emscripten VS design

Browsers limit the ability for these platforms to use raw sockets, there simply is no API for it. The best that can be done /today/ is to use WebSockets, which are not the same thing any can't be used for HTTP requests without the server expecting a WebSocket connection:

https://github.com/emscripten-core/emscripten/issues/5196#is...

Only half true. Emscripten implements the SDL 1.2 (and also SDL_mixer 1.2) API in Javascript here: https://github.com/emscripten-core/emscripten/blob/main/src/.... On the other hand SDL 2 (and SDL_mixer 2) are proper ports (which you linked to).

So there's quite a size penalty to using SDL 2 rather than SDL 1.2.

Playing with low-level stuff is fun, but I won't use it anywhere in productionable code. Well, at least without considerable experience and understanding of the Emscripten code base.

Thank you for your comment!

WASM gave Figma a lot of speed by default for a lot of perf-sensitive code like rendering, layouts, applying styles and materializing component instances, our GUI code is mostly React and CSS.

WASM engine performance has not been a problem for us, instead we are constantly looking forward improvements in the devex department: debugging, profiling and modularization.

One of the largest challenges of the platform we face today is the heap size limit. While Chrome supports up to 4GB today, that's not yet the case for all browsers. And even with that, we are still discovering bugs in the toolchain (see this recent issue filed by one of our engineers) https://github.com/emscripten-core/emscripten/issues/20137

The challenge of the perf-testing at scale in our company is helping developers to detect perf regressions when they don't expect them - accidental algorithmic errors, misused caches, over-rendering React components, dangerously inefficient CSS directives, etc.

https://github.com/emscripten-forge/recipes/tree/main/recipe...

Re: emscripten fs implementations: https://github.com/emscripten-core/emscripten/issues/15041#i... https://github.com/jupyterlite/jupyterlite/issues/315

Moving onto the project, let’s first install Emscripten from their git repository. Emscripten will compile C into Wasm code. An important note is that I will be using Mac OS for this project. If you want to follow along using Windows, use this link. To Begin, open your terminal and clone down Emscripten with:

I got pointed to this one here: https://github.com/emscripten-core/emscripten/issues/15487

If you want to do it, go to town. This is the only reference I could find to anybody targeting wasm with i2pd frankly I really hope the person inquiring in the issue is also you.

Right, and if that momentum is going to last 20 years, then that's going to dictate what's a good strategic decision and what isn't for the next 20 years. Thanks for letting me know what the good options might be when my infant daughter is halfway through college, that doesn't help me save for it in the meantime.

Prior familiarity is a very good reason to pick an option for a greenfield project if you're operating on any type of serious budget (time or money), especially if you need to hire others to help out. There's also the annoying reality that most libraries for new/up-and-coming languages are simply inadequate, despite whatever claims they make.

For instance, one of my personal side projects involves getting familiar with WebAssembly (note: not on a serious budget), and I'm using emscripten to transcode because that's what the internet seemed to think was the closest thing to a standard toolkit. I found a bug simply by combining two pieces of example code from Emscripten's own documentation (you'll note I'm transcoding from c++ due to prior familiarity): https://github.com/emscripten-core/emscripten/issues/17143

This is not a dig on emscripten per se, merely pointing out that it's probably not mature enough for the stress of corporate-scale development, where you encounter all sorts of crazy edge cases well beyond the sample code. Java over the years has obtained that level of maturity. The edge cases are largely solved or at least known, and there's an army of experts and consultants ready to help if there's a problem. When time is money, that matters. It determines the risk profile of any project, greenfield or otherwise.

Java's momentum hasn't stopped, at best it's simply slowing. And at this rate it'll take decades to come to a stop, and decades more to recede to any meaningful degree. I'll also point out that C is very much alive and well in the embedded world. Plenty of job postings looking for C experience explicitly.

First of all, a quick rundown of what WASM is. It stands for Web Assembly. In essence, similar to how Java compiles down to a bytecode that is interpreted by a Java Virtual Machine, Web Assembly is a different bytecode interpreted by the browser. Many different languages can compile into WASM, and Javascript can interface with it like a module. In my case, I wrote a lot of the source code in Rust and compiled it down to a WASM module, then called into it from Javascript.

WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable compilation target for programming languages, enabling deployment on the web for client and server applications. - https://webassembly.org

With WebAssembly we can compile our C++ codebase into a wasm module for the browser. So when you look at a SciChart.js chart you're actually seeing our C++ graphics engine wrapped for JavaScript.

I should add, however, that the unmentioned elephant in the room is V8 JIT (TurboFan), which simply doesn't handle irreducible control flow. While there are some valid theoretical arguments around the current arrangement in Wasm, looking at the history of the associated discussions makes it pretty obvious that having V8 support Wasm and generate fast code similar to what it can do for asm.js was an overriding concern in many cases. And Google straight up said that if Wasm has ICF, they will not bother supporting such cases, so it will be done by a much slower fallback:

https://github.com/WebAssembly/design/issues/796#issuecommen...

AFAIK no other Wasm implementation has the same constraint - the rest generally tend to desugar everything to jumps and then proceed from there. So this is, at least to some extent, yet another case of a large company effectively forcing an open standard to be more convenient for them specifically.

https://github.com/WebAssembly/design/issues/1397

> Currently allocating more than ~300MB of memory is not reliable on Chrome on Android without resorting to Chrome-specific workarounds, nor in Safari on iOS.

That's about allocating CPU memory but the GPU memory situation is similar.

As far as I can tell (5 minutes of internet research) this was to allow easier compilation to JavaScript as a fallback in the days when WASM wasn't widely supported.

"Please add goto" issue has been open since 2016:

https://github.com/WebAssembly/design/issues/796

Most interesting comment:

> The upcoming Go 1.11 release will have experimental support for WebAssembly. This will include full support for all of Go's features, including goroutines, channels, etc. However, the performance of the generated WebAssembly is currently not that good.

> This is mainly because of the missing goto instruction. Without the goto instruction we had to resort to using a toplevel loop and jump table in every function. Using the relooper algorithm is not an option for us, because when switching between goroutines we need to be able to resume execution at different points of a function. The relooper can not help with this, only a goto instruction can.

> It is awesome that WebAssembly got to the point where it can support a language like Go. But to be truly the assembly of the web, WebAssembly should be equally powerful as other assembly languages. Go has an advanced compiler which is able to emit very efficient assembly for a number of other platforms. This is why I would like to argue that it is mainly a limitation of WebAssembly and not of the Go compiler that it is not possible to also use this compiler to emit efficient assembly for the web.

^ https://github.com/WebAssembly/design/issues/796#issuecommen...

When I implemented a WASM compiler, the only source of float-based non-determinism I found was in the exact byte representation of NaN. Floating point math is deterministic. See https://webassembly.org/docs/faq/#why-is-there-no-fast-math-... and https://github.com/WebAssembly/design/blob/main/Nondetermini....

> To work with GC, you need some way to track if the GC'd object is accessible in WASM itself.

I've never heard of a GC with that kind of API. Usually any native code that holds a GC reference would either mark that reference as a root explicitly (eg. https://github.com/WebAssembly/design/issues/1459) or ensure that it can be traced from a parent object. Either way, this should prevent collection of the object. I agree that explicitly checking whether a GC'd object has been freed would not make any sense.

> The reason why you probably need a custom string type is so you can actually embed string literals without relying on interop with the environment.

WASM already has ways of embedding flat string data. This can be materialized into GC/heap objects at module startup. This must happen in some form anyway, as all GC-able objects must be registered with the GC upon creation, for them to be discoverable as candidates for collection.

Overall I still don't understand the issue. There is so much prior art for these patterns in native extensions for Python, PHP, Ruby, etc.

Giving you a buffer that grows is the allocation approach I am talking about. This is not how your OS works. Your OS itself works with an allocator that does a pretty good job making sure that your memory ends up not fragmented. Because WASM is in between, the OS is not in control of the memory, and instead the browser is. The browser implementation of "bring your own allocator" is cute but realistically just a waste of time for everybody who wants to deploy a wasm app because whatever allocator you bring is crippled by the overarching allocator of the browser messing everything up.

It seems like the vendors are recognizing this though, with firefox now having a discard function aparently!

https://github.com/WebAssembly/design/issues/1397