sys-libs/compiler-rt: enable atomic builtin

Several packages depend on GCC's libatomic to perform atomic operations.
For example, this compiles without -latomic:
```c
_Atomic struct {
    int v[1];
} a;
atomic_store(&a, a);
```
But this fails with error "undefined reference to __atomic_store_16"
without -latomic:
```c
_Atomic struct {
    int v[4];
} b;
atomic_store(&b, b);
```

LLVM does not have a libatomic.so, but an atomic builtin to support such
operations.  However, it is disabled by default to allow use of system
libatomic while using LLVM as a compiler.  Pure LLVM environments
without GCC installed require this builtin.  This commit adds
`-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF` cmake option to enable
the builtin.

Bug: https://bugs.gentoo.org/911340
Signed-off-by: mojyack <mojyack@gmail.com>
Closes: https://github.com/gentoo/gentoo/pull/39168
Signed-off-by: Michał Górny <mgorny@gentoo.org>

6 files changed, 855 insertions, 0 deletions

diff --git a/sys-libs/compiler-rt/compiler-rt-15.0.7-r2.ebuild b/sys-libs/compiler-rt/compiler-rt-15.0.7-r2.ebuild
new file mode 100644
index 000000000000..830a5dc0145e
--- /dev/null
+++ b/sys-libs/compiler-rt/compiler-rt-15.0.7-r2.ebuild
@@ -0,0 +1,150 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..11} )
+inherit cmake flag-o-matic llvm llvm.org python-any-r1 toolchain-funcs
+
+DESCRIPTION="Compiler runtime library for clang (built-in part)"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="${LLVM_VERSION}"
+KEYWORDS="~amd64 ~arm ~arm64 ~ppc64 ~riscv ~x86 ~amd64-linux ~ppc-macos ~x64-macos"
+IUSE="+abi_x86_32 abi_x86_64 +clang debug test"
+RESTRICT="!test? ( test ) !clang? ( test )"
+
+DEPEND="
+	sys-devel/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? ( sys-devel/clang:${LLVM_MAJOR} )
+	test? (
+		$(python_gen_any_dep ">=dev-python/lit-15[\${PYTHON_USEDEP}]")
+		=sys-devel/clang-${LLVM_VERSION}*:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+"
+
+LLVM_COMPONENTS=( compiler-rt cmake llvm/cmake )
+LLVM_PATCHSET=${PV/_/-}
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version ">=dev-python/lit-15[${PYTHON_USEDEP}]"
+}
+
+pkg_pretend() {
+	if ! use clang && ! tc-is-clang; then
+		ewarn "Building using a compiler other than clang may result in broken atomics"
+		ewarn "library. Enable USE=clang unless you have a very good reason not to."
+	fi
+}
+
+pkg_setup() {
+	# Darwin Prefix builds do not have llvm installed yet, so rely on
+	# bootstrap-prefix to set the appropriate path vars to LLVM instead
+	# of using llvm_pkg_setup.
+	if [[ ${CHOST} != *-darwin* ]] || has_version sys-devel/llvm; then
+		LLVM_MAX_SLOT=${LLVM_MAJOR} llvm_pkg_setup
+	fi
+	python-any-r1_pkg_setup
+}
+
+test_compiler() {
+	$(tc-getCC) ${CFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	# pre-set since we need to pass it to cmake
+	BUILD_DIR=${WORKDIR}/${P}_build
+
+	if use clang; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	if ! test_compiler; then
+		local nolib_flags=( -nodefaultlibs -lc )
+
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		elif test_compiler "${nolib_flags[@]}" -nostartfiles; then
+			# Avoiding -nostartfiles earlier on for bug #862540,
+			# and set available entry symbol for bug #862798.
+			nolib_flags+=( -nostartfiles -emain )
+
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_VERSION}"
+
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
+		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
+		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF
+		-DCOMPILER_RT_BUILD_MEMPROF=OFF
+		-DCOMPILER_RT_BUILD_ORC=OFF
+		-DCOMPILER_RT_BUILD_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_SANITIZERS=OFF
+		-DCOMPILER_RT_BUILD_XRAY=OFF
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+	)
+
+	if use amd64; then
+		mycmakeargs+=(
+			-DCAN_TARGET_i386=$(usex abi_x86_32)
+			-DCAN_TARGET_x86_64=$(usex abi_x86_64)
+		)
+	fi
+
+	if use prefix && [[ "${CHOST}" == *-darwin* ]] ; then
+		mycmakeargs+=(
+			# setting -isysroot is disabled with compiler-rt-prefix-paths.patch
+			# this allows adding arm64 support using SDK in EPREFIX
+			-DDARWIN_macosx_CACHED_SYSROOT="${EPREFIX}/MacOSX.sdk"
+			# Set version based on the SDK in EPREFIX.
