New patch to review for coreboot: 0c44f9a xcompile: improve mips toolchain handling

[Vadim Bendebury]

Vadim Bendebury ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/9997

-gerrit

commit 0c44f9a93127b41b76287536cee88005d634ccdd
Author: Vadim Bendebury 
Date:   Sat Apr 25 13:05:10 2015 -0700

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 
---
 util/xcompile/xcompile | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/util/xcompile/xcompile b/util/xcompile/xcompile
index 4a0fcf7..e079c9d 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