Re: [gentoo-soc] Weekly Report: Porting relibc Relibc

[Ahmed Soliman]

Hi,

I will try to add a short description here, However, the post should
be describing most of the technical issues that I kept track of.

So i was working on compiling gcc under gentoo and having it linked
against relibc. there were plugins for LTO that are part of gcc but
used via ld. The plugins are shared object styles, so in order for
them to work I needed a working dlopen, dlclose and dlsym. which was
not yet implemented in relibc. I implemented all 3, There were
challenges where relibc and rust stdlib are not referentially
transparent. And that caused problems where there was a relibc copy
statically linked against ld.so for internal use and one that is
dynamically linked against an arbitrary a.out for external use and
although both are the same binary wise, they cannot be used
interchangeably for some reason. It was hard figuring out.

That is also why I mentioned that gdb wasn't useful, not because it
wasn't working (in fact I added support for it in a previous patch
set) but because of the nature of the bug I faced, It was not
something that one can pinpoint quickly when using a debugger.

Thanks,
Ahmed.

On Mon, 6 Jul 2020 at 08:22, Luca Barbato <lu_zero@g.o> wrote:
>
> On 06/07/2020 00:06, Ahmed Soliman wrote:
> > Hello,
> >
>
> Hi, when gdb is having problems, rr might help you. I guess you know it
> already but just in case :)
>
> Thank you for your nice blogpost.
>
> lu
>
>