[PATCH] D53524: [ThinLTO] Enable LTOUnit only when it is needed

[Peter Collingbourne via Phabricator via cfe-commits]

pcc requested changes to this revision.
pcc added a comment.
This revision now requires changes to proceed.

The reason why LTO unit is always enabled is so that you can link translation units compiled with `-fsanitize=cfi` and/or `-fwhole-program-vtables` against translation units compiled without CFI/WPD. With this change we will see miscompiles in the translation units compiled with CFI/WPD if they use vtables in the translation units compiled without CFI/WPD. If we really need this option I think it should be an opt out.


Repository:
  rC Clang

https://reviews.llvm.org/D53524