Move the toolchain to C23

[dogruis]

What would it cost to move the toolchain to C23?
Is this even feasible?

I want to know what's blocking it.

[dciabrin]

I know that gcc13 is totally an option for k68k, and I believe for proper c23 we'd need to rebase to at least gcc15. We can certainly keep newlib and binutils the same for the time being.

I just tried substituting gcc 11 for gcc 15, and we have to get rid of the gcc patch that ngdevkit was carrying along to build on macos.
The configure options have changed sufficiently that right now my local build is failing in linux, but I see where. So I'll try to come up with a test build later this week and report back.

[dogruis]

That would be great to port it to C23. Right now I am defining macros in order to fit both C23 and C99 in my hardware abstraction layer, in my game engine to fit both SDL3 and ngdevkit.

#if __STDC_VERSION__ >= 202311L
#define LOT_NODISCARD [[nodiscard]]
#define LOT_ENUM_UNDERLYING(T)   : T
#else
#define LOT_NODISCARD
#define LOT_ENUM_UNDERLYING(T)
#endif

Which I can then invoke like this.

LOT_NODISCARD bool hal_init(void);

And I'd like to avoid that and use the extra flavour C23 brings.

[dciabrin]

I made good progress on building the toolchain on linux. With https://github.com/dciabrin/ngdevkit-toolchain/tree/gcc-15, you can compile it locally, but I still need to rework the build process because you can't compile and target --prefix=/usr due to permissions issues.

Once that is fixed, I'll make sure the build works on macOS and Win, and that this also works with the hardened build flags from the usual distros.

Note that I'll try to take the occasion to make ngdevkit-toolchain depend on ISL, because right now it's been disable due to some packaging issues I had in the past. Re-adding ISL would enable other loop unrolling optimizations IIUC.

[dogruis]

Amazing, I didn't think I would get such a fast reply on this and unlock optimisations.

[dciabrin]

OK I have rebase to gcc 15.3, it seems to be building all the examples fine on my host.
I've checked that ubuntu, fedora, brew and msys2 packages have been rebuilt succesfully.

I've just updated the README.md to advertise gcc 15.3, so hopefully everything should be in good shape now.

I haven't touched anything in newlib though, so you'd only get the benefits of C23 suppport in gcc, not anything major coming from a more recent version of the libc. I believe that's OK though, since the libc is really not used much.

Tell me if that's what you were expecting and we can close this discussion.

[dogruis]

I've seen all the changes you've done across the tool chain and each distribution repo as well as homebrew. And it's exactly what I had in mind.

This discussion is closed 🔐

Thanks a lot for your effort and I'm always happy to help if you need anything.