+			# This disables i386 for SDK >= 10.15
+			-DDARWIN_macosx_OVERRIDE_SDK_VERSION="$(realpath ${EPREFIX}/MacOSX.sdk | sed -e 's/.*MacOSX\(.*\)\.sdk/\1/')"
+			# Use our libtool instead of looking it up with xcrun
+			-DCMAKE_LIBTOOL="${EPREFIX}/usr/bin/${CHOST}-libtool"
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+
+			-DCOMPILER_RT_TEST_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang"
+			-DCOMPILER_RT_TEST_CXX_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang++"
+		)
+	fi
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-builtins
+}
diff --git a/sys-libs/compiler-rt/compiler-rt-16.0.6-r6.ebuild b/sys-libs/compiler-rt/compiler-rt-16.0.6-r6.ebuild
new file mode 100644
index 000000000000..e43bba60aa8b
--- /dev/null
+++ b/sys-libs/compiler-rt/compiler-rt-16.0.6-r6.ebuild
@@ -0,0 +1,178 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..12} )
+inherit cmake crossdev flag-o-matic llvm llvm.org python-any-r1 toolchain-funcs
+
+DESCRIPTION="Compiler runtime library for clang (built-in part)"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="${LLVM_MAJOR}"
+KEYWORDS="~amd64 ~arm ~arm64 ~loong ~ppc64 ~riscv ~x86 ~amd64-linux ~arm64-macos ~ppc-macos ~x64-macos"
+IUSE="+abi_x86_32 abi_x86_64 +clang debug test"
+RESTRICT="!test? ( test ) !clang? ( test )"
+
+DEPEND="
+	sys-devel/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? ( sys-devel/clang:${LLVM_MAJOR} )
+	test? (
+		$(python_gen_any_dep ">=dev-python/lit-15[\${PYTHON_USEDEP}]")
+		=sys-devel/clang-${LLVM_VERSION}*:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+"
+
+LLVM_COMPONENTS=( compiler-rt cmake llvm/cmake )
+LLVM_PATCHSET=${PV}-r4
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version ">=dev-python/lit-15[${PYTHON_USEDEP}]"
+}
+
+pkg_pretend() {
+	if ! use clang && ! tc-is-clang; then
+		ewarn "Building using a compiler other than clang may result in broken atomics"
+		ewarn "library. Enable USE=clang unless you have a very good reason not to."
+	fi
+}
+
+pkg_setup() {
+	# Darwin Prefix builds do not have llvm installed yet, so rely on
+	# bootstrap-prefix to set the appropriate path vars to LLVM instead
+	# of using llvm_pkg_setup.
+	if [[ ${CHOST} != *-darwin* ]] || has_version sys-devel/llvm; then
+		LLVM_MAX_SLOT=${LLVM_MAJOR} llvm_pkg_setup
+	fi
+
+	if target_is_not_host || tc-is-cross-compiler ; then
+		# strips vars like CFLAGS="-march=x86_64-v3" for non-x86 architectures
+		CHOST=${CTARGET} strip-unsupported-flags
+		# overrides host docs otherwise
+		DOCS=()
+	fi
+	python-any-r1_pkg_setup
+}
+
+test_compiler() {
+	target_is_not_host && return
+	$(tc-getCC) ${CFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	# pre-set since we need to pass it to cmake
+	BUILD_DIR=${WORKDIR}/${P}_build
+
+	if use clang && ! is_crosspkg; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	if ! is_crosspkg && ! test_compiler ; then
+		local nolib_flags=( -nodefaultlibs -lc )
+
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		elif test_compiler "${nolib_flags[@]}" -nostartfiles; then
+			# Avoiding -nostartfiles earlier on for bug #862540,
+			# and set available entry symbol for bug #862798.
