www-client/firefox: support mold linker in 109.0

Closes: https://github.com/gentoo/gentoo/pull/28366
Signed-off-by: Joonas Niilola <juippis@gentoo.org>

1 files changed, 64 insertions, 10 deletions

diff --git a/www-client/firefox/firefox-109.0.ebuild b/www-client/firefox/firefox-109.0.ebuild
index c2e92bead6a2..e6d4ce7a40de 100644
--- a/www-client/firefox/firefox-109.0.ebuild
+++ b/www-client/firefox/firefox-109.0.ebuild
@@ -88,7 +88,10 @@ BDEPEND="${PYTHON_DEPS}
 			sys-devel/clang:15
 			sys-devel/llvm:15
 			clang? (
-				sys-devel/lld:15
+				|| (
+					sys-devel/lld:15
+					sys-devel/mold
+				)
 				virtual/rust:0/llvm-15
 				pgo? ( =sys-libs/compiler-rt-sanitizers-15*[profile] )
 			)
@@ -97,7 +100,10 @@ BDEPEND="${PYTHON_DEPS}
 			sys-devel/clang:14
 			sys-devel/llvm:14
 			clang? (
-				sys-devel/lld:14
+				|| (
+					sys-devel/lld:14
+					sys-devel/mold
+				)
 				virtual/rust:0/llvm-14
 				pgo? ( =sys-libs/compiler-rt-sanitizers-14*[profile] )
 			)
@@ -227,7 +233,7 @@ llvm_check_deps() {
 		return 1
 	fi
 
-	if use clang ; then
+	if use clang && tc-ld-is-lld ; then
 		if ! has_version -b "sys-devel/lld:${LLVM_SLOT}" ; then
 			einfo "sys-devel/lld:${LLVM_SLOT} is missing! Cannot use LLVM slot ${LLVM_SLOT} ..." >&2
 			return 1
@@ -427,6 +433,40 @@ mozconfig_use_with() {
 	mozconfig_add_options_ac "$(use ${1} && echo +${1} || echo -${1})" "${flag}"
 }
 
+# This is a straight copypaste from toolchain-funcs.eclass's 'tc-ld-is-lld', and is temporarily
+# placed here until toolchain-funcs.eclass gets an official support for mold linker.
+# Please see:
+# https://github.com/gentoo/gentoo/pull/28366 ||
+# https://github.com/gentoo/gentoo/pull/28355
+tc-ld-is-mold() {
+	local out
+
+	# Ensure ld output is in English.
+	local -x LC_ALL=C
+
+	# First check the linker directly.
+	out=$($(tc-getLD "$@") --version 2>&1)
+	if [[ ${out} == *"mold"* ]] ; then
+		return 0
+	fi
+
+	# Then see if they're selecting mold via compiler flags.
+	# Note: We're assuming they're using LDFLAGS to hold the
+	# options and not CFLAGS/CXXFLAGS.
+	local base="${T}/test-tc-linker"
+	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} == *"mold"* ]] ; then
+		return 0
+	fi
+
+	# No mold here!
+	return 1
+}
+
 virtwl() {
 	debug-print-function ${FUNCNAME} "$@"
 
@@ -486,7 +526,7 @@ pkg_setup() {
 
 		llvm_pkg_setup
 
-		if use clang && use lto ; then
+		if use clang && use lto && tc-ld-is-lld ; then
 			local version_lld=$(ld.lld --version 2>/dev/null | awk '{ print $2 }')
 			[[ -n ${version_lld} ]] && version_lld=$(ver_cut 1 "${version_lld}")
 			[[ -z ${version_lld} ]] && die "Failed to read ld.lld version!"
@@ -856,13 +896,18 @@ src_configure() {
 
 	if use lto ; then
 		if use clang ; then
-			# Upstream only supports lld when using clang
-			mozconfig_add_options_ac "forcing ld=lld due to USE=clang and USE=lto" --enable-linker=lld
+			# Upstream only supports lld or mold when using clang.
+			if tc-ld-is-mold ; then
+				mozconfig_add_options_ac "using ld=mold due to system selection" --enable-linker=mold
+			else
+				mozconfig_add_options_ac "forcing ld=lld due to USE=clang and USE=lto" --enable-linker=lld
+			fi
 
 			mozconfig_add_options_ac '+lto' --enable-lto=cross
 
 		else
-			# ThinLTO is currently broken, see bmo#1644409
+			# ThinLTO is currently broken, see bmo#1644409.
+			# mold does not support gcc+lto combination.
 			mozconfig_add_options_ac '+lto' --enable-lto=full
 			mozconfig_add_options_ac "linker is set to bfd" --enable-linker=bfd
 		fi
@@ -878,10 +923,19 @@ src_configure() {
 	else
 		# Avoid auto-magic on linker
 		if use clang ; then
-			# This is upstream's default
-			mozconfig_add_options_ac "forcing ld=lld due to USE=clang" --enable-linker=lld
+			# lld is upstream's default
+			if tc-ld-is-mold ; then
+				mozconfig_add_options_ac "using ld=mold due to system selection" --enable-linker=mold
+			else
+				mozconfig_add_options_ac "forcing ld=lld due to USE=clang" --enable-linker=lld
+			fi
+
 		else
-			mozconfig_add_options_ac "linker is set to bfd" --enable-linker=bfd
+			if tc-ld-is-mold ; then
+				mozconfig_add_options_ac "using ld=mold due to system selection" --enable-linker=mold
+			else
+				mozconfig_add_options_ac "linker is set to bfd due to USE=-clang" --enable-linker=bfd
+			fi
 		fi
 	fi