awesome-jit VS wasm3

https://github.com/wdv4758h/awesome-jit. Take a look on MIR jit.

Out of curiosity, are you planning on (progressively, slowly) rolling your own JIT, or using something like DynASM (https://luajit.org/dynasm_features.html), libFirm (https://pp.ipd.kit.edu/firm/Features.html), or some other preexisting thing (eg https://github.com/wdv4758h/awesome-jit) in the space?

FWIW, I understand that LuaJIT gets some of its insane real-world performance from a JIT and VM design that's effectively shrink-wrapped around Lua semantics/intrinsics - it's not general-purpose. I've read (unfortunately don't remember exactly where) that people have tried to run off with the JIT and VM and use it in other projects, but never succeeded because of the tight coupling.

In the same way, while a bespoke 64/32-bit x86+ARM JIT would be a reasonable undertaking, it could make for a pretty interesting target with a potentially wide-ranging set of uses.

For example, it could be the VM+JIT combination that all those people dissecting LuaJIT were looking for :).

I could see something like this becoming an attractive option for games that want an exceptionally simple runtime. Sort of like a scaled-down NekoVM (nee Haxe).

Broadly speaking, I get the (potentially incorrect) impression (from a very naive/inexperienced POV) that MiniVM+JIT would be looking to close a more widely-scoped, higher-level loop than something like libFirm would be. So it'd be closer to Cling (https://root.cern/cling/) than raw LLVM, perhaps (albeit with 0.01% of the code size :D). It is for this reason that I kind of pause for a minute and ponder that a fully integrated JIT could be a pretty good idea. It would absolutely make the irreducible complexity of the project balloon, with reasonable motivation likely necessary to maintain cohesion.

If I were to backseat-drive for a minute :) the first thing I'd rant about is how attractive modern JITs need trivial ways to verify code correctness, both online (how exactly was *this* specific generated code constructed - so, straightforward logging) but also (and particularly) offline (humans staring at the JIT source code and mentally stepping through its behavior - and succeeding (miracles!!) because the code is small and well-written). If the JIT implemented in such a straightforward manner, end users wanting to run potentially malicious user-supplied code with high performance in potentially security-sensitive settings might be attracted to the project. (Mike Pall made bank for a while while CloudFlare was using LuaJIT for its WAF... ahem...)

I came across this reference of how to break out of LuaJIT 2.1 (2015) a while back: https://www.corsix.org/content/malicious-luajit-bytecode - and every time I take a look at the code I switch away from the tab :) (and sometimes step away from the computer for a minute :D). It's solely a demonstration of "this is how it would work", and clarifies that LuaJIT makes no sandbox guarantees about the code it executes, but reading through it, the amount of Stuff™ going on represents a surface area that to me (naively) seems just... like LuaJIT as a whole is generally too large to easily reason about from a security standpoint (oh yeah, besides being written in assembly language...). This might be inexperience speaking, but I can't help but wonder whether a smaller, simpler implementation might be able to implement a secure JIT; for all I know this might be an impossible P=NP pipe dream I haven't fully grasped yet, I guess what I'm trying to figure out is whether "small enough to mentally reason through" and "large enough to do a few things quickly" have practical overlap?

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On an unrelated note, something I discovered recently and which I thought I'd idly mention is that JITs might seem to have a bit of a hard time on Android. I can't (yet) tell if this is LuaJIT-specific or "anything that's a JIT"-specific: KOReader (Android eBook reader, implemented entirely using LuaJIT) has a bunch of very scary magic Things™ it seems to need to do to make LuaJIT even work at all on Android (https://github.com/koreader/android-luajit-launcher/blob/mas...), due to a apparently-current issue causing issues across different domains (https://github.com/LuaJIT/LuaJIT/issues/285), which has been apparently cropping up going back years (https://www.freelists.org/post/luajit/Android-performance-dr... (2013)). KOReader has even nontrivially patched LuaJIT's C code in places (https://github.com/koreader/android-luajit-launcher/blob/bb0...) with purposes I am yet to fully understand (it might just be for debugging). I happened to be considering idly playing around with Lua on Android (currently fascinated with interpreted/JITed runtimes) and after stumbling on this I'm debating whether to use Lua instead, ha. I've been meaning to ask around on the LuaJIT list and wherever KOReader discusses stuff to learn more, after focusing on actually getting LuaJIT linked into an Android project and poking around. Haven't got to it yet. This could be an absolutely massive red herring that I'm going deer-in-headlights about because it just looks off-in-the-weeds, or potentially significant. It might also be absolutely irrelevant, but as I noted I'm not (yet) sure how to tell.

Here is a good overview: https://github.com/wdv4758h/awesome-jit

As long as this is happening, might as well try some of my favorites: https://github.com/wasm3/wasm3, https://github.com/WebAssembly/wabt, https://github.com/bytecodealliance/wasmtime

This means that newly created wasm blobs will stop being able to run in wasm3.

On a side note, I can't help feeling sorry for the people that advocate for C over C++ when I see commits like https://github.com/wasm3/wasm3/commit/121575febe8aa1b544fbcb...

