sys-libs/libcxx{,abi}: Fix build for max_align_t

9 files changed, 413 insertions, 0 deletions

diff --git a/sys-libs/libcxx/Manifest b/sys-libs/libcxx/Manifest
new file mode 100644
index 00000000..06387ac8
--- /dev/null
+++ b/sys-libs/libcxx/Manifest
@@ -0,0 +1,5 @@
+AUX 0001-check-for-musl-libcs-max_align_t.patch 725 SHA256 83810d4a065ba8554ac626e9281711bab4e68135b719a1891dd61f71a5efd1bd SHA512 0e151920d5325f73a7735d20baf5d14bb96d20351e7169ccd5dd98617a6e46c0add8e24b359f00430d211f9c0a27d519cb2e4b6f51be8121de21ccf53981940f WHIRLPOOL bc7dfe9b65d02f45539f5d9e55fb55202fda2bb212d31963a61d145513b5087d1fff033fac15d78cc5a93daddbdab7c3043077b97d38ca2d7789fe513fc231ee
+AUX libcxx-3.9-cmake-link-flags.patch 1014 SHA256 2a67d309f5aa802a8cb3d7fe76dff0a9c797e88a63f43fda758f9626afc8d4d0 SHA512 5df85c66bf865900197effe3905976bf165b4c4d79b8d14352753f6baca93ab5dc26bf735fd9478a0c13df489b860d8b629240134b7e26be6233138ea95dbab3 WHIRLPOOL b99590b6a0e1f4c0738d6bf95b4b379685a5ca5a32370938928656481234e22cf1acc788075a6af331406a70c8d8b0f81111ad392454df72ef58181d07d76d56
+DIST libcxx-4.0.0.src.tar.xz 1450376 SHA256 4f4d33c4ad69bf9e360eebe6b29b7b19486948b1a41decf89d4adec12473cf96 SHA512 6dad794c00919955e14710def169cdcde8a1743431479e993c4a6a3c87c2fd9f5dbd6e17542e524981eed0783dce70384c356b74ef3c6d70598c6ff03454b1dd WHIRLPOOL 2c5074087e306d100c96ae5b7175e1e1792f0317c7be6231692c80423ec716732c08293fe14fe6da5cd52d8709d6ce0a240009df24e717ab0eb9093ac7679af7
+EBUILD libcxx-4.0.0.ebuild 6360 SHA256 0b91ce9074adf0efe985110457d9ed59b405c263c6dbbdf0b30a4a0de981bd23 SHA512 0bd6c446a6073f3ebb6d41893d8fe45b527404590cfa38e352486ec612f010e2ca56ccb2fe19ffc23c98442464e48525e62717d0ad4928c45f9b0d0143180700 WHIRLPOOL 2ef81c93ef940240ebea9415f8b3a9024dc4b5932abd0446038a6548a528322fdf9c1240c186e42d81a79f7b46813106a6d9cb74b619cdf0747d2f95ed2e408d
+MISC metadata.xml 854 SHA256 3ec547619ec9246a8013afa8185cc2ec300c77ea5f7794627765fa54e5b8f621 SHA512 8ef3feab266e09442a42baced2d72667fa8b1290624c2c84bab7b173ead72669568847f6e995388fc1d7bc722381f60805d87b2a0cc2d04ae0c49e36bec3802a WHIRLPOOL 3ef9e4095a710085257d418bbb2ad7f10bfe026d65f1684fb75a36418ccd3c314521cb24ec7afd552551a114edc958aa7d3cafab5e8b38975f697767c6adb355
diff --git a/sys-libs/libcxx/files/0001-check-for-musl-libcs-max_align_t.patch b/sys-libs/libcxx/files/0001-check-for-musl-libcs-max_align_t.patch
new file mode 100644
index 00000000..d1094c9e
--- /dev/null
+++ b/sys-libs/libcxx/files/0001-check-for-musl-libcs-max_align_t.patch
@@ -0,0 +1,26 @@
+From 7a72799513088762bef49b55438f3c42acc50ab2 Mon Sep 17 00:00:00 2001
+From: 
+Date: Fri, 23 Jun 2017 22:27:04 -0500
+Subject: [PATCH] check-for-musl-libcs-max_align_t
+
+---
+ include/stddef.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/stddef.h b/include/stddef.h
+index 8841bbe..faf8552 100644
+--- a/include/stddef.h
++++ b/include/stddef.h
+@@ -53,7 +53,8 @@ using std::nullptr_t;
+ }
+ 
+ // Re-use the compiler's <stddef.h> max_align_t where possible.
