jansvoboda11 added a comment. In D120334#3338314 <https://reviews.llvm.org/D120334#3338314>, @yurai007 wrote:
> In D120334#3337961 <https://reviews.llvm.org/D120334#3337961>, @jansvoboda11 > wrote: > >> The performance implications are pretty interesting! Have you tried avoiding >> the copy altogether by just storing the reference? > > Yes, actually that was my first attempt but I failed miserably. > LangOpts::LineComment is mutated in Lexer so LangOpts cannot be simply > const&. Making it non-const reference is technically doable with some extra > adjustment for Lexer constructors. > However I'm worried a bit how it would impact external LangOpts users after > mutating LineComment member by Lexer. As long as LangOpts acts as simple > cache it's easy to reason about but when we start to share it with Lexer > callers I'm not longer sure. That's why eventually base class approach was > chosen. Got it. It seems like getting rid of the `LineComment` mutation would be pretty straightforward though. I don't expect any big perf win by replacing copy of a handful of bitfields with indirection, but it would be interesting to see the experiment nonetheless. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D120334/new/ https://reviews.llvm.org/D120334 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
