Re: GCCJIT dynamic down casting (GCC16 or future GCC17)

On Thu, 2026-05-07 at 11:28 +0200, Basile STARYNKEVITCH wrote:
> Hello all,
> 
> I do have (and even compiled it from source code a few days ago) GCC
> 16
> with libgccjit enabled (this on Linux/x86-64).
> 
> gcc-16 (Debian 16-20260425-1) 16.0.1 20260425 (prerelease) [gcc-16
> r16-
> 8812-gd9c07462a22]
> 
> https://gcc.gnu.org/onlinedocs/jit/topics/objects.html
> mentions upcasting 
> > casting methods for upcasting from subclasses to parent classes
> 
> But is there any dynamic downcasting (or way to dynamically query the
> GCCJIT "class" of any gcc_jit_object pointer)?
> 
> E.g. suppose I have some gcc_jit_object* jp pointer.
> 
> How can I know if jp is representing a struct, a left value, a field,
> a
> parameter, a number constant etc....

I don't think there is a way to do this built into libgccjit.  One way
to do it when working with libgccjit is to store the information
yourself when the process creates the various gcc_jit_objects (e.g. a
mapping from gcc_jit_object * back to the underlying objects in your
program), and to access that when writing out the json.

Dave

> 
> I am serializing GCCJIT representation to JSON in my open source
> RefPerSys software, its commit 94d149cbaa71 
> 
> Thanks for your insights
>