64? (
		llvm_targets_X86
	)
	arm? (
		llvm_targets_ARM
	)
	arm64? (
		llvm_targets_AArch64
	)
	loong? (
		llvm_targets_LoongArch
	)
	m68k? (
		llvm_targets_M68k
	)
	mips? (
		llvm_targets_Mips
	)
	ppc? (
		llvm_targets_PowerPC
	)
	ppc64? (
		llvm_targets_PowerPC
	)
	riscv? (
		llvm_targets_RISCV
	)
	sparc? (
		llvm_targets_Sparc
	)
	x86? (
		llvm_targets_X86
	)

	default-fortify-source-2? (
		!default-fortify-source-3
		!test
	)
	default-fortify-source-3? (
		!default-fortify-source-2
		!test
	)
	default-full-relro? (
		!default-partial-relro
		!test
	)
	default-partial-relro? (
		!default-full-relro
		!test
	)
	default-stack-clash-protection? (
		!test
	)
	hardened? (
		!test
		default-fortify-source-3
		default-full-relro
		default-ssp-buffer-size-4
		default-stack-clash-protection
		pie
		ssp
	)
	ssp? (
		!test
	)
"
RDEPEND+="
	${PYTHON_DEPS}
	>=llvm-core/clang-common-${PV}
	rocm? (
		dev-libs/rocm-device-libs:0/5.7
	)
	static-analyzer? (
		dev-lang/perl:*
	)
	xml? (
		dev-libs/libxml2:2=[${MULTILIB_USEDEP}]
	)
	~llvm-core/llvm-${PV}:${LLVM_MAJOR}=[${MULTILIB_USEDEP},debug=]
"

DEPEND="
	${RDEPEND}
"
BDEPEND="
	${PYTHON_DEPS}
	>=dev-build/cmake-3.16
	doc? (
		$(python_gen_cond_dep '
			dev-python/recommonmark[${PYTHON_USEDEP}]
			dev-python/sphinx[${PYTHON_USEDEP}]
		')
	)
	test? ( ~llvm-core/lld-${PV} )
	xml? ( virtual/pkgconfig )
"
PDEPEND="
	~llvm-core/clang-runtime-${PV}
	llvm-core/clang-toolchain-symlinks:${LLVM_MAJOR}
"
RESTRICT="
	!test? ( test )
"
LLVM_COMPONENTS=(
	"clang"
	"clang-tools-extra"
	"cmake"
)
LLVM_MANPAGES=0
#LLVM_PATCHSET=${PV}-r6
LLVM_TEST_COMPONENTS=(
	"llvm/utils"
)
LLVM_USE_TARGETS="llvm"
llvm.org_set_globals

# Multilib notes:
# 1. ABI_* flags control ABIs libclang* is built for only.
# 2. clang is always capable of compiling code for all ABIs for enabled
#    target. However, you will need appropriate crt* files (installed
#    e.g. by sys-devel/gcc and sys-libs/glibc).
# 3. ${CHOST}-clang wrappers are always installed for all ABIs included
#    in the current profile (i.e. alike supported by sys-devel/gcc).
#
# Therefore: use llvm-core/clang[${MULTILIB_USEDEP}] only if you need
# multilib clang* libraries (not runtime, not wrappers).

pkg_setup() {
	LLVM_MAX_SLOT=${LLVM_MAJOR}
	python-single-r1_pkg_setup
	if tc-is-gcc ; then
		local gcc_slot=$(best_version "sys-devel/gcc" \
			| sed -e "s|sys-devel/gcc-||g")
		gcc_slot=$(ver_cut 1-3 ${gcc_slot})
		# gcc-major-version is broken with gcc hardened 11.2.1_p20220115
		if (( $(ver_cut 1 ${gcc_slot}) != $(ver_cut 1 $(_gcc_fullversion)) )) ; then
# Prevent: undefined reference to `std::__throw_bad_array_new_length()'
ewarn
ewarn "Detected not using latest gcc."
ewarn
ewarn "Build may break if highest gcc version not chosen and profile not"
ewarn "sourced.  To fix do the following:"
ewarn
ewarn "  gcc-config -l"
ewarn "  gcc-config ${CHOST}-${gcc_slot}	# It must match at least one row from \ "
ewarn "						# the above list."
ewarn "  source /etc/profile"
ewarn
		fi
	fi

