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Re: missing symbols in libstdc++.so.6 built from the 4.9 branch
- From: Jonathan Wakely <jwakely dot gcc at gmail dot com>
- To: John David Anglin <dave dot anglin at bell dot net>
- Cc: Matthias Klose <doko at ubuntu dot com>, "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>, gcc Development <gcc at gcc dot gnu dot org>, Ramana Radhakrishnan <ramana dot radhakrishnan at arm dot com>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Aurelien Jarno <aurel32 at debian dot org>
- Date: Tue, 1 Jul 2014 21:30:17 +0100
- Subject: Re: missing symbols in libstdc++.so.6 built from the 4.9 branch
- Authentication-results: sourceware.org; auth=none
- References: <53B273E6 dot 8040402 at ubuntu dot com> <CAH6eHdRQt13=pQesbAOwOVVYuuQQw=rD-cWC0+Ugv7ndDBJ+3w at mail dot gmail dot com> <BLU436-SMTP48F2A40D90438F0564A7BC97070 at phx dot gbl>
On 1 July 2014 20:58, John David Anglin wrote:
> On 1-Jul-14, at 5:32 AM, Jonathan Wakely wrote:
>
>> On 1 July 2014 09:40, Matthias Klose wrote:
>>>
>>> - HPPA (build log [2]), is missing all the future_base symbols and
>>> exception_ptr13exception symbols, current_exception and
>>> rethrow_exception.
>>
>>
>> This implies ATOMIC_INT_LOCK_FREE <= 1 for that target. Our future and
>> exception_ptr implementations rely on usable atomics.
>
>
> ARM and HPPA use kernel assisted libraries for atomic support. Not exactly
> lock free, but possibly good enough...
>
> Currently, c-cppbuiltin.c doesn't provide proper defines for this support.
> We
> currently define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4, etc, in
> pa-linux.h. I'll experiment with defining ATOMIC_INT_LOCK_FREE there.
It should already be defined, but its value is what matters for
libstdc++'s purposes.
To be honest I'm not sure if we really need the value to be greater
than one, if it's equal to one that might work. We'd need to check
though.