WASI gc - fix stack range

[pavelsavara]

Currently the stack range is

• end of memory (by LLVM)
• and size is hardcoded

LLVM doesn't give us better range until WASI SDK has llvm/llvm-project@1532be9

inspired by emscripten

[ghost]

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Issue Details

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Author:	pavelsavara
Assignees:	pavelsavara
Labels:	arch-wasm
Milestone:	8.0.0

[vargaz]

Doesn't wasi have pthread_attr_getstack () or a similar API ? Is it planned ?

[pavelsavara]

Doesn't wasi have pthread_attr_getstack () or a similar API ? Is it planned ?

Since we are talking about shadow stack in the linear memory, the wasm VM itself would not probably allocate the buffer.
In emscripten it's part of the thread structure

https://github.com/emscripten-core/emscripten/blob/cfe2bdfe2692457cb5f5770672f6e5ccb3ffc2f2/src/library_pthread.js#L999-L1000

I guess POSIX layer in the WASI-SDK could do the allocation, but right now the SDK doesn't even have pthread.h

Threads are WASI proposal at the moment.
There is wasmtime --wasm-features threads which doesn't mean it has WASI nor POSIX API.
It looks like WASI API draft to me.

https://github.com/bytecodealliance/wasmtime/blob/4f0445b9e803dacfce6527e5f380724c91bfd669/examples/threads.c#LL179C45-L179C49

I don't know enough yet about any of it, but it's on my radar.