	if [[ -n "${MAKEOPTS}" ]] ; then
		local nmakeopts=$(echo "${MAKEOPTS}" \
			| grep -o -E -e "-j[ ]*[0-9]+( |$)" \
			| sed -e "s|-j||g" -e "s|[ ]*||" \
			| tail -n 1)
		if [[ -n "${nmakeopts}" ]] && (( ${nmakeopts} > 1 )) ; then
ewarn
ewarn "MAKEOPTS=-jN should be -j1 if linking with BFD or <= 4 GiB RAM or"
ewarn "<= 3 GiB per core."
ewarn "Adjust your per-package package.env to avoid very long linking times."
ewarn
		fi
	fi

ewarn
ewarn "If you encounter the following during the build:"
ewarn
ewarn "FAILED: lib/Tooling/ASTNodeAPI.json"
ewarn
ewarn "Build ~clang-${PV} with only gcc and ~llvm-${PV} without LTO."
ewarn
ewarn
ewarn "To avoid missing symbols, both clang-${PV} and llvm-${PV} should be"
ewarn "built with the same commit."
ewarn

	if [[ "${CC}" == "clang" ]] ; then
		local clang_path="clang-${LLVM_MAJOR}"
		if which "${clang_path}" 2>/dev/null 1>/dev/null && "${clang_path}" --help \
			| grep "symbol lookup error" ; then
eerror
eerror "The entire slot should be uninstalled and set CC=gcc and CXX=g++"
eerror
			die
		fi
	fi

ewarn
ewarn "To avoid long linking delays, close programs that produce unexpectedly"
ewarn "high disk activity (web browsers) and possibly switch to -j1."
ewarn

# See https://bugs.gentoo.org/767700
einfo
einfo "To remove the hard USE mask for llvm_targets_*, do:"
einfo
	local t
	for t in ${ALL_LLVM_TARGET_FLAGS[@]} ; do
echo "echo \"${CATEGORY}/${PN} -${t}\" >> ${EROOT}/etc/portage/profile/package.use.force"
	done
	for t in ${ALL_LLVM_EXPERIMENTAL_TARGETS[@]/#/llvm_targets_} ; do
echo "echo \"${CATEGORY}/${PN} -${t}\" >> ${EROOT}/etc/portage/profile/package.use.mask"
	done
einfo
einfo "However, some packages still need some or all of these.  Some are"
einfo "mentioned in bug #767700."
einfo
}

src_unpack() {
	llvm.org_src_unpack
}

eapply_hardened() {
ewarn
ewarn "The hardened USE flag and associated patches via default_* are still in"
ewarn "testing."
ewarn
	local hardened_features=""
	local patches_hardened=()
	if use pie ; then
		hardened_features+="PIE, "
	fi
	if use ssp ; then
		patches_hardened+=(
			"${FILESDIR}/clang-12.0.1-enable-SSP-by-default.patch"
		)
		hardened_features+="SSP, "
	fi
	if use default-ssp-buffer-size-4 ; then
		patches_hardened+=(
			"${FILESDIR}/clang-16.0.0.9999-change-SSP-buffer-size-to-4.patch"
		)
	fi
	if use default-fortify-source-2 ; then
		patches_hardened+=(
			"${FILESDIR}/clang-14.0.0.9999-set-_FORTIFY_SOURCE-to-2-by-default.patch"
		)
		hardened_features+="_FORITIFY_SOURCE=2, "
	fi
	if use default-fortify-source-3 ; then
		patches_hardened+=(
			"${FILESDIR}/clang-14.0.0.9999-set-_FORTIFY_SOURCE-to-3-by-default.patch"
		)
		hardened_features+="_FORITIFY_SOURCE=3, "
		ewarn
		ewarn "The _FORITIFY_SOURCE=3 is in testing."
		ewarn
	fi
	if use default-full-relro ; then
		patches_hardened+=(
			"${FILESDIR}/clang-12.0.1-enable-full-relro-by-default.patch"
		)
		hardened_features+="Full RELRO, "
		ewarn
		ewarn "The Full RELRO is in testing."
		ewarn
	fi
	if use default-partial-relro ; then
		patches_hardened+=(
			"${FILESDIR}/clang-12.0.1-enable-partial-relro-by-default.patch"
		)
		hardened_features+="Partial RELRO, "
		ewarn
		ewarn "The Partial RELRO is in testing."
		ewarn
	fi
	if use default-stack-clash-protection ; then
		if use x86 || use amd64 ; then
			patches_hardened+=(
				"${FILESDIR}/clang-18.0.0.9999-2b033a3-enable-SCP-by-default.patch"
			)
			hardened_features+="SCP, "
		elif use arm64 ; then
			ewarn
			ewarn "arm64 -fstack-clash-protection is not default ON.  The feature is still"
			ewarn "in development."
			ewarn
		fi
	fi
	if use hardened || use hardened-compat ; then
		patches_hardened+=(
			"${FILESDIR}/clang-12.0.1-version-info.patch"
		)
	fi
	if use cet ; then
		patches_hardened+=(
			"${FILESDIR}/clang-17.0.0.9999-enable-cf-protection-full-by-default.patch"
		)
		hardened_features+="CET, "
		ewarn
		ewarn "The CET as default is in testing."
		ewarn
	fi
	patches_hardened+=(
		"${FILESDIR}/clang-18.0.0.9999-cross-dso-cfi-link-with-shared.patch"
	)
	eapply ${patches_hardened[@]}

