LLVM  10.0.0svn
MemoryBuffer.cpp
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1 //===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===//
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 implements the MemoryBuffer interface.
10 //
11 //===----------------------------------------------------------------------===//
12 
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/Config/config.h"
16 #include "llvm/Support/Errc.h"
17 #include "llvm/Support/Errno.h"
20 #include "llvm/Support/Path.h"
21 #include "llvm/Support/Process.h"
22 #include "llvm/Support/Program.h"
24 #include <cassert>
25 #include <cerrno>
26 #include <cstring>
27 #include <new>
28 #include <sys/types.h>
29 #include <system_error>
30 #if !defined(_MSC_VER) && !defined(__MINGW32__)
31 #include <unistd.h>
32 #else
33 #include <io.h>
34 #endif
35 using namespace llvm;
36 
37 //===----------------------------------------------------------------------===//
38 // MemoryBuffer implementation itself.
39 //===----------------------------------------------------------------------===//
40 
42 
43 /// init - Initialize this MemoryBuffer as a reference to externally allocated
44 /// memory, memory that we know is already null terminated.
45 void MemoryBuffer::init(const char *BufStart, const char *BufEnd,
46  bool RequiresNullTerminator) {
47  assert((!RequiresNullTerminator || BufEnd[0] == 0) &&
48  "Buffer is not null terminated!");
49  BufferStart = BufStart;
50  BufferEnd = BufEnd;
51 }
52 
53 //===----------------------------------------------------------------------===//
54 // MemoryBufferMem implementation.
55 //===----------------------------------------------------------------------===//
56 
57 /// CopyStringRef - Copies contents of a StringRef into a block of memory and
58 /// null-terminates it.
59 static void CopyStringRef(char *Memory, StringRef Data) {
60  if (!Data.empty())
61  memcpy(Memory, Data.data(), Data.size());
62  Memory[Data.size()] = 0; // Null terminate string.
63 }
64 
65 namespace {
66 struct NamedBufferAlloc {
67  const Twine &Name;
68  NamedBufferAlloc(const Twine &Name) : Name(Name) {}
69 };
70 }
71 
72 void *operator new(size_t N, const NamedBufferAlloc &Alloc) {
73  SmallString<256> NameBuf;
74  StringRef NameRef = Alloc.Name.toStringRef(NameBuf);
75 
76  char *Mem = static_cast<char *>(operator new(N + NameRef.size() + 1));
77  CopyStringRef(Mem + N, NameRef);
78  return Mem;
79 }
80 
81 namespace {
82 /// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
83 template<typename MB>
84 class MemoryBufferMem : public MB {
85 public:
86  MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) {
87  MemoryBuffer::init(InputData.begin(), InputData.end(),
88  RequiresNullTerminator);
89  }
90 
91  /// Disable sized deallocation for MemoryBufferMem, because it has
92  /// tail-allocated data.
93  void operator delete(void *p) { ::operator delete(p); }
94 
95  StringRef getBufferIdentifier() const override {
96  // The name is stored after the class itself.
97  return StringRef(reinterpret_cast<const char *>(this + 1));
98  }
99 
100  MemoryBuffer::BufferKind getBufferKind() const override {
102  }
103 };
104 }
105 
106 template <typename MB>
108 getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize,
109  uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile);
110 
111 std::unique_ptr<MemoryBuffer>
113  bool RequiresNullTerminator) {
114  auto *Ret = new (NamedBufferAlloc(BufferName))
115  MemoryBufferMem<MemoryBuffer>(InputData, RequiresNullTerminator);
116  return std::unique_ptr<MemoryBuffer>(Ret);
117 }
118 
119 std::unique_ptr<MemoryBuffer>
120 MemoryBuffer::getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator) {
121  return std::unique_ptr<MemoryBuffer>(getMemBuffer(
122  Ref.getBuffer(), Ref.getBufferIdentifier(), RequiresNullTerminator));
123 }
124 
126 getMemBufferCopyImpl(StringRef InputData, const Twine &BufferName) {
127  auto Buf = WritableMemoryBuffer::getNewUninitMemBuffer(InputData.size(), BufferName);
128  if (!Buf)
130  memcpy(Buf->getBufferStart(), InputData.data(), InputData.size());
131  return std::move(Buf);
132 }
133 
134 std::unique_ptr<MemoryBuffer>
135 MemoryBuffer::getMemBufferCopy(StringRef InputData, const Twine &BufferName) {
136  auto Buf = getMemBufferCopyImpl(InputData, BufferName);
137  if (Buf)
138  return std::move(*Buf);
139  return nullptr;
140 }
141 
143 MemoryBuffer::getFileOrSTDIN(const Twine &Filename, int64_t FileSize,
144  bool RequiresNullTerminator) {
145  SmallString<256> NameBuf;
146  StringRef NameRef = Filename.toStringRef(NameBuf);
147 
148  if (NameRef == "-")
149  return getSTDIN();
150  return getFile(Filename, FileSize, RequiresNullTerminator);
151 }
152 
154 MemoryBuffer::getFileSlice(const Twine &FilePath, uint64_t MapSize,
155  uint64_t Offset, bool IsVolatile) {
156  return getFileAux<MemoryBuffer>(FilePath, -1, MapSize, Offset, false,
157  IsVolatile);
158 }
159 
160 //===----------------------------------------------------------------------===//
161 // MemoryBuffer::getFile implementation.
