[lld] [lld-macho] Scope addrsig keepUnique marking to code sections (PR #192636)

[Ellis Hoag via llvm-commits]

ellishg wrote:

I'm honestly a little uneasy about this change. I can certainly imagine a case where a data symbol is address significant, especially in embedded systems. And it feels wrong for the linker to ignore the directive. A better solution is to understand why LLVM thinks they should be address significant. 

In practice, I can understand why this is necessary and I believe that it won't be harmful to fold these particular sections. I just worry about the confusion if lld folds a section that it was explicitly told not to fold. 

Perhaps we can land this to fix the regression, but link a GitHub issue explaining the problem in the comment and maybe a thread on discourse for discussion. 

https://github.com/llvm/llvm-project/pull/192636