xcompile: improve mips toolchain handling

The mips toolchain used by coreboot so far comes from Chrome OS chroot
and is built explicitly for little endian code generation.

Other flavors of MIPS toolchain usually generate big endian code by
default and require command line options to switch to little endian
mode.

This patch adds another variable to the set of compiler flags examined
to determine compiler compatibility. This results in adding another
nested for loop in test_architecture(). To avoid the need to break
from different levels of nesting, processing of the successful case is
taken out from test_architecture().

With this change the Mentor Graphics provided mips GCC toolchain is
accepted by xcompile, resulting in the following output:

 ARCH_SUPPORTED+=mips
 SUBARCH_SUPPORTED+=mips mipsel
 CC_mips:=mips-linux-gnu-gcc
 CFLAGS_mips:= -Wno-unused-but-set-variable  -fno-stack-protector -Wl,--build-id=none -mno-abicalls -fno-pic -EL
 CPP_mips:=mips-linux-gnu-cpp
 AS_mips:=mips-linux-gnu-as
 LD_mips:=mips-linux-gnu-ld
 NM_mips:=mips-linux-gnu-nm
 OBJCOPY_mips:=mips-linux-gnu-objcopy
 OBJDUMP_mips:=mips-linux-gnu-objdump
 READELF_mips:=mips-linux-gnu-readelf
 STRIP_mips:=mips-linux-gnu-strip
 AR_mips:=mips-linux-gnu-ar

Change-Id: I4da384b366880929693c59dc0e1c522b35c41bea
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/9997
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

1 files changed, 24 insertions, 16 deletions

diff --git a/util/xcompile/xcompile b/util/xcompile/xcompile
index 4a0fcf79f63e..e079c9d81d17 100755
--- a/util/xcompile/xcompile
+++ b/util/xcompile/xcompile
@@ -80,13 +80,15 @@ testas() {
 	local twidth="$2"
 	local arch="$3"
 	local use_dash_twidth="$4"
+	local endian="$5"
 	local obj_file="$TMPFILE.o"
 	local full_arch="elf$twidth-$arch"
 
 	rm -f "$obj_file"
 	[ -n "$use_dash_twidth" ] && use_dash_twidth="--$twidth"
-	${gccprefix}as $use_dash_twidth -o "$obj_file" $TMPFILE 2>/dev/null ||
-		return 1
+	[ -n "$endian" ] && endian="-$endian"
+	${gccprefix}as $use_dash_twidth $endian -o "$obj_file" $TMPFILE \
+		2>/dev/null || return 1
 
 	# Check output content type.
 	local obj_type="$(${gccprefix}objdump -p $obj_file)"
@@ -147,6 +149,10 @@ detect_special_flags() {
 	mipsel)
 		testcc "$CC" "$CFLAGS -mno-abicalls -fno-pic" && \
 		  CFLAGS+=" -mno-abicalls -fno-pic"
+
+                # Enforce little endian mode.
+		testcc "$CC" "$CFLAGS -EL" && \
+		  CFLAGS+=" -EL"
 		;;
 	esac
 }
@@ -215,14 +221,15 @@ arch_config_mipsel() {
 	TWIDTH="32"
 	TSUPP="mips mipsel"
 	TABI="elf"
+	TENDIAN="EL"
 }
 
 test_architecture() {
 	local architecture=$1
-	local gccprefix search
+	local endian gccprefix search
 
 	GCCPREFIX="invalid"
-	unset TARCH TBFDARCH TCLIST TWIDTH TSUPP TABI
+	unset TABI TARCH TBFDARCH TCLIST TENDIAN TSUPP TWIDTH
 	if type arch_config_$architecture > /dev/null; then
 		arch_config_$architecture
 	else
@@ -247,23 +254,24 @@ test_architecture() {
 	for TBFDARCH in $TBFDARCHS; do
 		for gccprefix in $search ""; do
 			program_exists "${gccprefix}as" || continue
-			testas "$gccprefix" "$TWIDTH" "$TBFDARCH" "" && break
-			testas "$gccprefix" "$TWIDTH" "$TBFDARCH" "TRUE" && break
+			for endian in $TENDIAN ""; do
+				testas "$gccprefix" "$TWIDTH" "$TBFDARCH" \
+					"" "$endian" && return 0
+				testas "$gccprefix" "$TWIDTH" "$TBFDARCH" \
+					"TRUE" "$endian" && return 0
+			done
 		done
-		[ "$GCCPREFIX" = "invalid" ] || break
 	done
 
-	if [ "$GCCPREFIX" = "invalid" ]; then
-		echo "Warning: no suitable GCC for $architecture." >&2
-		continue
-	fi
-	CC="${GCCPREFIX}"gcc
-
-	detect_special_flags "$architecture"
-	report_arch_toolchain
+	echo "Warning: no suitable GCC for $architecture." >&2
+	return 1
 }
 
 # This loops over all supported architectures.
 for architecture in $SUPPORTED_ARCHITECTURES; do
-	test_architecture $architecture
+	if test_architecture $architecture; then
+		CC="${GCCPREFIX}"gcc
+		detect_special_flags "$architecture"
+		report_arch_toolchain
+	fi
 done