+			nolib_flags+=( -nostartfiles -emain )
+
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_MAJOR}"
+
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
+		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
+		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF
+		-DCOMPILER_RT_BUILD_MEMPROF=OFF
+		-DCOMPILER_RT_BUILD_ORC=OFF
+		-DCOMPILER_RT_BUILD_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_SANITIZERS=OFF
+		-DCOMPILER_RT_BUILD_XRAY=OFF
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+	)
+
+	if use amd64 && ! target_is_not_host; then
+		mycmakeargs+=(
+			-DCAN_TARGET_i386=$(usex abi_x86_32)
+			-DCAN_TARGET_x86_64=$(usex abi_x86_64)
+		)
+	fi
+
+	if is_crosspkg; then
+		# Needed to target built libc headers
+		export CFLAGS="${CFLAGS} -isystem /usr/${CTARGET}/usr/include"
+		mycmakeargs+=(
+			# Without this, the compiler will compile a test program
+			# and fail due to no builtins.
+			-DCMAKE_C_COMPILER_WORKS=1
+			-DCMAKE_CXX_COMPILER_WORKS=1
+
+			# Without this, compiler-rt install location is not unique
+			# to target triples, only to architecture.
+			# Needed if you want to target multiple libcs for one arch.
+			-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
+
+			-DCMAKE_ASM_COMPILER_TARGET="${CTARGET}"
+			-DCMAKE_C_COMPILER_TARGET="${CTARGET}"
+			-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+		)
+	fi
+
+	if use prefix && [[ "${CHOST}" == *-darwin* ]] ; then
+		mycmakeargs+=(
+			# setting -isysroot is disabled with compiler-rt-prefix-paths.patch
+			# this allows adding arm64 support using SDK in EPREFIX
+			-DDARWIN_macosx_CACHED_SYSROOT="${EPREFIX}/MacOSX.sdk"
+			# Set version based on the SDK in EPREFIX.
+			# This disables i386 for SDK >= 10.15
+			-DDARWIN_macosx_OVERRIDE_SDK_VERSION="$(realpath ${EPREFIX}/MacOSX.sdk | sed -e 's/.*MacOSX\(.*\)\.sdk/\1/')"
+			# Use our libtool instead of looking it up with xcrun
+			-DCMAKE_LIBTOOL="${EPREFIX}/usr/bin/${CHOST}-libtool"
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+
+			-DCOMPILER_RT_TEST_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang"
+			-DCOMPILER_RT_TEST_CXX_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang++"
+		)
+	fi
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-builtins
+}
diff --git a/sys-libs/compiler-rt/compiler-rt-17.0.6-r2.ebuild b/sys-libs/compiler-rt/compiler-rt-17.0.6-r2.ebuild
new file mode 100644
index 000000000000..c5c7bdc62a1b
--- /dev/null
+++ b/sys-libs/compiler-rt/compiler-rt-17.0.6-r2.ebuild
@@ -0,0 +1,178 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..12} )
+inherit cmake crossdev flag-o-matic llvm llvm.org python-any-r1 toolchain-funcs
+
+DESCRIPTION="Compiler runtime library for clang (built-in part)"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="${LLVM_MAJOR}"
+KEYWORDS="~amd64 ~arm ~arm64 ~loong ~ppc64 ~riscv ~x86 ~amd64-linux ~arm64-macos ~ppc-macos ~x64-macos"
+IUSE="+abi_x86_32 abi_x86_64 +clang debug test"
+RESTRICT="!test? ( test ) !clang? ( test )"
+
+DEPEND="
+	sys-devel/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? ( sys-devel/clang:${LLVM_MAJOR} )
+	test? (
+		$(python_gen_any_dep ">=dev-python/lit-15[\${PYTHON_USEDEP}]")
+		=sys-devel/clang-${LLVM_VERSION}*:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+"
+
+LLVM_COMPONENTS=( compiler-rt cmake llvm/cmake )
+LLVM_PATCHSET=${PV}
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version ">=dev-python/lit-15[${PYTHON_USEDEP}]"
+}
+
+pkg_pretend() {
+	if ! use clang && ! tc-is-clang; then
+		ewarn "Building using a compiler other than clang may result in broken atomics"
+		ewarn "library. Enable USE=clang unless you have a very good reason not to."
