[PATCH] D46896: [llvm-objcopy] Add --strip-unneeded option

[James Henderson via Phabricator via llvm-commits]

jhenderson added a comment.

I'm happy to defer to @jakehehrlich's preferences here, but FWIW, I think GNU objcopy's behaviour is actually the wrong way around regarding the Global/Weak symbols: if you strip a defined symbol from an ET_REL ELF that isn't referenced within that ELF, the file can still be used in a link, you just can't reference anything that wasn't already referenced by that object file. Stripping symbols from ET_DYN/EXEC is okay, as it should have zero impact on the runtime behaviour (although debugging etc might not be as trivial). Anything that requires symbols at runtime should be using dynamic relocations and dynamic symbols, which this behaviour won't touch.

I think we need to be slightly wary of using ET_* types directly, because it will make it hard for vendors to add their own ET_* types to the list of things that should/should not be affected by some behaviour. If we do decide to go down the route of matching objcopy's behaviour here and therefore need to distinguish between relocatable and executable types, I'd suggest adding helper functions to wrap them, and call those instead of testing e_type directly.


Repository:
  rL LLVM

https://reviews.llvm.org/D46896