1 //===--- GlobalModuleIndex.h - Global Module Index --------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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?"
15 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_CLANG_SERIALIZATION_GLOBALMODULEINDEX_H
17 #define LLVM_CLANG_SERIALIZATION_GLOBALMODULEINDEX_H
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/SmallPtrSet.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringMap.h"
23 #include "llvm/ADT/StringRef.h"
28 class BitstreamCursor;
37 class IdentifierIterator;
38 class PCHContainerOperations;
39 class PCHContainerReader;
41 namespace serialization {
45 using llvm::SmallVector;
46 using llvm::SmallVectorImpl;
47 using llvm::StringRef;
48 using serialization::ModuleFile;
50 /// \brief A global index for a set of module files, providing information about
51 /// the identifiers within those module files.
53 /// The global index is an aid for name lookup into modules, offering a central
54 /// place where one can look for identifiers determine which
55 /// module files contain any information about that identifier. This
56 /// allows the client to restrict the search to only those module files known
57 /// to have a information about that identifier, improving performance. Moreover,
58 /// the global module index may know about module files that have not been
59 /// imported, and can be queried to determine which modules the current
60 /// translation could or should load to fix a problem.
61 class GlobalModuleIndex {
62 /// \brief Buffer containing the index file, which is lazily accessed so long
63 /// as the global module index is live.
64 std::unique_ptr<llvm::MemoryBuffer> Buffer;
66 /// \brief The hash table.
68 /// This pointer actually points to a IdentifierIndexTable object,
69 /// but that type is only accessible within the implementation of
70 /// GlobalModuleIndex.
71 void *IdentifierIndex;
73 /// \brief Information about a given module file.
75 ModuleInfo() : File(), Size(), ModTime() { }
77 /// \brief The module file, once it has been resolved.
80 /// \brief The module file name.
83 /// \brief Size of the module file at the time the global index was built.
86 /// \brief Modification time of the module file at the time the global
90 /// \brief The module IDs on which this module directly depends.
91 /// FIXME: We don't really need a vector here.
92 llvm::SmallVector<unsigned, 4> Dependencies;
95 /// \brief A mapping from module IDs to information about each module.
97 /// This vector may have gaps, if module files have been removed or have
98 /// been updated since the index was built. A gap is indicated by an empty
100 llvm::SmallVector<ModuleInfo, 16> Modules;
102 /// \brief Lazily-populated mapping from module files to their
103 /// corresponding index into the \c Modules vector.
104 llvm::DenseMap<ModuleFile *, unsigned> ModulesByFile;
106 /// \brief The set of modules that have not yet been resolved.
108 /// The string is just the name of the module itself, which maps to the
110 llvm::StringMap<unsigned> UnresolvedModules;
112 /// \brief The number of identifier lookups we performed.
113 unsigned NumIdentifierLookups;
115 /// \brief The number of identifier lookup hits, where we recognize the
117 unsigned NumIdentifierLookupHits;
119 /// \brief Internal constructor. Use \c readIndex() to read an index.
120 explicit GlobalModuleIndex(std::unique_ptr<llvm::MemoryBuffer> Buffer,
121 llvm::BitstreamCursor Cursor);
123 GlobalModuleIndex(const GlobalModuleIndex &) = delete;
124 GlobalModuleIndex &operator=(const GlobalModuleIndex &) = delete;
127 ~GlobalModuleIndex();
129 /// \brief An error code returned when trying to read an index.
131 /// \brief No error occurred.
133 /// \brief No index was found.
135 /// \brief Some other process is currently building the index; it is not
138 /// \brief There was an unspecified I/O error reading or writing the index.
142 /// \brief Read a global index file for the given directory.
144 /// \param Path The path to the specific module cache where the module files
145 /// for the intended configuration reside.
147 /// \returns A pair containing the global module index (if it exists) and
149 static std::pair<GlobalModuleIndex *, ErrorCode>
150 readIndex(StringRef Path);
152 /// \brief Returns an iterator for identifiers stored in the index table.
154 /// The caller accepts ownership of the returned object.
155 IdentifierIterator *createIdentifierIterator() const;
157 /// \brief Retrieve the set of modules that have up-to-date indexes.
159 /// \param ModuleFiles Will be populated with the set of module files that
160 /// have been indexed.
161 void getKnownModules(SmallVectorImpl<ModuleFile *> &ModuleFiles);
163 /// \brief Retrieve the set of module files on which the given module file
164 /// directly depends.
165 void getModuleDependencies(ModuleFile *File,
166 SmallVectorImpl<ModuleFile *> &Dependencies);
168 /// \brief A set of module files in which we found a result.
169 typedef llvm::SmallPtrSet<ModuleFile *, 4> HitSet;
171 /// \brief Look for all of the module files with information about the given
172 /// identifier, e.g., a global function, variable, or type with that name.
174 /// \param Name The identifier to look for.
176 /// \param Hits Will be populated with the set of module files that have
177 /// information about this name.
179 /// \returns true if the identifier is known to the index, false otherwise.
180 bool lookupIdentifier(StringRef Name, HitSet &Hits);
182 /// \brief Note that the given module file has been loaded.
184 /// \returns false if the global module index has information about this
185 /// module file, and true otherwise.
186 bool loadedModuleFile(ModuleFile *File);
188 /// \brief Print statistics to standard error.
191 /// \brief Print debugging view to standard error.
194 /// \brief Write a global index into the given
196 /// \param FileMgr The file manager to use to load module files.
197 /// \param PCHContainerRdr - The PCHContainerOperations to use for loading and
198 /// creating modules.
199 /// \param Path The path to the directory containing module files, into
200 /// which the global index will be written.
201 static ErrorCode writeIndex(FileManager &FileMgr,
202 const PCHContainerReader &PCHContainerRdr,