162 //===----------------------------------------------------------------------===//
163 
164 namespace {
165 /// Memory maps a file descriptor using sys::fs::mapped_file_region.
166 ///
167 /// This handles converting the offset into a legal offset on the platform.
168 template<typename MB>
169 class MemoryBufferMMapFile : public MB {
171 
172  static uint64_t getLegalMapOffset(uint64_t Offset) {
173  return Offset & ~(sys::fs::mapped_file_region::alignment() - 1);
174  }
175 
176  static uint64_t getLegalMapSize(uint64_t Len, uint64_t Offset) {
177  return Len + (Offset - getLegalMapOffset(Offset));
178  }
179 
180  const char *getStart(uint64_t Len, uint64_t Offset) {
181  return MFR.const_data() + (Offset - getLegalMapOffset(Offset));
182  }
183 
184 public:
185  MemoryBufferMMapFile(bool RequiresNullTerminator, sys::fs::file_t FD, uint64_t Len,
186  uint64_t Offset, std::error_code &EC)
187  : MFR(FD, MB::Mapmode, getLegalMapSize(Len, Offset),
188  getLegalMapOffset(Offset), EC) {
189  if (!EC) {
190  const char *Start = getStart(Len, Offset);
191  MemoryBuffer::init(Start, Start + Len, RequiresNullTerminator);
192  }
193  }
194 
195  /// Disable sized deallocation for MemoryBufferMMapFile, because it has
196  /// tail-allocated data.
197  void operator delete(void *p) { ::operator delete(p); }
198 
199  StringRef getBufferIdentifier() const override {
200  // The name is stored after the class itself.
201  return StringRef(reinterpret_cast<const char *>(this + 1));
202  }
203 
204  MemoryBuffer::BufferKind getBufferKind() const override {
206  }
207 };
208 }
209 
212  const ssize_t ChunkSize = 4096*4;
213  SmallString<ChunkSize> Buffer;
214  // Read into Buffer until we hit EOF.
215  for (;;) {
216  Buffer.reserve(Buffer.size() + ChunkSize);
218  FD, makeMutableArrayRef(Buffer.end(), ChunkSize));
219  if (!ReadBytes)
220  return errorToErrorCode(ReadBytes.takeError());
221  if (*ReadBytes == 0)
222  break;
223  Buffer.set_size(Buffer.size() + *ReadBytes);
224  }
225 
226  return getMemBufferCopyImpl(Buffer, BufferName);
227 }
228 
229 
231 MemoryBuffer::getFile(const Twine &Filename, int64_t FileSize,
232  bool RequiresNullTerminator, bool IsVolatile) {
233  return getFileAux<MemoryBuffer>(Filename, FileSize, FileSize, 0,
234  RequiresNullTerminator, IsVolatile);
235 }
236 
237 template <typename MB>
239 getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize,
240  uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator,
241  bool IsVolatile);
242 
243 template <typename MB>
245 getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize,
246  uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile) {
247  Expected<sys::fs::file_t> FDOrErr =
249  if (!FDOrErr)
250  return errorToErrorCode(FDOrErr.takeError());
251  sys::fs::file_t FD = *FDOrErr;
252  auto Ret = getOpenFileImpl<MB>(FD, Filename, FileSize, MapSize, Offset,
253  RequiresNullTerminator, IsVolatile);
254  sys::fs::closeFile(FD);
255  return Ret;
256 }
257 
259 WritableMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize,
260  bool IsVolatile) {
261  return getFileAux<WritableMemoryBuffer>(Filename, FileSize, FileSize, 0,
262  /*RequiresNullTerminator*/ false,
263  IsVolatile);
264 }
265 
267 WritableMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize,
268  uint64_t Offset, bool IsVolatile) {
269  return getFileAux<WritableMemoryBuffer>(Filename, -1, MapSize, Offset, false,
270  IsVolatile);
271 }
272 
273 std::unique_ptr<WritableMemoryBuffer>
275  using MemBuffer = MemoryBufferMem<WritableMemoryBuffer>;
276  // Allocate space for the MemoryBuffer, the data and the name. It is important
277  // that MemoryBuffer and data are aligned so PointerIntPair works with them.
