[Bug gold/15200] Runtime undefined reference to __exidx_start/_end

[dougkwan at google dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15200

--- Comment #6 from Doug Kwan <dougkwan at google dot com> 2013-03-07 05:42:20 
UTC ---
The symbols do not have same visibility.  gold in general is
compatible with GNU ld.  If you look at src/ld/emulparams/, you will
set that the __bss symbols are exported but the __exidx symbols are
defined hidden.  gold matches the behaviour of ld.  If you look at
defstd.cc in gold, you will again see that some of these symbols are
hidden but some are not.

-Doug


On Wed, Mar 6, 2013 at 9:31 PM, petechou at gmail dot com
<address@hidden> wrote:
> http://sourceware.org/bugzilla/show_bug.cgi?id=15200
>
> --- Comment #5 from pete <petechou at gmail dot com> 2013-03-07 05:31:25 UTC 
> ---
> (In reply to comment #4)
>> The symbols __exidx_end & __exidx_start were exported incorrectly in
>> the past.  This is fixed in both ld & gold in the sense that these
>> symbols are defined by not exported.  I think defining these symbols
>> when there is a non-weak definition in a DSO is not the right thing to
>> do.  This is basically multiple definition and usually is an error.
>
> If so, all section/segment symbols should be defined (if needed) by not
> exported?
>
> But when there is a non-weak definition in a DSO, it's still possible to find
> ld.gold define and export segment symbols like __bss_start (See
> gold.defstd.cc:214. only_if_ref is set to false). And there is no multiple
> definition error.
>
> $ readelf -Ds libc.so | grep __bss_start
>   268 311: 0000d898     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start__
>   619 470: 0000d898     0 NOTYPE  GLOBAL DEFAULT ABS __bss_start
>
> $ arm-linux-androideabi-ld.gold -shared -o libplasma.so plasma.o libc.so
>
> $ readelf -s libplasma.so | grep __bss_start
>     73: 00004148     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
>    168: 00004148     0 NOTYPE  GLOBAL DEFAULT  ABS __bss_start
>
>> I am not working on the Android NDK so I can't give you a good
>> suggestion here.  Does using the latest NDK fixes your problem?
>>
>
> Yes, there is no this issue with the latest NDK.
>
> -
> Thanks,
> Pete
>
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