+	fi
+}
+
+pkg_setup() {
+	# Darwin Prefix builds do not have llvm installed yet, so rely on
+	# bootstrap-prefix to set the appropriate path vars to LLVM instead
+	# of using llvm_pkg_setup.
+	if [[ ${CHOST} != *-darwin* ]] || has_version sys-devel/llvm; then
+		LLVM_MAX_SLOT=${LLVM_MAJOR} llvm_pkg_setup
+	fi
+
+	if target_is_not_host || tc-is-cross-compiler ; then
+		# strips vars like CFLAGS="-march=x86_64-v3" for non-x86 architectures
+		CHOST=${CTARGET} strip-unsupported-flags
+		# overrides host docs otherwise
+		DOCS=()
+	fi
+	python-any-r1_pkg_setup
+}
+
+test_compiler() {
+	target_is_not_host && return
+	$(tc-getCC) ${CFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	# pre-set since we need to pass it to cmake
+	BUILD_DIR=${WORKDIR}/${P}_build
+
+	if use clang && ! is_crosspkg; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	if ! is_crosspkg && ! test_compiler ; then
+		local nolib_flags=( -nodefaultlibs -lc )
+
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		elif test_compiler "${nolib_flags[@]}" -nostartfiles; then
+			# Avoiding -nostartfiles earlier on for bug #862540,
+			# and set available entry symbol for bug #862798.
+			nolib_flags+=( -nostartfiles -emain )
+
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_MAJOR}"
+
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
+		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
+		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF
+		-DCOMPILER_RT_BUILD_MEMPROF=OFF
+		-DCOMPILER_RT_BUILD_ORC=OFF
+		-DCOMPILER_RT_BUILD_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_SANITIZERS=OFF
+		-DCOMPILER_RT_BUILD_XRAY=OFF
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+	)
+
+	if use amd64 && ! target_is_not_host; then
+		mycmakeargs+=(
+			-DCAN_TARGET_i386=$(usex abi_x86_32)
+			-DCAN_TARGET_x86_64=$(usex abi_x86_64)
+		)
+	fi
+
+	if is_crosspkg; then
+		# Needed to target built libc headers
+		export CFLAGS="${CFLAGS} -isystem /usr/${CTARGET}/usr/include"
+		mycmakeargs+=(
+			# Without this, the compiler will compile a test program
+			# and fail due to no builtins.
+			-DCMAKE_C_COMPILER_WORKS=1
+			-DCMAKE_CXX_COMPILER_WORKS=1
+
+			# Without this, compiler-rt install location is not unique
+			# to target triples, only to architecture.
+			# Needed if you want to target multiple libcs for one arch.
+			-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
+
+			-DCMAKE_ASM_COMPILER_TARGET="${CTARGET}"
+			-DCMAKE_C_COMPILER_TARGET="${CTARGET}"
+			-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+		)
+	fi
+
+	if use prefix && [[ "${CHOST}" == *-darwin* ]] ; then
+		mycmakeargs+=(
+			# setting -isysroot is disabled with compiler-rt-prefix-paths.patch
+			# this allows adding arm64 support using SDK in EPREFIX
+			-DDARWIN_macosx_CACHED_SYSROOT="${EPREFIX}/MacOSX.sdk"
+			# Set version based on the SDK in EPREFIX.
