Author: Sam McCall Date: 2022-10-05T20:55:53+02:00 New Revision: 6ea83fc98fd120066c3c42d88c5517ab811152bc
URL: https://github.com/llvm/llvm-project/commit/6ea83fc98fd120066c3c42d88c5517ab811152bc DIFF: https://github.com/llvm/llvm-project/commit/6ea83fc98fd120066c3c42d88c5517ab811152bc.diff LOG: [clangd] Don't clone SymbolSlab::Builder arenas when finalizing. SymbolSlab::Builder has an arena to store strings of owned symbols, and deduplicates them. build() copies all the strings and deduplicates them again! This is potentially useful: we may have overwritten a symbol and rendered some strings unreachable. However in practice this is not the case. When testing on a variety of files in LLVM (e.g. SemaExpr.cpp), the strings for the full preamble index are 3MB and shrink by 0.4% (12KB). For comparison the serializde preamble is >50MB. There are also hundreds of smaller slabs (file sharding) that do not shrink at all. CPU time spent on this is significant (something like 3-5% of buildPreamble). We're better off not bothering. Differential Revision: https://reviews.llvm.org/D135231 Added: Modified: clang-tools-extra/clangd/index/Symbol.cpp Removed: ################################################################################ diff --git a/clang-tools-extra/clangd/index/Symbol.cpp b/clang-tools-extra/clangd/index/Symbol.cpp index 365aceec51251..ac840a668ac2b 100644 --- a/clang-tools-extra/clangd/index/Symbol.cpp +++ b/clang-tools-extra/clangd/index/Symbol.cpp @@ -61,12 +61,9 @@ SymbolSlab SymbolSlab::Builder::build() && { SortedSymbols.push_back(std::move(Entry.second)); llvm::sort(SortedSymbols, [](const Symbol &L, const Symbol &R) { return L.ID < R.ID; }); - // We may have unused strings from overwritten symbols. Build a new arena. - llvm::BumpPtrAllocator NewArena; - llvm::UniqueStringSaver Strings(NewArena); - for (auto &S : SortedSymbols) - own(S, Strings); - return SymbolSlab(std::move(NewArena), std::move(SortedSymbols)); + // We may have unused strings from overwritten symbols. + // In practice, these are extremely small, it's not worth compacting. + return SymbolSlab(std::move(Arena), std::move(SortedSymbols)); } llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const SymbolSlab &Slab) { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits