Is WebAssembly a JIT?

In WebAssembly, things like types are explicit, so the JIT doesn’t need to make assumptions about types based on data it gathers during runtime. This means it doesn’t have to go through reoptimization cycles.

Why WebAssembly is faster?

WebAssembly also performs better compared to recent technologies with a similar goal. Firstly, it can outperform asm. js from optimizations beyond what can be done with JavaScript, WebAssembly has faster download with smaller code size, it does not require parsing as it’s already in a binary format.

Does WebAssembly need JavaScript?

Thus, to access any Web API, WebAssembly needs to call out to JavaScript, which then makes the Web API call. Emscripten therefore creates the HTML and JavaScript glue code needed to achieve this.

Which browser supports WebAssembly?

Which products support it? Firefox and Chrome browsers currently support the wasm format on Linux, MacOS, Windows and Android. The latest versions of Edge and Safari now include WebAssembly support as well.

Will WebAssembly ever be supported by C++?

As WebAssembly evolves it will support more languages than C/C++, and we hope that other compilers will support it as well, even for the C/C++ language, for example GCC. The WebAssembly working group found it easier to start with LLVM support because they had more experience with that toolchain from their Emscripten and PNaCl work.

Is WebAssembly a replacement for JavaScript?

No! WebAssembly is designed to be a complement to, not replacement of, JavaScript. While WebAssembly will, over time, allow many languages to be compiled to the Web, JavaScript has an incredible amount of momentum and will remain the single, privileged (as described above) dynamic language of the Web.

What is WebAssembly and why should you care?

WebAssembly minimizes costs by having a design that allows (though not requires) a browser to implement WebAssembly inside its existing JavaScript engine (thereby reusing the JavaScript engine’s existing compiler backend, ES6 module loading frontend, security sandboxing mechanisms and other supporting VM components).

Is it possible to run JIT code on Xtensa?

The JIT code uses LLVM, and mainline LLVM doesn’t yet support Xtensa. There’s a LLVM for Xtensa under development so I’m building that, which on my laptop is not a fast process. To actually run this code it’s got to target Xtensa but also the libraries themselves have to be compiled for Xtensa.