	if use hardened || use hardened-compat ; then
		hardened_features=$(echo "${hardened_features}" \
			| sed -e "s|, $||g")
		sed -i -e "s|__HARDENED_FEATURES__|${hardened_features}|g" \
			lib/Driver/Driver.cpp || die
	fi
}

src_prepare() {
	# Create an extra parent dir for relative CLANG_RESOURCE_DIR access.
	mkdir -p "${WORKDIR}/x/y" || die
	BUILD_DIR="${WORKDIR}/x/y/clang"

	llvm.org_src_prepare

	eapply -p2 "${FILESDIR}/${PN}-17.0.0.9999-stdatomic-force.patch"

	eapply "${FILESDIR}/clang-17.0.4-fix-glibc-limits.h-relative-path.patch"

	#use pgo && \
	eapply "${FILESDIR}/clang-16.0.0.9999-add-include-path.patch"

	eapply_hardened

	# Add Gentoo Portage Prefix for Darwin.  See prefix-dirs.patch.
	eprefixify \
		lib/Lex/InitHeaderSearch.cpp \
		lib/Driver/ToolChains/Darwin.cpp || die

	if ! use prefix-guest && [[ -n ${EPREFIX} ]]; then
		sed -i "/LibDir.*Loader/s@return \"\/\"@return \"${EPREFIX}/\"@" \
			lib/Driver/ToolChains/Linux.cpp \
			|| die
	fi
}

check_distribution_components() {
	if [[ ${CMAKE_MAKEFILE_GENERATOR} == ninja ]]; then
		local all_targets=() my_targets=() l
		cd "${BUILD_DIR}" || die

		while read -r l; do
			if [[ ${l} == install-*-stripped:* ]]; then
				l=${l#install-}
				l=${l%%-stripped*}

				case ${l} in
					# meta-targets
					clang-libraries|distribution)
						continue
						;;
					# tools
					clang|clangd|clang-*)
						;;
					# static libraries
					clang*|findAllSymbols)
						continue
						;;
					# conditional to USE=doc
					docs-clang-html|docs-clang-tools-html)
						use doc || continue
						;;
				esac

				all_targets+=( "${l}" )
			fi
		done < <(${NINJA} -t targets all)

		while read -r l; do
			my_targets+=( "${l}" )
		done < <(get_distribution_components $"\n")

		local add=() remove=()
		for l in "${all_targets[@]}"; do
			if ! has "${l}" "${my_targets[@]}"; then
				add+=( "${l}" )
			fi
		done
		for l in "${my_targets[@]}"; do
			if ! has "${l}" "${all_targets[@]}"; then
				remove+=( "${l}" )
			fi
		done

		if [[ ${#add[@]} -gt 0 || ${#remove[@]} -gt 0 ]]; then
			eqawarn "get_distribution_components() is outdated!"
			eqawarn "   Add: ${add[*]}"
			eqawarn "Remove: ${remove[*]}"
		fi
		cd - >/dev/null || die
	fi
}

