[1765] | 1 | #!/bin/sh
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| 2 |
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| 3 | debug=false
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| 4 |
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[2725] | 5 | # Linker flags used:
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| 6 | #
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| 7 | # Informational:
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| 8 | # --warn-common
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| 9 | # -Map $EXE.map
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| 10 | # --verbose
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| 11 | #
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| 12 | # Optimizations:
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| 13 | # --sort-common reduces padding
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| 14 | # --sort-section alignment reduces padding
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| 15 | # --gc-sections throws out unused sections,
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| 16 | # does not work for shared libs
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| 17 | # -On Not used, maybe useful?
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| 18 | #
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| 19 | # List of files to link:
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| 20 | # $l_list == --start-group -llib1 -llib2 --end-group
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| 21 | # --start-group $O_FILES $A_FILES --end-group
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| 22 | #
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| 23 | # Shared library link:
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| 24 | # -shared self-explanatory
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| 25 | # -fPIC position-independent code
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| 26 | # --enable-new-dtags ?
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| 27 | # -z,combreloc ?
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| 28 | # -soname="libbusybox.so.$BB_VER"
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| 29 | # --undefined=lbb_main Seed name to start pulling from
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| 30 | # (otherwise we'll need --whole-archive)
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| 31 | # -static Not used, but may be useful! manpage:
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| 32 | # "... This option can be used with -shared.
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| 33 | # Doing so means that a shared library
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| 34 | # is being created but that all of the library's
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| 35 | # external references must be resolved by pulling
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| 36 | # in entries from static libraries."
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| 37 |
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| 38 |
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[1765] | 39 | try() {
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[2725] | 40 | printf "%s\n" "Output of:" >$EXE.out
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| 41 | printf "%s\n" "$*" >>$EXE.out
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| 42 | printf "%s\n" "==========" >>$EXE.out
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| 43 | $debug && echo "Trying: $*"
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| 44 | $@ >>$EXE.out 2>&1
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| 45 | return $?
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[1765] | 46 | }
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| 47 |
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[2725] | 48 | check_cc() {
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| 49 | local tempname="/tmp/temp.$$.$RANDOM"
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| 50 | # Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :(
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| 51 | # "-xc": C language. "/dev/null" is an empty source file.
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| 52 | if $CC $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then
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| 53 | echo "$1";
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| 54 | else
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| 55 | echo "$2";
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| 56 | fi
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| 57 | rm "$tempname".o 2>/dev/null
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| 58 | }
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| 59 |
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| 60 | check_libc_is_glibc() {
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| 61 | local tempname="/tmp/temp.$$.$RANDOM"
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| 62 | echo "\
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| 63 | #include <stdlib.h>
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| 64 | /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
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| 65 | #if defined(__GLIBC__) && !defined(__UCLIBC__)
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| 66 | syntax error here
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| 67 | #endif
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| 68 | " >"$tempname".c
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| 69 | if $CC "$tempname".c -c -o "$tempname".o >/dev/null 2>&1; then
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| 70 | echo "$2";
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| 71 | else
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| 72 | echo "$1";
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| 73 | fi
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| 74 | rm "$tempname".c "$tempname".o 2>/dev/null
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| 75 | }
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| 76 |
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| 77 | EXE="$1"
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| 78 | CC="$2"
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| 79 | CFLAGS="$3"
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| 80 | LDFLAGS="$4"
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| 81 | O_FILES="$5"
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| 82 | A_FILES="$6"
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| 83 | LDLIBS="$7"
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| 84 |
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| 85 | # The --sort-section option is not supported by older versions of ld
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| 86 | SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""`
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| 87 |
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| 88 | START_GROUP="-Wl,--start-group"
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| 89 | END_GROUP="-Wl,--end-group"
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| 90 | INFO_OPTS="-Wl,--warn-common -Wl,-Map,$EXE.map -Wl,--verbose"
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| 91 |
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| 92 | # gold may not support --sort-common (yet)
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| 93 | SORT_COMMON=`check_cc "-Wl,--sort-common" ""`
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| 94 |
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| 95 | # Static linking against glibc produces buggy executables
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| 96 | # (glibc does not cope well with ld --gc-sections).
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| 97 | # See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
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| 98 | # Note that glibc is unsuitable for static linking anyway.
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| 99 | # We are removing -Wl,--gc-sections from link command line.
