Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Support/MemoryBuffer.h
Line
Count
Source (jump to first uncovered line)
1
//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- 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 MemoryBuffer interface.
10
//
11
//===----------------------------------------------------------------------===//
12
13
#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
14
#define LLVM_SUPPORT_MEMORYBUFFER_H
15
16
#include "llvm-c/Types.h"
17
#include "llvm/ADT/ArrayRef.h"
18
#include "llvm/ADT/StringRef.h"
19
#include "llvm/ADT/Twine.h"
20
#include "llvm/Support/CBindingWrapping.h"
21
#include "llvm/Support/ErrorOr.h"
22
#include "llvm/Support/FileSystem.h"
23
#include <cstddef>
24
#include <cstdint>
25
#include <memory>
26
27
namespace llvm {
28
29
class MemoryBufferRef;
30
31
/// This interface provides simple read-only access to a block of memory, and
32
/// provides simple methods for reading files and standard input into a memory
33
/// buffer.  In addition to basic access to the characters in the file, this
34
/// interface guarantees you can read one character past the end of the file,
35
/// and that this character will read as '\0'.
36
///
37
/// The '\0' guarantee is needed to support an optimization -- it's intended to
38
/// be more efficient for clients which are reading all the data to stop
39
/// reading when they encounter a '\0' than to continually check the file
40
/// position to see if it has reached the end of the file.
41
class MemoryBuffer {
42
  const char *BufferStart; // Start of the buffer.
43
  const char *BufferEnd;   // End of the buffer.
44
45
protected:
46
1.08M
  MemoryBuffer() = default;
47
48
  void init(const char *BufStart, const char *BufEnd,
49
            bool RequiresNullTerminator);
50
51
  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
52
      sys::fs::mapped_file_region::readonly;
53
54
public:
55
  MemoryBuffer(const MemoryBuffer &) = delete;
56
  MemoryBuffer &operator=(const MemoryBuffer &) = delete;
57
  virtual ~MemoryBuffer();
58
59
44.5M
  const char *getBufferStart() const { return BufferStart; }
60
1.78M
  const char *getBufferEnd() const   { return BufferEnd; }
61
56.3M
  size_t getBufferSize() const { return BufferEnd-BufferStart; }
62
63
21.9M
  StringRef getBuffer() const {
64
21.9M
    return StringRef(BufferStart, getBufferSize());
65
21.9M
  }
66
67
  /// Return an identifier for this buffer, typically the filename it was read
68
  /// from.
69
0
  virtual StringRef getBufferIdentifier() const { return "Unknown buffer"; }
70
71
  /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer
72
  /// if successful, otherwise returning null. If FileSize is specified, this
73
  /// means that the client knows that the file exists and that it has the
74
  /// specified size.
75
  ///
76
  /// \param IsVolatile Set to true to indicate that the contents of the file
77
  /// can change outside the user's control, e.g. when libclang tries to parse
78
  /// while the user is editing/updating the file or if the file is on an NFS.
79
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
80
  getFile(const Twine &Filename, int64_t FileSize = -1,
81
          bool RequiresNullTerminator = true, bool IsVolatile = false);
82
83
  /// Read all of the specified file into a MemoryBuffer as a stream
84
  /// (i.e. until EOF reached). This is useful for special files that
85
  /// look like a regular file but have 0 size (e.g. /proc/cpuinfo on Linux).
86
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
87
  getFileAsStream(const Twine &Filename);
88
89
  /// Given an already-open file descriptor, map some slice of it into a
90
  /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize.
91
  /// Since this is in the middle of a file, the buffer is not null terminated.
92
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
93
  getOpenFileSlice(sys::fs::file_t FD, const Twine &Filename, uint64_t MapSize,
94
                   int64_t Offset, bool IsVolatile = false);
95
96
  /// Given an already-open file descriptor, read the file and return a
97
  /// MemoryBuffer.
