1 //===--- GlobalModuleIndex.h - Global Module 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 // This file defines the GlobalModuleIndex class, which manages a global index 10 // containing all of the identifiers known to the various modules within a given 11 // subdirectory of the module cache. It is used to improve the performance of 12 // queries such as "do any modules know about this identifier?" 13 // 14 //===----------------------------------------------------------------------===// 15 #ifndef LLVM_CLANG_SERIALIZATION_GLOBALMODULEINDEX_H 16 #define LLVM_CLANG_SERIALIZATION_GLOBALMODULEINDEX_H 17 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SmallPtrSet.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/ADT/StringMap.h" 22 #include "llvm/ADT/StringRef.h" 23 #include "llvm/Support/Error.h" 24 #include <memory> 25 #include <utility> 26 27 namespace llvm { 28 class BitstreamCursor; 29 class MemoryBuffer; 30 } 31 32 namespace clang { 33 34 class DirectoryEntry; 35 class FileEntry; 36 class FileManager; 37 class IdentifierIterator; 38 class PCHContainerOperations; 39 class PCHContainerReader; 40 41 namespace serialization { 42 class ModuleFile; 43 } 44 45 /// A global index for a set of module files, providing information about 46 /// the identifiers within those module files. 47 /// 48 /// The global index is an aid for name lookup into modules, offering a central 49 /// place where one can look for identifiers determine which 50 /// module files contain any information about that identifier. This 51 /// allows the client to restrict the search to only those module files known 52 /// to have a information about that identifier, improving performance. Moreover, 53 /// the global module index may know about module files that have not been 54 /// imported, and can be queried to determine which modules the current 55 /// translation could or should load to fix a problem. 56 class GlobalModuleIndex { 57 using ModuleFile = serialization::ModuleFile; 58 59 /// Buffer containing the index file, which is lazily accessed so long 60 /// as the global module index is live. 61 std::unique_ptr<llvm::MemoryBuffer> Buffer; 62 63 /// The hash table. 64 /// 65 /// This pointer actually points to a IdentifierIndexTable object, 66 /// but that type is only accessible within the implementation of 67 /// GlobalModuleIndex. 68 void *IdentifierIndex; 69 70 /// Information about a given module file. 71 struct ModuleInfo { 72 ModuleInfo() : File(), Size(), ModTime() { } 73 74 /// The module file, once it has been resolved. 75 ModuleFile *File; 76 77 /// The module file name. 78 std::string FileName; 79 80 /// Size of the module file at the time the global index was built. 81 off_t Size; 82 83 /// Modification time of the module file at the time the global 84 /// index was built. 85 time_t ModTime; 86 87 /// The module IDs on which this module directly depends. 88 /// FIXME: We don't really need a vector here. 89 llvm::SmallVector<unsigned, 4> Dependencies; 90 }; 91 92 /// A mapping from module IDs to information about each module. 93 /// 94 /// This vector may have gaps, if module files have been removed or have 95 /// been updated since the index was built. A gap is indicated by an empty 96 /// file name. 97 llvm::SmallVector<ModuleInfo, 16> Modules; 98 99 /// Lazily-populated mapping from module files to their 100 /// corresponding index into the \c Modules vector. 101 llvm::DenseMap<ModuleFile *, unsigned> ModulesByFile; 102 103 /// The set of modules that have not yet been resolved. 104 /// 105 /// The string is just the name of the module itself, which maps to the 106 /// module ID. 107 llvm::StringMap<unsigned> UnresolvedModules; 108 109 /// The number of identifier lookups we performed. 110 unsigned NumIdentifierLookups; 111 112 /// The number of identifier lookup hits, where we recognize the 113 /// identifier. 114 unsigned NumIdentifierLookupHits; 115 116 /// Internal constructor. Use \c readIndex() to read an index. 117 explicit GlobalModuleIndex(std::unique_ptr<llvm::MemoryBuffer> Buffer, 118 llvm::BitstreamCursor Cursor); 119 120 GlobalModuleIndex(const GlobalModuleIndex &) = delete; 121 GlobalModuleIndex &operator=(const GlobalModuleIndex &) = delete; 122 123 public: 124 ~GlobalModuleIndex(); 125 126 /// Read a global index file for the given directory. 127 /// 128 /// \param Path The path to the specific module cache where the module files 129 /// for the intended configuration reside. 130 /// 131 /// \returns A pair containing the global module index (if it exists) and 132 /// the error. 133 static std::pair<GlobalModuleIndex *, llvm::Error> 134 readIndex(llvm::StringRef Path); 135 136 /// Returns an iterator for identifiers stored in the index table. 137 /// 138 /// The caller accepts ownership of the returned object. 139 IdentifierIterator *createIdentifierIterator() const; 140 141 /// Retrieve the set of modules that have up-to-date indexes. 142 /// 143 /// \param ModuleFiles Will be populated with the set of module files that 144 /// have been indexed. 145 void getKnownModules(llvm::SmallVectorImpl<ModuleFile *> &ModuleFiles); 146 147 /// Retrieve the set of module files on which the given module file 148 /// directly depends. 149 void getModuleDependencies(ModuleFile *File, 150 llvm::SmallVectorImpl<ModuleFile *> &Dependencies); 151 152 /// A set of module files in which we found a result. 153 typedef llvm::SmallPtrSet<ModuleFile *, 4> HitSet; 154 155 /// Look for all of the module files with information about the given 156 /// identifier, e.g., a global function, variable, or type with that name. 157 /// 158 /// \param Name The identifier to look for. 159 /// 160 /// \param Hits Will be populated with the set of module files that have 161 /// information about this name. 162 /// 163 /// \returns true if the identifier is known to the index, false otherwise. 164 bool lookupIdentifier(llvm::StringRef Name, HitSet &Hits); 165 166 /// Note that the given module file has been loaded. 167 /// 168 /// \returns false if the global module index has information about this 169 /// module file, and true otherwise. 170 bool loadedModuleFile(ModuleFile *File); 171 172 /// Print statistics to standard error. 173 void printStats(); 174 175 /// Print debugging view to standard error. 176 void dump(); 177 178 /// Write a global index into the given 179 /// 180 /// \param FileMgr The file manager to use to load module files. 181 /// \param PCHContainerRdr - The PCHContainerOperations to use for loading and 182 /// creating modules. 183 /// \param Path The path to the directory containing module files, into 184 /// which the global index will be written. 185 static llvm::Error writeIndex(FileManager &FileMgr, 186 const PCHContainerReader &PCHContainerRdr, 187 llvm::StringRef Path); 188 }; 189 } 190 191 #endif 192
Indexes created Wed Jun 10 00:26:05 UTC 2026