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| 100 | GC_SECTIONS=`(
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| 101 | . ./.config
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| 102 | if test x"$CONFIG_STATIC" = x"y"; then
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| 103 | check_libc_is_glibc "" "-Wl,--gc-sections"
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| 104 | else
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| 105 | echo "-Wl,--gc-sections"
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| 106 | fi
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| 107 | )`
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| 108 |
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| 109 | # The --gc-sections option is not supported by older versions of ld
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| 110 | if test -n "$GC_SECTIONS"; then
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| 111 | GC_SECTIONS=`check_cc "$GC_SECTIONS" ""`
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| 112 | fi
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| 113 |
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[1765] | 114 | # Sanitize lib list (dups, extra spaces etc)
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[2725] | 115 | LDLIBS=`echo "$LDLIBS" | xargs -n1 | sort | uniq | xargs`
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[1765] | 116 |
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| 117 | # First link with all libs. If it fails, bail out
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[2725] | 118 | echo "Trying libraries: $LDLIBS"
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| 119 | # "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
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| 120 | l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
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| 121 | test "x$l_list" != "x" && l_list="$START_GROUP $l_list $END_GROUP"
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| 122 | try $CC $CFLAGS $LDFLAGS \
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| 123 | -o $EXE \
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| 124 | $SORT_COMMON \
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| 125 | $SORT_SECTION \
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| 126 | $GC_SECTIONS \
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| 127 | $START_GROUP $O_FILES $A_FILES $END_GROUP \
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| 128 | $l_list \
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[1765] | 129 | || {
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[2725] | 130 | echo "Failed: $l_list"
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| 131 | cat $EXE.out
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[1765] | 132 | exit 1
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| 133 | }
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| 134 |
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| 135 | # Now try to remove each lib and build without it.
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| 136 | # Stop when no lib can be removed.
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[2725] | 137 | while test "$LDLIBS"; do
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| 138 | $debug && echo "Trying libraries: $LDLIBS"
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[1765] | 139 | all_needed=true
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[2725] | 140 | last_needed=false
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| 141 | for one in $LDLIBS; do
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| 142 | without_one=`echo " $LDLIBS " | sed "s/ $one / /g" | xargs`
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| 143 | # "lib1 lib2 lib3" -> "-llib1 -llib2 -llib3"
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[1765] | 144 | l_list=`echo "$without_one" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
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[2725] | 145 | test x"$l_list" != x"" && l_list="$START_GROUP $l_list $END_GROUP"
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[1765] | 146 | $debug && echo "Trying -l options: '$l_list'"
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[2725] | 147 | try $CC $CFLAGS $LDFLAGS \
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| 148 | -o $EXE \
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| 149 | $SORT_COMMON \
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| 150 | $SORT_SECTION \
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| 151 | $GC_SECTIONS \
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| 152 | $START_GROUP $O_FILES $A_FILES $END_GROUP \
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| 153 | $l_list
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| 154 | if test $? = 0; then
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| 155 | echo " Library $one is not needed, excluding it"
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| 156 | LDLIBS="$without_one"
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| 157 | all_needed=false
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| 158 | last_needed=false
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[1765] | 159 | else
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[2725] | 160 | echo " Library $one is needed, can't exclude it (yet)"
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| 161 | last_needed=true
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[1765] | 162 | fi
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| 163 | done
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| 164 | # All libs were needed, can't remove any
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| 165 | $all_needed && break
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[2725] | 166 | # Optimization: was the last tried lib needed?
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| 167 | if $last_needed; then
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| 168 | # Was it the only one lib left? Don't test again then.
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| 169 | { echo "$LDLIBS" | grep -q ' '; } || break
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| 170 | fi
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[1765] | 171 | done
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| 172 |
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| 173 | # Make the binary with final, minimal list of libs
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[2725] | 174 | echo "Final link with: ${LDLIBS:-<none>}"
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| 175 | l_list=`echo "$LDLIBS" | sed -e 's/ / -l/g' -e 's/^/-l/' -e 's/^-l$//'`
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| 176 | test "x$l_list" != "x" && l_list="$START_GROUP $l_list $END_GROUP"
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[1765] | 177 | # --verbose gives us gobs of info to stdout (e.g. linker script used)
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| 178 | if ! test -f busybox_ldscript; then
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[2725] | 179 | try $CC $CFLAGS $LDFLAGS \
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| 180 | -o $EXE \
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| 181 | $SORT_COMMON \
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| 182 | $SORT_SECTION \
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| 183 | $GC_SECTIONS \
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| 184 | $START_GROUP $O_FILES $A_FILES $END_GROUP \
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| 185 | $l_list \
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| 186 | $INFO_OPTS \
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| 187 | || {
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| 188 | cat $EXE.out
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| 189 | exit 1
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| 190 | }
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[1765] | 191 | else
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| 192 | echo "Custom linker script 'busybox_ldscript' found, using it"
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[2725] | 193 | # Add SORT_BY_ALIGNMENT to linker script (found in $EXE.out):
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[1765] | 194 | # .rodata : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) }
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| 195 | # *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*)
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| 196 | # *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*)
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[2725] | 197 | # This will eliminate most of the padding (~3kb).
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| 198 | # Hmm, "ld --sort-section alignment" should do it too.