98
  ///
99
  /// \param IsVolatile Set to true to indicate that the contents of the file
100
  /// can change outside the user's control, e.g. when libclang tries to parse
101
  /// while the user is editing/updating the file or if the file is on an NFS.
102
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
103
  getOpenFile(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize,
104
              bool RequiresNullTerminator = true, bool IsVolatile = false);
105
106
  /// Open the specified memory range as a MemoryBuffer. Note that InputData
107
  /// must be null terminated if RequiresNullTerminator is true.
108
  static std::unique_ptr<MemoryBuffer>
109
  getMemBuffer(StringRef InputData, StringRef BufferName = "",
110
               bool RequiresNullTerminator = true);
111
112
  static std::unique_ptr<MemoryBuffer>
113
  getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true);
114
115
  /// Open the specified memory range as a MemoryBuffer, copying the contents
116
  /// and taking ownership of it. InputData does not have to be null terminated.
117
  static std::unique_ptr<MemoryBuffer>
118
  getMemBufferCopy(StringRef InputData, const Twine &BufferName = "");
119
120
  /// Read all of stdin into a file buffer, and return it.
121
  static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN();
122
123
  /// Open the specified file as a MemoryBuffer, or open stdin if the Filename
124
  /// is "-".
125
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
126
  getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1,
127
                 bool RequiresNullTerminator = true);
128
129
  /// Map a subrange of the specified file as a MemoryBuffer.
130
  static ErrorOr<std::unique_ptr<MemoryBuffer>>
131
  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
132
               bool IsVolatile = false);
133
134
  //===--------------------------------------------------------------------===//
135
  // Provided for performance analysis.
136
  //===--------------------------------------------------------------------===//
137
138
  /// The kind of memory backing used to support the MemoryBuffer.
139
  enum BufferKind {
140
    MemoryBuffer_Malloc,
141
    MemoryBuffer_MMap
142
  };
143
144
  /// Return information on the memory mechanism used to support the
145
  /// MemoryBuffer.
146
  virtual BufferKind getBufferKind() const = 0;
147
148
  MemoryBufferRef getMemBufferRef() const;
149
};
150
151
/// This class is an extension of MemoryBuffer, which allows copy-on-write
152
/// access to the underlying contents.  It only supports creation methods that
153
/// are guaranteed to produce a writable buffer.  For example, mapping a file
154
/// read-only is not supported.
155
class WritableMemoryBuffer : public MemoryBuffer {
156
protected:
157
817k
  WritableMemoryBuffer() = default;
158
159
  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
160
      sys::fs::mapped_file_region::priv;
161
162
public:
163
  using MemoryBuffer::getBuffer;
164
  using MemoryBuffer::getBufferEnd;
165
  using MemoryBuffer::getBufferStart;
166
167
  // const_cast is well-defined here, because the underlying buffer is
168
  // guaranteed to have been initialized with a mutable buffer.
169
838k
  char *getBufferStart() {
170
838k
    return const_cast<char *>(MemoryBuffer::getBufferStart());
171
838k
  }
172
483k
  char *getBufferEnd() {
173
483k
    return const_cast<char *>(MemoryBuffer::getBufferEnd());
174
483k
  }
175
483k
  MutableArrayRef<char> getBuffer() {
176
483k
    return {getBufferStart(), getBufferEnd()};
177
483k
  }
178
179
  static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
180
  getFile(const Twine &Filename, int64_t FileSize = -1,
181
          bool IsVolatile = false);
182
183
  /// Map a subrange of the specified file as a WritableMemoryBuffer.
184
  static ErrorOr<std::unique_ptr<WritableMemoryBuffer>>
185
  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset,
186
               bool IsVolatile = false);
187
188
  /// Allocate a new MemoryBuffer of the specified size that is not initialized.
189
  /// Note that the caller should initialize the memory allocated by this
190
  /// method. The memory is owned by the MemoryBuffer object.
191
  static std::unique_ptr<WritableMemoryBuffer>
192
  getNewUninitMemBuffer(size_t Size, const Twine &BufferName = "");
193
194
  /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note
195
  /// that the caller need not initialize the memory allocated by this method.
