WebAssembly / WebAssembly/spec
wasm64: support memory larger than 16 GB
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Description
I asked this question at https://github.com/emscripten-core/emscripten/discussions/23966 and was told it's a limitation imposed by the spec.
In wasm64, the spec caps the maximum memory to 16 GB in https://github.com/WebAssembly/memory64/blob/9003cd5e24e53b84cd9027ea3dd7ae57159a6db1/document/js-api/index.bs#L1785.
Could we please get wasm64 to support as much memory available from the host machine's RAM? I'd also like to understand reasons behind the 16GB limit when technically 64-bit integers can be used to index memories much larger than 16GB.
@sbc100
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the WebAssembly memory64 specification and the JS API memory section linked in the issue, especially the cited limit at document/js-api/index.bs#L1785. Investigate the specification rationale for the 16 GB cap and identify the proposal and test changes required to support larger memories. Done means a reviewed specification-level direction, not just an implementation change.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- wasm
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100