get_distribution_components() {
	local sep=${1-;}

	local out=(
		# common stuff
		clang-cmake-exports
		clang-headers
		clang-resource-headers
		libclang-headers

		aarch64-resource-headers
		arm-common-resource-headers
		arm-resource-headers
		core-resource-headers
		cuda-resource-headers
		hexagon-resource-headers
		hip-resource-headers
		hlsl-resource-headers
		mips-resource-headers
		opencl-resource-headers
		openmp-resource-headers
		ppc-htm-resource-headers
		ppc-resource-headers
		riscv-resource-headers
		systemz-resource-headers
		utility-resource-headers
		ve-resource-headers
		webassembly-resource-headers
		windows-resource-headers
		x86-resource-headers

		# libs
		clang-cpp
		libclang
	)

	if multilib_is_native_abi; then
		out+=(
			# common stuff
			bash-autocomplete
			libclang-python-bindings

			# tools
			amdgpu-arch
			c-index-test
			clang
			clang-format
			clang-installapi
			clang-linker-wrapper
			clang-nvlink-wrapper
			clang-offload-bundler
			clang-offload-packager
			clang-refactor
			clang-repl
			clang-rename
			clang-scan-deps
			diagtool
			hmaptool
			nvptx-arch

			# needed for cross-compiling Clang
			clang-tblgen
		)

		if use extra; then
			out+=(
				# extra tools
				clang-apply-replacements
				clang-change-namespace
				clang-doc
				clang-include-cleaner
				clang-include-fixer
				clang-move
				clang-pseudo
				clang-query
				clang-reorder-fields
				clang-tidy
				clang-tidy-headers
				clangd
				find-all-symbols
				modularize
				pp-trace
			)
		fi

		if llvm_are_manpages_built; then
			out+=( docs-clang-man )
			use extra && out+=( docs-clang-tools-man )
		fi

		if use doc; then
			out+=( docs-clang-html )
			use extra && out+=( docs-clang-tools-html )
		fi

		use static-analyzer && out+=(
			clang-check
			clang-extdef-mapping
			scan-build
			scan-build-py
			scan-view
		)
	fi

	printf "%s${sep}" "${out[@]}"
}

_gcc_fullversion() {
	gcc --version | head -n 1 | grep -o -E -e "[0-9_p.]+" | head -n 1
}

multilib_src_configure() {
	llvm_prepend_path "${LLVM_MAJOR}"


	# TODO:  Add GCC-10 and below checks to add exceptions to -O* flag downgrading.
	# Leave a note if you know the commit that fixes the internal compiler error below.
	if tc-is-gcc && ( \
		( ver_test $(_gcc_fullversion) -lt 11.2.1_p20220112 ) \
	)
	then
		# Build time bug with gcc 10.3.0, 11.2.0:
		# internal compiler error: maximum number of LRA assignment passes is achieved (30)

		# Apply if using GCC
		ewarn
		ewarn "Detected <=sys-devel/gcc-11.2.1_p20220112.  Downgrading to -Os to avoid"
		ewarn "bug.  Re-emerge >=sys-devel/gcc-11.2.1_p20220112 for a more optimized"
		ewarn "build with >= -O2."
		ewarn
		replace-flags '-O3' '-Os'
		replace-flags '-O2' '-Os'
	fi

	# LLVM can have very high memory consumption while linking,
	# exhausting the limit on 32-bit linker executable
	use x86 && local -x LDFLAGS="${LDFLAGS} -Wl,--no-keep-memory"

	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"

	# Fix longer than usual build times when building webkit-gtk.
	# Bump to next fastest build setting.
	replace-flags -O0 -O1

	# Fix longer than usual build times when building rocm ebuilds in sci-libs.
	# -O3 may cause random segfaults during build like in rocSPARSE.
	replace-flags -O1 -O2
	replace-flags -Oz -O2
	replace-flags -Os -O2
	replace-flags -O3 -O2
	replace-flags -Ofast -O2
	replace-flags -O4 -O2

