Re: Interfacing with external code using libgccjit

["Marc Nieper-Wißkirchen" <marc.nieper@gmail.com>]

The simplest way IMO is to write a stub in C with ordinary functions
that calls into GMP and MPFR, and then call the C stub from libgccjit
code. When you enable LTO, the stub should be optimized away.

Am Fr., 16. Juni 2023 um 21:08 Uhr schrieb Basile Starynkevitch
<basile@starynkevitch.net>:
>
>
> On 6/16/23 19:27, David Malcolm via Jit wrote:
> > On Thu, 2023-06-15 at 21:59 +0200, Anselm Schüler wrote:
> >> Hi, I’m very new to libgccjit and was hoping to use it to implement a
> >> DSL that abstracts over some high-precision mathematics.
> > Hi!
> >
> >> However, to do that, I need to interface with a high-precision
> >> library
> >> such as GMP or MPFR.
> >> I’m wondering if that’s possible.
> > It ought to be possible, but you need some way to express the
> > declarations from the library's headers via the ligccjit API; we don't
> > yet have a convenient way to take a header and express it in libgccjit
> > form.  As you note, doing it "by hand" is laborious; sorry that we
> > don't yet have an automated way of doing this.  Possible approaches
> > would be to use a library that can parse C headers, such as:
> >    https://github.com/vnmakarov/mir
> > or perhaps using libabigail to work with the ABI representation:
> >    https://sourceware.org/libabigail/
> > (which would be parsing the debug data)
> >
>
> Another possible approach might be to use some GCC plugin (perhaps
> inspired by some code from https://github.com/bstarynk/bismon ...) to
> parse the GMP or MPFR header files, and later inject some constants
> (describing the external code, such as GMP or MPFR) into libgccjit
>
>
>
>
> Maybe future GCC support for C++ 2x modules could be also relevant
>
> Cheers
>
> --
> Basile Starynkevitch                  <basile@starynkevitch.net>
> (only mine opinions / les opinions sont miennes uniquement)
> 92340 Bourg-la-Reine, France
> web page: starynkevitch.net/Basile/
>