[PATCH] D25854: [lto] Kill undefined extern_weak declarations before opt

[Evgeniy Stepanov via llvm-commits]

eugenis added a comment.

It appears that this optimization is only possible in executables.

Extern_weak declarations can not be bound at link time when building a shared library, because any available definition is not final, and even the lack of any definition is not final.

This means that CFI will have to deal with undefined extern_weak declarations somehow, which makes this change only a minor optimization, so I'm going to drop it for now. I agree with the thinlto comments, and if I decide to work on this again, I'll start with an RFC.


Repository:
  rL LLVM

https://reviews.llvm.org/D25854