	# For PGO
	if tc-is-gcc ; then
# error: number of counters in profile data for function '...' does not match its profile data (counter 'arcs', expected 7 and have 13) [-Werror=coverage-mismatch]
# The PGO profiles are isolated.  The Code is the same.
		append-flags -Wno-error=coverage-mismatch
	fi

	filter-flags -m32 -m64 -mx32 -m31 '-mabi=*'
	[[ ${CHOST} =~ "risc" ]] && filter-flags '-march=*'
	export CFLAGS="$(get_abi_CFLAGS ${ABI}) ${CFLAGS}"
	export CXXFLAGS="$(get_abi_CFLAGS ${ABI}) ${CXXFLAGS}"

	# [Err 8]: control flow integrity check for type '.*' failed during non-virtual call (vtable address 0x[0-9a-z]+)
	# [Err 5]: runtime error: control flow integrity check for type '.*' failed during cast to unrelated type (vtable address 0x[0-9a-z]+)
	# llvm-core/clang no-cfi-nvcall.conf no-cfi-cast.conf # Build time failures: [Err 8] with llvm header, [Err 5] with gcc header
	if tc-is-clang ; then
		if is-flagq "-fsanitize=*cfi" ; then
			ewarn
			ewarn "Using -fsanitize=cfi without"
			ewarn "-fno-sanitize=cfi-nvcall,cfi-derived-cast,cfi-unrelated-cast"
			ewarn "may break build."
			ewarn
		fi
		if is-flagq "-fsanitize=*cfi-nvcall" ; then
			ewarn
			ewarn "Using -fsanitize=cfi-nvcall may break build."
			ewarn
		fi
		if is-flagq "-fsanitize=*cfi-derived-cast" ; then
			ewarn
			ewarn "Using -fsanitize=cfi-derived-cast may break build."
			ewarn
		fi
		if is-flagq "-fsanitize=*cfi-unrelated-cast" ; then
			ewarn
			ewarn "Using -fsanitize=cfi-unrelated-cast may break build."
			ewarn
		fi
	fi

	einfo
	einfo "*FLAGS for ${ABI}:"
	einfo
	einfo "  CFLAGS=${CFLAGS}"
	einfo "  CXXFLAGS=${CXXFLAGS}"
	einfo "  LDFLAGS=${LDFLAGS}"
	einfo "  PATH=${PATH}"
	if tc-is-cross-compiler ; then
		einfo "  IS_CROSS_COMPILE=True"
	else
		einfo "  IS_CROSS_COMPILE=False"
	fi
	einfo

	use debug && CMAKE_BUILD_TYPE="Debug" || CMAKE_BUILD_TYPE="Release"
	local mycmakeargs=(
		-DDEFAULT_SYSROOT=$(usex prefix-guest "" "${EPREFIX}")
		-DCMAKE_INSTALL_PREFIX="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}"
		-DCMAKE_INSTALL_MANDIR="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/share/man"
		-DLLVM_ROOT="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}"
		-DCLANG_CONFIG_FILE_SYSTEM_DIR="${EPREFIX}/etc/clang"
		-DCLANG_CONFIG_FILE_USER_DIR="~/.config/clang"
		# relative to bindir
		-DCLANG_RESOURCE_DIR="../../../../lib/clang/${LLVM_MAJOR}"

		-DBUILD_SHARED_LIBS=OFF
		-DCLANG_LINK_CLANG_DYLIB=ON
		-DLLVM_DISTRIBUTION_COMPONENTS=$(get_distribution_components)
		-DCLANG_INCLUDE_TESTS=$(usex test)
		-DLLVM_INCLUDE_TESTS=$(usex test)

		-DLLVM_TARGETS_TO_BUILD="${LLVM_TARGETS// /;}"

		# These are not propagated reliably, so redefine them.
		-DLLVM_ENABLE_EH=ON
		-DLLVM_ENABLE_RTTI=ON

		# libgomp support fails to find headers without explicit -I
		# furthermore, it provides only syntax checking
		-DCLANG_DEFAULT_OPENMP_RUNTIME=libomp

		# Disable CUDA to autodetect GPU, so build for all.
		-DCMAKE_DISABLE_FIND_PACKAGE_CUDAToolkit=ON

		# Disable linking to HSA to avoid automagic dep.
		# Load it dynamically instead.
		-DCMAKE_DISABLE_FIND_PACKAGE_hsa-runtime64=ON

		-DCLANG_DEFAULT_PIE_ON_LINUX=$(usex pie)

		-DCLANG_ENABLE_LIBXML2=$(usex xml)
		-DCLANG_ENABLE_ARCMT=$(usex static-analyzer)
		-DCLANG_ENABLE_STATIC_ANALYZER=$(usex static-analyzer)
		# TODO: CLANG_ENABLE_HLSL?