278  // TODO: Is 16-byte alignment enough? We copy small object files with large
279  // alignment expectations into this buffer.
280  SmallString<256> NameBuf;
281  StringRef NameRef = BufferName.toStringRef(NameBuf);
282  size_t AlignedStringLen = alignTo(sizeof(MemBuffer) + NameRef.size() + 1, 16);
283  size_t RealLen = AlignedStringLen + Size + 1;
284  char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
285  if (!Mem)
286  return nullptr;
287 
288  // The name is stored after the class itself.
289  CopyStringRef(Mem + sizeof(MemBuffer), NameRef);
290 
291  // The buffer begins after the name and must be aligned.
292  char *Buf = Mem + AlignedStringLen;
293  Buf[Size] = 0; // Null terminate buffer.
294 
295  auto *Ret = new (Mem) MemBuffer(StringRef(Buf, Size), true);
296  return std::unique_ptr<WritableMemoryBuffer>(Ret);
297 }
298 
299 std::unique_ptr<WritableMemoryBuffer>
301  auto SB = WritableMemoryBuffer::getNewUninitMemBuffer(Size, BufferName);
302  if (!SB)
303  return nullptr;
304  memset(SB->getBufferStart(), 0, Size);
305  return SB;
306 }
307 
309  size_t FileSize,
310  size_t MapSize,
311  off_t Offset,
312  bool RequiresNullTerminator,
313  int PageSize,
314  bool IsVolatile) {
315  // mmap may leave the buffer without null terminator if the file size changed
316  // by the time the last page is mapped in, so avoid it if the file size is
317  // likely to change.
318  if (IsVolatile)
319  return false;
320 
321  // We don't use mmap for small files because this can severely fragment our
322  // address space.
323  if (MapSize < 4 * 4096 || MapSize < (unsigned)PageSize)
324  return false;
325 
326  if (!RequiresNullTerminator)
327  return true;
328 
329  // If we don't know the file size, use fstat to find out. fstat on an open
330  // file descriptor is cheaper than stat on a random path.
331  // FIXME: this chunk of code is duplicated, but it avoids a fstat when
332  // RequiresNullTerminator = false and MapSize != -1.
333  if (FileSize == size_t(-1)) {
335  if (sys::fs::status(FD, Status))
336  return false;
337  FileSize = Status.getSize();
338  }
339 
340  // If we need a null terminator and the end of the map is inside the file,
341  // we cannot use mmap.
342  size_t End = Offset + MapSize;
343  assert(End <= FileSize);
344  if (End != FileSize)
345  return false;
346 
347  // Don't try to map files that are exactly a multiple of the system page size
348  // if we need a null terminator.
349  if ((FileSize & (PageSize -1)) == 0)
350  return false;
351 
352 #if defined(__CYGWIN__)
353  // Don't try to map files that are exactly a multiple of the physical page size
354  // if we need a null terminator.
355  // FIXME: We should reorganize again getPageSize() on Win32.
356  if ((FileSize & (4096 - 1)) == 0)
357  return false;
358 #endif
359 
360  return true;
361 }
362 
364 getReadWriteFile(const Twine &Filename, uint64_t FileSize, uint64_t MapSize,
365  uint64_t Offset) {
368  if (!FDOrErr)
369  return errorToErrorCode(FDOrErr.takeError());
370  sys::fs::file_t FD = *FDOrErr;
371 
372  // Default is to map the full file.
373  if (MapSize == uint64_t(-1)) {
374  // If we don't know the file size, use fstat to find out. fstat on an open
375  // file descriptor is cheaper than stat on a random path.
