dev-libs/gmp: pass --enable-fat for x86 (includes more asm)

Vanilla (_not_ from an ebuild) gmp will probe CHOST and then
deduce its *own* tuple based on the currently used CPU, abusing
its own custom config.guess (which our econf overwrites). This
value is used to decide which accelerated asm is compiled in (MPN_PATH).

In ebuilds, we override and refresh config.guess and friends because
it's a common portability problem to have stale versions which don't
even recognise e.g. riscv as an arch. But gmp's non-standard use
of these files poses a problem for us.

We can't simply resort to just not refreshing/changing the files
because we need to be able to build binary packages on a system
without them being super specific to the machine they were built
on with no way of controlling it (we may want to look at a USE
flag for this going forward though).

For now, we can use --enable-fat which produces a generic libgmp
which can load various asm at runtime based on the CPU in use - success!

Unfortunately, --enable-fat only does anything on x86 for the time
being, so !x86 is still in the same situation as before this commit,
but this is progress at least.

Thanks goes to Nikita Zlobin <nick87720z@gmail.com> for noticing
the problem originally (and being persistent with investigating it).

Temporarily unkeyworded until I can test this a bit more.

Bug: https://bugs.gentoo.org/883201
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 130 insertions, 0 deletions

diff --git a/dev-libs/gmp/gmp-6.2.1-r3.ebuild b/dev-libs/gmp/gmp-6.2.1-r3.ebuild
new file mode 100644
index 000000000000..840288dd1207
--- /dev/null
+++ b/dev-libs/gmp/gmp-6.2.1-r3.ebuild
@@ -0,0 +1,130 @@
+# Copyright 1999-2022 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit libtool multilib-minimal toolchain-funcs
+
+MY_PV=${PV/_p*}
+MY_PV=${MY_PV/_/-}
+
+MANUAL_PV=${MY_PV}
+MANUAL_PV=6.2.1
+
+MY_P=${PN}-${MY_PV}
+PLEVEL=${PV/*p}
+
+DESCRIPTION="Library for arbitrary-precision arithmetic on different type of numbers"
+HOMEPAGE="https://gmplib.org/"
+SRC_URI="ftp://ftp.gmplib.org/pub/${MY_P}/${MY_P}.tar.xz
+	mirror://gnu/${PN}/${MY_P}.tar.xz
+	doc? ( https://gmplib.org/${PN}-man-${MANUAL_PV}.pdf )"
+SRC_URI+=" https://dev.gentoo.org/~sam/distfiles/${CATEGORY}/${PN}/${P}-arm64-darwin.patch.bz2"
+S="${WORKDIR}"/${MY_P%a}
+
+LICENSE="|| ( LGPL-3+ GPL-2+ )"
+# The subslot reflects the C & C++ SONAMEs.
+SLOT="0/10.4"
+# Unkeyworded temporarily for some more testing
+#KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~x64-cygwin ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
+IUSE="+asm doc +cxx pic static-libs"
+
+BDEPEND="
+	app-arch/xz-utils
+	sys-devel/m4
+"
+
+DOCS=( AUTHORS ChangeLog NEWS README doc/configuration doc/isa_abi_headache )
+HTML_DOCS=( doc )
+
+MULTILIB_WRAPPED_HEADERS=( /usr/include/gmp.h )
+
+PATCHES=(
+	"${FILESDIR}"/${PN}-6.1.0-noexecstack-detect.patch
+	"${FILESDIR}"/${PN}-6.2.1-no-zarch.patch
+	"${WORKDIR}"/${P}-arm64-darwin.patch
+	"${FILESDIR}"/${P}-CVE-2021-43618.patch
+)
+
+src_prepare() {
+	default
+
+	# We cannot run autotools here as gcc depends on this package
+	elibtoolize
+
+	# bug #536894
+	if [[ ${CHOST} == *-darwin* ]] ; then
+		eapply "${FILESDIR}"/${PN}-6.1.2-gcc-apple-4.0.1.patch
+	fi
+
+	# GMP uses the "ABI" env var during configure as does Gentoo (econf).
+	# So, to avoid patching the source constantly, wrap things up.
+	mv configure configure.wrapped || die
+	cat <<-\EOF > configure
+	#!/usr/bin/env sh
+	exec env ABI="${GMPABI}" "$0.wrapped" "$@"
+	EOF
+
+	# Patches to original configure might have lost the +x bit.
+	chmod a+rx configure{,.wrapped} || die
+}
+
+multilib_src_configure() {
+	# Because of our 32-bit userland, 1.0 is the only HPPA ABI that works
+	# https://gmplib.org/manual/ABI-and-ISA.html#ABI-and-ISA (bug #344613)
+	if [[ ${CHOST} == hppa2.0-* ]] ; then
+		GMPABI="1.0"
+	fi
+
+	# ABI mappings (needs all architectures supported)
+	case ${ABI} in
+		32|x86)       GMPABI=32;;
+		64|amd64|n64) GMPABI=64;;
+		[onx]32)      GMPABI=${ABI};;
+	esac
+	export GMPABI
+
+	tc-export CC
+
+	local myeconfargs=(
+		CC_FOR_BUILD="$(tc-getBUILD_CC)"
+
+		--localstatedir="${EPREFIX}"/var/state/gmp
+		--enable-shared
+
+		# fat is needed to avoid gmp installing either purely generic
+		# or specific-to-used-CPU (which our config.guess refresh prevents at the moment).
+		# Both Fedora and opensuse use this option to tackle the issue, bug #883201.
+		#
+		# This only works for x86, so we're still getting non-performant
+		# builds on other arches until we figure something out!
+		$(use_enable asm fat)
+		$(use_enable asm assembly)
+		$(use_enable cxx)
+		$(use_enable static-libs static)
+
+		# --with-pic forces static libraries to be built as PIC
+		# and without TEXTRELs. musl does not support TEXTRELs: bug #707332
+		$(use pic && echo --with-pic)
+	)
+
+	ECONF_SOURCE="${S}" econf "${myeconfargs[@]}"
+}
+
+multilib_src_install() {
+	emake DESTDIR="${D}" install
+
+	# Should be a standalone lib
+	rm -f "${ED}"/usr/$(get_libdir)/libgmp.la
+
+	# This requires libgmp
+	local la="${ED}/usr/$(get_libdir)/libgmpxx.la"
+	if ! use static-libs ; then
+		rm -f "${la}" || die
+	fi
+}
+
+multilib_src_install_all() {
+	einstalldocs
+	use doc && cp "${DISTDIR}"/gmp-man-${MANUAL_PV}.pdf "${ED}"/usr/share/doc/${PF}/
+}