Re: Abort in elflink.c: elf_link_check_versioned_symbol

["H.J. Lu" <hjl.tools@gmail.com>]

On Wed, Sep 2, 2009 at 5:49 AM, Ramana
Radhakrishnan<ramana.radhakrishnan@arm.com> wrote:
> Hi Ian,
>
> Thanks for your email and apologies for the late response.
>
> On Wed, 2009-08-26 at 07:59 -0700, Ian Lance Taylor wrote:
>> Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> writes:
>>
>> > The symbol for which this abort happens is
>> > _ZNSsC1IN9__gnu_cxx17__normal_iteratorIPcSsEEEET_S4_RKSaIcE from libstdc
>> > ++.so. Looking at this symbol in libstdc++.so, I can see that this is
>> > versioned and weak as below but the actual symbol doesn't appear in the
>> > shared object.
>> >
>> >>From the Symbol Table of libstdc++
>> >
>> >   936: 0008e1e4    40 FUNC    WEAK   DEFAULT   11
>> > _ZNSsC1IN9__gnu_cxx17__normal_iteratorIPcSsEEEET_S4_RKSaIcE@@GLIBCXX_3.4
>>
>> That is a real symbol definition.  It merely happens to be marked weak.
>
> Fair enough. If this is a real symbol definition and happens to be just
> marked weak , then shouldn't all references resolve to this symbol.
>
>>
>> I think what is happening is that elf_link_check_versioned_symbol
>> assumes that it will only be called when the regular symbol resolution
>> code did not resolve the symbol.  So it does not expect to see an
>> unhidden symbol here; an unhidden symbol should already have been
>> resolved.  So you should find out why elf_link_check_versioned_symbol is
>> being called here.
>
> elf_link_check_versioned_symbol is being called from the following call
> stack
>
> Breakpoint 1, _bfd_abort (file=0xe2c18
> "/home/ramrad01/sources/src/bfd/elflink.c", line=8440, fn=0xe36f0
> "elf_link_check_versioned_symbol")
> at /home/ramrad01/sources/src/bfd/bfd.c:928
> 928     {
> (gdb) bt
> #0  _bfd_abort (file=0xe2c18 "/home/ramrad01/sources/src/bfd/elflink.c",
> line=8440, fn=0xe36f0 "elf_link_check_versioned_symbol")
> at /home/ramrad01/sources/src/bfd/bfd.c:928
> #1  0x00068474 in elf_link_check_versioned_symbol (info=<value optimized
> out>, bed=0xbeffca84, h=0x1a405e0)
> at /home/ramrad01/sources/src/bfd/elflink.c:8440
> #2  0x00068a4c in elf_link_output_extsym (h=0x1a405e0, data=<value
> optimized out>) at /home/ramrad01/sources/src/bfd/elflink.c:8531
> #3  0x00039308 in bfd_hash_traverse (table=0x110578, func=0x68484
> <elf_link_output_extsym>, info=0xbeffca84)
> at /home/ramrad01/sources/src/bfd/hash.c:603
> #4  0x0006f114 in bfd_elf_final_link (abfd=0x16b18, info=0x845a8)
> at /home/ramrad01/sources/src/bfd/elflink.c:10588
> #5  0x0004a99c in elf32_arm_final_link (abfd=0xe2c18, info=0x20f8)
> at /home/ramrad01/sources/src/bfd/elf32-arm.c:9296
> #6  0x0001ea1c in ldwrite ()
> at /home/ramrad01/sources/src/ld/ldwrite.c:567
> #7  0x0001de58 in main (argc=0, argv=0x9984)
> at /home/ramrad01/sources/src/ld/ldmain.c:464
> (gdb) up
> #1  0x00068474 in elf_link_check_versioned_symbol (info=<value optimized
> out>, bed=0xbeffca84, h=0x1a405e0)
> at /home/ramrad01/sources/src/bfd/elflink.c:8440
> 8440                  abort ();
> (gdb) up
> #2  0x00068a4c in elf_link_output_extsym (h=0x1a405e0, data=<value
> optimized out>) at /home/ramrad01/sources/src/bfd/elflink.c:8531
> 8531      if (! finfo->info->relocatable
>
>
> As you can see this is getting called from bfd_elf_final_link which ends
> up calling elf_link_output_extsym where the abort happens.
>
> The reason that we call this in elf_link_output_extsym from the
> following comment is -
>
> (gdb) l 8536
> 8531      if (! finfo->info->relocatable
> 8532          && (! finfo->info->shared)
> 8533          && h->forced_local
> 8534          && h->ref_dynamic
> 8535          && !h->dynamic_def
> 8536          && !h->dynamic_weak
> 8537          && ! elf_link_check_versioned_symbol (finfo->info, bed,
> h))
> 8538        {
> 8539          (*_bfd_error_handler)
> 8540            (_("%B: %s symbol `%s' in %B is referenced by DSO"),
>
>
> which appears to be correct. From what you say and looking at the code
> it appears as though one might have to refactor the code accordingly -
> to give errors depending on when this function is called ?
>
>

It is quite strange. If you can provide a testcase which I can reproduce
with a cross linker, I will take a look.

Thanks.

-- 
H.J.