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

   1 //===--- SymbolCollector.h ---------------------------------------*- 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 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOLCOLLECTOR_H
   9 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOLCOLLECTOR_H
  10
  11 #include "CollectMacros.h"
  12 #include "index/CanonicalIncludes.h"
  13 #include "index/Ref.h"
  14 #include "index/Relation.h"
  15 #include "index/Symbol.h"
  16 #include "index/SymbolID.h"
  17 #include "index/SymbolOrigin.h"
  18 #include "clang/AST/ASTContext.h"
  19 #include "clang/AST/Decl.h"
  20 #include "clang/Basic/SourceLocation.h"
  21 #include "clang/Basic/SourceManager.h"
  22 #include "clang/Index/IndexDataConsumer.h"
  23 #include "clang/Index/IndexSymbol.h"
  24 #include "clang/Sema/CodeCompleteConsumer.h"
  25 #include "llvm/ADT/ArrayRef.h"
  26 #include "llvm/ADT/DenseMap.h"
  27 #include <functional>
  28
  29 namespace clang {
  30 namespace clangd {
  31
  32 /// Collect declarations (symbols) from an AST.
  33 /// It collects most declarations except:
  34 /// - Implicit declarations
  35 /// - Anonymous declarations (anonymous enum/class/struct, etc)
  36 /// - Declarations in anonymous namespaces in headers
  37 /// - Local declarations (in function bodies, blocks, etc)
  38 /// - Template specializations
  39 /// - Library-specific private declarations (e.g. private declaration generated
  40 /// by protobuf compiler)
  41 ///
  42 /// References to main-file symbols are not collected.
  43 ///
  44 /// See also shouldCollectSymbol(...).
  45 ///
  46 /// Clients (e.g. clangd) can use SymbolCollector together with
  47 /// index::indexTopLevelDecls to retrieve all symbols when the source file is
  48 /// changed.
  49 class SymbolCollector : public index::IndexDataConsumer {
  50 public:
  51   struct Options {
  52     /// When symbol paths cannot be resolved to absolute paths (e.g. files in
  53     /// VFS that does not have absolute path), combine the fallback directory
  54     /// with symbols' paths to get absolute paths. This must be an absolute
  55     /// path.
  56     std::string FallbackDir;
  57     bool CollectIncludePath = false;
  58     /// If set, this is used to map symbol #include path to a potentially
  59     /// different #include path.
  60     const CanonicalIncludes *Includes = nullptr;
  61     // Populate the Symbol.References field.
  62     bool CountReferences = false;
  63     /// The symbol ref kinds that will be collected.
  64     /// If not set, SymbolCollector will not collect refs.
  65     /// Note that references of namespace decls are not collected, as they
  66     /// contribute large part of the index, and they are less useful compared
  67     /// with other decls.
  68     RefKind RefFilter = RefKind::Unknown;
  69     /// If set to true, SymbolCollector will collect all refs (from main file
  70     /// and included headers); otherwise, only refs from main file will be
  71     /// collected.
  72     /// This flag is only meaningful when RefFilter is set.
  73     bool RefsInHeaders = false;
  74     // Every symbol collected will be stamped with this origin.
  75     SymbolOrigin Origin = SymbolOrigin::Unknown;
  76     /// Collect macros.
  77     /// Note that SymbolCollector must be run with preprocessor in order to
  78     /// collect macros. For example, `indexTopLevelDecls` will not index any
  79     /// macro even if this is true.
  80     bool CollectMacro = false;
  81     /// Collect symbols local to main-files, such as static functions, symbols
  82     /// inside an anonymous namespace, function-local classes and its member
  83     /// functions.
  84     bool CollectMainFileSymbols = true;
  85     /// Collect references to main-file symbols.
  86     bool CollectMainFileRefs = false;
  87     /// Collect symbols with reserved names, like __Vector_base.
  88     /// This does not currently affect macros (many like _WIN32 are important!)
  89     bool CollectReserved = false;
  90     /// If set to true, SymbolCollector will collect doc for all symbols.
  91     /// Note that documents of symbols being indexed for completion will always
  92     /// be collected regardless of this option.
  93     bool StoreAllDocumentation = false;
  94     /// If this is set, only collect symbols/references from a file if
  95     /// `FileFilter(SM, FID)` is true. If not set, all files are indexed.
  96     std::function<bool(const SourceManager &, FileID)> FileFilter = nullptr;
  97   };
  98
  99   SymbolCollector(Options Opts);
 100   ~SymbolCollector();
 101
 102   /// Returns true is \p ND should be collected.
