Re: Possible fix for Perl failing with ../lib/auto/POSIX/POSIX.so: Undefined symbol "__flt_rounds" on ARM

On 2012.06.12 10:49, Konstantin Belousov wrote:
> On Tue, Jun 12, 2012 at 10:18:58AM +0200, Jan Sieka wrote:
>> On 2012.06.09 18:11, Tim Kientzle wrote:
>>>
>>> On Jun 5, 2012, at 8:09 AM, Jan Sieka wrote:
>>>
>>>> Hello Ian!
>>>>
>>>> I tried recently to compile and run Perl 5.12 on ARM (SheevaPlug) using
>>>> HEAD from 22.05.2012 and got the following error while trying to run:
>>>> /usr/ports/lang/perl5.12 # make test
>>>> [...]
>>>> ../lib/auto/POSIX/POSIX.so: Undefined symbol "__flt_rounds
>>>> [...]
>>>>
>>>> After investigating the issue it appeared that __flt_rounds symbol is
>>>> not exported by libc. Applying the following patch, recompilling world
>>>> and Perl fixed the problem and allowed to use Perl on SheevaPlug:
>>>>
>>>> diff --git a/lib/libc/arm/Symbol.map b/lib/libc/arm/Symbol.map
>>>> index e8c7f1d..8cdcdaf 100644
>>>> --- a/lib/libc/arm/Symbol.map
>>>> +++ b/lib/libc/arm/Symbol.map
>>>> _at__at_ -70,6 +70,7 _at__at_ FBSDprivate_1.0 {
>>>>         __divdf3;
>>>>         __floatsisf;
>>>>         __floatsidf;
>>>> +       __flt_rounds;
>>>>         __fixsfsi;
>>>>         __fixdfsi;
>>>>         __fixunssfsi;
>>>>
>>>> Can you comment whether this is a correct solution?
>>>
>>> Great!  I had the same problem compiling Python last
>>> week and had planned to track it down.
>>>
>>> I just committed this to -CURRENT and will also
>>> merge it to the armv6 tree.
>> Hello Tim!
>>
>> Thanks for committing this but unfortunately that patch wasn't correct.
>> I had another discussion on freebsd-current_at_ (I forgot to do a
>> cross-list CC - now fixed) about how to add symbols to Symbols.map files
>> (see this thread:
>> http://lists.freebsd.org/pipermail/freebsd-current/2012-June/034511.html) and
>> from the answer and hints given by Konstantin Belousov I have prepared
>> another patch that adheres to library versioning guidelines. If nobody
>> objects this patch then feel free to commit it:
>>
>> diff --git a/lib/libc/arm/Symbol.map b/lib/libc/arm/Symbol.map
>> index dc46013..48f6747 100644
>> --- a/lib/libc/arm/Symbol.map
>> +++ b/lib/libc/arm/Symbol.map
>> _at__at_ -33,6 +33,10 _at__at_ FBSD_1.0 {
>>          sbrk;
>>   };
>>
>> +FBSD_1.3 {
>> +       __flt_rounds;
>> +};
>> +
>>   FBSDprivate_1.0 {
>>          /* PSEUDO syscalls */
>>          __sys_getlogin;
>>
>> I have verified the above patch is working on SheevaPlug on FreeBSD
>> 10-CURRENT from 2012-05-15 and Perl 5.12.4. Perl has to be recompiled
>> after applying this patch.
> Well, both committed version and this version should work, the question
> is which fix is right. Is __flt_rounds supposed to be linked to by
> applications ? If the symbols are used by normal programs, that I think
> we should indeed guarantee ABI stability for them, and FBSD_1.3
> namespace is the right namespace to use.
Both versions work indeed. I have analysed other architectures' 
lib/libc/<arch>/Symbol.map files and __flt_rounds should go into FBSD_ and *not* 
into FBSDprivate section. I have verified that at least one of the Perl's 
libraries (POSIX.so) links to __flt_rounds. Python also links to this function. 
So to the best of my knowledge current patch is the righteous one.

Best regards,

Jan Sieka