[swift-dev] Having 64-bit swift_retain/release ignore all negative pointer values

[Joe Groff]

> On Oct 13, 2016, at 2:04 PM, Alexis <abeingessner at apple.com> wrote:
> 
> Correct me if I’m wrong, but aren’t all kernel addresses negative on x64 and AArch64? Would this then mean any attempt to use Swift in kernel-space requires a distinct ABI?

That's correct, but we'd likely already have to have a separate "kernel" ABI due to our assumptions about spare bits in pointers. It also seems unlikely to me that kernel developers would want to use our refcounting scheme as is.

-Joe