13 # --sort-common reduces padding
14 # --sort-section alignment reduces padding
15 # --gc-sections throws out unused sections,
16 # does not work for shared libs
17 # -On Not used, maybe useful?
19 # List of files to link:
20 # $l_list == --start-group -llib1 -llib2 --end-group
21 # --start-group $O_FILES $A_FILES --end-group
23 # Shared library link:
24 # -shared self-explanatory
25 # -fPIC position-independent code
26 # --enable-new-dtags ?
28 # -soname="libbusybox.so.$BB_VER"
29 # --undefined=lbb_main Seed name to start pulling from
30 # (otherwise we'll need --whole-archive)
31 # -static Not used, but may be useful! manpage:
32 # "... This option can be used with -shared.
33 # Doing so means that a shared library
34 # is being created but that all of the library's
35 # external references must be resolved by pulling
36 # in entries from static libraries."
40 printf "%s\n" "Output of:" >$EXE.out
41 printf "%s\n" "$*" >>$EXE.out
42 printf "%s\n" "==========" >>$EXE.out
43 $debug && echo "Trying: $*"
50 if $CC $1 -shared -o /dev/null -xc /dev/null >/dev/null 2>&1; then
57 check_libc_is_glibc() {
58 local tempname="/tmp/temp.$$.$RANDOM.c"
61 /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
62 #if defined(__GLIBC__) && !defined(__UCLIBC__)
66 if $CC "$tempname" -c -o /dev/null >/dev/null 2>&1; then
81 # The -Wl,--sort-section option is not supported by older versions of ld
82 SORT_SECTION=`check_cc "-Wl,--sort-section -Wl,alignment" ""`
84 # Static linking against glibc produces buggy executables
85 # (glibc does not cope well with ld --gc-sections).
86 # See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
87 # Note that glibc is unsuitable for static linking anyway.
88 # We are removing -Wl,--gc-sections from link command line.
91 if test x"$CONFIG_STATIC" = x"y"; then
92 check_libc_is_glibc "" "-Wl,--gc-sections"
94 echo "-Wl,--gc-sections"
98 # Sanitize lib list (dups, extra spaces etc)
99 LDLIBS=`echo "$LDLIBS" | xargs -n1 | sort | uniq | xargs`
101 # First link with all libs. If it fails, bail out
102 echo "Trying libraries: $LDLIBS"
103 # "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
104 l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
105 test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
111 -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
114 echo "Failed: $* $l_list"
119 # Now try to remove each lib and build without it.
120 # Stop when no lib can be removed.
121 while test "$LDLIBS"; do
122 $debug && echo "Trying libraries: $LDLIBS"
124 for one in $LDLIBS; do
125 without_one=`echo " $LDLIBS " | sed "s/ $one / /g" | xargs`
126 # "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
127 l_list=`echo "$without_one" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
128 test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
129 $debug && echo "Trying -l options: '$l_list'"
135 -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
138 echo " Library $one is not needed"
139 LDLIBS="$without_one"
142 echo " Library $one is needed"
145 # All libs were needed, can't remove any
147 # If there is no space char, the list has just one lib.
148 # I'm not sure that in this case lib really is 100% needed.
149 # Let's try linking without it anyway... thus commented out.
150 #{ echo "$LDLIBS" | grep -q ' '; } || break
153 # Make the binary with final, minimal list of libs
154 echo "Final link with: ${LDLIBS:-<none>}"
155 l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
156 test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group"
157 # --verbose gives us gobs of info to stdout (e.g. linker script used)
158 if ! test -f busybox_ldscript; then
164 -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
167 -Wl,-Map -Wl,$EXE.map \
174 echo "Custom linker script 'busybox_ldscript' found, using it"
175 # Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
176 # .rodata : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) }
177 # *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*)
178 # *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*)
179 # This will eliminate most of the padding (~3kb).
180 # Hmm, "ld --sort-section alignment" should do it too.
186 -Wl,-T -Wl,busybox_ldscript \
187 -Wl,--start-group $O_FILES $A_FILES -Wl,--end-group \
190 -Wl,-Map -Wl,$EXE.map \
200 sharedlib_dir="0_lib"
202 if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
203 mkdir "$sharedlib_dir" 2>/dev/null
204 test -d "$sharedlib_dir" || {
205 echo "Cannot make directory $sharedlib_dir"
208 ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
210 EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
214 -Wl,--enable-new-dtags \
216 -Wl,-soname="libbusybox.so.$BB_VER" \
217 -Wl,--undefined=lbb_main \
220 -Wl,--start-group $A_FILES -Wl,--end-group \
223 -Wl,-Map -Wl,$EXE.map \
226 echo "Linking $EXE failed"
230 $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
231 chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
232 echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
235 if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
236 EXE="$sharedlib_dir/busybox_unstripped"
242 -Wl,--start-group $O_FILES -Wl,--end-group \
243 -L"$sharedlib_dir" -lbusybox \
245 -Wl,-Map -Wl,$EXE.map \
248 echo "Linking $EXE failed"
252 $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
253 echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
256 if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
257 echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
258 gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
262 while read name main junk; do
265 void lbb_prepare(const char *applet, char **argv);
266 int $main(int argc, char **argv);
268 int main(int argc, char **argv)
270 lbb_prepare(\"$name\", argv);
271 return $main(argc, argv);
273 " >"$sharedlib_dir/applet.c"
275 EXE="$sharedlib_dir/$name"
276 try $CC $LDFLAGS "$sharedlib_dir/applet.c" \
281 -L"$sharedlib_dir" -lbusybox \
284 echo "Linking $EXE failed"
288 rm -- "$sharedlib_dir/applet.c" $EXE.out
289 $STRIP -s --remove-section=.note --remove-section=.comment $EXE
294 # libbusybox.so is needed only for -lbusybox at link time,
295 # it is not needed at runtime. Deleting to reduce confusion.
296 rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
297 exit 0 # or else we may confuse make