Coverage Report

Created: 2020-02-15 09:57

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Frontend/PrecompiledPreamble.h
Line
Count
Source (jump to first uncovered line)
1
//===--- PrecompiledPreamble.h - Build precompiled preambles ----*- 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
// Helper class to build precompiled preamble.
10
//
11
//===----------------------------------------------------------------------===//
12
13
#ifndef LLVM_CLANG_FRONTEND_PRECOMPILED_PREAMBLE_H
14
#define LLVM_CLANG_FRONTEND_PRECOMPILED_PREAMBLE_H
15
16
#include "clang/Lex/Lexer.h"
17
#include "clang/Lex/Preprocessor.h"
18
#include "llvm/ADT/IntrusiveRefCntPtr.h"
19
#include "llvm/Support/AlignOf.h"
20
#include "llvm/Support/MD5.h"
21
#include <cstddef>
22
#include <memory>
23
#include <system_error>
24
#include <type_traits>
25
26
namespace llvm {
27
class MemoryBuffer;
28
namespace vfs {
29
class FileSystem;
30
}
31
} // namespace llvm
32
33
namespace clang {
34
class CompilerInstance;
35
class CompilerInvocation;
36
class DeclGroupRef;
37
class PCHContainerOperations;
38
39
/// Runs lexer to compute suggested preamble bounds.
40
PreambleBounds ComputePreambleBounds(const LangOptions &LangOpts,
41
                                     llvm::MemoryBuffer *Buffer,
42
                                     unsigned MaxLines);
43
44
class PreambleCallbacks;
45
46
/// A class holding a PCH and all information to check whether it is valid to
47
/// reuse the PCH for the subsequent runs. Use BuildPreamble to create PCH and
48
/// CanReusePreamble + AddImplicitPreamble to make use of it.
49
class PrecompiledPreamble {
50
  class PCHStorage;
51
  struct PreambleFileHash;
52
53
public:
54
  /// Try to build PrecompiledPreamble for \p Invocation. See
55
  /// BuildPreambleError for possible error codes.
56
  ///
57
  /// \param Invocation Original CompilerInvocation with options to compile the
58
  /// file.
59
  ///
60
  /// \param MainFileBuffer Buffer with the contents of the main file.
61
  ///
62
  /// \param Bounds Bounds of the preamble, result of calling
63
  /// ComputePreambleBounds.
64
  ///
65
  /// \param Diagnostics Diagnostics engine to be used while building the
66
  /// preamble.
67
  ///
68
  /// \param VFS An instance of vfs::FileSystem to be used for file
69
  /// accesses.
70
  ///
71
  /// \param PCHContainerOps An instance of PCHContainerOperations.
72
  ///
73
  /// \param StoreInMemory Store PCH in memory. If false, PCH will be stored in
74
  /// a temporary file.
75
  ///
76
  /// \param Callbacks A set of callbacks to be executed when building
77
  /// the preamble.
78
  static llvm::ErrorOr<PrecompiledPreamble>
79
  Build(const CompilerInvocation &Invocation,
80
        const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
81
        DiagnosticsEngine &Diagnostics,
82
        IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
83
        std::shared_ptr<PCHContainerOperations> PCHContainerOps,
84
        bool StoreInMemory, PreambleCallbacks &Callbacks);
85
86
176
  PrecompiledPreamble(PrecompiledPreamble &&) = default;
87
0
  PrecompiledPreamble &operator=(PrecompiledPreamble &&) = default;
88
89
  /// PreambleBounds used to build the preamble.
90
  PreambleBounds getBounds() const;
91
92
  /// Returns the size, in bytes, that preamble takes on disk or in memory.
93
  /// For on-disk preambles returns 0 if filesystem operations fail. Intended to
94
  /// be used for logging and debugging purposes only.
95
  std::size_t getSize() const;
96
97
  /// Check whether PrecompiledPreamble can be reused for the new contents(\p
98
  /// MainFileBuffer) of the main file.
99
  bool CanReuse(const CompilerInvocation &Invocation,
100
                const llvm::MemoryBuffer *MainFileBuffer, PreambleBounds Bounds,
101
                llvm::vfs::FileSystem *VFS) const;
102
103
  /// Changes options inside \p CI to use PCH from this preamble. Also remaps
104
  /// main file to \p MainFileBuffer and updates \p VFS to ensure the preamble
105
  /// is accessible.
