scripts/trylink - codeaurora/busybox - Gitiles

 #!/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" ""`

 # gold may not support --sort-common (yet)
 SORT_COMMON=`check_cc "-Wl,--sort-common" ""`

 # 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 \
 	$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 \
 		$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 \
 	    $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 \
 	    $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 \
 	    $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 \
 	    $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 \
 		$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
	#!/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" ""`

	# gold may not support --sort-common (yet)
	SORT_COMMON=`check_cc "-Wl,--sort-common" ""`

	# 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 \
	$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 \
	$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 \
	$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 \
	$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 \
	$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 \
	$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 \
	$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