It can, wasm3 is a wasm interpretor ported to a lot of bare metal microcontrollers: https://github.com/wasm3/wasm3

On other benchmarks I'm seeing numbers closer to 20% slower, e.g. https://github.com/wasm3/wasm3/blob/main/docs/Performance.md and https://github.com/second-state/wasm32-wasi-benchmark. It's numerical code, which is the best case scenario for a native binary. It's much closer on an average web app or server workload, e.g. https://krausest.github.io/js-framework-benchmark/current.html - you can find WASM frameworks that beat most JS frameworks on there, but that is not as impressive considering the state of the JS ecosystem. Overall, it's already under 50%, and there is still plenty of room for improvement.

Can miniwasm share memory with the host? wasm3 doesn't allow this[1] and requires you to allocate VM memory and pass it to the host, but that has several downsides (some buffers come from external sources so this requires a memcpy; the VM memory location isn't stable so you can't store a pointer to it on the host; etc.).

I'm really interested in a fast interpreter-only Wasm VM that can allow the host to share some of its memory with the VM.

[1]: https://github.com/wasm3/wasm3/issues/114

> This product family will never run Linux, as developers will need to develop a new firmware from scratch. This is obviously not a problem for the earbuds, but a big limitation for the player

Perhaps not Linux, but I suspect there would be a place here for a Unix-like platform that feels familiar. If for example we could get wide-adoption of something like the JVM or wasm3 [0] on these platforms, code could become quite portable, despite wildly different architectures.

For example, Apache's NuttX [1] (that I first learned from Lupyuen, a guy making great progress working with Pine64 products).

> Processing wise, this chip is well sufficient for TWS headphones, but very inadequate for an audio player. It will not drive a good screen, it nor run high-resolution flacs or (probably?) support a high-quality, high-bandwidth codec. In fact, a first generation iPod Nano (retailing for $149 in 2006) had 16MB RAM, so over 16 times what the PinePod would offer. In fact, even the features of any custom firmware are limited from so little memory

I wouldn't call it time just yet. Displays can be interacted with intelligently (to reduce pixel bandwidth) and ultra high quality audio codecs offer diminishing returns, especially when you don't have a DAC or headphones to make the most of them.

My advice to Pine64 would be this:

1. Consolidate your product lines. The Pinebook is just a slower Pinebook Pro, just go with the Pinebook Pro. The PineTab is just a Pinebook without the keyboard, again I would consolidate this with the Pinebook Pro and just make the keyboard detachable.

2. The SBCs should just go straight into the device, thus creating a clear upgrade path for future products. If you want a PineBook Pro running Quartz, just swap the boards (of course with daughter boards for USB expansion, display driver, power, etc).

3. Don't be afraid to kill off products. The Pinebook and PineTab have never seen a new release. The PinePhone appears to be taking a back seat to the PinePhone Pro. The PineCube is basically DoA due to the processing power struggling to process the camera image.

More generally, try to do fewer things, but do them well.

[0] https://github.com/wasm3/wasm3

[1] https://nuttx.apache.org/docs/latest/

[2] https://lupyuen.github.io/articles/sensor

I think SIMD was a distraction to our conversation, most code doesn't use it and in the future the length agnostic, flexible vectors; https://github.com/WebAssembly/flexible-vectors/blob/master/... are a better solution. They are a lot like RVV; https://github.com/riscv/riscv-v-spec, research around vector processing is why RISC-V exists in the first place!

I was trying to find the smallest Rust Wasm interpreters I could find, I should have read the source first, I only really use wasmtime, but this one looks very interesting, zero deps, zero unsafe.

16.5kloc of Rust https://github.com/rhysd/wain

The most complete wasm env for small devices is wasm3

20kloc of C https://github.com/wasm3/wasm3

I get what you are saying as to be so small that there isn't a place of bugs to hide.

> “There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.” CAR Hoare

Even a 100 line program can't be guaranteed to be free of bugs. These programs need embedded tests to ensure that the layer below them is functioning as intended. They cannot and should not run open loop. Speaking of 300+ reimplementations, I am sure that RISC-V has already exceeded that. The smallest readable implementation is like 200 lines of code; https://github.com/BrunoLevy/learn-fpga/blob/master/FemtoRV/...

I don't think Wasm suffers from the base extension issue you bring up. It will get larger, but 1.0 has the right algebraic properties to be useful forever. Wasm does require an environment, for archival purposes that environment should be written in Wasm, with api for instantiating more envs passed into the first env. There are two solutions to the Wasm generating and calling Wasm problem. First would be a trampoline, where one returns Wasm from the first Wasm program which is then re-instantiated by the outer env. The other would be to pass in the api to create new Wasm envs over existing memory buffers.

See, https://copy.sh/v86/

MS-DOS, NES or C64 are useful for archival purposes because they are dead, frozen in time along with a large corpus of software. But there is a ton of complexity in implementing those systems with enough fidelity to run software.

Lua, Typed Assembly; https://en.wikipedia.org/wiki/Typed_assembly_language and Sector Lisp; https://github.com/jart/sectorlisp seem to have the right minimalism and compactness for archival purposes. Maybe it is sectorlisp+rv32+wasm.

If there are directions you would like Wasm to go, I really recommend attending the Wasm CG meetings.

https://github.com/WebAssembly/meetings

When it comes to an archival system, I'd like it to be able to run anything from an era, not just specially crafted binaries. I think Wasm meets that goal.

https://gist.github.com/dabeaz/7d8838b54dba5006c58a40fc28da9...

It allows WebAssembly to be programs which are run using a runtime on the command line, like Wasmtime, Wasmer, Wasm3, etc. Sometimes, you want to have a program which acts like a server, in that it can receive connections and send responses. This is what the patch for Tokio does.