106
  /// Requires that CanReuse() is true.
107
  /// For in-memory preambles, PrecompiledPreamble instance continues to own the
108
  /// MemoryBuffer with the Preamble after this method returns. The caller is
109
  /// responsible for making sure the PrecompiledPreamble instance outlives the
110
  /// compiler run and the AST that will be using the PCH.
111
  void AddImplicitPreamble(CompilerInvocation &CI,
112
                           IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
113
                           llvm::MemoryBuffer *MainFileBuffer) const;
114
115
  /// Configure \p CI to use this preamble.
116
  /// Like AddImplicitPreamble, but doesn't assume CanReuse() is true.
117
  /// If this preamble does not match the file, it may parse differently.
118
  void OverridePreamble(CompilerInvocation &CI,
119
                        IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
120
                        llvm::MemoryBuffer *MainFileBuffer) const;
121
122
private:
123
  PrecompiledPreamble(PCHStorage Storage, std::vector<char> PreambleBytes,
124
                      bool PreambleEndsAtStartOfLine,
125
                      llvm::StringMap<PreambleFileHash> FilesInPreamble);
126
127
  /// A temp file that would be deleted on destructor call. If destructor is not
128
  /// called for any reason, the file will be deleted at static objects'
129
  /// destruction.
130
  /// An assertion will fire if two TempPCHFiles are created with the same name,
131
  /// so it's not intended to be used outside preamble-handling.
132
  class TempPCHFile {
133
  public:
134
    // A main method used to construct TempPCHFile.
135
    static llvm::ErrorOr<TempPCHFile> CreateNewPreamblePCHFile();
136
137
  private:
138
    TempPCHFile(std::string FilePath);
139
140
  public:
141
    TempPCHFile(TempPCHFile &&Other);
142
    TempPCHFile &operator=(TempPCHFile &&Other);
143
144
    TempPCHFile(const TempPCHFile &) = delete;
145
    ~TempPCHFile();
146
147
    /// A path where temporary file is stored.
148
    llvm::StringRef getFilePath() const;
149
150
  private:
151
    void RemoveFileIfPresent();
152
153
  private:
154
    llvm::Optional<std::string> FilePath;
155
  };
156
157
  class InMemoryPreamble {
158
  public:
159
    std::string Data;
160
  };
161
162
  class PCHStorage {
163
  public:
164
    enum class Kind { Empty, InMemory, TempFile };
165
166
352
    PCHStorage() = default;
167
    PCHStorage(TempPCHFile File);
168
    PCHStorage(InMemoryPreamble Memory);
169
170
    PCHStorage(const PCHStorage &) = delete;
171
    PCHStorage &operator=(const PCHStorage &) = delete;
172
173
    PCHStorage(PCHStorage &&Other);
174
    PCHStorage &operator=(PCHStorage &&Other);
175
176
    ~PCHStorage();
177
178
    Kind getKind() const;
179
180
    TempPCHFile &asFile();
181
    const TempPCHFile &asFile() const;
182
183
    InMemoryPreamble &asMemory();
184
    const InMemoryPreamble &asMemory() const;
185
186
  private:
187
    void destroy();
188
    void setEmpty();
189
190
  private:
191
    Kind StorageKind = Kind::Empty;
192
    llvm::AlignedCharArrayUnion<TempPCHFile, InMemoryPreamble> Storage = {};
193
  };
194
195
  /// Data used to determine if a file used in the preamble has been changed.
196
  struct PreambleFileHash {
197
    /// All files have size set.
198
    off_t Size = 0;
199
200
    /// Modification time is set for files that are on disk.  For memory
201
    /// buffers it is zero.
202
    time_t ModTime = 0;
203
204
    /// Memory buffers have MD5 instead of modification time.  We don't
205
    /// compute MD5 for on-disk files because we hope that modification time is
206
    /// enough to tell if the file was changed.
