MaskRay added a comment. In D154043#4459446 <https://reviews.llvm.org/D154043#4459446>, @simon_tatham wrote:
> The details of this approach look good to me, but is this the best place to > solve it? Doing it in clang means that //every// language front end that > wants to use either of these sanitizers is responsible for doing this same > work: tagging every IR function with `align 4` if it also has `!kcfi_type` or > `!func_sanitize`, and perhaps also checking the target-features to decide > whether to do that. > > I'd imagined the problem being solved at a lower level, when converting the > IR into actual function prologues, so that all front ends generating IR would > benefit from the fix. In D154043#4460665 <https://reviews.llvm.org/D154043#4460665>, @efriedma wrote: > I also think it makes sense to fix the alignment when we lower the metadata, > not in the frontend, unless I'm missing something. > > It's not clear to me how "strict-align" is relevant; if sanitizer lowering is > generating "align 4" loads, the relevant pointers need to be appropriately > aligned regardless of the cost of unaligned loads. Misaligned loads are > undefined behavior in LLVM IR on all targets. (32-bit ARM in particular has > cases where 32-bit unaligned loads are supported, but certain load > instruction variations enforce alignment.) OK. See D154125 <https://reviews.llvm.org/D154125> for the MachineFunction.cpp approach. If we go that direction, I'll abandon this patch. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D154043/new/ https://reviews.llvm.org/D154043 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
