clang-tools-extra/clangd/index/MemIndex.h

   1 //===--- MemIndex.h - Dynamic in-memory symbol index. -------------- C++-*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_MEMINDEX_H
  10 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_MEMINDEX_H
  11
  12 #include "index/Index.h"
  13 #include "llvm/ADT/StringSet.h"
  14 #include <mutex>
  15
  16 namespace clang {
  17 namespace clangd {
  18
  19 /// MemIndex is a naive in-memory index suitable for a small set of symbols.
  20 class MemIndex : public SymbolIndex {
  21 public:
  22   MemIndex() = default;
  23   // All symbols and refs must outlive this index.
  24   template <typename SymbolRange, typename RefRange, typename RelationRange>
  25   MemIndex(SymbolRange &&Symbols, RefRange &&Refs, RelationRange &&Relations) {
  26     for (const Symbol &S : Symbols)
  27       Index[S.ID] = &S;
  28     for (const std::pair<SymbolID, llvm::ArrayRef<Ref>> &R : Refs)
  29       this->Refs.try_emplace(R.first, R.second.begin(), R.second.end());
  30     for (const Relation &R : Relations)
  31       this->Relations[std::make_pair(R.Subject,
  32                                      static_cast<uint8_t>(R.Predicate))]
  33           .push_back(R.Object);
  34   }
  35   // Symbols are owned by BackingData, Index takes ownership.
  36   template <typename SymbolRange, typename RefRange, typename RelationRange,
  37             typename Payload>
  38   MemIndex(SymbolRange &&Symbols, RefRange &&Refs, RelationRange &&Relations,
  39            Payload &&BackingData, size_t BackingDataSize)
  40       : MemIndex(std::forward<SymbolRange>(Symbols),
  41                  std::forward<RefRange>(Refs),
  42                  std::forward<RelationRange>(Relations)) {
  43     KeepAlive = std::shared_ptr<void>(
  44         std::make_shared<Payload>(std::move(BackingData)), nullptr);
  45     this->BackingDataSize = BackingDataSize;
  46   }
  47
  48   template <typename SymbolRange, typename RefRange, typename RelationRange,
  49             typename FileRange, typename Payload>
  50   MemIndex(SymbolRange &&Symbols, RefRange &&Refs, RelationRange &&Relations,
  51            FileRange &&Files, IndexContents IdxContents, Payload &&BackingData,
  52            size_t BackingDataSize)
  53       : MemIndex(std::forward<SymbolRange>(Symbols),
  54                  std::forward<RefRange>(Refs),
  55                  std::forward<RelationRange>(Relations),
  56                  std::forward<Payload>(BackingData), BackingDataSize) {
  57     this->Files = std::forward<FileRange>(Files);
  58     this->IdxContents = IdxContents;
  59   }
  60
  61   /// Builds an index from slabs. The index takes ownership of the data.
  62   static std::unique_ptr<SymbolIndex> build(SymbolSlab Symbols, RefSlab Refs,
  63                                             RelationSlab Relations);
  64
  65   bool
  66   fuzzyFind(const FuzzyFindRequest &Req,
  67             llvm::function_ref<void(const Symbol &)> Callback) const override;
  68
  69   void lookup(const LookupRequest &Req,
  70               llvm::function_ref<void(const Symbol &)> Callback) const override;
  71
  72   bool refs(const RefsRequest &Req,
  73             llvm::function_ref<void(const Ref &)> Callback) const override;
  74
  75   void relations(const RelationsRequest &Req,
  76                  llvm::function_ref<void(const SymbolID &, const Symbol &)>
  77                      Callback) const override;
  78
  79   llvm::unique_function<IndexContents(llvm::StringRef) const>
  80   indexedFiles() const override;
  81
  82   size_t estimateMemoryUsage() const override;
  83
  84 private:
  85   // Index is a set of symbols that are deduplicated by symbol IDs.
  86   llvm::DenseMap<SymbolID, const Symbol *> Index;
  87   // A map from symbol ID to symbol refs, support query by IDs.
  88   llvm::DenseMap<SymbolID, llvm::ArrayRef<Ref>> Refs;
  89   // A map from (subject, predicate) pair to objects.
  90   static_assert(sizeof(RelationKind) == sizeof(uint8_t),
  91                 "RelationKind should be of same size as a uint8_t");
  92   llvm::DenseMap<std::pair<SymbolID, uint8_t>, std::vector<SymbolID>> Relations;
  93   // Set of files which were used during this index build.
  94   llvm::StringSet<> Files;
  95   // Contents of the index (symbols, references, etc.)
  96   IndexContents IdxContents;
  97   std::shared_ptr<void> KeepAlive; // poor man's move-only std::any
  98   // Size of memory retained by KeepAlive.
  99   size_t BackingDataSize = 0;
 100 };
 101
 102 } // namespace clangd
 103 } // namespace clang
 104
 105 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_MEMINDEX_H