WebAssembly compiled module cache

Is your feature request related to a problem? Please describe.

Large WASM modules take a while to compile, impacting startup times. Browsers solve this problem by caching compiled module data.

WebAssembly is a promising media for software distribution. It makes sense to compile for WebAssembly once, instead of shipping multiple binaries for each supported CPU architecture / OS pair, doesn't it? There's a growing number of tools targeting this particular segment, e.g. https://wasmer.io.

Node.js has unique advantages as a WASM runner:

• WASI as a standardised interface for interfacing with the OS (e.g. accessing files, etc.) is insufficient for most practical needs. With Node, one can leverage a plethora of high quality battle-tested cross platform libraries.

• V8 is top notch! It beats competing WASM engines in terms of compile times, resource consumption and the footprint of compiled WASM files (a single data point: V8 produces 160MiB for a 50MiB WASM file, a competitor generates 1+GiB).

• NPM is super robust. Competitors have their own package managers but not particularly reliable ones.

The only component missing in Node.js is a compiled module cache.

It takes 47s to compile the previously mentioned 50MiB WASM file. With a cache POC, the startup time is reduced to under 1s.

Describe the solution you'd like

require('wasm/cache').loadFile('module.wasm')

as a cache-enabled moral equivalent of

WebAssembly.compile(require('fs').readFileSync('module.wasm'))

Cache files to be stored in OS-mandated cache directory, e.g. ~/.cache/node/wasm-cache on Linux.

Describe alternatives you've considered

It used to be possible to serialise a WebAssembly module to a file explicitly. #18265

It stopped working since Node.js 13 due to changes in V8 and there's no way to make it work again.

Instead of introducing a new API, it is possible to enhance WebAssembly.compile/WebAssembly.compileStreaming. Unfortunately, it's hard to come up with a good cache key. We could sha256 the data, but that's inefficient.

L’issue ne nomme aucun fichier d’implémentation ni aucun test ; commencez par examiner les points d’entrée WebAssembly.compile et WebAssembly.compileStreaming ainsi que l’historique de sérialisation dans #18265. Le travail est considéré comme terminé lorsqu’un cache de modules compilés pris en charge peut charger module.wasm depuis un répertoire de cache du système d’exploitation, tout en traitant les questions liées aux clés de cache et la forme d’API proposée.