207
    llvm::MD5::MD5Result MD5 = {};
208
209
    static PreambleFileHash createForFile(off_t Size, time_t ModTime);
210
    static PreambleFileHash
211
    createForMemoryBuffer(const llvm::MemoryBuffer *Buffer);
212
213
    friend bool operator==(const PreambleFileHash &LHS,
214
6
                           const PreambleFileHash &RHS) {
215
6
      return LHS.Size == RHS.Size && 
LHS.ModTime == RHS.ModTime5
&&
216
6
             
LHS.MD5 == RHS.MD55
;
217
6
    }
218
    friend bool operator!=(const PreambleFileHash &LHS,
219
6
                           const PreambleFileHash &RHS) {
220
6
      return !(LHS == RHS);
221
6
    }
222
  };
223
224
  /// Helper function to set up PCH for the preamble into \p CI and \p VFS to
225
  /// with the specified \p Bounds.
226
  void configurePreamble(PreambleBounds Bounds, CompilerInvocation &CI,
227
                         IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS,
228
                         llvm::MemoryBuffer *MainFileBuffer) const;
229
230
  /// Sets up the PreprocessorOptions and changes VFS, so that PCH stored in \p
231
  /// Storage is accessible to clang. This method is an implementation detail of
232
  /// AddImplicitPreamble.
233
  static void
234
  setupPreambleStorage(const PCHStorage &Storage,
235
                       PreprocessorOptions &PreprocessorOpts,
236
                       IntrusiveRefCntPtr<llvm::vfs::FileSystem> &VFS);
237
238
  /// Manages the memory buffer or temporary file that stores the PCH.
239
  PCHStorage Storage;
240
  /// Keeps track of the files that were used when computing the
241
  /// preamble, with both their buffer size and their modification time.
242
  ///
243
  /// If any of the files have changed from one compile to the next,
244
  /// the preamble must be thrown away.
245
  llvm::StringMap<PreambleFileHash> FilesInPreamble;
246
  /// The contents of the file that was used to precompile the preamble. Only
247
  /// contains first PreambleBounds::Size bytes. Used to compare if the relevant
248
  /// part of the file has not changed, so that preamble can be reused.
249
  std::vector<char> PreambleBytes;
250
  /// See PreambleBounds::PreambleEndsAtStartOfLine
251
  bool PreambleEndsAtStartOfLine;
252
};
253
254
/// A set of callbacks to gather useful information while building a preamble.
255
class PreambleCallbacks {
256
public:
257
88
  virtual ~PreambleCallbacks() = default;
258
259
  /// Called before FrontendAction::BeginSourceFile.
260
  /// Can be used to store references to various CompilerInstance fields
261
  /// (e.g. SourceManager) that may be interesting to the consumers of other
262
  /// callbacks.
263
  virtual void BeforeExecute(CompilerInstance &CI);
264
  /// Called after FrontendAction::Execute(), but before
265
  /// FrontendAction::EndSourceFile(). Can be used to transfer ownership of
266
  /// various CompilerInstance fields before they are destroyed.
267
  virtual void AfterExecute(CompilerInstance &CI);
268
  /// Called after PCH has been emitted. \p Writer may be used to retrieve
269
  /// information about AST, serialized in PCH.
270
  virtual void AfterPCHEmitted(ASTWriter &Writer);
271
  /// Called for each TopLevelDecl.
272
  /// NOTE: To allow more flexibility a custom ASTConsumer could probably be
273
  /// used instead, but having only this method allows a simpler API.
274
  virtual void HandleTopLevelDecl(DeclGroupRef DG);
275
  /// Creates wrapper class for PPCallbacks so we can also process information
276
  /// about includes that are inside of a preamble
277
  virtual std::unique_ptr<PPCallbacks> createPPCallbacks();
278
  /// The returned CommentHandler will be added to the preprocessor if not null.
279
  virtual CommentHandler *getCommentHandler();
280
};
281
282
enum class BuildPreambleError {
283
  CouldntCreateTempFile = 1,
284
  CouldntCreateTargetInfo,
285
  BeginSourceFileFailed,
286
  CouldntEmitPCH,
287
  BadInputs
288
};
289
290
class BuildPreambleErrorCategory final : public std::error_category {
291
public:
292
  const char *name() const noexcept override;
293
  std::string message(int condition) const override;
294
};
295
296
std::error_code make_error_code(BuildPreambleError Error);
297
} // namespace clang
298
299
namespace std {
300
template <>
301
struct is_error_code_enum<clang::BuildPreambleError> : std::true_type {};
302
} // namespace std
303
304
#endif