1 files changed, 389 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/MemoryBuffer.cpp b/contrib/llvm/lib/Support/MemoryBuffer.cpp
new file mode 100644
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+++ b/contrib/llvm/lib/Support/MemoryBuffer.cpp
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+//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the MemoryBuffer interface.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/Errno.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
+#include "llvm/Support/Program.h"
+#include "llvm/Support/system_error.h"
+#include <cassert>
+#include <cstdio>
+#include <cstring>
+#include <cerrno>
+#include <new>
+#include <sys/types.h>
+#include <sys/stat.h>
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
+#include <unistd.h>
+#else
+#include <io.h>
+#endif
+#include <fcntl.h>
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer implementation itself.
+//===----------------------------------------------------------------------===//
+
+MemoryBuffer::~MemoryBuffer() { }
+
+/// init - Initialize this MemoryBuffer as a reference to externally allocated
+/// memory, memory that we know is already null terminated.
+void MemoryBuffer::init(const char *BufStart, const char *BufEnd,
+                        bool RequiresNullTerminator) {
+  assert((!RequiresNullTerminator || BufEnd[0] == 0) &&
+         "Buffer is not null terminated!");
+  BufferStart = BufStart;
+  BufferEnd = BufEnd;
+}
+
+//===----------------------------------------------------------------------===//
+// MemoryBufferMem implementation.
+//===----------------------------------------------------------------------===//
+
+/// CopyStringRef - Copies contents of a StringRef into a block of memory and
+/// null-terminates it.
+static void CopyStringRef(char *Memory, StringRef Data) {
+  memcpy(Memory, Data.data(), Data.size());
+  Memory[Data.size()] = 0; // Null terminate string.
+}
+
+/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it.
+template <typename T>
+static T *GetNamedBuffer(StringRef Buffer, StringRef Name,
+                         bool RequiresNullTerminator) {
+  char *Mem = static_cast<char*>(operator new(sizeof(T) + Name.size() + 1));
+  CopyStringRef(Mem + sizeof(T), Name);
+  return new (Mem) T(Buffer, RequiresNullTerminator);
+}
+
+namespace {
+/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
+class MemoryBufferMem : public MemoryBuffer {
+public:
+  MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) {
+    init(InputData.begin(), InputData.end(), RequiresNullTerminator);
+  }
+
+  virtual const char *getBufferIdentifier() const {
+     // The name is stored after the class itself.
+    return reinterpret_cast<const char*>(this + 1);
+  }
+  
+  virtual BufferKind getBufferKind() const {
+    return MemoryBuffer_Malloc;
+  }
+};
+}
+
+/// getMemBuffer - Open the specified memory range as a MemoryBuffer.  Note
+/// that InputData must be a null terminated if RequiresNullTerminator is true!
+MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
+                                         StringRef BufferName,
+                                         bool RequiresNullTerminator) {
+  return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName,
+                                         RequiresNullTerminator);
+}
+
+/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
+/// copying the contents and taking ownership of it.  This has no requirements
+/// on EndPtr[0].
+MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
+                                             StringRef BufferName) {
+  MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
+  if (!Buf) return 0;
+  memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
+         InputData.size());
+  return Buf;
+}
+
+/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
+/// that is not initialized.  Note that the caller should initialize the
+/// memory allocated by this method.  The memory is owned by the MemoryBuffer
+/// object.
+MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
+                                                  StringRef BufferName) {
+  // Allocate space for the MemoryBuffer, the data and the name. It is important
+  // that MemoryBuffer and data are aligned so PointerIntPair works with them.
+  size_t AlignedStringLen =
+    RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1,
+                       sizeof(void*)); // TODO: Is sizeof(void*) enough?
+  size_t RealLen = AlignedStringLen + Size + 1;
+  char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
+  if (!Mem) return 0;
+
+  // The name is stored after the class itself.
+  CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
+
+  // The buffer begins after the name and must be aligned.
+  char *Buf = Mem + AlignedStringLen;
+  Buf[Size] = 0; // Null terminate buffer.
+
+  return new (Mem) MemoryBufferMem(StringRef(Buf, Size), true);
+}
+
+/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
+/// is completely initialized to zeros.  Note that the caller should
+/// initialize the memory allocated by this method.  The memory is owned by
+/// the MemoryBuffer object.
+MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
+  MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
+  if (!SB) return 0;
+  memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
+  return SB;
+}
+
+
+/// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
+/// if the Filename is "-".  If an error occurs, this returns null and fills
+/// in *ErrStr with a reason.  If stdin is empty, this API (unlike getSTDIN)
+/// returns an empty buffer.
+error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename,
+                                        OwningPtr<MemoryBuffer> &result,
+                                        int64_t FileSize) {
+  if (Filename == "-")
+    return getSTDIN(result);
+  return getFile(Filename, result, FileSize);
+}
+
+error_code MemoryBuffer::getFileOrSTDIN(const char *Filename,
+                                        OwningPtr<MemoryBuffer> &result,
+                                        int64_t FileSize) {
+  if (strcmp(Filename, "-") == 0)
+    return getSTDIN(result);
+  return getFile(Filename, result, FileSize);
+}
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer::getFile implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+/// MemoryBufferMMapFile - This represents a file that was mapped in with the
+/// sys::Path::MapInFilePages method.  When destroyed, it calls the
+/// sys::Path::UnMapFilePages method.
