ilya-biryukov marked an inline comment as done. ilya-biryukov added inline comments.
================ Comment at: clangd/Context.h:65 + Context *Parent; + TypedValueMap Data; +}; ---------------- klimek wrote: > sammccall wrote: > > ilya-biryukov wrote: > > > sammccall wrote: > > > > ilya-biryukov wrote: > > > > > sammccall wrote: > > > > > > We add complexity here (implementation and conceptual) to allow > > > > > > multiple properties to be set at the same level (vs having a key > > > > > > and an AnyStorage and making Context a linked list). > > > > > > Is this for performance? I'm not convinced it'll actually be faster > > > > > > for our workloads, or that it matters. > > > > > Conceptually, a `Context` is more convenient to use when it stores > > > > > multiple values. This allows to put a bunch of things and assign > > > > > meaning to `Context` (i.e., a `Context` for processing a single LSP > > > > > request, global context). If `Context`s were a linked list, the > > > > > intermediate `Context`s would be hard to assign the meaning to. > > > > > > > > > > That being said, storage strategy for `Context`s is an implementation > > > > > detail and could be changed anytime. I don't have big preferences > > > > > here, but I think that storing a linked list of maps has, in general, > > > > > a better performance than storing a linked list. > > > > > And given that it's already there, I'd leave it this way. > > > > With the new shared_ptr semantics: > > > > > > > > Context D = move(C).derive(K1, V1).derive(K2, V2); > > > > > > > > Is just as meaningful as > > > > > > > > Context D = move(C).derive().add(K1, V1).add(K2, V2); > > > > > > > > Yeah, the list of maps in an implementation detail. It's one that comes > > > > with a bunch of complexity (`ContextBuilder` and most of > > > > `TypedValueMap`). It really doesn't seem to buy us anything (the > > > > performance is both uninteresting and seems likely to be worse in this > > > > specific case with very few entries). > > > The thing I like about it is that the `Context`s are layered properly in > > > a sense that there's a Context corresponding to the request, a Context > > > corresponding to the forked subrequests, etc. > > > If we change the interface, we'll be creating a bunch of temporary > > > Contexts that don't correspond to a nice meaningful abstraction (like > > > request) in my head, even though we don't give those contexts any names. > > > > > > I do agree we currently pay with some complexity for that. Though I'd > > > argue it's all hidden from the users of the interface, as building and > > > consuming contexts is still super-easy and you don't need to mention > > > ContextBuilder or TypedValueMap. And the implementation complexity is > > > totally manageable from my point of view, but I am the one who > > > implemented it in the first place, so there's certainly a bias there. > > I don't see temporary unnamed `Context`s being any different from temporary > > unnamed `ContextBuilder`s. > > > > But we've gone around on this point a bit, and this really seems to be a > > question of taste. @klimek, can we have a third opinion? > > > > The options we're looking at are: > > - `Context` stores a map and a parent pointer. `derive()` returns a > > `ContextBuilder` used to create new contexts containing 0 or more new KV > > pairs. `TypedValueMap` stores the payloads. > > - `Context` stores a single KV pair and a parent pointer. `derive(K, V)` > > is used to create a new context with one new KV pair. A Key-pointer and > > AnyStorage in `Context` store the payloads, the rest of `TypedValueMap` > > goes away. > I'd agree that Context::derive(K, V) would be simpler here, mainly because > there is only one way to pass around contexts while we're building them up; > specifically, there's no temptation to pass around ContextBuilders. Done. `ContextBuilder` and `TypedValueMap` are now removed. Repository: rCTE Clang Tools Extra https://reviews.llvm.org/D40485 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