376  if (FileSize == uint64_t(-1)) {
378  std::error_code EC = sys::fs::status(FD, Status);
379  if (EC)
380  return EC;
381 
382  // If this not a file or a block device (e.g. it's a named pipe
383  // or character device), we can't mmap it, so error out.
384  sys::fs::file_type Type = Status.type();
385  if (Type != sys::fs::file_type::regular_file &&
388 
389  FileSize = Status.getSize();
390  }
391  MapSize = FileSize;
392  }
393 
394  std::error_code EC;
395  std::unique_ptr<WriteThroughMemoryBuffer> Result(
396  new (NamedBufferAlloc(Filename))
397  MemoryBufferMMapFile<WriteThroughMemoryBuffer>(false, FD, MapSize,
398  Offset, EC));
399  if (EC)
400  return EC;
401  return std::move(Result);
402 }
403 
405 WriteThroughMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize) {
406  return getReadWriteFile(Filename, FileSize, FileSize, 0);
407 }
408 
409 /// Map a subrange of the specified file as a WritableMemoryBuffer.
411 WriteThroughMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize,
412  uint64_t Offset) {
413  return getReadWriteFile(Filename, -1, MapSize, Offset);
414 }
415 
416 template <typename MB>
418 getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize,
419  uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator,
420  bool IsVolatile) {
422 
423  // Default is to map the full file.
424  if (MapSize == uint64_t(-1)) {
425  // If we don't know the file size, use fstat to find out. fstat on an open
426  // file descriptor is cheaper than stat on a random path.
427  if (FileSize == uint64_t(-1)) {
429  std::error_code EC = sys::fs::status(FD, Status);
430  if (EC)
431  return EC;
432 
433  // If this not a file or a block device (e.g. it's a named pipe
434  // or character device), we can't trust the size. Create the memory
435  // buffer by copying off the stream.
436  sys::fs::file_type Type = Status.type();
437  if (Type != sys::fs::file_type::regular_file &&
439  return getMemoryBufferForStream(FD, Filename);
440 
441  FileSize = Status.getSize();
442  }
443  MapSize = FileSize;
444  }
445 
446  if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
447  PageSize, IsVolatile)) {
448  std::error_code EC;
449  std::unique_ptr<MB> Result(
450  new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile<MB>(
451  RequiresNullTerminator, FD, MapSize, Offset, EC));
452  if (!EC)
453  return std::move(Result);
454  }
455 
456  auto Buf = WritableMemoryBuffer::getNewUninitMemBuffer(MapSize, Filename);
457  if (!Buf) {
458  // Failed to create a buffer. The only way it can fail is if
459  // new(std::nothrow) returns 0.
461  }
462 
463  // Read until EOF, zero-initialize the rest.
464  MutableArrayRef<char> ToRead = Buf->getBuffer();
465  while (!ToRead.empty()) {
466  Expected<size_t> ReadBytes =
467  sys::fs::readNativeFileSlice(FD, ToRead, Offset);
468  if (!ReadBytes)
469  return errorToErrorCode(ReadBytes.takeError());
470  if (*ReadBytes == 0) {
471  std::memset(ToRead.data(), 0, ToRead.size());
472  break;
473  }
474  ToRead = ToRead.drop_front(*ReadBytes);
475  Offset += *ReadBytes;
476  }
477 
478  return std::move(Buf);
479 }
480 
482 MemoryBuffer::getOpenFile(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize,
483  bool RequiresNullTerminator, bool IsVolatile) {
484  return getOpenFileImpl<MemoryBuffer>(FD, Filename, FileSize, FileSize, 0,
485  RequiresNullTerminator, IsVolatile);
486 }
487 
489 MemoryBuffer::getOpenFileSlice(sys::fs::file_t FD, const Twine &Filename, uint64_t MapSize,
490  int64_t Offset, bool IsVolatile) {
491  assert(MapSize != uint64_t(-1));
492  return getOpenFileImpl<MemoryBuffer>(FD, Filename, -1, MapSize, Offset, false,
493  IsVolatile);
494 }
495 
497  // Read in all of the data from stdin, we cannot mmap stdin.
498  //
499  // FIXME: That isn't necessarily true, we should try to mmap stdin and
500  // fallback if it fails.
