6ea83fc98f
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
81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
//===--- Symbol.cpp ----------------------------------------------*- C++-*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "Symbol.h"
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#include <cmath>
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namespace clang {
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namespace clangd {
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llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, Symbol::SymbolFlag F) {
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if (F == Symbol::None)
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return OS << "None";
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std::string S;
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if (F & Symbol::Deprecated)
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S += "deprecated|";
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if (F & Symbol::IndexedForCodeCompletion)
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S += "completion|";
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return OS << llvm::StringRef(S).rtrim('|');
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}
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llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Symbol &S) {
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return OS << S.Scope << S.Name;
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}
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float quality(const Symbol &S) {
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// This avoids a sharp gradient for tail symbols, and also neatly avoids the
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// question of whether 0 references means a bad symbol or missing data.
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if (S.References < 3)
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return 1;
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return std::log(S.References);
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}
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SymbolSlab::const_iterator SymbolSlab::find(const SymbolID &ID) const {
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auto It = llvm::partition_point(Symbols,
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[&](const Symbol &S) { return S.ID < ID; });
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if (It != Symbols.end() && It->ID == ID)
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return It;
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return Symbols.end();
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}
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// Copy the underlying data of the symbol into the owned arena.
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static void own(Symbol &S, llvm::UniqueStringSaver &Strings) {
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visitStrings(S, [&](llvm::StringRef &V) { V = Strings.save(V); });
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}
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void SymbolSlab::Builder::insert(const Symbol &S) {
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own(Symbols[S.ID] = S, UniqueStrings);
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}
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SymbolSlab SymbolSlab::Builder::build() && {
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// Sort symbols into vector so the slab can binary search over them.
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std::vector<Symbol> SortedSymbols;
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SortedSymbols.reserve(Symbols.size());
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for (auto &Entry : Symbols)
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SortedSymbols.push_back(std::move(Entry.second));
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llvm::sort(SortedSymbols,
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[](const Symbol &L, const Symbol &R) { return L.ID < R.ID; });
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// We may have unused strings from overwritten symbols.
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// In practice, these are extremely small, it's not worth compacting.
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return SymbolSlab(std::move(Arena), std::move(SortedSymbols));
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}
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llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const SymbolSlab &Slab) {
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OS << "{";
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llvm::StringRef Sep = "";
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for (const auto &S : Slab) {
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OS << Sep << S;
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Sep = ", ";
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}
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OS << "}";
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return OS;
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}
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} // namespace clangd
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} // namespace clang
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