 103   static bool shouldCollectSymbol(const NamedDecl &ND, const ASTContext &ASTCtx,
 104                                   const Options &Opts, bool IsMainFileSymbol);
 105
 106   void initialize(ASTContext &Ctx) override;
 107
 108   void setPreprocessor(std::shared_ptr<Preprocessor> PP) override {
 109     this->PP = PP.get();
 110   }
 111   void setPreprocessor(Preprocessor &PP) { this->PP = &PP; }
 112
 113   bool
 114   handleDeclOccurrence(const Decl *D, index::SymbolRoleSet Roles,
 115                        ArrayRef<index::SymbolRelation> Relations,
 116                        SourceLocation Loc,
 117                        index::IndexDataConsumer::ASTNodeInfo ASTNode) override;
 118
 119   bool handleMacroOccurrence(const IdentifierInfo *Name, const MacroInfo *MI,
 120                              index::SymbolRoleSet Roles,
 121                              SourceLocation Loc) override;
 122
 123   void handleMacros(const MainFileMacros &MacroRefsToIndex);
 124
 125   SymbolSlab takeSymbols() { return std::move(Symbols).build(); }
 126   RefSlab takeRefs() { return std::move(Refs).build(); }
 127   RelationSlab takeRelations() { return std::move(Relations).build(); }
 128
 129   /// Returns true if we are interested in references and declarations from \p
 130   /// FID. If this function return false, bodies of functions inside those files
 131   /// will be skipped to decrease indexing time.
 132   bool shouldIndexFile(FileID FID);
 133
 134   void finish() override;
 135
 136 private:
 137   const Symbol *addDeclaration(const NamedDecl &, SymbolID,
 138                                bool IsMainFileSymbol);
 139   void addDefinition(const NamedDecl &, const Symbol &DeclSymbol);
 140   void processRelations(const NamedDecl &ND, const SymbolID &ID,
 141                         ArrayRef<index::SymbolRelation> Relations);
 142
 143   llvm::Optional<SymbolLocation> getTokenLocation(SourceLocation TokLoc);
 144
 145   llvm::Optional<std::string> getIncludeHeader(const Symbol &S, FileID);
 146
 147   SymbolID getSymbolIDCached(const Decl *D);
 148   SymbolID getSymbolIDCached(const llvm::StringRef MacroName,
 149                              const MacroInfo *MI, const SourceManager &SM);
 150
 151   // All Symbols collected from the AST.
 152   SymbolSlab::Builder Symbols;
 153   // File IDs for Symbol.IncludeHeaders.
 154   // The final spelling is calculated in finish().
 155   llvm::DenseMap<SymbolID, FileID> IncludeFiles;
 156   void setIncludeLocation(const Symbol &S, SourceLocation);
 157   // Indexed macros, to be erased if they turned out to be include guards.
 158   llvm::DenseSet<const IdentifierInfo *> IndexedMacros;
 159   // All refs collected from the AST. It includes:
 160   //   1) symbols declared in the preamble and referenced from the main file (
 161   //     which is not a header), or
 162   //   2) symbols declared and referenced from the main file (which is a header)
 163   RefSlab::Builder Refs;
 164   // All relations collected from the AST.
 165   RelationSlab::Builder Relations;
 166   ASTContext *ASTCtx;
 167   Preprocessor *PP = nullptr;
 168   std::shared_ptr<GlobalCodeCompletionAllocator> CompletionAllocator;
 169   std::unique_ptr<CodeCompletionTUInfo> CompletionTUInfo;
 170   Options Opts;
 171   struct SymbolRef {
 172     SourceLocation Loc;
 173     FileID FID;
 174     index::SymbolRoleSet Roles;
 175     const Decl *Container;
 176     bool Spelled;
 177   };
 178   void addRef(SymbolID ID, const SymbolRef &SR);
 179   // Symbols referenced from the current TU, flushed on finish().
 180   llvm::DenseSet<SymbolID> ReferencedSymbols;
 181   // Maps canonical declaration provided by clang to canonical declaration for
 182   // an index symbol, if clangd prefers a different declaration than that
 183   // provided by clang. For example, friend declaration might be considered
 184   // canonical by clang but should not be considered canonical in the index
 185   // unless it's a definition.
 186   llvm::DenseMap<const Decl *, const Decl *> CanonicalDecls;
 187   // Cache whether to index a file or not.
 188   llvm::DenseMap<FileID, bool> FilesToIndexCache;
 189   // Encapsulates calculations and caches around header paths, which headers
 190   // to insert for which symbol, etc.
 191   class HeaderFileURICache;
 192   std::unique_ptr<HeaderFileURICache> HeaderFileURIs;
 193   llvm::DenseMap<const Decl *, SymbolID> DeclToIDCache;
 194   llvm::DenseMap<const MacroInfo *, SymbolID> MacroToIDCache;
 195 };
 196
 197 } // namespace clangd
 198 } // namespace clang
 199
 200 #endif