1#!/bin/sh 2 3debug=false 4 5try() { 6 added="$1" 7 shift 8 $debug && echo "Trying: $* $added" 9 "$@" $added 2>busybox_ld.err 10} 11 12# Sanitize lib list (dups, extra spaces etc) 13#echo "BBOX_LIB_LIST=$BBOX_LIB_LIST" 14BBOX_LIB_LIST=`echo "$BBOX_LIB_LIST" | xargs -n1 | sort | uniq | xargs` 15 16# First link with all libs. If it fails, bail out 17echo "Trying libraries: $BBOX_LIB_LIST" 18l_list=`echo "$BBOX_LIB_LIST" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'` 19test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group" 20try "$l_list" "$@" \ 21|| { 22 echo "Failed: $* -Wl,--start-group $l_list -Wl,--end-group" 23 cat busybox_ld.err 24 exit 1 25} 26 27# Now try to remove each lib and build without it. 28# Stop when no lib can be removed. 29while test "$BBOX_LIB_LIST"; do 30 $debug && echo "Trying libraries: $BBOX_LIB_LIST" 31 all_needed=true 32 for one in $BBOX_LIB_LIST; do 33 without_one=`echo " $BBOX_LIB_LIST " | sed "s/ $one / /g" | xargs` 34 l_list=`echo "$without_one" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'` 35 test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group" 36 $debug && echo "Trying -l options: '$l_list'" 37 if try "$l_list" "$@"; then 38 echo "Library $one is not needed" 39 BBOX_LIB_LIST="$without_one" 40 all_needed=false 41 else 42 echo "Library $one is needed" 43 fi 44 done 45 # All libs were needed, can't remove any 46 $all_needed && break 47 # If there is no space char, the list has just one lib. 48 # I'm not sure that in this case lib really is 100% needed. 49 # Let's try linking without it anyway... thus commented out. 50 #{ echo "$BBOX_LIB_LIST" | grep -q ' '; } || break 51done 52 53# Make the binary with final, minimal list of libs 54echo "Final link with: $BBOX_LIB_LIST" 55l_list=`echo "$BBOX_LIB_LIST" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'` 56test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group -Wl,--verbose" 57# --verbose gives us gobs of info to stdout (e.g. linker script used) 58if ! test -f busybox_ldscript; then 59 try "$l_list -Wl,--verbose" "$@" >busybox_ld.out 60else 61 echo "Custom linker script 'busybox_ldscript' found, using it" 62 # Add SORT_BY_ALIGNMENT to linker script (found in busybox_ld.out): 63 # .rodata : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) } 64 # *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*) 65 # *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*) 66 # This will eliminate most of the data padding (~3kb). 67 try "$l_list -Wl,--verbose -Wl,-T -Wl,busybox_ldscript" "$@" >busybox_ld.out 68fi 69