+			# This disables i386 for SDK >= 10.15
+			-DDARWIN_macosx_OVERRIDE_SDK_VERSION="$(realpath ${EPREFIX}/MacOSX.sdk | sed -e 's/.*MacOSX\(.*\)\.sdk/\1/')"
+			# Use our libtool instead of looking it up with xcrun
+			-DCMAKE_LIBTOOL="${EPREFIX}/usr/bin/${CHOST}-libtool"
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+
+			-DCOMPILER_RT_TEST_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang"
+			-DCOMPILER_RT_TEST_CXX_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang++"
+		)
+	fi
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-builtins
+}
diff --git a/sys-libs/compiler-rt/compiler-rt-18.1.8-r2.ebuild b/sys-libs/compiler-rt/compiler-rt-18.1.8-r2.ebuild
new file mode 100644
index 000000000000..6fae972ab61d
--- /dev/null
+++ b/sys-libs/compiler-rt/compiler-rt-18.1.8-r2.ebuild
@@ -0,0 +1,173 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..13} )
+inherit cmake crossdev flag-o-matic llvm.org llvm-utils python-any-r1
+inherit toolchain-funcs
+
+DESCRIPTION="Compiler runtime library for clang (built-in part)"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="${LLVM_MAJOR}"
+KEYWORDS="~amd64 ~arm ~arm64 ~loong ~mips ~ppc64 ~riscv ~x86 ~amd64-linux ~arm64-macos ~ppc-macos ~x64-macos"
+IUSE="+abi_x86_32 abi_x86_64 +clang debug test"
+RESTRICT="!test? ( test ) !clang? ( test )"
+
+DEPEND="
+	sys-devel/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? ( sys-devel/clang:${LLVM_MAJOR} )
+	test? (
+		$(python_gen_any_dep ">=dev-python/lit-15[\${PYTHON_USEDEP}]")
+		=sys-devel/clang-${LLVM_VERSION}*:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+"
+
+LLVM_COMPONENTS=( compiler-rt cmake llvm/cmake )
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version ">=dev-python/lit-15[${PYTHON_USEDEP}]"
+}
+
+pkg_pretend() {
+	if ! use clang && ! tc-is-clang; then
+		ewarn "Building using a compiler other than clang may result in broken atomics"
+		ewarn "library. Enable USE=clang unless you have a very good reason not to."
+	fi
+}
+
+pkg_setup() {
+	if target_is_not_host || tc-is-cross-compiler ; then
+		# strips vars like CFLAGS="-march=x86_64-v3" for non-x86 architectures
+		CHOST=${CTARGET} strip-unsupported-flags
+		# overrides host docs otherwise
+		DOCS=()
+	fi
+	python-any-r1_pkg_setup
+}
+
+test_compiler() {
+	target_is_not_host && return
+	$(tc-getCC) ${CFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	llvm_prepend_path "${LLVM_MAJOR}"
+
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	# pre-set since we need to pass it to cmake
+	BUILD_DIR=${WORKDIR}/${P}_build
+
+	if use clang && ! is_crosspkg; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	if ! is_crosspkg && ! test_compiler ; then
+		local nolib_flags=( -nodefaultlibs -lc )
+
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		elif test_compiler "${nolib_flags[@]}" -nostartfiles; then
+			# Avoiding -nostartfiles earlier on for bug #862540,
+			# and set available entry symbol for bug #862798.
+			nolib_flags+=( -nostartfiles -e main )
+
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_MAJOR}"
+
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
+		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
+		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF
+		-DCOMPILER_RT_BUILD_MEMPROF=OFF
+		-DCOMPILER_RT_BUILD_ORC=OFF
+		-DCOMPILER_RT_BUILD_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_SANITIZERS=OFF
+		-DCOMPILER_RT_BUILD_XRAY=OFF
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+	)
+
+	if use amd64 && ! target_is_not_host; then
+		mycmakeargs+=(
+			-DCAN_TARGET_i386=$(usex abi_x86_32)
+			-DCAN_TARGET_x86_64=$(usex abi_x86_64)
+		)
+	fi
+
+	if is_crosspkg; then
+		# Needed to target built libc headers
+		export CFLAGS="${CFLAGS} -isystem /usr/${CTARGET}/usr/include"
+		mycmakeargs+=(
+			# Without this, the compiler will compile a test program
+			# and fail due to no builtins.
+			-DCMAKE_C_COMPILER_WORKS=1
+			-DCMAKE_CXX_COMPILER_WORKS=1
+
+			# Without this, compiler-rt install location is not unique
+			# to target triples, only to architecture.
+			# Needed if you want to target multiple libcs for one arch.
+			-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
+
+			-DCMAKE_ASM_COMPILER_TARGET="${CTARGET}"
+			-DCMAKE_C_COMPILER_TARGET="${CTARGET}"
+			-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+		)
+	fi
+
+	if use prefix && [[ "${CHOST}" == *-darwin* ]] ; then
+		mycmakeargs+=(
+			# setting -isysroot is disabled with compiler-rt-prefix-paths.patch
+			# this allows adding arm64 support using SDK in EPREFIX
+			-DDARWIN_macosx_CACHED_SYSROOT="${EPREFIX}/MacOSX.sdk"
+			# Set version based on the SDK in EPREFIX.
