X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=scripts%2Ftrylink;h=8c8854679be80d0294ebb3e807c3a446a1fa8933;hb=7dd0ce49531b6340950b4a3eedbef1c958a475d9;hp=e756461c8f2c8fe25f9cbde0b0d38140ef6af5a1;hpb=d62fd84d4b309bc5fa6548288b82f21189d4f53f;p=oweals%2Fbusybox.git diff --git a/scripts/trylink b/scripts/trylink index e756461c8..8c8854679 100755 --- a/scripts/trylink +++ b/scripts/trylink @@ -2,23 +2,107 @@ 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: $*" - "$@" >>$EXE.out 2>&1 - exitcode=$? - cat $EXE.out - return $exitcode + $@ >>$EXE.out 2>&1 + return $? +} + +check_cc() { + local tempname="/tmp/temp.$$.$RANDOM" + # Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :( + # "-xc": C language. "/dev/null" is an empty source file. + if $CC $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then + echo "$1"; + else + echo "$2"; + fi + rm "$tempname".o 2>/dev/null +} + +check_libc_is_glibc() { + local tempname="/tmp/temp.$$.$RANDOM" + echo "\ + #include + /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */ + #if defined(__GLIBC__) && !defined(__UCLIBC__) + syntax error here + #endif + " >"$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" -LDFLAGS="$3" -O_FILES="$4" -A_FILES="$5" -LDLIBS="$6" +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` @@ -28,14 +112,15 @@ 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 $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ +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 \ - >/dev/null \ || { - echo "Failed: $* $l_list" + echo "Failed: $l_list" cat $EXE.out exit 1 } @@ -45,46 +130,59 @@ try $CC $LDFLAGS \ while test "$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 $l_list -Wl,--end-group" + test x"$l_list" != x"" && l_list="-Wl,--start-group $l_list -Wl,--end-group" $debug && echo "Trying -l options: '$l_list'" - try $CC $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ + 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 \ - >/dev/null + $l_list if test $? = 0; then - echo "Library $one is not needed" + 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 $all_needed && break - # If there is no space char, the list has just one lib. - # I'm not sure that in this case lib really is 100% needed. - # Let's try linking without it anyway... thus commented out. - #{ echo "$LDLIBS" | 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 # Make the binary with final, minimal list of libs -echo "Final link with: $LDLIBS" +echo "Final link with: ${LDLIBS:-}" l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'` -test "x$l_list" != "x" && l_list="-Wl,--start-group $l_list -Wl,--end-group -Wl,--verbose" +test "x$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 $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ + 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,--verbose \ - >/dev/null + $l_list \ + -Wl,--warn-common \ + -Wl,-Map,$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): @@ -92,16 +190,25 @@ else # *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*) # *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*) # This will eliminate most of the padding (~3kb). - try $CC $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ + # 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,--verbose \ - -Wl,-T -Wl,busybox_ldscript \ - >/dev/null + $l_list \ + -Wl,--warn-common \ + -Wl,-Map,$EXE.map \ + -Wl,--verbose \ + || { + cat $EXE.out + exit 1 + } fi -. .config +. ./.config sharedlib_dir="0_lib" @@ -114,83 +221,90 @@ if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped" - try $CC $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -shared -fPIC -Wl,--enable-new-dtags \ - -Wl,--start-group -Wl,--whole-archive $A_FILES -Wl,--no-whole-archive -Wl,--end-group \ - $l_list -Wl,--verbose \ - -Wl,-soname="libbusybox.so.$BB_VER" \ - -Wl,-z,combreloc \ - >/dev/null \ + 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" + $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 $LDFLAGS \ - -o $EXE -Wl,-Map -Wl,$EXE.map \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ - -Wl,--start-group $O_FILES -Wl,--end-group \ - -Wl,--verbose \ - -L"$sharedlib_dir" -lbusybox \ - >/dev/null \ + 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" + $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 - while read name main cname; do - - test x"$cname" = "x[" && cname=test - test x"$cname" = "x[[" && cname=test + > applet_lst.tmp + while read name main junk; do echo "\ -void bbox_prepare_main(void); +void lbb_prepare(const char *applet, char **argv); int $main(int argc, char **argv); -const char *applet_name = \"$name\"; - int main(int argc, char **argv) { - bbox_prepare_main(); + lbb_prepare(\"$name\", argv); return $main(argc, argv); } " >"$sharedlib_dir/applet.c" EXE="$sharedlib_dir/$name" - try $CC $LDFLAGS "$sharedlib_dir/applet.c" \ - -o $EXE \ - -Wl,--warn-common -Wl,--sort-common -Wl,--gc-sections \ - -L"$sharedlib_dir" -lbusybox \ - >/dev/null \ + 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 + cat $EXE.out exit 1 } rm -- "$sharedlib_dir/applet.c" $EXE.out - strip -s --remove-section=.note --remove-section=.comment $EXE - echo "applet linked against libbusybox: $EXE" + $STRIP -s --remove-section=.note --remove-section=.comment $EXE - done /dev/null +rm "$sharedlib_dir"/libbusybox.so 2>/dev/null +exit 0 # or else we may confuse make