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

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.

I noted that the commit in question added the __flt_rounds symbol to the
existing group of symbols probably related to FPU handling. The same
question stands for that symbols too, is their placement into
FBSDprivate namespace right ?