1 //===--- GlobalModuleIndex.h - Global Module Index --------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the GlobalModuleIndex class, which manages a global index 11 // containing all of the identifiers known to the various modules within a given 12 // subdirectory of the module cache. It is used to improve the performance of 13 // queries such as "do any modules know about this identifier?" 14 // 15 //===----------------------------------------------------------------------===// 16 #ifndef LLVM_CLANG_SERIALIZATION_GLOBAL_MODULE_INDEX_H 17 #define LLVM_CLANG_SERIALIZATION_GLOBAL_MODULE_INDEX_H 18 19 #include "llvm/ADT/DenseMap.h" 20 #include "llvm/ADT/OwningPtr.h" 21 #include "llvm/ADT/SmallPtrSet.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/ADT/StringMap.h" 24 #include "llvm/ADT/StringRef.h" 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 38 namespace serialization { 39 class ModuleFile; 40 } 41 42 using llvm::SmallVector; 43 using llvm::SmallVectorImpl; 44 using llvm::StringRef; 45 using serialization::ModuleFile; 46 47 /// \brief A global index for a set of module files, providing information about 48 /// the identifiers within those module files. 49 /// 50 /// The global index is an aid for name lookup into modules, offering a central 51 /// place where one can look for identifiers determine which 52 /// module files contain any information about that identifier. This 53 /// allows the client to restrict the search to only those module files known 54 /// to have a information about that identifier, improving performance. Moreover, 55 /// the global module index may know about module files that have not been 56 /// imported, and can be queried to determine which modules the current 57 /// translation could or should load to fix a problem. 58 class GlobalModuleIndex { 59 /// \brief Buffer containing the index file, which is lazily accessed so long 60 /// as the global module index is live. 61 llvm::OwningPtr<llvm::MemoryBuffer> Buffer; 62 63 /// \brief 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 /// \brief Information about a given module file. 71 struct ModuleInfo { 72 ModuleInfo() : File(), Size(), ModTime() { } 73 74 /// \brief The module file, once it has been resolved. 75 ModuleFile *File; 76 77 /// \brief The module file name. 78 std::string FileName; 79 80 /// \brief Size of the module file at the time the global index was built. 81 off_t Size; 82 83 /// \brief Modification time of the module file at the time the global 84 /// index was built. 85 time_t ModTime; 86 87 /// \brief 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 /// \brief 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 /// \brief Lazily-populated mapping from module files to their 100 /// corresponding index into the \c Modules vector. 101 llvm::DenseMap<ModuleFile *, unsigned> ModulesByFile; 102 103 /// \brief 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 /// \brief The number of identifier lookups we performed. 110 unsigned NumIdentifierLookups; 111 112 /// \brief The number of identifier lookup hits, where we recognize the 113 /// identifier. 114 unsigned NumIdentifierLookupHits; 115 116 /// \brief Internal constructor. Use \c readIndex() to read an index. 117 explicit GlobalModuleIndex(llvm::MemoryBuffer *Buffer, 118 llvm::BitstreamCursor Cursor); 119 120 GlobalModuleIndex(const GlobalModuleIndex &) LLVM_DELETED_FUNCTION; 121 GlobalModuleIndex &operator=(const GlobalModuleIndex &) LLVM_DELETED_FUNCTION; 122 123 public: 124 ~GlobalModuleIndex(); 125 126 /// \brief An error code returned when trying to read an index. 127 enum ErrorCode { 128 /// \brief No error occurred. 129 EC_None, 130 /// \brief No index was found. 131 EC_NotFound, 132 /// \brief Some other process is currently building the index; it is not 133 /// available yet. 134 EC_Building, 135 /// \brief There was an unspecified I/O error reading or writing the index. 136 EC_IOError 137 }; 138 139 /// \brief Read a global index file for the given directory. 140 /// 141 /// \param Path The path to the specific module cache where the module files 142 /// for the intended configuration reside. 143 /// 144 /// \returns A pair containing the global module index (if it exists) and 145 /// the error code. 146 static std::pair<GlobalModuleIndex *, ErrorCode> 147 readIndex(StringRef Path); 148 149 /// \brief Returns an iterator for identifiers stored in the index table. 150 /// 151 /// The caller accepts ownership of the returned object. 152 IdentifierIterator *createIdentifierIterator() const; 153 154 /// \brief Retrieve the set of modules that have up-to-date indexes. 155 /// 156 /// \param ModuleFiles Will be populated with the set of module files that 157 /// have been indexed. 158 void getKnownModules(SmallVectorImpl<ModuleFile *> &ModuleFiles); 159 160 /// \brief Retrieve the set of module files on which the given module file 161 /// directly depends. 162 void getModuleDependencies(ModuleFile *File, 163 SmallVectorImpl<ModuleFile *> &Dependencies); 164 165 /// \brief A set of module files in which we found a result. 166 typedef llvm::SmallPtrSet<ModuleFile *, 4> HitSet; 167 168 /// \brief Look for all of the module files with information about the given 169 /// identifier, e.g., a global function, variable, or type with that name. 170 /// 171 /// \param Name The identifier to look for. 172 /// 173 /// \param Hits Will be populated with the set of module files that have 174 /// information about this name. 175 /// 176 /// \returns true if the identifier is known to the index, false otherwise. 177 bool lookupIdentifier(StringRef Name, HitSet &Hits); 178 179 /// \brief Note that the given module file has been loaded. 180 /// 181 /// \returns false if the global module index has information about this 182 /// module file, and true otherwise. 183 bool loadedModuleFile(ModuleFile *File); 184 185 /// \brief Print statistics to standard error. 186 void printStats(); 187 188 /// \brief Write a global index into the given 189 /// 190 /// \param FileMgr The file manager to use to load module files. 191 /// 192 /// \param Path The path to the directory containing module files, into 193 /// which the global index will be written. 194 static ErrorCode writeIndex(FileManager &FileMgr, StringRef Path); 195 }; 196 197 } 198 199 #endif 200