+-#if !defined(__CLANG_MAX_ALIGN_T_DEFINED) && !defined(_GCC_MAX_ALIGN_T)
++#if !defined(__CLANG_MAX_ALIGN_T_DEFINED) && !defined(_GCC_MAX_ALIGN_T) && \
++    !defined(__DEFINED_max_align_t)
+ typedef long double max_align_t;
+ #endif
+ 
+-- 
+2.13.1
+
diff --git a/sys-libs/libcxx/files/libcxx-3.9-cmake-link-flags.patch b/sys-libs/libcxx/files/libcxx-3.9-cmake-link-flags.patch
new file mode 100644
index 00000000..bef5bc18
--- /dev/null
+++ b/sys-libs/libcxx/files/libcxx-3.9-cmake-link-flags.patch
@@ -0,0 +1,23 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index d618e83..0e76525 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -293,6 +293,18 @@ remove_flags(-DNDEBUG -UNDEBUG -D_DEBUG
+ # so they don't get transformed into -Wno and -errors respectivly.
+ remove_flags(-Wno-pedantic -pedantic-errors -pedantic)
+ 
++# FIXME: this is cribbed from HandleLLVMOptions.cmake.
++if(LIBCXX_STANDALONE_BUILD)
++  # Pass -Wl,-z,defs. This makes sure all symbols are defined. Otherwise a DSO
++  # build might work on ELF but fail on MachO/COFF.
++  if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" OR WIN32 OR CYGWIN OR
++          ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" OR
++          ${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD") AND
++     NOT LLVM_USE_SANITIZER)
++    set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-z,defs")
++  endif()
++endif()
++
+ # Required flags ==============================================================
+ add_compile_flags_if_supported(-std=c++11)
+ if (NOT MSVC AND NOT LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG)
diff --git a/sys-libs/libcxx/libcxx-4.0.0.ebuild b/sys-libs/libcxx/libcxx-4.0.0.ebuild
new file mode 100644
index 00000000..dad54c23
--- /dev/null
+++ b/sys-libs/libcxx/libcxx-4.0.0.ebuild
@@ -0,0 +1,200 @@
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=6
+
+# Ninja provides better scalability and cleaner verbose output, and is used
+# throughout all LLVM projects.