		-DPython3_EXECUTABLE="${PYTHON}"
	)

	if ! use elibc_musl; then
		mycmakeargs+=(
			-DPPC_LINUX_DEFAULT_IEEELONGDOUBLE=$(usex ieee-long-double)
		)
	fi

	use test && mycmakeargs+=(
		-DLLVM_BUILD_TESTS=ON
		-DLLVM_LIT_ARGS="$(get_lit_flags)"
	)

	if multilib_is_native_abi; then
		local build_docs=OFF
		if llvm_are_manpages_built; then
			build_docs=ON
			mycmakeargs+=(
				-DLLVM_BUILD_DOCS=ON
				-DLLVM_ENABLE_SPHINX=ON
				-DCLANG_INSTALL_SPHINX_HTML_DIR="${EPREFIX}/usr/share/doc/${PF}/html"
				-DSPHINX_WARNINGS_AS_ERRORS=OFF
			)
			if use extra; then
				mycmakeargs+=(
					-DCLANG-TOOLS_INSTALL_SPHINX_HTML_DIR="${EPREFIX}/usr/share/doc/${PF}/tools-extra"
				)
			fi
		fi
		mycmakeargs+=(
			-DCLANG_INCLUDE_DOCS=${build_docs}
		)
	fi
	if multilib_native_use extra; then
		mycmakeargs+=(
			-DLLVM_EXTERNAL_CLANG_TOOLS_EXTRA_SOURCE_DIR="${WORKDIR}"/clang-tools-extra
			-DCLANG_TOOLS_EXTRA_INCLUDE_DOCS=${build_docs}
		)
	else
		mycmakeargs+=(
			-DLLVM_TOOL_CLANG_TOOLS_EXTRA_BUILD=OFF
		)
	fi

	if [[ -n "${EPREFIX}" ]]; then
		mycmakeargs+=(
			-DGCC_INSTALL_PREFIX="${EPREFIX}/usr"
		)
	fi

	if tc-is-cross-compiler; then
		has_version -b llvm-core/clang:${LLVM_MAJOR} ||
			die "llvm-core/clang:${LLVM_MAJOR} is required on the build host."
		local tools_bin=${BROOT}/usr/lib/llvm/${LLVM_MAJOR}/bin
		mycmakeargs+=(
			-DLLVM_TOOLS_BINARY_DIR="${tools_bin}"
			-DCLANG_TABLEGEN="${tools_bin}"/clang-tblgen
		)
	fi

	# LLVM can have very high memory consumption while linking,
	# exhausting the limit on 32-bit linker executable
	use x86 && local -x LDFLAGS="${LDFLAGS} -Wl,--no-keep-memory"

	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"

	mycmakeargs+=(
		-DCMAKE_C_COMPILER="${CC}"
		-DCMAKE_CXX_COMPILER="${CXX}"
		-DCMAKE_ASM_COMPILER="${CC}"
	)

	cmake_src_configure

	multilib_is_native_abi && check_distribution_components
}

multilib_src_compile() {
	cmake_build distribution
}

multilib_src_test() {
	if use hardened ; then
		ewarn
		ewarn "Tests are broken with the enable-SSP-and-PIE-by-default.patch"
		ewarn
	fi
	# respect TMPDIR!
	local -x LIT_PRESERVES_TMP=1
	local test_targets=( check-clang )
	if multilib_native_use extra; then
		test_targets+=(
			check-clang-tools
			check-clangd
		)
	fi
	cmake_build "${test_targets[@]}"
}

src_install() {
	MULTILIB_WRAPPED_HEADERS=(
		/usr/include/clang/Config/config.h
	)

	multilib-minimal_src_install

	# Move runtime headers to /usr/lib/clang, where they belong
	mv "${ED}"/usr/include/clangrt "${ED}"/usr/lib/clang || die
	# move (remaining) wrapped headers back
	if use extra; then
		mv "${T}"/clang-tidy "${ED}"/usr/include/ || die
	fi
	mv "${ED}"/usr/include "${ED}"/usr/lib/llvm/${LLVM_MAJOR}/include || die

