Re: Symbol visibility revised

["H . J . Lu" <hjl at valinux dot com>]

On Mon, May 01, 2000 at 07:38:18PM +0200, Martin v. Loewis wrote:
> This patch implements some of the symbol visibility aspects in the
> static linker, which my previous patch assumed as the dynamic linker's
> responsibility. It includes the patch Chip sent last month. The
> immediate need for this patch is GCC's usage of .hidden as part of the
> new C++ ABI, and the lack for .hidden support in dynamic linkers.
> 

Here is the testcase. It failed with your patch.

# ./foo
zsh: 4370 segmentation fault  ./foo
# objdump --dynamic-reloc libfoo.so

libfoo.so:     file format elf32-i386

zsh: 4366 segmentation fault  objdump --dynamic-reloc libfoo.so
# readelf -r libfoo.so
......
Relocation section '.rel.plt' at offset 0x634 contains 6 entries:
  Offset    Info  Type            Symbol's Value  Symbol's Name
  000018fc  01907 R_386_JUMP_SLOT       00000000  atexit                   
  00001900  01b07 R_386_JUMP_SLOT       00000000  __register_frame_info    
  00001904  01e07 R_386_JUMP_SLOT       00000000  __deregister_frame_info  
  00001908  02107 R_386_JUMP_SLOT       00000000  printf                   
  0000190c  ffffff07 R_386_JUMP_SLOT       bad symbol index: 00ffffff
  00001910  02907 R_386_JUMP_SLOT       00000000  __gmon_start__           

You have to fix the PLT entries for hidden symbols.