+: ${CMAKE_MAKEFILE_GENERATOR:=ninja}
+# (needed due to CMAKE_BUILD_TYPE != Gentoo)
+CMAKE_MIN_VERSION=3.7.0-r1
+PYTHON_COMPAT=( python2_7 )
+
+inherit cmake-multilib llvm python-any-r1 toolchain-funcs
+
+DESCRIPTION="New implementation of the C++ standard library, targeting C++11"
+HOMEPAGE="http://libcxx.llvm.org/"
+SRC_URI="http://releases.llvm.org/${PV/_//}/${P/_/}.src.tar.xz"
+
+LICENSE="|| ( UoI-NCSA MIT )"
+SLOT="0"
+KEYWORDS="~amd64 ~arm64 ~x86"
+IUSE="elibc_glibc elibc_musl +libcxxabi libcxxrt +libunwind +static-libs test"
+REQUIRED_USE="libunwind? ( || ( libcxxabi libcxxrt ) )
+	?? ( libcxxabi libcxxrt )"
+
+RDEPEND="
+	libcxxabi? ( ~sys-libs/libcxxabi-${PV}[libunwind=,static-libs?,${MULTILIB_USEDEP}] )
+	libcxxrt? ( sys-libs/libcxxrt[libunwind=,static-libs?,${MULTILIB_USEDEP}] )
+	!libcxxabi? ( !libcxxrt? ( >=sys-devel/gcc-4.7:=[cxx] ) )"
+# LLVM 4 required for llvm-config --cmakedir
+# clang-3.9.0 installs necessary target symlinks unconditionally
+# which removes the need for MULTILIB_USEDEP
+DEPEND="${RDEPEND}
+	test? ( >=sys-devel/clang-3.9.0
+		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]') )
+	app-arch/xz-utils
+	>=sys-devel/llvm-4"
+
+S=${WORKDIR}/${P/_/}.src
+
+DOCS=( CREDITS.TXT )
+
+PATCHES=(
+	# Add link flag "-Wl,-z,defs" to avoid underlinking; this is needed in a
+	# out-of-tree build.
+	"${FILESDIR}/${PN}-3.9-cmake-link-flags.patch"
+	"${FILESDIR}/0001-check-for-musl-libcs-max_align_t.patch"
+)
+
+# least intrusive of all
+CMAKE_BUILD_TYPE=RelWithDebInfo
+
+python_check_deps() {
+	has_version "dev-python/lit[${PYTHON_USEDEP}]"
+}
+
+pkg_setup() {
+	llvm_pkg_setup
+	use test && python-any-r1_pkg_setup
+
+	if ! use libcxxabi && ! use libcxxrt && ! tc-is-gcc ; then
+		eerror "To build ${PN} against libsupc++, you have to use gcc. Other"
+		eerror "compilers are not supported. Please set CC=gcc and CXX=g++"
+		eerror "and try again."
+		die
+	fi
+	if tc-is-gcc && [[ $(gcc-version) < 4.7 ]] ; then
+		eerror "${PN} needs to be built with gcc-4.7 or later (or other"
+		eerror "conformant compilers). Please use gcc-config to switch to"
+		eerror "gcc-4.7 or later version."
+		die
+	fi
+}
+
+multilib_src_configure() {
+	local cxxabi cxxabi_incs
+	if use libcxxabi; then
+		cxxabi=libcxxabi
+		cxxabi_incs="${EPREFIX}/usr/include/libcxxabi"
+	elif use libcxxrt; then
+		cxxabi=libcxxrt
+		cxxabi_incs="${EPREFIX}/usr/include/libcxxrt"
+	else
+		local gcc_inc="${EPREFIX}/usr/lib/gcc/${CHOST}/$(gcc-fullversion)/include/g++-v$(gcc-major-version)"
+		cxxabi=libsupc++
+		cxxabi_incs="${gcc_inc};${gcc_inc}/${CHOST}"
+	fi
+
+	# we want -lgcc_s for unwinder, and for compiler runtime when using
+	# gcc, clang with gcc runtime (or any unknown compiler)
+	local extra_libs=() want_gcc_s=ON
+	if use libunwind; then
+		# work-around missing -lunwind upstream
+		extra_libs+=( -lunwind )
+		# if we're using libunwind and clang with compiler-rt, we want
+		# to link to compiler-rt instead of -lgcc_s
+		if tc-is-clang; then
+			# get the full library list out of 'pretend mode'
+			# and grep it for libclang_rt references
+			local args=( $($(tc-getCC) -### -x c - 2>&1 | tail -n 1) )
+			local i
+			for i in "${args[@]}"; do
+				if [[ ${i} == *libclang_rt* ]]; then
+					want_gcc_s=OFF
+					extra_libs+=( "${i}" )
+				fi
+			done
+		fi
+	fi
+
+	local libdir=$(get_libdir)
+	local mycmakeargs=(
+		-DLIBCXX_LIBDIR_SUFFIX=${libdir#lib}
+		-DLIBCXX_ENABLE_SHARED=ON
+		-DLIBCXX_ENABLE_STATIC=$(usex static-libs)
+		-DLIBCXX_CXX_ABI=${cxxabi}
+		-DLIBCXX_CXX_ABI_INCLUDE_PATHS=${cxxabi_incs}
+		# we're using our own mechanism for generating linker scripts
+		-DLIBCXX_ENABLE_ABI_LINKER_SCRIPT=OFF
+		-DLIBCXX_HAS_MUSL_LIBC=$(usex elibc_musl)
+		-DLIBCXX_HAS_GCC_S_LIB=${want_gcc_s}
+		-DLIBCXX_INCLUDE_TESTS=$(usex test)
+		-DCMAKE_SHARED_LINKER_FLAGS="${extra_libs[*]} ${LDFLAGS}"
+	)
+
+	if use test; then
+		mycmakeargs+=(
+			# this can be any directory, it just needs to exist...
