tc-ld-is-gold/tc-ld-disable-gold: add helpers for detecting & disabling gold

2 files changed, 122 insertions, 2 deletions

diff --git a/eclass/tests/toolchain-funcs.sh b/eclass/tests/toolchain-funcs.sh
index d8fb97e5bc73..af440325990d 100755
--- a/eclass/tests/toolchain-funcs.sh
+++ b/eclass/tests/toolchain-funcs.sh
@@ -51,9 +51,62 @@ do
 
 	if [[ ${actual} != ${exp:-${CHOST}} ]] ; then
 		eerror "Failure for CHOST: ${CHOST} Expected: ${exp} != Actual: ${actual}"
-		((++ret))
+		: $((++ret))
 	fi
 done
 tend ${ret}
 
+#
+# TEST: tc-ld-is-gold
+#
+tbegin "tc-ld-is-gold (bfd selected)"
+LD=ld.bfd tc-ld-is-gold && ret=1 || ret=0
+tend ${ret}
+
+tbegin "tc-ld-is-gold (gold selected)"
+LD=ld.gold tc-ld-is-gold
+ret=$?
+tend ${ret}
+
+tbegin "tc-ld-is-gold (bfd selected via flags)"
+LD=ld.gold LDFLAGS=-fuse-ld=bfd tc-ld-is-gold
+ret=$?
+tend ${ret}
+
+tbegin "tc-ld-is-gold (gold selected via flags)"
+LD=ld.bfd LDFLAGS=-fuse-ld=gold tc-ld-is-gold
+ret=$?
+tend ${ret}
+
+#
+# TEST: tc-ld-disable-gold
+#
+tbegin "tc-ld-disable-gold (bfd selected)"
+(
+export LD=ld.bfd LDFLAGS=
+ewarn() { :; }
+tc-ld-disable-gold
+[[ ${LD} == "ld.bfd" && -z ${LDFLAGS} ]]
+)
+tend $?
+
+tbegin "tc-ld-disable-gold (gold selected)"
+(
+export LD=ld.gold LDFLAGS=
+ewarn() { :; }
+tc-ld-disable-gold
+[[ ${LD} == "ld.bfd" || ${LDFLAGS} == *"-fuse-ld=bfd"* ]]
+)
+tend $?
+
+tbegin "tc-ld-disable-gold (gold selected via flags)"
+(
+export LD= LDFLAGS="-fuse-ld=gold"
+ewarn() { :; }
+tc-ld-disable-gold
+[[ ${LD} == *"/ld.bfd" || ${LDFLAGS} == "-fuse-ld=gold -fuse-ld=bfd" ]]
+)
+tend $?
+
+
 texit
diff --git a/eclass/toolchain-funcs.eclass b/eclass/toolchain-funcs.eclass
index 80317735f3be..d3c5a67eca29 100644
--- a/eclass/toolchain-funcs.eclass
+++ b/eclass/toolchain-funcs.eclass
@@ -1,6 +1,6 @@
 # Copyright 1999-2015 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
-# $Header: /var/cvsroot/gentoo-x86/eclass/toolchain-funcs.eclass,v 1.134 2015/03/16 19:26:39 vapier Exp $
+# $Header: /var/cvsroot/gentoo-x86/eclass/toolchain-funcs.eclass,v 1.135 2015/03/16 21:12:27 vapier Exp $
 
 # @ECLASS: toolchain-funcs.eclass
 # @MAINTAINER:
@@ -305,6 +305,73 @@ econf_build() {
 	tc-env_build econf --build=${CBUILD} --host=${CBUILD} "$@"
 }
 
+# @FUNCTION: tc-ld-is-gold
+# @USAGE: [toolchain prefix]
+# @DESCRIPTION:
+# Return true if the current linker is set to gold.
+tc-ld-is-gold() {
+	local out
+
+	# First check the linker directly.
+	out=$($(tc-getLD "$@") --version 2>&1)
+	if [[ ${out} == *"GNU gold"* ]] ; then
+		return 0
+	fi
+
+	# Then see if they're selecting gold via compiler flags.
+	# Note: We're assuming they're using LDFLAGS to hold the
+	# options and not CFLAGS/CXXFLAGS.
+	local base="${T}/test-tc-gold"
+	cat <<-EOF > "${base}.c"
+	int main() { return 0; }
+	EOF
+	out=$($(tc-getCC "$@") ${CFLAGS} ${CPPFLAGS} ${LDFLAGS} -Wl,--version "${base}.c" -o "${base}" 2>&1)
+	rm -f "${base}"*
+	if [[ ${out} == *"GNU gold"* ]] ; then
+		return 0
+	fi
+
+	# No gold here!
+	return 1
+}
+
+# @FUNCTION: tc-ld-disable-gold
+# @USAGE: [toolchain prefix]
+# @DESCRIPTION:
+# If the gold linker is currently selected, configure the compilation
+# settings so that we use the older bfd linker instead.
+tc-ld-disable-gold() {
+	if ! tc-ld-is-gold "$@" ; then
+		# They aren't using gold, so nothing to do!
+		return
+	fi
+
+	ewarn "Forcing usage of the BFD linker instead of GOLD"
+
+	# Set up LD to point directly to bfd if it's available.
+	local bfd_ld="$(tc-getLD "$@").bfd"
+	local path_ld=$(which "${bfd_ld}" 2>/dev/null)
+	[[ -e ${path_ld} ]] && export LD=${bfd_ld}
+
+	# Set up LDFLAGS to select gold based on the gcc version.
+	local major=$(gcc-major-version "$@")
+	local minor=$(gcc-minor-version "$@")
+	if [[ ${major} -lt 4 ]] || [[ ${major} -eq 4 && ${minor} -lt 8 ]] ; then
+		# <=gcc-4.7 requires some coercion.  Only works if bfd exists.
+		if [[ -e ${path_ld} ]] ; then
+			local d="${T}/bfd-linker"
+			mkdir -p "${d}"
+			ln -sf "${path_ld}" "${d}"/ld
+			export LDFLAGS="${LDFLAGS} -B${d}"
+		else
+			die "unable to locate a BFD linker to bypass gold"
+		fi
+	else
+		# gcc-4.8+ supports -fuse-ld directly.
+		export LDFLAGS="${LDFLAGS} -fuse-ld=bfd"
+	fi
+}
+
 # @FUNCTION: tc-has-openmp
 # @USAGE: [toolchain prefix]
 # @DESCRIPTION: