c2nim VS ikos

Also on the game development front, I maintain a raylib wrapper https://github.com/planetis-m/naylib As long utilities like c2nim https://github.com/nim-lang/c2nim exist, it's trivial to create bindings of C/C++ libraries. One thing I want to experiment more is making it more automatic by writing a callback exposed by c2nim that transform the generated code using Nim's AST. But regardless in that project I was able to write safe language abstractions on top of the bindings that provide a more native experience. It has scope-based memory management, generics and ... function overloading.

Rust also has a library called safer_ffi that makes FFI easier, and I tried to use that, but the library seems to be immature, and I could not get arguments in Rust functions. If this library can be used properly, it will be possible to output C header files from Rust functions and automatically generate Nim interface functions from C header files using c2nim. We look forward to further development of this feature.

Well I'm 99.5% certain at least. Even now I'm uncertain of the C syntax. And I've not been bold enough to test 3rd order C function pointers. I figure that's probably C code you don't wanna touch if possible.

https://github.com/nim-lang/c2nim/blob/11f2c5363dfe7e8c7c8ce...

The other annoying one is that "signed" and "unsigned" are basically adjectives, but "long" can be both a type and a modifier. So it's difficult to parse unless you're the target C compiler. Technically you can, but you have to use backtracking.

c2nim is a tool to translate ANSI C code to Nim. The output is human-readable Nim code that is meant to be tweaked by hand after the translation process. If you are tired of wrapping C library, you can try futhark which supports "simply import C header files directly into Nim". Similar to futhark, cinterop allows one to interop with C/C++ code without having to create wrappers. nimLUA is a glue code generator to bind Nim and Lua together using Nim's powerful macro. nimpy and nimporter is a bridge between Nim and Python. rnim is a bridge between R and Nim. nimjl is a bridge between Nim and Julia! Last but not least, genny generates a shared library and bindings for many languages such as Python, Node.js, C.

Now if only a full binding generator for C and C++ headers to Nim was done, the language would really be cooking!

"What do you mean, Nim has two of these already?"

Yeah, I know, and -- not to hurt anyone's feelings -- but: they kind of suck. And there's no way I see them able to be extended to do the job fully, based on the way they're currently built.

Those are some bold claims to make!

So before I get stoned to death (no offense to the authors, I am grateful that they exist and have used them both) let me attempt an explanation and back up these statements.

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To start off, the two tools available are "c2nim" and "nimterop". c2nim is a Nim official library, while nimterop is a community library.

  https://github.com/nim-lang/c2nim

Yes. Nim compiles to C and has a lot of features for interacting with C code. You can easily call C routines from Nim and Nim functions from C. There's a bit of a ceremony you need to go through, but most of it can be automated with c2nim tool: https://github.com/nim-lang/c2nim

I beg to differ: there are a few tools which are comparable.

Frama-C (https://www.frama-c.com) is an open source framework that has, among its analyzers, one based on abstract interpretation (https://www.frama-c.com/fc-plugins/eva.html) that is very similar in spirit to Astree.

MOPSA (https://mopsa.lip6.fr) is another open-source project (albeit more recent, and in a more "academic" stage) that also provides abstract interpretation to analyze C programs for flaws.

NASA also released IKOS (https://github.com/NASA-SW-VnV/ikos), on the same vein.

Of course they lack the polish of a product which costs tens of thousands of euros per license, but they are open source, and their purpose is the same: to ensure code safety via formal methods, in particular abstract interpretation.

It is possible to get these tools to analyze some code and generate no complaints, which ensures absence of several kinds of problems, such as memory safety issues.

Then again, it's hard to know exactly how much they differ from Astree, since you need a license to compare them, and I don't even know if you are allowed to publish such comparisons.

I've been playing around with running IKOS (https://github.com/NASA-SW-VnV/ikos), it sounds very cool but doesn't seem to be super well maintained. I've managed to compile my project to llvm bit-code and run the IKSO on it, but the actual analysis seems to be buggy. There are open issues for the problems I encountered, but the make the analysis pretty useless (it thinks most functions are unreachable).

> https://www.absint.com/astree/index.htm

This looks interesting. It's based on abstract interpretation which is more or less the most powerful approach for imperative code available. (Because the way it works it's likely slow as hell though, I guess).

But it's closed source. One of this kind of products where you need to asks for the price… I think we all know what this means: It'll be laughably expensive.

I don't see any offer for OpenSource projects frankly.

> https://github.com/NASA-SW-VnV/ikos

Also abstract interpretation based. Looks less polished than the first one at first glance.

It's under some questionable license. According to OSI it's OpenSource. According to the FSF it's not. (The FSF argument sounds strong. They're right in my opinion. This NASA license does not look like OpenSource).

But an OpenSource project could use it for free I assume.

> https://github.com/static-analysis-engineering/CodeHawk-C

Much more constrained in scope than the other ones. But looks a little bit "too academic" imho: Uses its own C parser and such.

At least it's OpenSource under MIT license.

Thanks for the links either way! Good to know about some tools in case one would need them at some point.

> I have planned to try using them on OpenZFS for a while, but I am still busy reviewing and fixing reports made by conventional static analyzers.

Stupid question about usual C development practices (as I don't have much contact with that):

Aren't analyzers today part of the build pipeline form the get go? Especially as C is known to be full of booby traps.

Imho it shouldn't be even possible to push anything that has issues discovered by tools.

This should be the lowest barrier as most code analyzers are at most able to spot quite obvious problems (the commercial one above is likely an exception to this "rule"). When even the usual "stupid analyzer" sees issues than the code is very likely in a very bad shape.

Adding such tools later on in the development is like activating warnings post factum: You'll get drowned in issues.

Especially in such critical domains as file-systems I would actually expect that the developers are using "the best tools money can buy" (or at least the best OpenSource tools available).

"Still fixing bugs found by some code analyzer" doesn't sound like someone should have much trust with their data in something like ZFS, to be honest… The statement sounds actually quite scary to me.

They have very unusual license which I have never seen before: https://github.com/NASA-SW-VnV/ikos/blob/master/LICENSE.txt

Is anyone familiar with it? Is it OSI certified? (it's not on the OSI's site).

Yeah there are tools that require adding contracts as comments. But again, there are also friction-less tools that don't require any changes (for example a NASA one).