+			# FIXME: remove this once https://reviews.llvm.org/D25093 is merged
+			-DLLVM_MAIN_SRC_DIR="${T}"
+			-DLIT_COMMAND="${EPREFIX}"/usr/bin/lit
+		)
+	fi
+	cmake-utils_src_configure
+}
+
+multilib_src_test() {
+	local clang_path=$(type -P "${CHOST:+${CHOST}-}clang" 2>/dev/null)
+
+	[[ -n ${clang_path} ]] || die "Unable to find ${CHOST}-clang for tests"
+	sed -i -e "/cxx_under_test/s^\".*\"^\"${clang_path}\"^" test/lit.site.cfg || die
+
+	cmake-utils_src_make check-libcxx
+}
+
+# Usage: deps
+gen_ldscript() {
+	local output_format
+	output_format=$($(tc-getCC) ${CFLAGS} ${LDFLAGS} -Wl,--verbose 2>&1 | sed -n 's/^OUTPUT_FORMAT("\([^"]*\)",.*/\1/p')
+	[[ -n ${output_format} ]] && output_format="OUTPUT_FORMAT ( ${output_format} )"
+
+	cat <<-END_LDSCRIPT
+/* GNU ld script
+   Include missing dependencies
+*/
+${output_format}
+GROUP ( $@ )
+END_LDSCRIPT
+}
+
+gen_static_ldscript() {
+	local libdir=$(get_libdir)
+	local cxxabi_lib=$(usex libcxxabi "libc++abi.a" "$(usex libcxxrt "libcxxrt.a" "libsupc++.a")")
+
+	# Move it first.
+	mv "${ED}/usr/${libdir}/libc++.a" "${ED}/usr/${libdir}/libc++_static.a" || die
+	# Generate libc++.a ldscript for inclusion of its dependencies so that
+	# clang++ -stdlib=libc++ -static works out of the box.
+	local deps="libc++_static.a ${cxxabi_lib} $(usex libunwind libunwind.a libgcc_eh.a)"
+	# On Linux/glibc it does not link without libpthread or libdl. It is
+	# fine on FreeBSD.
+	use elibc_glibc && deps+=" libpthread.a libdl.a"
+
+	gen_ldscript "${deps}" > "${ED}/usr/${libdir}/libc++.a" || die
+}
+
+gen_shared_ldscript() {
+	local libdir=$(get_libdir)
+	# libsupc++ doesn't have a shared version
+	local cxxabi_lib=$(usex libcxxabi "libc++abi.so" "$(usex libcxxrt "libcxxrt.so" "libsupc++.a")")
+
+	mv "${ED}/usr/${libdir}/libc++.so" "${ED}/usr/${libdir}/libc++_shared.so" || die
+	local deps="libc++_shared.so ${cxxabi_lib} $(usex libunwind libunwind.so libgcc_s.so)"
+
+	gen_ldscript "${deps}" > "${ED}/usr/${libdir}/libc++.so" || die
+}
+
+multilib_src_install() {
+	cmake-utils_src_install
+	gen_shared_ldscript
+	use static-libs && gen_static_ldscript
+}
+
+pkg_postinst() {
+	elog "This package (${PN}) is mainly intended as a replacement for the C++"
+	elog "standard library when using clang."
