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88  /// other does not know about, because the global index can be out-of-date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