QuietMisdreavus added inline comments.
================ Comment at: clang/lib/ExtractAPI/Serialization/SymbolGraphSerializer.cpp:510 Symbols.emplace_back(std::move(*Obj)); + PathComponentContext.pop_back(); } ---------------- dang wrote: > dang wrote: > > zixuw wrote: > > > zixuw wrote: > > > > QuietMisdreavus wrote: > > > > > zixuw wrote: > > > > > > What's the cost/would it worth it to wrap the `emplace_back`s and > > > > > > `pop_back`s of `PathComponentContext` in meaningful APIs like > > > > > > `enterPathComponentContext` and `exitPathComponentContext`? > > > > > > That way the code is more self-explanatory and easier to read. It > > > > > > took me some time and mental resources to figure out why the > > > > > > `pop_back` is placed here. > > > > > What's the use of having the `emplace_back` call inside > > > > > `serializeAPIRecord` but to pop it outside? It seems like it's easier > > > > > to mess up for new kinds of records. > > > > The reason to `emplace_back` the path component inside > > > > `serializeAPIRecord` is that the `pathComponent` field of the `Record` > > > > is serialized in there so you want to include the name of the symbol > > > > itself in the path component list. > > > > The `pop_back` is delayed til all other additional serialization for a > > > > specific kind of record, for example `serializeEnumRecord` handles all > > > > the enum cases after processing the enum record itself using > > > > `serializeAPIRecord`. So in order to correctly include the enum name in > > > > the path components of all the enum cases, the enum name has to stay in > > > > `PathComponentContext` until all members are serialized. > > > > > > > > This is exactly the reason why I wanted a clearer API to make it easier > > > > to see. > > > Hmm now that I thought about this, it seems that it would be easier to > > > understand and avoid bugs if we lift > > > `PathComponentContext.emplace_back`/`enterPathComponentContext` out of > > > `serializeAPIRecord`, because we have access to the record name before > > > that anyway. > > > > > > So we establish a pre-condition of `serializeAPIRecord` that the correct > > > path components would be set up in `PathComponentContext` before the call > > > so we could still serialize the field inside that method. And in specific > > > `serialize*Record` methods we push the record name, and pop out at the > > > end. > > > > > > This way the push and pop operations would appear in pairs in a single > > > block, saving the confusion and mental work of jumping across functions > > > to see how `PathComponentContext` is evolving. > > If you think we should have a specialized API I am happy to do this. I > > figured it was self-explanatory by the name of `PathComponentContext` but > > it clearly isn't so needs addressing. I put the `emplace_back` call in > > `serializeAPIRecord` since all the specific serialization methods call it. > > I thought it would make it impossible to forget to add them. @zixuw is > > correct in the reason why the pop is outside we don't want to pop before we > > have serialized the sub records by agree it is ugly and potentially error > > prone. I can see three ways forward for improving the ergonomics of this > > since this seems to be problematic: > > - Provide `serializeAPIRecord` a continuation to serialize the sub records > > or additional fields, that way we can move the pop inside > > `serializeAPIRecord` I am not a fan personally because we get into JS style > > closure hell if we start doing this... > > - Use a visitor pattern where the visitor would be responsible for managing > > `PathComponentContext` and do the appropriate push/pops in the `visit` > > methods. We would need to add a APIRecordVisitor type, and appropriate > > visit methods for each APIRecord. This would make sense because the records > > should really know how to visit themselves. > > - Just add a specialized API although it seems it would really easy to > > forget to remove path components. > > > > Let me know what you think is the way forward. > Unless we go with the last option, I think this should be a follow up patch > since it would a structural change. I'm most a fan of the `APIRecordVisitor` option, but you're right in that that would be a rather involved change. Now that you've said that the arrangement is for encoding sub-records, it makes sense to me. As an alternative, i think moving the `emplace_back` outside of `serializeAPIRecord` is actually my other preferred arrangement; without some other way of calculating the path components on-the-fly (e.g. walking up DeclContexts) simply having `serializeAPIRecord` look at what's there and have the wrapper calls deal with setting up its state sounds the most reasonable to me. That way, as @zixuw said, the `emplace_back` and `pop_back` calls are at least lexically close to each other. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D123045/new/ https://reviews.llvm.org/D123045 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