502 
504 }
505 
508  Expected<sys::fs::file_t> FDOrErr =
510  if (!FDOrErr)
511  return errorToErrorCode(FDOrErr.takeError());
512  sys::fs::file_t FD = *FDOrErr;
514  getMemoryBufferForStream(FD, Filename);
515  sys::fs::closeFile(FD);
516  return Ret;
517 }
518 
521  StringRef Identifier = getBufferIdentifier();
522  return MemoryBufferRef(Data, Identifier);
523 }
524 
virtual StringRef getBufferIdentifier() const
Return an identifier for this buffer, typically the filename it was read from.
Definition: MemoryBuffer.h:69
void init(const char *BufStart, const char *BufEnd, bool RequiresNullTerminator)
init - Initialize this MemoryBuffer as a reference to externally allocated memory, memory that we know is already null terminated.
Represents either an error or a value T.
Definition: ErrorOr.h:56
MutableArrayRef< T > makeMutableArrayRef(T &OneElt)
Construct a MutableArrayRef from a single element.
Definition: ArrayRef.h:508
StringRef getBuffer() const
Definition: MemoryBuffer.h:63
This class represents lattice values for constants.
Definition: AllocatorList.h:23
constexpr char IsVolatile[]
Key for Kernel::Arg::Metadata::mIsVolatile.
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
static ErrorOr< std::unique_ptr< MB > > getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, bool IsVolatile)
static ErrorOr< std::unique_ptr< WritableMemoryBuffer > > getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset, bool IsVolatile=false)
Map a subrange of the specified file as a WritableMemoryBuffer.
This class provides various memory handling functions that manipulate MemoryBlock instances...
Definition: Memory.h:53
static std::unique_ptr< MemoryBuffer > getMemBuffer(StringRef InputData, StringRef BufferName="", bool RequiresNullTerminator=true)
Open the specified memory range as a MemoryBuffer.
StringRef toStringRef(SmallVectorImpl< char > &Out) const
This returns the twine as a single StringRef if it can be represented as such.
Definition: Twine.h:455
This class represents a memory mapped file.
Definition: FileSystem.h:1160
Error takeError()
Take ownership of the stored error.
Definition: Error.h:552
void reserve(size_type N)
Definition: SmallVector.h:369
Represents the result of a call to sys::fs::status().
Definition: FileSystem.h:246
CD_OpenExisting - When opening a file:
Definition: FileSystem.h:748
const char * const_data() const
Get a const view of the data.
Expected< size_t > readNativeFileSlice(file_t FileHandle, MutableArrayRef< char > Buf, uint64_t Offset)
Reads Buf.size() bytes from FileHandle at offset Offset into Buf.
virtual BufferKind getBufferKind() const =0
Return information on the memory mechanism used to support the MemoryBuffer.
static ErrorOr< std::unique_ptr< MemoryBuffer > > getOpenFileSlice(sys::fs::file_t FD, const Twine &Filename, uint64_t MapSize, int64_t Offset, bool IsVolatile=false)
Given an already-open file descriptor, map some slice of it into a MemoryBuffer.
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:80
StringRef getBuffer() const
Definition: MemoryBuffer.h:272
static ErrorOr< std::unique_ptr< MemoryBuffer > > getOpenFile(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, bool RequiresNullTerminator=true, bool IsVolatile=false)
Given an already-open file descriptor, read the file and return a MemoryBuffer.
The access may reference the value stored in memory.
std::error_code make_error_code(BitcodeError E)
static ErrorOr< std::unique_ptr< WritableMemoryBuffer > > getFile(const Twine &Filename, int64_t FileSize=-1, bool IsVolatile=false)
Tagged union holding either a T or a Error.
Definition: yaml2obj.h:21
LLVM_NODISCARD bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:140
MutableArrayRef< T > drop_front(size_t N=1) const
Drop the first N elements of the array.
Definition: ArrayRef.h:361
static std::unique_ptr< WritableMemoryBuffer > getNewMemBuffer(size_t Size, const Twine &BufferName="")
Allocate a new zero-initialized MemoryBuffer of the specified size.
LLVM_NODISCARD size_t size() const
size - Get the string size.
Definition: StringRef.h:144
static bool shouldUseMmap(sys::fs::file_t FD, size_t FileSize, size_t MapSize, off_t Offset, bool RequiresNullTerminator, int PageSize, bool IsVolatile)
static unsigned getPageSizeEstimate()
Get the process&#39;s estimated page size.
