reinit the tree, so we can have metadata

1 files changed, 173 insertions, 0 deletions

diff --git a/eclass/llvm.eclass b/eclass/llvm.eclass
new file mode 100644
index 000000000000..d9518fe62266
--- /dev/null
+++ b/eclass/llvm.eclass
@@ -0,0 +1,173 @@
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: llvm.eclass
+# @MAINTAINER:
+# Michał Górny <mgorny@gentoo.org>
+# @AUTHOR:
+# Michał Górny <mgorny@gentoo.org>
+# @BLURB: Utility functions to build against slotted LLVM
+# @DESCRIPTION:
+# The llvm.eclass provides utility functions that can be used to build
+# against specific version of slotted LLVM (with fallback to :0 for old
+# versions).
+#
+# This eclass does not generate dependency strings. You need to write
+# a proper dependency string yourself to guarantee that appropriate
+# version of LLVM is installed.
+#
+# Example use for a package supporting LLVM 3.8 to 5:
+# @CODE
+# inherit cmake-utils llvm
+#
+# RDEPEND="
+#	<sys-devel/llvm-6_rc:=
+#	|| (
+#		sys-devel/llvm:5
+#		sys-devel/llvm:4
+#		>=sys-devel/llvm-3.8:0
+#	)
+# "
+#
+# LLVM_MAX_SLOT=5
+#
+# # only if you need to define one explicitly
+# pkg_setup() {
+#	llvm_pkg_setup
+#	do-something-else
+# }
+# @CODE
+#
+# Example for a package needing LLVM+clang w/ a specific target:
+# @CODE
+# inherit cmake-utils llvm
+#
+# # note: do not use := on both clang and llvm, it can match different
+# # slots then. clang pulls llvm in, so we can skip the latter.
+# RDEPEND="
+#	>=sys-devel/clang-4:=[llvm_targets_AMDGPU(+)]
+# "
+#
+# llvm_check_deps() {
+#	has_version "sys-devel/clang:${LLVM_SLOT}[llvm_targets_AMDGPU(+)]"
+# }
+# @CODE
+
+case "${EAPI:-0}" in
+	0|1|2|3|4|5)
+		die "Unsupported EAPI=${EAPI:-0} (too old) for ${ECLASS}"
+		;;
+	6)
+		;;
+	*)
+		die "Unsupported EAPI=${EAPI} (unknown) for ${ECLASS}"
+		;;
+esac
+
+EXPORT_FUNCTIONS pkg_setup
+
+if [[ ! ${_LLVM_ECLASS} ]]; then
+
+# @ECLASS-VARIABLE: LLVM_MAX_SLOT
+# @DEFAULT_UNSET
+# @DESCRIPTION:
+# Highest LLVM slot supported by the package. Needs to be set before
+# llvm_pkg_setup is called. If unset, no upper bound is assumed.
+
+# @ECLASS-VARIABLE: _LLVM_KNOWN_SLOTS
+# @INTERNAL
+# @DESCRIPTION:
+# Correct values of LLVM slots, newest first.
+declare -g -r _LLVM_KNOWN_SLOTS=( 6 5 4 )
+
+# @FUNCTION: get_llvm_prefix
+# @USAGE: [<max_slot>]
+# @DESCRIPTION:
+# Find the newest LLVM install that is acceptable for the package,
+# and print an absolute path to it.
+#
+# If <max_slot> is specified, then only LLVM versions that are not newer
+# than <max_slot> will be considered. Otherwise, all LLVM versions would
+# be considered acceptable. The function does not support specifying
+# minimal supported version -- the developer must ensure that a version
+# new enough is installed via providing appropriate dependencies.
+#
+# If llvm_check_deps() function is defined within the ebuild, it will
+# be called to verify whether a particular slot is accepable. Within
+# the function scope, LLVM_SLOT will be defined to the SLOT value
+# (0, 4, 5...). The function should return a true status if the slot
+# is acceptable, false otherwise. If llvm_check_deps() is not defined,
+# the function defaults to checking whether sys-devel/llvm:${LLVM_SLOT}
+# is installed.
+get_llvm_prefix() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	local max_slot=${1}
+	local slot
+	for slot in "${_LLVM_KNOWN_SLOTS[@]}"; do
+		# skip higher slots
+		if [[ -n ${max_slot} ]]; then
+			if [[ ${max_slot} == ${slot} ]]; then
+				max_slot=
+			else
+				continue
+			fi
+		fi
+
+		if declare -f llvm_check_deps >/dev/null; then
+			local LLVM_SLOT=${slot}
+			llvm_check_deps || continue
+		else
+			# check if LLVM package is installed
+			has_version "sys-devel/llvm:${slot}" || continue
+		fi
+
+		echo "${EPREFIX}/usr/lib/llvm/${slot}"
+		return
+	done
+
+	# max_slot should have been unset in the iteration
+	if [[ -n ${max_slot} ]]; then
+		die "${FUNCNAME}: invalid max_slot=${max_slot}"
+	fi
+
+	# fallback to :0
+	# assume it's always <= 4 (the lower max_slot allowed)
+	if has_version "sys-devel/llvm:0"; then
+		echo "${EPREFIX}/usr"
+		return
+	fi
+
+	die "No LLVM slot${1:+ <= ${1}} found installed!"
+}
+
+# @FUNCTION: llvm_pkg_setup
+# @DESCRIPTION:
+# Prepend the appropriate executable directory for the newest
+# acceptable LLVM slot to the PATH. For path determination logic,
+# please see the get_llvm_prefix documentation.
+#
+# The highest acceptable LLVM slot can be set in LLVM_MAX_SLOT variable.
+# If it is unset or empty, any slot is acceptable.
+#
+# The PATH manipulation is only done for source builds. The function
+# is a no-op when installing a binary package.
+#
+# If any other behavior is desired, the contents of the function
+# should be inlined into the ebuild and modified as necessary.
+llvm_pkg_setup() {
+	debug-print-function ${FUNCNAME} "${@}"
+
+	if [[ ${MERGE_TYPE} != binary ]]; then
+		local llvm_prefix=$(get_llvm_prefix "${LLVM_MAX_SLOT}")
+
+		# do not prepend /usr/bin, it's not necessary and breaks other
+		# prepends, https://bugs.gentoo.org/622866
+		if [[ ${llvm_prefix} != ${EPREFIX}/usr ]]; then
+			export PATH=${llvm_prefix}/bin:${PATH}
+		fi
+	fi
+}
+
+_LLVM_ECLASS=1
+fi