[PATCH] D124688: [clangd] parse all make_unique-like functions in preamble

Sat Apr 30 03:44:08 PDT 2022

sammccall added a comment.

Trying this on a few files, this seems like it increases preamble sizes up to 1% or so:

                       | Before    | After
  ---------------------+-----------+----------
  AST.cpp              | 42249648  | 42419732
  XRefsTests.cpp       | 56525116  | 56763768
  SelectionDAGISel.cpp | 37546764  | 37668564
  internal_s.cc        | 59582216  | 60024876
  internal_m.cc        | 192084984 | 193850560
  internal_l.cc        | 365811816 | 368841388

I can't see any reason to think that RAM/CPU usage would be out of proportion to this.
A 1% regression here isn't trivial but seems worthwhile for significant functional improvements.
I suppose we can add:

- diagnostics (already with this patch)
- inlay hints
- signature help

WDYT about keeping this behind a flag until these are working?
For diagnostics alone, I'm not sure this is a good tradeoff (otherwise why would we restrict it to variadics? FWIW allowing all function templates to be parsed is +4% to preamble size for internal_l.cc.

I'm less concerned about the effects on the main file, partly because preambles are a bigger performance cliff, and partly because we're probably only regressing in cases where the user really is seeing benefits too.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124688/new/

https://reviews.llvm.org/D124688