Definition: Process.h:56
static ErrorOr< std::unique_ptr< MB > > getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile)
file_t getStdinHandle()
Return an open handle to standard in.
static void CopyStringRef(char *Memory, StringRef Data)
CopyStringRef - Copies contents of a StringRef into a block of memory and null-terminates it...
static ErrorOr< std::unique_ptr< MemoryBuffer > > getSTDIN()
Read all of stdin into a file buffer, and return it.
static ErrorOr< std::unique_ptr< WriteThroughMemoryBuffer > > getFile(const Twine &Filename, int64_t FileSize=-1)
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:290
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
static std::unique_ptr< WritableMemoryBuffer > getNewUninitMemBuffer(size_t Size, const Twine &BufferName="")
Allocate a new MemoryBuffer of the specified size that is not initialized.
std::error_code status(const Twine &path, file_status &result, bool follow=true)
Get file status as if by POSIX stat().
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:148
void set_size(size_t N)
Set the array size to N, which the current array must have enough capacity for.
Definition: SmallVector.h:66
Expected< file_t > openNativeFileForReadWrite(const Twine &Name, CreationDisposition Disp, OpenFlags Flags, unsigned Mode=0666)
Opens the file with the given name in a write-only or read-write mode, returning its open file descri...
Definition: FileSystem.h:1093
Expected< size_t > readNativeFile(file_t FileHandle, MutableArrayRef< char > Buf)
Reads Buf.size() bytes from FileHandle into Buf.
static ErrorOr< std::unique_ptr< WritableMemoryBuffer > > getMemoryBufferForStream(sys::fs::file_t FD, const Twine &BufferName)
size_t size() const
Definition: SmallVector.h:52
Expected< file_t > openNativeFileForRead(const Twine &Name, OpenFlags Flags=OF_None, SmallVectorImpl< char > *RealPath=nullptr)
Opens the file with the given name in a read-only mode, returning its open file descriptor.
std::error_code closeFile(file_t &F)
Close the file object.
MemoryBufferRef getMemBufferRef() const
static std::unique_ptr< MemoryBuffer > getMemBufferCopy(StringRef InputData, const Twine &BufferName="")
Open the specified memory range as a MemoryBuffer, copying the contents and taking ownership of it...
StringRef getBufferIdentifier() const
Definition: MemoryBuffer.h:274
iterator begin() const
Definition: StringRef.h:115
std::error_code ChangeStdinToBinary()
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset, bool IsVolatile=false)
Map a subrange of the specified file as a MemoryBuffer.
static ErrorOr< std::unique_ptr< WriteThroughMemoryBuffer > > getReadWriteFile(const Twine &Filename, uint64_t FileSize, uint64_t MapSize, uint64_t Offset)
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFileOrSTDIN(const Twine &Filename, int64_t FileSize=-1, bool RequiresNullTerminator=true)
Open the specified file as a MemoryBuffer, or open stdin if the Filename is "-".
static ErrorOr< std::unique_ptr< WritableMemoryBuffer > > getMemBufferCopyImpl(StringRef InputData, const Twine &BufferName)
uint64_t alignTo(uint64_t Size, Align A)
Returns a multiple of A needed to store Size bytes.
Definition: Alignment.h:163
Provides a library for accessing information about this process and other processes on the operating ...
file_type
An enumeration for the file system&#39;s view of the type.
Definition: FileSystem.h:66
virtual ~MemoryBuffer()
#define N
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFileAsStream(const Twine &Filename)
Read all of the specified file into a MemoryBuffer as a stream (i.e.
uint32_t Size
Definition: Profile.cpp:46
BufferKind
The kind of memory backing used to support the MemoryBuffer.
Definition: MemoryBuffer.h:139
T * data() const
Definition: ArrayRef.h:328
static cl::opt< int > PageSize("imp-null-check-page-size", cl::desc("The page size of the target in bytes"), cl::init(4096), cl::Hidden)
static ErrorOr< std::unique_ptr< MemoryBuffer > > getFile(const Twine &Filename, int64_t FileSize=-1, bool RequiresNullTerminator=true, bool IsVolatile=false)
Open the specified file as a MemoryBuffer, returning a new MemoryBuffer if successful, otherwise returning null.
LLVM_NODISCARD const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:136
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static ErrorOr< std::unique_ptr< WriteThroughMemoryBuffer > > getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset)
Map a subrange of the specified file as a ReadWriteMemoryBuffer.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
iterator end() const
Definition: StringRef.h:117
std::error_code errorToErrorCode(Error Err)
Helper for converting an ECError to a std::error_code.
Definition: Error.cpp:93
bool empty() const
empty - Check if the array is empty.
Definition: ArrayRef.h:143