[matsadler]

I think the goal of this right now is just to match the C version.

The C implementation of YJIT supported x86 Unix/Linux platforms, and it sounds like adding Windows and arm64 support, plus other improvements was a daunting task with the tools C provides.

Now it’s in Rust we’ll hopefully see further improvements quicker.

[anitil]

This is the first time I've felt that Rust is starting to eat C's lunch.

[tormeh]

Rust will eclipse C++. C is a harder nut to crack, particularly for the embedded space where ease of implementing and maintaining a compiler back-end/code-emitter for your new weird 8-bit architecture is important. C is pretty close to an assembly macro and it's barely updated, which is great for that use-case. But for use cases like interpreters Rust is perfectly suitable.

[vlovich123]

This position is like saying C or C++ won't eat ASM's lunch. While technically true since there's a lot of ASM code still being written, especially for extremely low-level or high performance code, the vast majority of C and C++ developers don't actually touch ASM (i.e. C/C++ dominate ASM in terms of number of developer hours spent).

I think you may also be overlooking the GCC backend for rustc and gccrs, a ground-up standalone reimplementation of the Rust language frontend for GCC. Both of those should drastically improve the coverage and availability of Rust to all the same platforms you would be using GCC to compile C code for.

Depending on the compiler support, you might get that architecture for free unless the vendor is providing their own C compiler. The harder part is that your new weird 8-bit architecture probably won't benefit as much from the strong nostd ecosystem of libraries, so the overhead of writing Rust won't be counterbalanced. Still, like I said at the outset, this is an extremely niche use-case. Rust doesn't have to wipe C or C++ from the map for it to crack that nut.

The harder nut for Rust to crack I think is actually C++. There are extremely large C++ codebases. Industry would love for there to be a significantly easier/cheaper story to tell in terms of integrating Rust with those codebases. That way you could set metrics around converting the codebase, new code has to be written in Rust etc. However, the challenge is that Rust can only replace components with very well-defined boundaries. Those boundaries are less clearly defined in C++ codebases than they are in C codebases (linkage + templates in particular are challenging). To truly crack the C++ nut probably requires solving this problem unless Rust codebases just starting eating C++ codebases commercially through development velocity (which is a much longer and harder path).

[rapsey]

Very few will actually rewrite code in rust. It is enough for Rust to be used for new projects which would otherwise be c or c++

[vlovich123]

It's extremely important for meaningful commercial Rust adoption for legacy codebases to be able to adopt it incrementally (i.e. all new code is Rust). I think you're underestimating how much C/C++ code there is out there (Linux Kernel, Chrome, all of Google's internal infrastructure, all of Amazon's internal infrastructure etc). We're talking about many billions dollars worth of code that is never going to get rewritten and lines of code that keep accruing. Now competitors starting today may make other choices but there's enormous value to be had by cracking the nut of seamless integration of progressive migration (i.e. so that you can say "no more new C++ code"). The failure of this lesson is seen in banks that continue to run on Fortran at best and at worst other businesses that continue to run on old unsupported languages/technologies. Thankfully, I think the tech companies are engineering-led and understand this so I suspect they're paying people to figure out this problem.

[isaacimagine]

If gcc supports Rust as a frontend ootb, I could see existing C/++ projects incrementally adopting components written in the language.

[pjmlp]

Good luck with that on anything GPU or HPC related, or industries with language standards.

Also until Rust compilers are bootstraped, they will always rely on a C++ infrastructure.

[FullyFunctional]

I've been around for a long time and I haven't seen a PL with this much momentum since Java was launched. Inertia is real, but the benefits over C++ are undeniable.

Bootstrapping seems a silly thing to be obsessed about as C++ will be around forever still, but it obviously can be bootstrapped if that becomes important.

[pjmlp]

Ada/SPARK already provided such benefits, and NVidia has chosen it instead of Rust for automotive firmware.

Rust momentum is meaningless for GPUs unless NVidia decides it gets to play in CUDA, and they are now one of the companies with more ISO C++ people on their payroll.

It is also meaningless for PlayStation, Nintendo and Xbox, unless the respective SDKs integrate Rust.

Bootstraping isn't silly, because LLVM and GCC are written in C++, so there isn't any "Rust will eclipse C+", when it depends on it for its existence.

[pcwalton]

SPARK doesn't provide the same feature set as Rust. If you want safe heap allocation in SPARK, then you get a garbage collector (unless you're talking really recent experimental extensions IIRC). If you want to forego the GC and remain memory-safe, then you also forego heap allocation. This might work for avionics code, but not for most apps.

Besides, the post you're replying to is talking about "momentum", and it's obvious in 2022 that Ada doesn't have the momentum that Rust does (however you define "momentum"). NVIDIA is not the entire industry.

Much of the rest of your post concerns video games, which are only a small portion of the total C++ code in existence. (And in any case it's not accurate to say that languages are "meaningless" unless the platform vendor officially supports them—console vendors don't maintain C# VMs either and yet Unity titles work just fine.)

[pcwalton]

WebRender is certainly "GPU related" and is shipping to millions of happy Firefox users.

And yes, LLVM is written in C++. So what? C++ compilers depend on C code in libc. Portions of libc are written in assembler. Some assembly instructions are decomposed into microcode. Yet nobody doubts that C++ has eclipsed assembly language in terms of importance to the industry nowadays. We'll always need a way for humans to read the actual instructions that the silicon interprets, but relatively few people need to be able to do that nowadays. That dynamic is what the parent post means by one language "eclipsing" another.

[pjmlp]

For how long? 3% and decreasing.

Libc is UNIX only.

As for the rest, it is useful to tone down hype with some cold water reality check.

[Ar-Curunir]

> tone down hype with some cold water reality check.

I mean, you're the one who keeps mentioning Ada/SPARK on every Rust thread, so if anyone needs to stop hyping things, it's perhaps you?

[rubyfan]

Can you say more about why you think that?

[anitil]

I started in C and generally when people say 'rewrite it in Rust' I just roll my eyes, because I know how hard that is. But seeing it happen on a sophisticated project has made me take another look.

Obviously for the embedded world everything is pitched at C currently and I don't think that will change, but for larger projects this is proof that my intuition was wrong.

I suppose that's a long winded way of saying that it might be time for me to learn Rust.