On Thu, Nov 16, 2017 at 11:50:12AM +0000, Will Deacon wrote: > Why don't we just not do LTO if the toolchain is busted?
Because LTO can not only potentially improve performance, especially when combined with PGO (Profile Guided Optimization), but it also makes it possible to enable features like Control Flow Integrity that can make kernel vulnerabilities more difficult to exploit: https://clang.llvm.org/docs/ControlFlowIntegrity.html > This feels like it will end up being a game of whack-a-mole as code > could be introduced that tickles known bugs on older toolchains. I'm not sure this is much different from dealing with older versions of the existing toolchain. Otherwise, we wouldn't need cc-version or other similar macros, for example. Sami