196
  /// The memory is owned by the MemoryBuffer object.
197
  static std::unique_ptr<WritableMemoryBuffer>
198
  getNewMemBuffer(size_t Size, const Twine &BufferName = "");
199
200
private:
201
  // Hide these base class factory function so one can't write
202
  //   WritableMemoryBuffer::getXXX()
203
  // and be surprised that he got a read-only Buffer.
204
  using MemoryBuffer::getFileAsStream;
205
  using MemoryBuffer::getFileOrSTDIN;
206
  using MemoryBuffer::getMemBuffer;
207
  using MemoryBuffer::getMemBufferCopy;
208
  using MemoryBuffer::getOpenFile;
209
  using MemoryBuffer::getOpenFileSlice;
210
  using MemoryBuffer::getSTDIN;
211
};
212
213
/// This class is an extension of MemoryBuffer, which allows write access to
214
/// the underlying contents and committing those changes to the original source.
215
/// It only supports creation methods that are guaranteed to produce a writable
216
/// buffer.  For example, mapping a file read-only is not supported.
217
class WriteThroughMemoryBuffer : public MemoryBuffer {
218
protected:
219
1
  WriteThroughMemoryBuffer() = default;
220
221
  static constexpr sys::fs::mapped_file_region::mapmode Mapmode =
222
      sys::fs::mapped_file_region::readwrite;
223
224
public:
225
  using MemoryBuffer::getBuffer;
226
  using MemoryBuffer::getBufferEnd;
227
  using MemoryBuffer::getBufferStart;
228
229
  // const_cast is well-defined here, because the underlying buffer is
230
  // guaranteed to have been initialized with a mutable buffer.
231
  char *getBufferStart() {
232
    return const_cast<char *>(MemoryBuffer::getBufferStart());
233
  }
234
  char *getBufferEnd() {
235
    return const_cast<char *>(MemoryBuffer::getBufferEnd());
236
  }
237
0
  MutableArrayRef<char> getBuffer() {
238
0
    return {getBufferStart(), getBufferEnd()};
239
0
  }
240
241
  static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>>
242
  getFile(const Twine &Filename, int64_t FileSize = -1);
243
244
  /// Map a subrange of the specified file as a ReadWriteMemoryBuffer.
245
  static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>>
246
  getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset);
247
248
private:
249
  // Hide these base class factory function so one can't write
250
  //   WritableMemoryBuffer::getXXX()
251
  // and be surprised that he got a read-only Buffer.
252
  using MemoryBuffer::getFileAsStream;
253
  using MemoryBuffer::getFileOrSTDIN;
254
  using MemoryBuffer::getMemBuffer;
255
  using MemoryBuffer::getMemBufferCopy;
256
  using MemoryBuffer::getOpenFile;
257
  using MemoryBuffer::getOpenFileSlice;
258
  using MemoryBuffer::getSTDIN;
259
};
260
261
class MemoryBufferRef {
262
  StringRef Buffer;
263
  StringRef Identifier;
264
265
public:
266
22.2k
  MemoryBufferRef() = default;
267
  MemoryBufferRef(const MemoryBuffer& Buffer)
268
24.8k
      : Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {}
269
  MemoryBufferRef(StringRef Buffer, StringRef Identifier)
270
72.7k
      : Buffer(Buffer), Identifier(Identifier) {}
271
272
1.52M
  StringRef getBuffer() const { return Buffer; }
273
274
254k
  StringRef getBufferIdentifier() const { return Identifier; }
275
276
704k
  const char *getBufferStart() const { return Buffer.begin(); }
277
84.0k
  const char *getBufferEnd() const { return Buffer.end(); }
278
28.3k
  size_t getBufferSize() const { return Buffer.size(); }
279
};
280
281
// Create wrappers for C Binding types (see CBindingWrapping.h).
282
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef)
283
284
} // end namespace llvm
285
286
#endif // LLVM_SUPPORT_MEMORYBUFFER_H