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| 199 | try $CC $CFLAGS $LDFLAGS \
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| 200 | -o $EXE \
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| 201 | $SORT_COMMON \
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| 202 | $SORT_SECTION \
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| 203 | $GC_SECTIONS \
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| 204 | -Wl,-T,busybox_ldscript \
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| 205 | $START_GROUP $O_FILES $A_FILES $END_GROUP \
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| 206 | $l_list \
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| 207 | $INFO_OPTS \
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| 208 | || {
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| 209 | cat $EXE.out
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| 210 | exit 1
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| 211 | }
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[1765] | 212 | fi
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[2725] | 213 |
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| 214 | . ./.config
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| 215 |
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| 216 | sharedlib_dir="0_lib"
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| 217 |
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| 218 | if test "$CONFIG_BUILD_LIBBUSYBOX" = y; then
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| 219 | mkdir "$sharedlib_dir" 2>/dev/null
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| 220 | test -d "$sharedlib_dir" || {
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| 221 | echo "Cannot make directory $sharedlib_dir"
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| 222 | exit 1
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| 223 | }
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| 224 | ln -s "libbusybox.so.$BB_VER" "$sharedlib_dir"/libbusybox.so 2>/dev/null
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| 225 |
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| 226 | EXE="$sharedlib_dir/libbusybox.so.${BB_VER}_unstripped"
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| 227 | try $CC $CFLAGS $LDFLAGS \
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| 228 | -o $EXE \
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| 229 | -shared -fPIC \
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| 230 | -Wl,--enable-new-dtags \
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| 231 | -Wl,-z,combreloc \
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| 232 | -Wl,-soname="libbusybox.so.$BB_VER" \
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| 233 | -Wl,--undefined=lbb_main \
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| 234 | $SORT_COMMON \
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| 235 | $SORT_SECTION \
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| 236 | $START_GROUP $A_FILES $END_GROUP \
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| 237 | $l_list \
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| 238 | $INFO_OPTS \
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| 239 | || {
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| 240 | echo "Linking $EXE failed"
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| 241 | cat $EXE.out
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| 242 | exit 1
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| 243 | }
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| 244 | $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/libbusybox.so.$BB_VER"
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| 245 | chmod a+x "$sharedlib_dir/libbusybox.so.$BB_VER"
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| 246 | echo "libbusybox: $sharedlib_dir/libbusybox.so.$BB_VER"
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| 247 | fi
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| 248 |
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| 249 | if test "$CONFIG_FEATURE_SHARED_BUSYBOX" = y; then
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| 250 | EXE="$sharedlib_dir/busybox_unstripped"
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| 251 | try $CC $CFLAGS $LDFLAGS \
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| 252 | -o $EXE \
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| 253 | $SORT_COMMON \
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| 254 | $SORT_SECTION \
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| 255 | $GC_SECTIONS \
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| 256 | $START_GROUP $O_FILES $END_GROUP \
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| 257 | -L"$sharedlib_dir" -lbusybox \
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[3232] | 258 | $l_list \
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[2725] | 259 | $INFO_OPTS \
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| 260 | || {
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| 261 | echo "Linking $EXE failed"
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| 262 | cat $EXE.out
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| 263 | exit 1
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| 264 | }
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| 265 | $STRIP -s --remove-section=.note --remove-section=.comment $EXE -o "$sharedlib_dir/busybox"
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| 266 | echo "busybox linked against libbusybox: $sharedlib_dir/busybox"
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| 267 | fi
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| 268 |
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| 269 | if test "$CONFIG_FEATURE_INDIVIDUAL" = y; then
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| 270 | echo "Linking individual applets against libbusybox (see $sharedlib_dir/*)"
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| 271 | gcc -DNAME_MAIN_CNAME -E -include include/autoconf.h include/applets.h \
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| 272 | | grep -v "^#" \
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| 273 | | grep -v "^$" \
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| 274 | > applet_lst.tmp
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| 275 | while read name main junk; do
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| 276 |
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| 277 | echo "\
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| 278 | void lbb_prepare(const char *applet, char **argv);
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| 279 | int $main(int argc, char **argv);
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| 280 |
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| 281 | int main(int argc, char **argv)
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| 282 | {
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| 283 | lbb_prepare(\"$name\", argv);
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| 284 | return $main(argc, argv);
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| 285 | }
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| 286 | " >"$sharedlib_dir/applet.c"
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| 287 |
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| 288 | EXE="$sharedlib_dir/$name"
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| 289 | try $CC $CFLAGS $LDFLAGS "$sharedlib_dir/applet.c" \
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| 290 | -o $EXE \
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| 291 | $SORT_COMMON \
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| 292 | $SORT_SECTION \
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| 293 | $GC_SECTIONS \
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| 294 | -L"$sharedlib_dir" -lbusybox \
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| 295 | -Wl,--warn-common \
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| 296 | || {
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| 297 | echo "Linking $EXE failed"
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| 298 | cat $EXE.out
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| 299 | exit 1
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| 300 | }
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| 301 | rm -- "$sharedlib_dir/applet.c" $EXE.out
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| 302 | $STRIP -s --remove-section=.note --remove-section=.comment $EXE
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| 303 |
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| 304 | done <applet_lst.tmp
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| 305 | fi
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| 306 |
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| 307 | # libbusybox.so is needed only for -lbusybox at link time,
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| 308 | # it is not needed at runtime. Deleting to reduce confusion.
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| 309 | rm "$sharedlib_dir"/libbusybox.so 2>/dev/null
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| 310 | exit 0 # or else we may confuse make
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