Re: [PATCH] Wasm support patch 2 (static syscalls)

[Szabolcs Nagy <nsz@port70.net>]

* Nicholas Wilson <nicholas.wilson@realvnc.com> [2017-11-28 14:53:58 +0000]:
> I think LTO would be required - but I might be missing something in your scheme? I'm considering the cases like __setxid and pthread_cancel, where the compiler can't work out which syscall numbers are possible (because the numbers come from another translation unit). In these cases, there's no way to eliminate any of the branches in your switch statement.
> 
> In particular, getuid() is such a common library call that I think we do want to be able to support it on Wasm, without having Musl link in everything. I mean, it's not an obscure piece of functionality, so it's worth a small refactor to make it usable with Wasm.

getuid is not affected, only __setxid and cancellable syscalls are.

__setxid is not that important and can be worked around in generic code,
but i don't see an easy solution for syscall_cp except that wasm
probably don't need cancellation at all so it can be just defined
to syscall.