+	elog "To use it, instead of libstdc++, use:"
+	elog "    clang++ -stdlib=libc++"
+	elog "to compile your C++ programs."
+}
diff --git a/sys-libs/libcxx/metadata.xml b/sys-libs/libcxx/metadata.xml
new file mode 100644
index 00000000..df0c52dc
--- /dev/null
+++ b/sys-libs/libcxx/metadata.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="person">
+		<email>aballier@gentoo.org</email>
+		<name>Alexis Ballier</name>
+	</maintainer>
+	<maintainer type="project">
+		<email>bsd@gentoo.org</email>
+		<name>BSD Project</name>
+	</maintainer>
+	<maintainer type="project">
+		<email>llvm@gentoo.org</email>
+		<name>LLVM Project</name>
+	</maintainer>
+	<use>
+		<flag name="libcxxabi">Build on top of <pkg>sys-libs/libcxxabi</pkg> instead of gcc's libsupc++ (avoids depending on gcc).</flag>
+		<flag name="libcxxrt">Build on top of <pkg>sys-libs/libcxxrt</pkg> instead of gcc's libsupc++ (avoids depending on gcc).</flag>
+		<flag name="libunwind">Use libunwind instead of libgcc_s for stack unwinding, thus avoiding dependence on gcc.</flag>
+	</use>
+</pkgmetadata>
diff --git a/sys-libs/libcxxabi/Manifest b/sys-libs/libcxxabi/Manifest
new file mode 100644
index 00000000..e94736bf
--- /dev/null
+++ b/sys-libs/libcxxabi/Manifest
@@ -0,0 +1,5 @@
+AUX 0001-check-for-musl-libcs-max_align_t.patch 725 SHA256 83810d4a065ba8554ac626e9281711bab4e68135b719a1891dd61f71a5efd1bd SHA512 0e151920d5325f73a7735d20baf5d14bb96d20351e7169ccd5dd98617a6e46c0add8e24b359f00430d211f9c0a27d519cb2e4b6f51be8121de21ccf53981940f WHIRLPOOL bc7dfe9b65d02f45539f5d9e55fb55202fda2bb212d31963a61d145513b5087d1fff033fac15d78cc5a93daddbdab7c3043077b97d38ca2d7789fe513fc231ee
+DIST libcxx-4.0.0.src.tar.xz 1450376 SHA256 4f4d33c4ad69bf9e360eebe6b29b7b19486948b1a41decf89d4adec12473cf96 SHA512 6dad794c00919955e14710def169cdcde8a1743431479e993c4a6a3c87c2fd9f5dbd6e17542e524981eed0783dce70384c356b74ef3c6d70598c6ff03454b1dd WHIRLPOOL 2c5074087e306d100c96ae5b7175e1e1792f0317c7be6231692c80423ec716732c08293fe14fe6da5cd52d8709d6ce0a240009df24e717ab0eb9093ac7679af7
+DIST libcxxabi-4.0.0.src.tar.xz 515560 SHA256 dca9cb619662ad2d3a0d685c4366078345247218c3702dd35bcaaa23f63481d8 SHA512 b69933a0bde00321323e98962cd54b78a48bc5e93448d7a5124cb5ef844497ba7648cd92fcbe476186c60c7742e3121841f150c142c2a14c1bf2aa26a8b93d64 WHIRLPOOL 1ec297df8fd7d2e8910f2db006cc5ae53abcca37cfab3f03c5371156f69fff39c1f9193eafa0cd907bb881c35948381b85cd86710e17c83e5b90be90e3841256
