diff options
Diffstat (limited to 'release/src/router/busybox/scripts/trylink')
| -rwxr-xr-x | release/src/router/busybox/scripts/trylink | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/release/src/router/busybox/scripts/trylink b/release/src/router/busybox/scripts/trylink new file mode 100755 index 00000000..8c885467 --- /dev/null +++ b/release/src/router/busybox/scripts/trylink @@ -0,0 +1,310 @@ +#!/bin/sh + +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() { + 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) +LDLIBS=`echo "$LDLIBS" | xargs -n1 | sort | uniq | xargs` + +# First link with all libs. If it fails, bail out +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: $l_list" + cat $EXE.out + exit 1 +} + +# Now try to remove each lib and build without it. +# Stop when no lib can be removed. +while test "$LDLIBS"; do + $debug && echo "Trying libraries: $LDLIBS" + all_needed=true + 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'" + 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, can't exclude it (yet)" + last_needed=true + fi + done + # All libs were needed, can't remove any + $all_needed && 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 + +# 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 |