Add memory sanitizer (msan) support for rand::getrandom_uninit (and io::read) about rustix HOT 3 OPEN

Do you have an example of this intrinsic being used? I'm not familiar enough with memory sanitizers to know what to do here.

It may also be a good idea to set up MSAN for this crate.

from rustix.

Do you have an example of this intrinsic being used? I'm not familiar enough with memory sanitizers to know what to do here.

I documented what LLVM libc does in src/util_syscall_linux.rs in rust-random/getrandom#463, and that PR also shows in src/linux_android.rshow to wraplibc::syscal` with it. It's not an intrinsic, but a function that is provided by memory sanitizer, and memory sanitizer itself is provided by libstd/libcore normally, but I don't know for sure if it just picks up what's in libc or whether it separately links memory sanitizer even when libc isn't available.

from rustix.

See rust-lang/rust#123619, which seems relevant to figuring out a strategy for linking in the msan runtime.

from rustix.