1//===- ModuleManager.cpp - Module Manager -----------------------*- 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 ModuleManager class, which manages a set of loaded
10//  modules for the ASTReader.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_SERIALIZATION_MODULEMANAGER_H
15#define LLVM_CLANG_SERIALIZATION_MODULEMANAGER_H
16
17#include "clang/Basic/LLVM.h"
18#include "clang/Basic/Module.h"
19#include "clang/Basic/SourceLocation.h"
20#include "clang/Serialization/ModuleFile.h"
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/ADT/IntrusiveRefCntPtr.h"
23#include "llvm/ADT/STLExtras.h"
24#include "llvm/ADT/SmallPtrSet.h"
25#include "llvm/ADT/SmallVector.h"
26#include "llvm/ADT/StringRef.h"
27#include "llvm/ADT/iterator.h"
28#include "llvm/ADT/iterator_range.h"
29#include <cstdint>
30#include <ctime>
31#include <memory>
32#include <string>
33#include <utility>
34
35namespace clang {
36
37class FileEntry;
38class FileManager;
39class GlobalModuleIndex;
40class HeaderSearch;
41class InMemoryModuleCache;
42class ModuleMap;
43class PCHContainerReader;
44
45namespace serialization {
46
47/// Manages the set of modules loaded by an AST reader.
48class ModuleManager {
49  /// The chain of AST files, in the order in which we started to load
50  /// them (this order isn't really useful for anything).
51  SmallVector<std::unique_ptr<ModuleFile>, 2> Chain;
52
53  /// The chain of non-module PCH files. The first entry is the one named
54  /// by the user, the last one is the one that doesn't depend on anything
55  /// further.
56  SmallVector<ModuleFile *, 2> PCHChain;
57
58  // The roots of the dependency DAG of AST files. This is used
59  // to implement short-circuiting logic when running DFS over the dependencies.
60  SmallVector<ModuleFile *, 2> Roots;
61
62  /// All loaded modules, indexed by name.
63  llvm::DenseMap<const FileEntry *, ModuleFile *> Modules;
64
65  /// FileManager that handles translating between filenames and
66  /// FileEntry *.
67  FileManager &FileMgr;
68
69  /// Cache of PCM files.
70  IntrusiveRefCntPtr<InMemoryModuleCache> ModuleCache;
71
72  /// Knows how to unwrap module containers.
73  const PCHContainerReader &PCHContainerRdr;
74
75  /// Preprocessor's HeaderSearchInfo containing the module map.
76  const HeaderSearch &HeaderSearchInfo;
77
78  /// A lookup of in-memory (virtual file) buffers
79  llvm::DenseMap<const FileEntry *, std::unique_ptr<llvm::MemoryBuffer>>
80      InMemoryBuffers;
81
82  /// The visitation order.
83  SmallVector<ModuleFile *, 4> VisitOrder;
84
85  /// The list of module files that both we and the global module index
86  /// know about.
87  ///
88  /// Either the global index or the module manager may have modules that the
89  /// other does not know about, because the global index can be out-of-date
90  /// (in which case the module manager could have modules it does not) and
91  /// this particular translation unit might not have loaded all of the modules
92  /// known to the global index.
93  SmallVector<ModuleFile *, 4> ModulesInCommonWithGlobalIndex;
94
95  /// The global module index, if one is attached.
96  ///
97  /// The global module index will actually be owned by the ASTReader; this is
98  /// just an non-owning pointer.
99  GlobalModuleIndex *GlobalIndex = nullptr;
100
101  /// State used by the "visit" operation to avoid malloc traffic in
102  /// calls to visit().
103  struct VisitState {
104    explicit VisitState(unsigned N) : VisitNumber(N, 0) {
105      Stack.reserve(N);
106    }
107
108    ~VisitState() {
109      delete NextState;
110    }
111
112    /// The stack used when marking the imports of a particular module
113    /// as not-to-be-visited.
114    SmallVector<ModuleFile *, 4> Stack;
115
116    /// The visit number of each module file, which indicates when
117    /// this module file was last visited.
118    SmallVector<unsigned, 4> VisitNumber;
119
120    /// The next visit number to use to mark visited module files.