+			# This disables i386 for SDK >= 10.15
+			-DDARWIN_macosx_OVERRIDE_SDK_VERSION="$(realpath ${EPREFIX}/MacOSX.sdk | sed -e 's/.*MacOSX\(.*\)\.sdk/\1/')"
+			# Use our libtool instead of looking it up with xcrun
+			-DCMAKE_LIBTOOL="${EPREFIX}/usr/bin/${CHOST}-libtool"
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+
+			-DCOMPILER_RT_TEST_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang"
+			-DCOMPILER_RT_TEST_CXX_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang++"
+		)
+	fi
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-builtins
+}
diff --git a/sys-libs/compiler-rt/compiler-rt-19.1.3-r1.ebuild b/sys-libs/compiler-rt/compiler-rt-19.1.3-r1.ebuild
new file mode 100644
index 000000000000..0e331798f968
--- /dev/null
+++ b/sys-libs/compiler-rt/compiler-rt-19.1.3-r1.ebuild
@@ -0,0 +1,175 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+PYTHON_COMPAT=( python3_{10..13} )
+inherit cmake crossdev flag-o-matic llvm.org llvm-utils python-any-r1
+inherit toolchain-funcs
+
+DESCRIPTION="Compiler runtime library for clang (built-in part)"
+HOMEPAGE="https://llvm.org/"
+
+LICENSE="Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )"
+SLOT="${LLVM_MAJOR}"
+KEYWORDS="~amd64 ~arm ~arm64 ~loong ~mips ~ppc64 ~riscv ~x86 ~amd64-linux ~arm64-macos ~ppc-macos ~x64-macos"
+IUSE="+abi_x86_32 abi_x86_64 +clang debug test"
+RESTRICT="!test? ( test ) !clang? ( test )"
+
+DEPEND="
+	sys-devel/llvm:${LLVM_MAJOR}
+"
+BDEPEND="
+	clang? ( sys-devel/clang:${LLVM_MAJOR} )
+	test? (
+		$(python_gen_any_dep ">=dev-python/lit-15[\${PYTHON_USEDEP}]")
+		=sys-devel/clang-${LLVM_VERSION}*:${LLVM_MAJOR}
+	)
+	!test? (
+		${PYTHON_DEPS}
+	)
+"
+
+LLVM_COMPONENTS=( compiler-rt cmake llvm/cmake )
+LLVM_TEST_COMPONENTS=( llvm/include/llvm/TargetParser )
+llvm.org_set_globals
+
+python_check_deps() {
+	use test || return 0
+	python_has_version ">=dev-python/lit-15[${PYTHON_USEDEP}]"
+}
+
+pkg_pretend() {
+	if ! use clang && ! tc-is-clang; then
+		ewarn "Building using a compiler other than clang may result in broken atomics"
+		ewarn "library. Enable USE=clang unless you have a very good reason not to."
+	fi
+}
+
+pkg_setup() {
+	if target_is_not_host || tc-is-cross-compiler ; then
+		# strips vars like CFLAGS="-march=x86_64-v3" for non-x86 architectures
+		CHOST=${CTARGET} strip-unsupported-flags
+		# overrides host docs otherwise
+		DOCS=()
+	fi
+	python-any-r1_pkg_setup
+}
+
+test_compiler() {
+	target_is_not_host && return
+	$(tc-getCC) ${CFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
+src_configure() {
+	llvm_prepend_path "${LLVM_MAJOR}"
+
+	# LLVM_ENABLE_ASSERTIONS=NO does not guarantee this for us, #614844
+	use debug || local -x CPPFLAGS="${CPPFLAGS} -DNDEBUG"
+
+	# pre-set since we need to pass it to cmake
+	BUILD_DIR=${WORKDIR}/${P}_build
+
+	if use clang && ! is_crosspkg; then
+		# Only do this conditionally to allow overriding with
+		# e.g. CC=clang-13 in case of breakage
+		if ! tc-is-clang ; then
+			local -x CC=${CHOST}-clang
+			local -x CXX=${CHOST}-clang++
+		fi
+
+		strip-unsupported-flags
+	fi
+
+	if ! is_crosspkg && ! test_compiler ; then
+		local nolib_flags=( -nodefaultlibs -lc )
+
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		elif test_compiler "${nolib_flags[@]}" -nostartfiles; then
+			# Avoiding -nostartfiles earlier on for bug #862540,
+			# and set available entry symbol for bug #862798.