	# Apply CHOST and version suffix to clang tools
	local clang_tools=( clang clang++ clang-cl clang-cpp )
	local abi i

	# cmake gives us:
	# - clang-X
	# - clang -> clang-X
	# - clang++, clang-cl, clang-cpp -> clang
	# we want to have:
	# - clang-X
	# - clang++-X, clang-cl-X, clang-cpp-X -> clang-X
	# - clang, clang++, clang-cl, clang-cpp -> clang*-X
	# also in CHOST variant
	for i in "${clang_tools[@]:1}"; do
		rm "${ED}/usr/lib/llvm/${LLVM_MAJOR}/bin/${i}" || die
		dosym "clang-${LLVM_MAJOR}" "/usr/lib/llvm/${LLVM_MAJOR}/bin/${i}-${LLVM_MAJOR}"
		dosym "${i}-${LLVM_MAJOR}" "/usr/lib/llvm/${LLVM_MAJOR}/bin/${i}"
	done

	# now create target symlinks for all supported ABIs
	for abi in $(get_all_abis); do
		local abi_chost=$(get_abi_CHOST "${abi}")
		for i in "${clang_tools[@]}"; do
			dosym "${i}-${LLVM_MAJOR}" \
				"/usr/lib/llvm/${LLVM_MAJOR}/bin/${abi_chost}-${i}-${LLVM_MAJOR}"
			dosym "${abi_chost}-${i}-${LLVM_MAJOR}" \
				"/usr/lib/llvm/${LLVM_MAJOR}/bin/${abi_chost}-${i}"
		done
	done
}

multilib_src_install() {
	DESTDIR=${D} cmake_build install-distribution

	# Move headers to /usr/include for wrapping & ABI mismatch checks.
	# (Also, drop the version suffix from runtime headers.)
	rm -rf "${ED}"/usr/include || die
	if [[ -e "${ED}"/usr/lib/llvm/${LLVM_MAJOR}/include ]] ; then
		mv \
			"${ED}"/usr/lib/llvm/${LLVM_MAJOR}/include \
			"${ED}"/usr/include \
			|| die
	fi
	if [[ -e "${ED}"/usr/lib/clang ]] ; then
		mv \
			"${ED}"/usr/lib/clang \
			"${ED}"/usr/include/clangrt \
			|| die
	fi
	if multilib_native_use extra && [[ -e "${ED}"/usr/include/clang-tidy ]] ; then
		# Don't wrap clang-tidy headers; the list is too long.
		# (They're fine for non-native ABI but enabling the targets is problematic.)
		mkdir -p "${T}/clang-tidy" || die
		cp -aT "${ED}"/usr/include/clang-tidy "${T}/" || die
		rm -rf "${ED}"/usr/include/clang-tidy || die
	fi
}

multilib_src_install_all() {
	python_fix_shebang "${ED}"
	if use static-analyzer; then
		python_optimize "${ED}"/usr/lib/llvm/${LLVM_MAJOR}/share/scan-view
	fi

	docompress "/usr/lib/llvm/${LLVM_MAJOR}/share/man"
	llvm_install_manpages
	# match 'html' non-compression
	use doc && docompress -x "/usr/share/doc/${PF}/tools-extra"
	# +x for some reason; TODO: investigate
	use static-analyzer && fperms a-x "/usr/lib/llvm/${LLVM_MAJOR}/share/man/man1/scan-build.1"
}

pkg_postinst() {
	if [[ -z "${ROOT}" && -f "${EPREFIX}"/usr/share/eselect/modules/compiler-shadow.eselect ]] ; then
		eselect compiler-shadow update all
	fi

	elog "You can find additional utility scripts in:"
	elog "  ${EROOT}/usr/lib/llvm/${LLVM_MAJOR}/share/clang"
	if use extra; then
		elog "Some of them are vim integration scripts (with instructions inside)."
		elog "The run-clang-tidy.py script requires the following additional package:"
		elog "  dev-python/pyyaml"
	fi
}

pkg_postrm() {
	if [[ -z "${ROOT}" && -f "${EPREFIX}"/usr/share/eselect/modules/compiler-shadow.eselect ]] ; then
		eselect compiler-shadow clean all
	fi
}