IMPORTANT: This crate appears to not work as of January 8th 2022. I'm not sure what's changed. Look here for an alternative: WebAssembly/binaryen#2934

This crate serves a very specific purpose.

When using WebAssembly in the browser it is possible to share a WebAssembly module between the main thread and workers.

Unfortunately the workers and main thread will by-default share a stack. This is no good because they'll constantly be writing over each other's stack!

It is possible to allocate a new stack for each worker, but there's no good way to set it...

until now

This library links a small snippet of raw WebAssembly that exports a global function ("set_stack_pointer") that can be used to set the stack pointer.

Add this crate to your cargo.toml and add use wasm_set_stack_pointer; somewhere in your code.

IMPORTANT: If you don't add use wasm_set_stack_pointer; the linker will strip away the set_stack_pointer function.

This library already has the WebAssembly generated so probably you don't need to do it yourself.

But if you want to build it yourself for some reason you'll need llvm-mc installed. llvm-mc comes with llvm if you have llvm installed.

Then run llvm-mc -triple=wasm32-unknown-unknown -filetype=obj set_stack_pointer.s > libset_stack_pointer.a

to place the library in this folder.

This library may become less relevant when this lands in LLVM 12.0: WebAssembly/binaryen#2934

That flag may be used to force LLVM to export the stack pointer as a WebAssembly global.