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by teunispeters 918 days ago
Write javascript engines in memory safe languages. I'd vote for rust as rust and javascript's APIs are pretty similar in style, structure, consistency and security/other issues that are not memory safety.

On that note, try valgrind on existing javascript engines, you might be "entertained". (I certainly was, but that was some years back.
2 comments
mike_hearn 918 days ago
How are Rust and JS APIs similar, and why would it matter?

AFAIK the only competitive JS engines written in memory safe languages are GraalJS and other JS-on-the-JVM runtimes. GraalJS has the advantage of being fully up to date, not having any memory unsafe code in it (the JIT compiler that makes it fast is a separate module, also written in a memory safe language, and the JS impl does not have low level code in it). And you can run it on SubstrateVM which is a virtual machine also written in a memory safe language, although of course small parts like the GC need to use unsafe features.

It also has other useful features like sandboxing and the ability to interop with other languages like Python or Java. Plus, it can actually sandbox native code as well because the "languages" that you can run on GraalVM include both wasm and more usefully LLVM bitcode, in which each individual C/C++ allocation becomes GC-managed and bounds checked.

So in terms of memory safety the Graal team are way ahead there.

(disclosure: I recently started part time work with the GraalVM team, but was a long term supporter before that)

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teunispeters 916 days ago
Rust and JS - er in short, there's a lot more to security than "memory safety". But then I've been in groups burned by NPM hacks in the past. I've tried Rust some but it looks like the same problems yet again. I'm wary, and going to give it time to mature - it's not interesting enough on its own - especially for someone more used to embedded programming spaces (C centric spaces, for good reasons).

As for the second - good to know! Seriously appreciate knowing that - not sure if/when I'll need it myself, but it's good to hear, and good that it's visible here!

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zozbot234 918 days ago
Most javascript engines are JIT-based and that's hard to make safe, you'd need a complete proof that the emitted assembly is correct. It's similar to the problem of proving correctness for any compiler.
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teunispeters 918 days ago
Oh, I've used such tests on other JIT based languages, as well as non-JIT. None made valgrind show quite so much show. I'm not sure I've ever seen less "memory safe" code bases.
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