Re: [AArch64/bfd/2.24] relocation truncated to fit: R_AARCH64_LD64_GOT_LO12_NC against

[David Abdurachmanov <david dot abdurachmanov at gmail dot com>]

On Jul 11, 2014, at 10:35 PM, Andreas Schwab wrote:

> David Abdurachmanov <david.abdurachmanov@gmail.com> writes:
> 
>> I got these linker errors:
>> 
>> libcvmfs.a(libcvmfs.a_pub.o): In function `TryArgumentFormatter':
>> :(.text+0x77044): relocation truncated to fit: R_AARCH64_LD64_GOT_LO12_NC against `js_GetErrorMessage'
> 
> That usually happens when there are conflicting declarations, ie. the
> same variable has different types in different translation units.  In
> other words, this is a bug in the sources, not in the linker.

  I have some doubts about it. I removed SpiderMonkey from dependencies and
from code, then I had problems with cURL. I updated cURL, then I had different
cURL relocation problem. It always seems to be related to functions, e.g.,
passing a callback (function pointer). It's always R_AARCH64_LD64_GOT_LO12_NC.

  The current one:

  libcvmfs.a(libcvmfs.a_pub.o): In function `Curl_http':
  :(.text+0x8234c): relocation truncated to fit: R_AARCH64_LD64_GOT_LO12_NC
against `Curl_FormReader'


  000000000007e20c <Curl_FormReader>:
    7e20c:       a9bc7bfd        stp     x29, x30, [sp,#-64]!
    7e210:       910003fd        mov     x29, sp
    7e214:       a90153f3        stp     x19, x20, [sp,#16]

    [snip]

  0000000000081424 <Curl_http>:
    81424:       d10443ff        sub     sp, sp, #0x110
    81428:       a9047bfd        stp     x29, x30, [sp,#64]
    8142c:       910103fd        add     x29, sp, #0x40
    81430:       a90553f3        stp     x19, x20, [sp,#80]
    81434:       a9065bf5        stp     x21, x22, [sp,#96]
    81438:       a90763f7        stp     x23, x24, [sp,#112]

    [snip]

    82338:       94000000        bl      7e1e8 <Curl_FormInit>
    8233c:       35001100        cbnz    w0, 8255c <Curl_http+0x1138>
    82340:       f941be60        ldr     x0, [x19,#888]
    82344:       f9002ae0        str     x0, [x23,#80]
    82348:       90000000        adrp    x0, 7e20c <Curl_FormReader>
    8234c:       f9400000        ldr     x0, [x0]
    82350:       f901c278        str     x24, [x19,#896]
    82354:       f901be60        str     x0, [x19,#888]

  Relocation section '.rela.text' at offset 0x7c7c70 contains 19929 entries:
     Offset             Info             Type               Symbol's Value
Symbol's Name + Addend
  000000000008234c  0000145300000138 R_AARCH64_LD64_GOT_LO1 000000000007e20c
Curl_FormReader + 0

  That is enough to break it:

  c++ test_libcvmfs.cc.o -o test_libcvmfs libcvmfs.a -lssl -lcrypto -lrt
-lpthread -ldl

  libcvmfs.a is a "combined" static library of libcvmfs_only.a, libz.a,
libsqlite3.a, libcurl.a, and libcares.a.

  Linking them altogether separate works fine (binary [test_libcvmfs] also
works):

  c++ test_libcvmfs.cc.o -o test_libcvmfs libcvmfs_only.a libz.a libsqlite3.a
libcurl.a libcares.a  -lssl -lcrypto -lrt -lpthread -ldl

  What they do is to unpack all static libraries (libcvmfs_only.a, libz.a,
libsqlite3.a, libcurl.a, libcares.a), then merge them all together (ld -r
${OBJECTS} -o ${MERGED_OBJ}) and then keeps the public and weak symbols
(objcopy --keep-global-symbols=$PUBLIC_SYMS
--keep-global-symbols=$tmpdir/W_syms $MERGED_OBJ $MERGED_PUBLIC_OBJ). Then it's
packages in ar archive.

  They combine them using combine_libs bash scripts:

  combine_libs -public libcvmfs_public_syms.txt libcvmfs.a libz.a libsqlite3.a
libcurl.a libcares.a libcvmfs_only.a

  combine_libs bash script is below.

  More ideas? I will keep debugging it.

  david

#!/bin/sh

set -x

PUBLIC_SYMS=""
if [ "$1" = "-public" ]; then
    shift
    PUBLIC_SYMS=$1
    shift
fi

OUTLIB=$1
shift

OBJECTS=""
TDIRS=""
for inlib; do
  inlib_base=`basename $inlib`
  tmpdir=${inlib_base}.objdir.$$
  TDIRS="$TDIRS $tmpdir"

  if ( mkdir $tmpdir &&
       cp $inlib $tmpdir/${inlib_base} &&
       cd $tmpdir &&
       ar x $inlib_base &&
       rm $inlib_base ); then
    OBJECTS="${OBJECTS} `ls $tmpdir/*`"
  else
    echo "Failed to extract $inlib for $OUTLIB."
    exit 1
  fi
done

# if a file containing a list of public symbols was specified, merge
# all the objects together and localize all non-public symbols
if [ "$PUBLIC_SYMS" != "" ]; then
  tmpdir=${OUTLIB}.objdir.$$
  TDIRS="$TDIRS $tmpdir"

  MERGED_OBJ=$tmpdir/`basename $OUTLIB`.o
  MERGED_PUBLIC_OBJ=$tmpdir/`basename $OUTLIB`_pub.o

  # Note that we avoid localizing weak global symbols, because doing so
  # causes STL stuff to fail when the library is linked.
  if ( mkdir $tmpdir &&
       ld -r ${OBJECTS} -o ${MERGED_OBJ} &&
       ( nm ${MERGED_OBJ} | awk ' $2 == "W" {print $3}' | sort | uniq > $tmpdir/W_syms ) &&
       objcopy --keep-global-symbols=$PUBLIC_SYMS --keep-global-symbols=$tmpdir/W_syms $MERGED_OBJ $MERGED_PUBLIC_OBJ); then

    # we just need this one merged object file
    OBJECTS=$MERGED_PUBLIC_OBJ
  else
    echo "Failed to produce merged public object for $OUTLIB."
    exit 1
  fi
fi

rm -f $OUTLIB
ar r $OUTLIB ${OBJECTS} || exit 1

for dir in $TDIRS; do
  rm -rf $dir
done

exit 0