erichkeane added a comment. In https://reviews.llvm.org/D54547#1301351, @voskresensky.vladimir wrote:
> I have some experience with PTH implementation, because had to fix it for > Java-port of Clang (https://github.com/java-port/clank). > > It was sometime ago, but making it completely workable was not hard. > As I remember the key fix was just to have PTH be EMITTED using raw-Lex mode > (where real keyword-IDs are not used, so all Token Kinds nicely fit 8-bits). > It worked, because on token automatically became keyword by PTHLexer::Lex: > ... > > // Change the kind of this identifier to the appropriate token kind, e.g. > // turning "for" into a keyword. > Tok.setKind(II->getTokenID()); > > ... > > We used PTH, because multiple translation units are parsed in the context of > single run. > In this case preprocessing phase was upto 10x faster when token stream was > deserialized from PTH (i.e. for all system headers lexed once). > Also it was helpful, because we were able to parse from concurrent threads > using the same shared immutable mmaped PTH. > > I thought clang-d service is using it to speed up indexing. Presumably, I could also just make PTH use another bit or two for the TokenID and it would work fine. However, when I mentioned this on IRC the general response was that it is a 'failed experiment'. In your use case, I wonder why you couldn't just use PCH and get even further performance improvements? https://reviews.llvm.org/D54547 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