+EBUILD libcxxabi-4.0.0.ebuild 2587 SHA256 a56f8b2024f6053162ad6edb86f37c41653eab35e941518ff4e48a5232294b25 SHA512 872c1d3d0e53febbf3c56ddfe2d98aa3f067f52334c6eea0ac04d4c4fd8a88388afacfd5ff846bef45d239e05617275e40e8c0da8c2e1bc735383baf56ddfb01 WHIRLPOOL bd5f94b7f8bd7c3c8ef3e6c730a33c1a0c4b14dcae83c2d0963eda7b63e768548f9067d3d07d8678d400f135f1f6b93a8803181cedbc93a35af646c37747131b
+MISC metadata.xml 350 SHA256 19efe268c0747e237a6e9f54dde3471b5b562fa6d7f698853bc09a06aa1b0460 SHA512 317dd7b59a711dd0461b5369f7e31ea196882b018e047e1dbae8077274d06cb68542c8762efb852cce0b8021bedea69c19aa0c124b9414a36cf1a9c00e0b9703 WHIRLPOOL 0f5edd5b7c2c2bed62c5a69286bf2f8f465b31716a8670549717b10f1f78a5b529d225244869ca2fc5680ccf043208905e1e34508dc4f74c639572d938db9d6e
diff --git a/sys-libs/libcxxabi/files/0001-check-for-musl-libcs-max_align_t.patch b/sys-libs/libcxxabi/files/0001-check-for-musl-libcs-max_align_t.patch
new file mode 100644
index 00000000..d1094c9e
--- /dev/null
+++ b/sys-libs/libcxxabi/files/0001-check-for-musl-libcs-max_align_t.patch
@@ -0,0 +1,26 @@
+From 7a72799513088762bef49b55438f3c42acc50ab2 Mon Sep 17 00:00:00 2001
+From: 
+Date: Fri, 23 Jun 2017 22:27:04 -0500
+Subject: [PATCH] check-for-musl-libcs-max_align_t
+
+---
+ include/stddef.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/stddef.h b/include/stddef.h
+index 8841bbe..faf8552 100644
+--- a/include/stddef.h
++++ b/include/stddef.h
+@@ -53,7 +53,8 @@ using std::nullptr_t;
+ }
+ 
+ // Re-use the compiler's <stddef.h> max_align_t where possible.
+-#if !defined(__CLANG_MAX_ALIGN_T_DEFINED) && !defined(_GCC_MAX_ALIGN_T)
++#if !defined(__CLANG_MAX_ALIGN_T_DEFINED) && !defined(_GCC_MAX_ALIGN_T) && \
++    !defined(__DEFINED_max_align_t)
+ typedef long double max_align_t;
+ #endif
+ 
+-- 
+2.13.1
+
diff --git a/sys-libs/libcxxabi/libcxxabi-4.0.0.ebuild b/sys-libs/libcxxabi/libcxxabi-4.0.0.ebuild
new file mode 100644
index 00000000..c1b0a603
--- /dev/null
+++ b/sys-libs/libcxxabi/libcxxabi-4.0.0.ebuild
@@ -0,0 +1,97 @@
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=6
+
+: ${CMAKE_MAKEFILE_GENERATOR:=ninja}
+# (needed due to CMAKE_BUILD_TYPE != Gentoo)
+CMAKE_MIN_VERSION=3.7.0-r1
+PYTHON_COMPAT=( python2_7 )
+
+inherit cmake-multilib llvm python-any-r1
+
+DESCRIPTION="Low level support for a standard C++ library"
+HOMEPAGE="http://libcxxabi.llvm.org/"
+SRC_URI="http://releases.llvm.org/${PV/_//}/${P/_/}.src.tar.xz
+	http://releases.llvm.org/${PV/_//}/libcxx-${PV/_/}.src.tar.xz"
+
+LICENSE="|| ( UoI-NCSA MIT )"
+SLOT="0"
+KEYWORDS="~amd64 ~arm64 ~x86"
+IUSE="+libunwind +static-libs test"