H.J.
----
#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.2.1).
# To extract the files from this archive, save it to some FILE, remove
# everything before the `!/bin/sh' line above, then type `sh FILE'.
#
# Made on 2000-04-07 21:10 PDT by <hjl@osmium.su.varesearch.com>.
# Source directory was `/home/hjl/bugs/gas/hidden'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode       name
# ------ ---------- ------------------------------------------
#     65 -rw-r--r-- foo.c
#     54 -rw-r--r-- main.c
#    438 -rw-r--r-- Makefile
#
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=FAILED
locale_dir=FAILED
first_param="$1"
for dir in $PATH
do
  if test "$gettext_dir" = FAILED && test -f $dir/gettext \
     && ($dir/gettext --version >/dev/null 2>&1)
  then
    set `$dir/gettext --version 2>&1`
    if test "$3" = GNU
    then
      gettext_dir=$dir
    fi
  fi
  if test "$locale_dir" = FAILED && test -f $dir/shar \
     && ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
  then
    locale_dir=`$dir/shar --print-text-domain-dir`
  fi
done
IFS="$save_IFS"
if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
then
  echo=echo
else
  TEXTDOMAINDIR=$locale_dir
  export TEXTDOMAINDIR
  TEXTDOMAIN=sharutils
  export TEXTDOMAIN
  echo="$gettext_dir/gettext -s"
fi
if touch -am -t 200112312359.59 $$.touch >/dev/null 2>&1 && test ! -f 200112312359.59 -a -f $$.touch; then
  shar_touch='touch -am -t $1$2$3$4$5$6.$7 "$8"'
elif touch -am 123123592001.59 $$.touch >/dev/null 2>&1 && test ! -f 123123592001.59 -a ! -f 123123592001.5 -a -f $$.touch; then
  shar_touch='touch -am $3$4$5$6$1$2.$7 "$8"'
elif touch -am 1231235901 $$.touch >/dev/null 2>&1 && test ! -f 1231235901 -a -f $$.touch; then
  shar_touch='touch -am $3$4$5$6$2 "$8"'
else
  shar_touch=:
  echo
  $echo 'WARNING: not restoring timestamps.  Consider getting and'
  $echo "installing GNU \`touch', distributed in GNU File Utilities..."
  echo
fi
rm -f 200112312359.59 123123592001.59 123123592001.5 1231235901 $$.touch
#
if mkdir _sh00820; then
  $echo 'x -' 'creating lock directory'
else
  $echo 'failed to create lock directory'
  exit 1
fi
# ============= foo.c ==============
if test -f 'foo.c' && test "$first_param" != -c; then
  $echo 'x -' SKIPPING 'foo.c' '(file already exists)'
else
  $echo 'x -' extracting 'foo.c' '(text)'
  sed 's/^X//' << 'SHAR_EOF' > 'foo.c' &&
void
bar ()
{
X  printf ("Hello\n");
}
X
void
foo ()
{
X  bar ();
}
SHAR_EOF
  (set 20 00 04 07 21 10 28 'foo.c'; eval "$shar_touch") &&
  chmod 0644 'foo.c' ||
  $echo 'restore of' 'foo.c' 'failed'
  if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
  && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
    md5sum -c << SHAR_EOF >/dev/null 2>&1 \
    || $echo 'foo.c:' 'MD5 check failed'
dcc44729d5741c566699aea1f88e2b02  foo.c
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'foo.c'`"
    test 65 -eq "$shar_count" ||
    $echo 'foo.c:' 'original size' '65,' 'current size' "$shar_count!"
  fi
fi
# ============= main.c ==============
if test -f 'main.c' && test "$first_param" != -c; then
  $echo 'x -' SKIPPING 'main.c' '(file already exists)'
else
  $echo 'x -' extracting 'main.c' '(text)'
  sed 's/^X//' << 'SHAR_EOF' > 'main.c' &&
void foo ();
X
int
main ()
{
X
X  foo ();
X
X  return 0;
}
SHAR_EOF
  (set 20 00 04 07 20 11 37 'main.c'; eval "$shar_touch") &&
  chmod 0644 'main.c' ||
  $echo 'restore of' 'main.c' 'failed'
  if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
  && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
    md5sum -c << SHAR_EOF >/dev/null 2>&1 \
    || $echo 'main.c:' 'MD5 check failed'
ffad46a6b66294bd257c1317767a44f6  main.c
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'main.c'`"
    test 54 -eq "$shar_count" ||
    $echo 'main.c:' 'original size' '54,' 'current size' "$shar_count!"
  fi
fi
# ============= Makefile ==============
if test -f 'Makefile' && test "$first_param" != -c; then
  $echo 'x -' SKIPPING 'Makefile' '(file already exists)'
else
  $echo 'x -' extracting 'Makefile' '(text)'
  sed 's/^X//' << 'SHAR_EOF' > 'Makefile' &&
CFLAGS=-O -B./
X
PROGS= foo
X
all: $(PROGS)
X	for f in $(PROGS); do echo "Running: $$f"; ./$$f; \
X	  if [ $$? != 0 ]; then echo Failed; fi; done
X
foo: libfoo.so main.c
X	$(CC) -o $@ $(CFLAGS) $^ -Wl,-rpath,. -rdynamic
X
libfoo.so: foo.o
X	$(CC) -shared -o $@ $(CFLAGS) $^
X
foo.o: foo.s
X	$(CC) -c $^
X
foo.s: foo.c
X	$(CC) -S  -fPIC $(CFLAGS) $^
X	echo ".hidden bar" >> $@
X
clean:
X	rm -f $(PROGS) *.so *.o *.s
X
X
shar:
X	shar *.c Makefile > bug.shar
SHAR_EOF
  (set 20 00 04 07 21 09 40 'Makefile'; eval "$shar_touch") &&
  chmod 0644 'Makefile' ||
  $echo 'restore of' 'Makefile' 'failed'
  if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
  && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
    md5sum -c << SHAR_EOF >/dev/null 2>&1 \
    || $echo 'Makefile:' 'MD5 check failed'
be6c034589a395c2b5be84245e795435  Makefile
SHAR_EOF
  else
    shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'Makefile'`"
    test 438 -eq "$shar_count" ||
    $echo 'Makefile:' 'original size' '438,' 'current size' "$shar_count!"
  fi
fi
rm -fr _sh00820
exit 0