[lld] [lld] Merge GOT entries for symbols that have been ICFed (PR #131630)

[Reid Kleckner via llvm-commits]

rnk wrote:

> After reviewing all the comments, I’m not convinced we should adopt this subtle linker code.

At a minimum, if we're establishing new requirements on input object files, we have to document the new requirements. Ideally, the linker would diagnose invalid inputs, where ADRP/LDR pairs get separated, although this may not be feasible.

I think I agree the Machine Outliner should not separate these instructions, because the potential savings from eliminating the load through GOT relaxation are greater than the size savings of outlining.

https://github.com/llvm/llvm-project/pull/131630