121    unsigned NextVisitNumber = 1;
122
123    /// The next visit state.
124    VisitState *NextState = nullptr;
125  };
126
127  /// The first visit() state in the chain.
128  VisitState *FirstVisitState = nullptr;
129
130  VisitState *allocateVisitState();
131  void returnVisitState(VisitState *State);
132
133public:
134  using ModuleIterator = llvm::pointee_iterator<
135      SmallVectorImpl<std::unique_ptr<ModuleFile>>::iterator>;
136  using ModuleConstIterator = llvm::pointee_iterator<
137      SmallVectorImpl<std::unique_ptr<ModuleFile>>::const_iterator>;
138  using ModuleReverseIterator = llvm::pointee_iterator<
139      SmallVectorImpl<std::unique_ptr<ModuleFile>>::reverse_iterator>;
140  using ModuleOffset = std::pair<uint32_t, StringRef>;
141
142  explicit ModuleManager(FileManager &FileMgr, InMemoryModuleCache &ModuleCache,
143                         const PCHContainerReader &PCHContainerRdr,
144                         const HeaderSearch &HeaderSearchInfo);
145  ~ModuleManager();
146
147  /// Forward iterator to traverse all loaded modules.
148  ModuleIterator begin() { return Chain.begin(); }
149
150  /// Forward iterator end-point to traverse all loaded modules
151  ModuleIterator end() { return Chain.end(); }
152
153  /// Const forward iterator to traverse all loaded modules.
154  ModuleConstIterator begin() const { return Chain.begin(); }
155
156  /// Const forward iterator end-point to traverse all loaded modules
157  ModuleConstIterator end() const { return Chain.end(); }
158
159  /// Reverse iterator to traverse all loaded modules.
160  ModuleReverseIterator rbegin() { return Chain.rbegin(); }
161
162  /// Reverse iterator end-point to traverse all loaded modules.
163  ModuleReverseIterator rend() { return Chain.rend(); }
164
165  /// A range covering the PCH and preamble module files loaded.
166  llvm::iterator_range<SmallVectorImpl<ModuleFile *>::const_iterator>
167  pch_modules() const {
168    return llvm::make_range(PCHChain.begin(), PCHChain.end());
169  }
170
171  /// Returns the primary module associated with the manager, that is,
172  /// the first module loaded
173  ModuleFile &getPrimaryModule() { return *Chain[0]; }
174
175  /// Returns the primary module associated with the manager, that is,
176  /// the first module loaded.
177  ModuleFile &getPrimaryModule() const { return *Chain[0]; }
178
179  /// Returns the module associated with the given index
180  ModuleFile &operator[](unsigned Index) const { return *Chain[Index]; }
181
182  /// Returns the module associated with the given file name.
183  ModuleFile *lookupByFileName(StringRef FileName) const;
184
185  /// Returns the module associated with the given module name.
186  ModuleFile *lookupByModuleName(StringRef ModName) const;
187
188  /// Returns the module associated with the given module file.
189  ModuleFile *lookup(const FileEntry *File) const;
190
191  /// Returns the in-memory (virtual file) buffer with the given name
192  std::unique_ptr<llvm::MemoryBuffer> lookupBuffer(StringRef Name);
193
194  /// Number of modules loaded
195  unsigned size() const { return Chain.size(); }
196
197  /// The result of attempting to add a new module.
198  enum AddModuleResult {
199    /// The module file had already been loaded.
200    AlreadyLoaded,
201
202    /// The module file was just loaded in response to this call.
203    NewlyLoaded,
204
205    /// The module file is missing.
206    Missing,
207
208    /// The module file is out-of-date.
209    OutOfDate
210  };
211
212  using ASTFileSignatureReader = ASTFileSignature (*)(StringRef);
213
214  /// Attempts to create a new module and add it to the list of known
215  /// modules.
216  ///
217  /// \param FileName The file name of the module to be loaded.
218  ///
219  /// \param Type The kind of module being loaded.
220  ///
221  /// \param ImportLoc The location at which the module is imported.
222  ///
223  /// \param ImportedBy The module that is importing this module, or NULL if
224  /// this module is imported directly by the user.