+
+RDEPEND="
+	libunwind? (
+		|| (
+			>=sys-libs/libunwind-1.0.1-r1[static-libs?,${MULTILIB_USEDEP}]
+			>=sys-libs/llvm-libunwind-3.9.0-r1[static-libs?,${MULTILIB_USEDEP}]
+		)
+	)"
+# LLVM 4 required for llvm-config --cmakedir
+DEPEND="${RDEPEND}
+	>=sys-devel/llvm-4
+	test? ( >=sys-devel/clang-3.9.0
+		~sys-libs/libcxx-${PV}[libcxxabi(-)]
+		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]') )"
+
+S=${WORKDIR}/${P/_/}.src
+S1=${WORKDIR}/libcxx
+
+# least intrusive of all
+CMAKE_BUILD_TYPE=RelWithDebInfo
+
+python_check_deps() {
+	has_version "dev-python/lit[${PYTHON_USEDEP}]"
+}
+
+pkg_setup() {
+	llvm_pkg_setup
+	use test && python-any-r1_pkg_setup
+}
+
+src_unpack() {
+	default
+
+	mv libcxx-* libcxx || die
+	cd ${S1}
+	eapply "${FILESDIR}"/0001-check-for-musl-libcs-max_align_t.patch
+}
+
+multilib_src_configure() {
+	local libdir=$(get_libdir)
+	local mycmakeargs=(
+		-DLIBCXXABI_LIBDIR_SUFFIX=${libdir#lib}
+		-DLIBCXXABI_ENABLE_SHARED=ON
+		-DLIBCXXABI_ENABLE_STATIC=$(usex static-libs)
+		-DLIBCXXABI_USE_LLVM_UNWINDER=$(usex libunwind)
+		-DLIBCXXABI_INCLUDE_TESTS=$(usex test)
+
+		-DLIBCXXABI_LIBCXX_INCLUDES="${WORKDIR}"/libcxx/include
+		# upstream is omitting standard search path for this
+		# probably because gcc & clang are bundling their own unwind.h
+		-DLIBCXXABI_LIBUNWIND_INCLUDES="${EPREFIX}"/usr/include
+		# this only needs to exist, it does not have to make sense
+		# FIXME: remove this once https://reviews.llvm.org/D25314 is merged
+		-DLIBCXXABI_LIBUNWIND_SOURCES="${T}"
+	)
+	if use test; then
+		mycmakeargs+=(
+			-DLIT_COMMAND="${EPREFIX}"/usr/bin/lit
+		)
+	fi
+	cmake-utils_src_configure
+}
+
+multilib_src_test() {
+	local clang_path=$(type -P "${CHOST:+${CHOST}-}clang" 2>/dev/null)
+
+	[[ -n ${clang_path} ]] || die "Unable to find ${CHOST}-clang for tests"
+	sed -i -e "/cxx_under_test/s^\".*\"^\"${clang_path}\"^" test/lit.site.cfg || die
+
+	cmake-utils_src_make check-libcxxabi
+}
+
+multilib_src_install_all() {
+	insinto /usr/include/libcxxabi
+	doins -r include/.
+}
diff --git a/sys-libs/libcxxabi/metadata.xml b/sys-libs/libcxxabi/metadata.xml
new file mode 100644
index 00000000..78c7d7d9
--- /dev/null
+++ b/sys-libs/libcxxabi/metadata.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+	<maintainer type="project">
+		<email>llvm@gentoo.org</email>
+	</maintainer>
+	<use>
+		<flag name="libunwind">Use libunwind instead of libgcc_s for stack unwinding, thus avoiding dependency on gcc</flag>
+	</use>
+</pkgmetadata>