debug=false
+# Linker flags used:
+#
+# Informational:
+# --warn-common
+# -Map $EXE.map
+# --verbose
+#
+# Optimizations:
+# --sort-common reduces padding
+# --sort-section alignment reduces padding
+# --gc-sections throws out unused sections,
+# does not work for shared libs
+# -On Not used, maybe useful?
+#
+# List of files to link:
+# $l_list == --start-group -llib1 -llib2 --end-group
+# --start-group $O_FILES $A_FILES --end-group
+#
+# Shared library link:
+# -shared self-explanatory
+# -fPIC position-independent code
+# --enable-new-dtags ?
+# -z,combreloc ?
+# -soname="libbusybox.so.$BB_VER"
+# --undefined=lbb_main Seed name to start pulling from
+# (otherwise we'll need --whole-archive)
+# -static Not used, but may be useful! manpage:
+# "... This option can be used with -shared.
+# Doing so means that a shared library
+# is being created but that all of the library's
+# external references must be resolved by pulling
+# in entries from static libraries."
+
+
try() {
- added="$1"
- shift
- $debug && echo "Trying: $* $added"
- "$@" $added 2>busybox_ld.err
+ printf "%s\n" "Output of:" >$EXE.out
+ printf "%s\n" "$*" >>$EXE.out
+ printf "%s\n" "==========" >>$EXE.out
+ $debug && echo "Trying: $*"
+ $@ >>$EXE.out 2>&1
+ return $?
}
+check_cc() {
+ local tempname="/tmp/temp.$$.$RANDOM"
+ # Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :(
+ # "-xc": C language. "/dev/null" is an empty source file.
+ if $CC $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then
+ echo "$1";
+ else
+ echo "$2";
+ fi
+ rm "$tempname".o 2>/dev/null
+}
+
+check_libc_is_glibc() {
+ local tempname="/tmp/temp.$$.$RANDOM"
+ echo "\
+ #include <stdlib.h>
+ /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
+ #if defined(__GLIBC__) && !defined(__UCLIBC__)
+ syntax error here
+ #endif
+ " >"$tempname".c
+ if $CC "$tempname".c -c -o "$tempname".o >/dev/null 2>&1; then
+ echo "$2";
+ else
+ echo "$1";
+ fi
+ rm "$tempname".c "$tempname".o 2>/dev/null
+}
+
+EXE="$1"
+CC="$2"
+CFLAGS="$3"
+LDFLAGS="$4"
+O_FILES="$5"
+A_FILES="$6"
+LDLIBS="$7"
+
+# The --sort-section option is not supported by older versions of ld
+SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""`
+
+# Static linking against glibc produces buggy executables
+# (glibc does not cope well with ld --gc-sections).
+# See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
+# Note that glibc is unsuitable for static linking anyway.
+# We are removing -Wl,--gc-sections from link command line.
+GC_SECTIONS=`(
+. ./.config
+if test x"$CONFIG_STATIC" = x"y"; then
+ check_libc_is_glibc "" "-Wl,--gc-sections"
+else
+ echo "-Wl,--gc-sections"
+fi
+)`
+
+# The --gc-sections option is not supported by older versions of ld
+if test -n "$GC_SECTIONS"; then
+ GC_SECTIONS=`check_cc "$GC_SECTIONS" ""`
+fi
+
# 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`
+LDLIBS=`echo "$LDLIBS" | xargs -n1 | sort | uniq | xargs`
# First link with all libs. If it fails, bail out
-l_list=`echo "$BBOX_LIB_LIST" | sed -e 's/ / -l/g' -e 's/^/-l/'`
-echo "Trying libraries: $BBOX_LIB_LIST"
-try "-Wl,--start-group $l_list -Wl,--end-group" "$@" \
+echo "Trying libraries: $LDLIBS"
+# "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
+l_list=`echo "$LDLIBS" | 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 $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
+ $l_list \
|| {
- echo "Failed: $* -Wl,--start-group $l_list -Wl,--end-group"
- cat busybox_ld.err
+ echo "Failed: $l_list"
+ cat $EXE.out
exit 1
}
-#### Hack disabled: conflicts with ld --verbose flag in last link phase
-
-##### Hack: we are not supposed to know executable name,
-##### but this hack cuts down link time
-####mv busybox_unstripped busybox_unstripped.tmp
-####mv busybox.map busybox.map.tmp
-
# Now try to remove each lib and build without it.
# Stop when no lib can be removed.
-####ever_discarded=false
-while test "$BBOX_LIB_LIST"; do
- $debug && echo "Trying libraries: $BBOX_LIB_LIST"
+while test "$LDLIBS"; do
+ $debug && echo "Trying libraries: $LDLIBS"
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/'`
- # If l_list is just "-l" without a lib, then make sure to test the
- # correct thing to fail: just using -l will fail, so the last lib
- # (usually m in my case) will incorrectly be added as needed.
