Re: Bits from dpkg developers - dpkg 1.16.1

[Florian Weimer <fw@deneb.enyo.de>]

* Bastien ROUCARIES:

> On Mon, Oct 3, 2011 at 3:02 PM, Florian Weimer <fw@deneb.enyo.de> wrote:
>> * Adam Borowski:
>>
>>>> I would defend static libs for scientific apps. Static libs show a
>>>> significant performance benefit (2-40%, median around 5-10% but sometimes
>>>> far more with C++ apps) and so are standard in HPC still;
>>>
>>> If you see that big a difference, you do a lot of cross-file calls in
>>> tight loops.
>>
>> Not necessarily.  -fPIC and -fPIE force calls to global functions
>> defined in the same translation unit to go through the PLT.  They
>> aren't translated to direct IP-relative calls.  For -fPIC, this is
>> required by the ELF specification (no kidding, this might seem strange
>> today).
>
> Could we add a gcc flag and be non conformant ?

I'm not sure if this is worth the deviation from upstream.  If we want
to break ABI, there far better options.

> I suppose it is only for using LD_PRELOAD.

Not sure.  LD_PRELOAD still works for cross-library calls, but it
would cease to redirect library-internal calls.  I really don't know
why ELF does this.