---
eclass/llvm.eclass | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 106 insertions(+)
create mode 100644 eclass/llvm.eclass
diff --git a/eclass/llvm.eclass b/eclass/llvm.eclass
new file mode 100644
index 000000000000..8c001fdbdb97
--- /dev/null
+++ b/eclass/llvm.eclass
@@ -0,0 +1,106 @@
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Id$
+
+# @ECLASS: llvm.eclass
+# @MAINTAINER:
+# Michał Górny <mgo...@gentoo.org>
+# @AUTHOR:
+# Michał Górny <mgo...@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
+# )
+# "
+#
+# src_configure() {
+# local mycmakeargs=(
+# -DLLVM_CONFIG="$(get_llvm_config 5)"
+# )
+# cmake-utils_src_configure
+# }
+# @CODE
+
+if [[ ! ${_LLVM_ECLASS} ]]; then
+
+# @ECLASS-VARIABLE: _LLVM_KNOWN_SLOTS
+# @INTERNAL
+# @DESCRIPTION:
+# Correct values of LLVM slots, newest first.
+declare -g -r _LLVM_KNOWN_SLOTS=( 5 4 )
+
+# @FUNCTION: get_llvm_config
+# @USAGE: [<max_slot>]
+# @DESCRIPTION:
+# Prints path to llvm-config executable for the newest matching version
+# of LLVM. If <max_slot> is provided, then no version newer than
+# the specified slot will be used. If it is not, the newest installed
+# version will be used.
+#
+# Note that the function does not support lower-bound version, so you
+# need to set proper dependencies. Otherwise, the function can return
+# a lower LLVM version than required.
+get_llvm_config() {
+ 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} == ${slot} ]]; then
+ max_slot=
+ else
+ continue
+ fi
+ fi
+
+ local p=${EPREFIX}/usr/lib/llvm/${slot}/bin
+ if [[ -x ${p}/llvm-config ]]; then
+ if [[ -n ${CHOST} && -x ${p}/${CHOST}-llvm-config ]];
then
+ echo "${p}/${CHOST}-llvm-config"
+ else
+ echo "${p}/llvm-config"
+ fi
+ return
+ fi
+ done
+
+ if [[ -n ${max_slot} ]]; then
+ die "${FUNCNAME}: invalid max_slot=${max_slot}"
+ fi
+
+ # fallback to :0
+ # assume it's always <= 4 (the lower max_slot allowed)
+ p=${EPREFIX}/usr/bin
+ if [[ -x ${p}/llvm-config ]]; then
+ if [[ -n ${CHOST} && -x ${p}/${CHOST}-llvm-config ]]; then
+ echo "${p}/${CHOST}-llvm-config"
+ else
+ echo "${p}/llvm-config"
+ fi
+ return
+ fi
+
+ die "No LLVM slot${1:+ <= ${1}} found in PATH!"
+}
+
+_LLVM_ECLASS=1
+fi
--
2.11.0
