93e1aaa1c7
This lets gcc optimize much better: text data bss dec hex filename 922846 910 13056 936812 e4b6c busybox_unstripped.nonconst 920255 910 13056 934221 e414d busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
118 lines
3.3 KiB
Bash
Executable File
118 lines
3.3 KiB
Bash
Executable File
#!/bin/sh
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# Called from top-level directory a-la
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#
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# scripts/generate_BUFSIZ.sh include/common_bufsiz.h
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. ./.config || exit 1
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debug=false
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common_bufsiz_h=$1
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test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm"
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test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc"
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regenerate() {
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cat >"$1.$$"
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test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return
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mv "$1.$$" "$1"
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}
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generate_std_and_exit() {
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$debug && echo "Default: bb_common_bufsiz1[] in bss"
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{
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echo "enum { COMMON_BUFSIZE = 1024 };"
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echo "extern char bb_common_bufsiz1[];"
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echo "#define setup_common_bufsiz() ((void)0)"
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} | regenerate "$common_bufsiz_h"
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exit 0
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}
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# User does not want any funky stuff?
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test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
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test -f busybox_unstripped || {
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# We did not try anything yet
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$debug && echo "Will try to fit bb_common_bufsiz1[] into _end[]"
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{
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echo "enum { COMMON_BUFSIZE = 1024 };"
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echo "extern char _end[]; /* linker-provided label */"
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echo "#define bb_common_bufsiz1 _end"
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echo "#define setup_common_bufsiz() ((void)0)"
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} | regenerate "$common_bufsiz_h"
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echo 1024 >"$common_bufsiz_h.BUFSIZE"
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exit 0
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}
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# Get _end address
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END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
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test x"$END" = x"" && generate_std_and_exit
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$debug && echo "END:0x$END $((0x$END))"
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END=$((0x$END))
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# Get PAGE_SIZE
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echo "\
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#include <sys/user.h>
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#if defined(PAGE_SIZE) && PAGE_SIZE > 0
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char page_size[PAGE_SIZE];
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#else
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char page_size[1];
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#endif
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" >page_size_$$.c
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$CC -c "page_size_$$.c" || generate_std_and_exit
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PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
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rm "page_size_$$.c" "page_size_$$.o"
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test x"$PAGE_SIZE" = x"" && generate_std_and_exit
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$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
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PAGE_SIZE=$((0x$PAGE_SIZE))
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test $PAGE_SIZE -lt 1024 && generate_std_and_exit
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# How much space between _end[] and next page?
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PAGE_MASK=$((PAGE_SIZE-1))
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REM=$(( (-END) & PAGE_MASK ))
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$debug && echo "REM:$REM"
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if test $REM -lt 1024; then
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# _end[] has no enough space for bb_common_bufsiz1[],
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# users will need to malloc it.
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{
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echo "enum { COMMON_BUFSIZE = 1024 };"
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echo "extern char *const bb_common_bufsiz1;"
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echo "void setup_common_bufsiz(void);"
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} | regenerate "$common_bufsiz_h"
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# Check that we aren't left with a buggy binary:
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if test -f "$common_bufsiz_h.BUFSIZE"; then
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rm "$common_bufsiz_h.BUFSIZE"
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echo "Warning! Space in _end[] is too small ($REM bytes)!"
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echo "Rerun make to build a binary which doesn't use it!"
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exit 1
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fi
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echo "COMMON_BUFSIZE = 1024 bytes, the buffer will be malloced"
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exit 0
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fi
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# _end[] has REM bytes for bb_common_bufsiz1[]
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OLD=1024
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test -f "$common_bufsiz_h.BUFSIZE" && OLD=`cat "$common_bufsiz_h.BUFSIZE"`
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$debug && echo "OLD:$OLD"
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{
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echo "enum { COMMON_BUFSIZE = $REM };"
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echo "extern char _end[]; /* linker-provided label */"
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echo "#define bb_common_bufsiz1 _end"
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echo "#define setup_common_bufsiz() ((void)0)"
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} | regenerate "$common_bufsiz_h"
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echo $REM >"$common_bufsiz_h.BUFSIZE"
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# Check that code did not grow too much and thus _end[] did not shrink:
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if test $OLD -gt $REM; then
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echo "Warning! Space in _end[] has decreased from $OLD to $REM bytes!"
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echo "Rerun make!"
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exit 1
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fi
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if test $OLD != $REM; then
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echo "Space in _end[] is $REM bytes. Rerun make to use larger COMMON_BUFSIZE."
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else
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echo "COMMON_BUFSIZE = $REM bytes"
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fi
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