225  ///
226  /// \param Generation The generation in which this module was loaded.
227  ///
228  /// \param ExpectedSize The expected size of the module file, used for
229  /// validation. This will be zero if unknown.
230  ///
231  /// \param ExpectedModTime The expected modification time of the module
232  /// file, used for validation. This will be zero if unknown.
233  ///
234  /// \param ExpectedSignature The expected signature of the module file, used
235  /// for validation. This will be zero if unknown.
236  ///
237  /// \param ReadSignature Reads the signature from an AST file without actually
238  /// loading it.
239  ///
240  /// \param Module A pointer to the module file if the module was successfully
241  /// loaded.
242  ///
243  /// \param ErrorStr Will be set to a non-empty string if any errors occurred
244  /// while trying to load the module.
245  ///
246  /// \return A pointer to the module that corresponds to this file name,
247  /// and a value indicating whether the module was loaded.
248  AddModuleResult addModule(StringRef FileName, ModuleKind Type,
249                            SourceLocation ImportLoc,
250                            ModuleFile *ImportedBy, unsigned Generation,
251                            off_t ExpectedSize, time_t ExpectedModTime,
252                            ASTFileSignature ExpectedSignature,
253                            ASTFileSignatureReader ReadSignature,
254                            ModuleFile *&Module,
255                            std::string &ErrorStr);
256
257  /// Remove the modules starting from First (to the end).
258  void removeModules(ModuleIterator First, ModuleMap *modMap);
259
260  /// Add an in-memory buffer the list of known buffers
261  void addInMemoryBuffer(StringRef FileName,
262                         std::unique_ptr<llvm::MemoryBuffer> Buffer);
263
264  /// Set the global module index.
265  void setGlobalIndex(GlobalModuleIndex *Index);
266
267  /// Notification from the AST reader that the given module file
268  /// has been "accepted", and will not (can not) be unloaded.
269  void moduleFileAccepted(ModuleFile *MF);
270
271  /// Visit each of the modules.
272  ///
273  /// This routine visits each of the modules, starting with the
274  /// "root" modules that no other loaded modules depend on, and
275  /// proceeding to the leaf modules, visiting each module only once
276  /// during the traversal.
277  ///
278  /// This traversal is intended to support various "lookup"
279  /// operations that can find data in any of the loaded modules.
280  ///
281  /// \param Visitor A visitor function that will be invoked with each
282  /// module. The return value must be convertible to bool; when false, the
283  /// visitation continues to modules that the current module depends on. When
284  /// true, the visitation skips any modules that the current module depends on.
285  ///
286  /// \param ModuleFilesHit If non-NULL, contains the set of module files
287  /// that we know we need to visit because the global module index told us to.
288  /// Any module that is known to both the global module index and the module
289  /// manager that is *not* in this set can be skipped.
290  void visit(llvm::function_ref<bool(ModuleFile &M)> Visitor,
291             llvm::SmallPtrSetImpl<ModuleFile *> *ModuleFilesHit = nullptr);
292
293  /// Attempt to resolve the given module file name to a file entry.
294  ///
295  /// \param FileName The name of the module file.
296  ///
297  /// \param ExpectedSize The size that the module file is expected to have.
298  /// If the actual size differs, the resolver should return \c true.
299  ///
300  /// \param ExpectedModTime The modification time that the module file is
301  /// expected to have. If the actual modification time differs, the resolver
302  /// should return \c true.
303  ///
304  /// \param File Will be set to the file if there is one, or null
305  /// otherwise.
306  ///
307  /// \returns True if a file exists but does not meet the size/
308  /// modification time criteria, false if the file is either available and
309  /// suitable, or is missing.
310  bool lookupModuleFile(StringRef FileName,
311                        off_t ExpectedSize,
312                        time_t ExpectedModTime,
313                        const FileEntry *&File);
314
315  /// View the graphviz representation of the module graph.
316  void viewGraph();
317
318  InMemoryModuleCache &getModuleCache() const { return *ModuleCache; }
319};
320
321} // namespace serialization
322
323} // namespace clang
324
325#endif // LLVM_CLANG_SERIALIZATION_MODULEMANAGER_H
326