- if test "x$without_one" != "x"; then
- l_list="-Wl,--start-group $l_list -Wl,--end-group"
- else
- # without_one is empty, so l_list has to be empty too
- l_list=""
- fi
+ last_needed=false
+ for one in $LDLIBS; do
+ without_one=`echo " $LDLIBS " | sed "s/ $one / /g" | xargs`
+ # "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
+ l_list=`echo "$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
-#### ever_discarded=true
+ try $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
+ $l_list
+ if test $? = 0; then
+ echo " Library $one is not needed, excluding it"
+ LDLIBS="$without_one"
+ all_needed=false
+ last_needed=false
else
- echo "Library $one is needed"
+ echo " Library $one is needed, can't exclude it (yet)"
+ last_needed=true
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
+ # Optimization: was the last tried lib needed?
+ if $last_needed; then
+ # Was it the only one lib left? Don't test again then.
+ { echo "$LDLIBS" | grep -q ' '; } || break
+ fi
done
-####mv busybox_unstripped.tmp busybox_unstripped
-####mv busybox.map.tmp busybox.map
-####$ever_discarded && {
- # 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/'`
- # --verbose gives us gobs of info to stdout (e.g. linker script used)
- if ! test -f busybox_ldscript; then
- try "-Wl,--start-group $l_list -Wl,--end-group -Wl,--verbose" "$@" >busybox_ld.out ####|| exit 1
- 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 "-Wl,--start-group $l_list -Wl,--end-group -Wl,--verbose -Wl,-T -Wl,busybox_ldscript" "$@" >busybox_ld.out
- fi
-####}
-####rm busybox_ld.err
-####exit 0 # Ensure "success" exit code
+# Make the binary with final, minimal list of libs
+echo "Final link with: ${LDLIBS:-<none>}"
+l_list=`echo "$LDLIBS" | 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"
+# --verbose gives us gobs of info to stdout (e.g. linker script used)
+if ! test -f busybox_ldscript; then
+ try $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
+ $l_list \
+ -Wl,--warn-common \
+ -Wl,-Map,$EXE.map \
+ -Wl,--verbose \
+ || {
+ cat $EXE.out
+ exit 1
+ }
+else
+ echo "Custom linker script 'busybox_ldscript' found, using it"
+ # Add SORT_BY_ALIGNMENT to linker script (found in $EXE.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 padding (~3kb).
+ # Hmm, "ld --sort-section alignment" should do it too.
+ try $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -Wl,-T,busybox_ldscript \
+ -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
+ $l_list \
+ -Wl,--warn-common \
+ -Wl,-Map,$EXE.map \
+ -Wl,--verbose \
+ || {
+ cat $EXE.out
+ exit 1
+ }
+fi
+
+. ./.config
+
+sharedlib_dir="0_lib"
+
+if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
+ mkdir "$sharedlib_dir" 2>/dev/null
+ test -d "$sharedlib_dir" || {
+ echo "Cannot make directory $sharedlib_dir"
+ exit 1
+ }
+ ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
+
+ EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
+ try $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -shared -fPIC \
+ -Wl,--enable-new-dtags \
+ -Wl,-z,combreloc \
+ -Wl,-soname="libbusybox.so.$BB_VER" \
+ -Wl,--undefined=lbb_main \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ -Wl,--start-group $A_FILES -Wl,--end-group \
+ $l_list \
+ -Wl,--warn-common \
+ -Wl,-Map,$EXE.map \
+ -Wl,--verbose \
+ || {
+ echo "Linking $EXE failed"
+ cat $EXE.out
+ exit 1
+ }
+ $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
+ chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
+ echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
+fi
+
+if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
+ EXE="$sharedlib_dir/busybox_unstripped"
+ try $CC $CFLAGS $LDFLAGS \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -Wl,--start-group $O_FILES -Wl,--end-group \
+ -L"$sharedlib_dir" -lbusybox \
+ -Wl,--warn-common \
+ -Wl,-Map,$EXE.map \
+ -Wl,--verbose \
+ || {
+ echo "Linking $EXE failed"
+ cat $EXE.out
+ exit 1
+ }
+ $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
+ echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
+fi
+
+if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
+ echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
+ gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
+ | grep -v "^#" \
+ | grep -v "^$" \
+ > applet_lst.tmp
+ while read name main junk; do
+
+ echo "\
+void lbb_prepare(const char *applet, char **argv);
+int $main(int argc, char **argv);
+
+int main(int argc, char **argv)
+{
+ lbb_prepare(\"$name\", argv);
+ return $main(argc, argv);
+}
+" >"$sharedlib_dir/applet.c"
+
+ EXE="$sharedlib_dir/$name"
+ try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
+ -o $EXE \
+ -Wl,--sort-common \
+ $SORT_SECTION \
+ $GC_SECTIONS \
+ -L"$sharedlib_dir" -lbusybox \
+ -Wl,--warn-common \
+ || {
+ echo "Linking $EXE failed"
+ cat $EXE.out
+ exit 1
+ }
+ rm -- "$sharedlib_dir/applet.c" $EXE.out
+ $STRIP -s --remove-section=.note --remove-section=.comment $EXE
+
+ done <applet_lst.tmp
+fi
+
+# libbusybox.so is needed only for -lbusybox at link time,
+# it is not needed at runtime. Deleting to reduce confusion.
+rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
+exit 0 # or else we may confuse make
projects / oweals / busybox.git / blobdiff