rpm-build/scripts/process-lto.in

#!/bin/sh -efu
#
# Process single file for LTO business.
# (Will be run multiple instances in parallel.)
#
# Based on brp-strip-lto (Fedora).
# Copyright (c) 2021 Vitaly Chikunov <vt@altlinux.org>.
# License: GPLv2+.
#
# Implementation notes:
# - eu-strip cannot be used due to absence of `-N`.

. @RPMCONFIGDIR@/rpmb-functions
ValidateBuildRoot

cd "$RPM_BUILD_ROOT"
mkdir -p .tmp

# If there is only slim lto, strip will produce "plugin needed to handle lto
# object" warning, because of stripping __gnu_lto_v1 symbol while remaining
# __gnu_lto_slim.
strip -p -R '.gnu.lto_*' -R '.gnu.debuglto_*' -N '__gnu_lto_v1' -- "$@" ||
	Fatal 'strip failed'

# Verify that we still have exportable symbols.
for f; do
	# Output in one line per symbol format.
	nm -g -A -P "$f" > .tmp/lto-nm.$$ 2>/dev/null
	if grep -F -q -w ': __gnu_lto_slim' .tmp/lto-nm.$$; then
		echo >> .tmp/lto-suggest
		if grep -F -q -v -w ': __gnu_lto_slim' .tmp/lto-nm.$$; then
			Fatal "$f: contains __gnu_lto_slim."
		else
			Fatal "$f: contains __gnu_lto_slim only."
		fi
	elif [ ! -s .tmp/lto-nm.$$ ]; then
		# This is only informational call of file.
		Warning "$f: contains no exportable symbols: $(file4 -b "$f")"
	fi
	rm .tmp/lto-nm.$$
done