+			nolib_flags+=( -nostartfiles -e main )
+
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CC} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
+	local mycmakeargs=(
+		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_MAJOR}"
+
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
+		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
+		-DCOMPILER_RT_BUILD_CTX_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF
+		-DCOMPILER_RT_BUILD_MEMPROF=OFF
+		-DCOMPILER_RT_BUILD_ORC=OFF
+		-DCOMPILER_RT_BUILD_PROFILE=OFF
+		-DCOMPILER_RT_BUILD_SANITIZERS=OFF
+		-DCOMPILER_RT_BUILD_XRAY=OFF
+
+		-DPython3_EXECUTABLE="${PYTHON}"
+	)
+
+	if use amd64 && ! target_is_not_host; then
+		mycmakeargs+=(
+			-DCAN_TARGET_i386=$(usex abi_x86_32)
+			-DCAN_TARGET_x86_64=$(usex abi_x86_64)
+		)
+	fi
+
+	if is_crosspkg; then
+		# Needed to target built libc headers
+		export CFLAGS="${CFLAGS} -isystem /usr/${CTARGET}/usr/include"
+		mycmakeargs+=(
+			# Without this, the compiler will compile a test program
+			# and fail due to no builtins.
+			-DCMAKE_C_COMPILER_WORKS=1
+			-DCMAKE_CXX_COMPILER_WORKS=1
+
+			# Without this, compiler-rt install location is not unique
+			# to target triples, only to architecture.
+			# Needed if you want to target multiple libcs for one arch.
+			-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON
+
+			-DCMAKE_ASM_COMPILER_TARGET="${CTARGET}"
+			-DCMAKE_C_COMPILER_TARGET="${CTARGET}"
+			-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
+		)
+	fi
+
+	if use prefix && [[ "${CHOST}" == *-darwin* ]] ; then
+		mycmakeargs+=(
+			# setting -isysroot is disabled with compiler-rt-prefix-paths.patch
+			# this allows adding arm64 support using SDK in EPREFIX
+			-DDARWIN_macosx_CACHED_SYSROOT="${EPREFIX}/MacOSX.sdk"
+			# Set version based on the SDK in EPREFIX.
+			# This disables i386 for SDK >= 10.15
+			-DDARWIN_macosx_OVERRIDE_SDK_VERSION="$(realpath ${EPREFIX}/MacOSX.sdk | sed -e 's/.*MacOSX\(.*\)\.sdk/\1/')"
+			# Use our libtool instead of looking it up with xcrun
+			-DCMAKE_LIBTOOL="${EPREFIX}/usr/bin/${CHOST}-libtool"
+		)
+	fi
+
+	if use test; then
+		mycmakeargs+=(
+			-DLLVM_EXTERNAL_LIT="${EPREFIX}/usr/bin/lit"
+			-DLLVM_LIT_ARGS="$(get_lit_flags)"
+
+			-DCOMPILER_RT_TEST_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang"
+			-DCOMPILER_RT_TEST_CXX_COMPILER="${EPREFIX}/usr/lib/llvm/${LLVM_MAJOR}/bin/clang++"
+		)
+	fi
+
+	cmake_src_configure
+}
+
+src_test() {
+	# respect TMPDIR!
+	local -x LIT_PRESERVES_TMP=1
+
+	cmake_build check-builtins
+}
diff --git a/sys-libs/compiler-rt/compiler-rt-20.0.0.9999.ebuild b/sys-libs/compiler-rt/compiler-rt-20.0.0.9999.ebuild
index 7642499a8792..e8c984678e90 100644
--- a/sys-libs/compiler-rt/compiler-rt-20.0.0.9999.ebuild
+++ b/sys-libs/compiler-rt/compiler-rt-20.0.0.9999.ebuild
@@ -100,6 +100,7 @@ src_configure() {
 	local mycmakeargs=(
 		-DCOMPILER_RT_INSTALL_PATH="${EPREFIX}/usr/lib/clang/${LLVM_MAJOR}"
 
+		-DCOMPILER_RT_EXCLUDE_ATOMIC_BUILTIN=OFF
 		-DCOMPILER_RT_INCLUDE_TESTS=$(usex test)
 		-DCOMPILER_RT_BUILD_CTX_PROFILE=OFF
 		-DCOMPILER_RT_BUILD_LIBFUZZER=OFF