[PATCH] D23834: [AArch64] Allow label arithmetic with add/sub/cmp

[Tim Northover via llvm-commits]

t.p.northover added a comment.

> How does the ELF logic deal with attempts to perform subtractions across sections (the equivalent of the first MachO problem)?


Ah, I see there's logic in ELFObjectWriter.cpp and it really is checking the section, so MachO probably can't benefit.

We probably want to diagnose attempts in MachO where MCAssembler::getAtom is different (or null) for each symbol. With that restriction, we can even cope if one of them is the defining (visible) symbol of the atom.


https://reviews.llvm.org/D23834