introduce and use close_on_exec_on(fd). -50 bytes.

[oweals/busybox.git] / scripts / trylink

diff --git a/scripts/trylink b/scripts/trylink
index 1cd50c6ed8dc91095d2ebeedd47831ba802a35a5..0b8f6c0625523c58ba993575822980a139bd8b5b 100755 (executable)
--- a/scripts/trylink
+++ b/scripts/trylink
@@ -6,13 +6,63 @@ try() {
     added="$1"
     shift
     $debug && echo "Trying: $* $added"
-    "$@" $added >busybox.map 2>busybox_ld.err \
-    && exit 0
+    "$@" $added 2>busybox_ld.err
 }
 
-try "" "$@"
-try "-lm" "$@"
-try "-lcrypt" "$@"
-try "-Wl,--start-group -lcrypt -lm -Wl,--end-group" "$@"
-# It failed. Let people see the error messages
-cat busybox_ld.err
+# Sanitize lib list (dups, extra spaces etc)
+#echo "BBOX_LIB_LIST=$BBOX_LIB_LIST"
+BBOX_LIB_LIST=`echo "$BBOX_LIB_LIST" | xargs -n1 | sort | uniq | xargs`
+
+# First link with all libs. If it fails, bail out
+echo "Trying libraries: $BBOX_LIB_LIST"
+l_list=`echo "$BBOX_LIB_LIST" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
+test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
+try "$l_list" "$@" \
+|| {
+    echo "Failed: $* -Wl,--start-group $l_list -Wl,--end-group"
+    cat busybox_ld.err
+    exit 1
+}
+
+# Now try to remove each lib and build without it.
+# Stop when no lib can be removed.
+while test "$BBOX_LIB_LIST"; do
+    $debug && echo "Trying libraries: $BBOX_LIB_LIST"
+    all_needed=true
+    for one in $BBOX_LIB_LIST; do
+       without_one=`echo " $BBOX_LIB_LIST " | sed "s/ $one / /g" | xargs`
+       l_list=`echo "$without_one" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
+       test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
+       $debug && echo "Trying -l options: '$l_list'"
+       if try "$l_list" "$@"; then
+               echo "Library $one is not needed"
+               BBOX_LIB_LIST="$without_one"
+               all_needed=false
+       else
+               echo "Library $one is needed"
+       fi
+    done
+    # All libs were needed, can't remove any
+    $all_needed && break
+    # If there is no space char, the list has just one lib.
+    # I'm not sure that in this case lib really is 100% needed.
+    # Let's try linking without it anyway... thus commented out.
+    #{ echo "$BBOX_LIB_LIST" | grep -q ' '; } || break
+done
+
+# Make the binary with final, minimal list of libs
+echo "Final link with: $BBOX_LIB_LIST"
+l_list=`echo "$BBOX_LIB_LIST" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
+test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group -Wl,--verbose"
+# --verbose gives us gobs of info to stdout (e.g. linker script used)
+if ! test -f busybox_ldscript; then
+    try "$l_list -Wl,--verbose" "$@" >busybox_ld.out
+else
+    echo "Custom linker script 'busybox_ldscript' found, using it"
+    # Add SORT_BY_ALIGNMENT to linker script (found in busybox_ld.out):
+    #  .rodata         : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) }
+    #  *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*)
+    #  *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*)
+    # This will eliminate most of the data padding (~3kb).
+    try "$l_list -Wl,--verbose -Wl,-T -Wl,busybox_ldscript" "$@" >busybox_ld.out
+fi