+class MemoryBufferMMapFile : public MemoryBufferMem {
+public:
+  MemoryBufferMMapFile(StringRef Buffer, bool RequiresNullTerminator)
+    : MemoryBufferMem(Buffer, RequiresNullTerminator) { }
+
+  ~MemoryBufferMMapFile() {
+    static int PageSize = sys::Process::GetPageSize();
+
+    uintptr_t Start = reinterpret_cast<uintptr_t>(getBufferStart());
+    size_t Size = getBufferSize();
+    uintptr_t RealStart = Start & ~(PageSize - 1);
+    size_t RealSize = Size + (Start - RealStart);
+
+    sys::Path::UnMapFilePages(reinterpret_cast<const char*>(RealStart),
+                              RealSize);
+  }
+  
+  virtual BufferKind getBufferKind() const {
+    return MemoryBuffer_MMap;
+  }
+};
+}
+
+error_code MemoryBuffer::getFile(StringRef Filename,
+                                 OwningPtr<MemoryBuffer> &result,
+                                 int64_t FileSize,
+                                 bool RequiresNullTerminator) {
+  // Ensure the path is null terminated.
+  SmallString<256> PathBuf(Filename.begin(), Filename.end());
+  return MemoryBuffer::getFile(PathBuf.c_str(), result, FileSize,
+                               RequiresNullTerminator);
+}
+
+error_code MemoryBuffer::getFile(const char *Filename,
+                                 OwningPtr<MemoryBuffer> &result,
+                                 int64_t FileSize,
+                                 bool RequiresNullTerminator) {
+  // First check that the "file" is not a directory
+  bool is_dir = false;
+  error_code err = sys::fs::is_directory(Filename, is_dir);
+  if (err)
+    return err;
+  if (is_dir)
+    return make_error_code(errc::is_a_directory);
+
+  int OpenFlags = O_RDONLY;
+#ifdef O_BINARY
+  OpenFlags |= O_BINARY;  // Open input file in binary mode on win32.
+#endif
+  int FD = ::open(Filename, OpenFlags);
+  if (FD == -1)
+    return error_code(errno, posix_category());
+
+  error_code ret = getOpenFile(FD, Filename, result, FileSize, FileSize,
+                               0, RequiresNullTerminator);
+  close(FD);
+  return ret;
+}
+
+static bool shouldUseMmap(int FD,
+                          size_t FileSize,
+                          size_t MapSize,
+                          off_t Offset,
+                          bool RequiresNullTerminator,
+                          int PageSize) {
+  // We don't use mmap for small files because this can severely fragment our
+  // address space.
+  if (MapSize < 4096*4)
+    return false;
+
+  if (!RequiresNullTerminator)
+    return true;
+
+
+  // If we don't know the file size, use fstat to find out.  fstat on an open
+  // file descriptor is cheaper than stat on a random path.
+  // FIXME: this chunk of code is duplicated, but it avoids a fstat when
+  // RequiresNullTerminator = false and MapSize != -1.
+  if (FileSize == size_t(-1)) {
+    struct stat FileInfo;
+    // TODO: This should use fstat64 when available.
+    if (fstat(FD, &FileInfo) == -1) {
+      return error_code(errno, posix_category());
+    }
+    FileSize = FileInfo.st_size;
+  }
+
+  // If we need a null terminator and the end of the map is inside the file,
+  // we cannot use mmap.
+  size_t End = Offset + MapSize;
+  assert(End <= FileSize);
+  if (End != FileSize)
+    return false;
+
+  // Don't try to map files that are exactly a multiple of the system page size
+  // if we need a null terminator.
+  if ((FileSize & (PageSize -1)) == 0)
+    return false;
+
+  return true;
+}
+
+error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
+                                     OwningPtr<MemoryBuffer> &result,
+                                     uint64_t FileSize, uint64_t MapSize,
+                                     int64_t Offset,
+                                     bool RequiresNullTerminator) {
+  static int PageSize = sys::Process::GetPageSize();
+
+  // Default is to map the full file.
+  if (MapSize == uint64_t(-1)) {
+    // If we don't know the file size, use fstat to find out.  fstat on an open
+    // file descriptor is cheaper than stat on a random path.
+    if (FileSize == uint64_t(-1)) {
+      struct stat FileInfo;
+      // TODO: This should use fstat64 when available.
+      if (fstat(FD, &FileInfo) == -1) {
+        return error_code(errno, posix_category());
+      }
+      FileSize = FileInfo.st_size;
+    }
+    MapSize = FileSize;
+  }
+
+  if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
+                    PageSize)) {
+    off_t RealMapOffset = Offset & ~(PageSize - 1);
+    off_t Delta = Offset - RealMapOffset;
+    size_t RealMapSize = MapSize + Delta;
+
+    if (const char *Pages = sys::Path::MapInFilePages(FD,
+                                                      RealMapSize,
+                                                      RealMapOffset)) {
+      result.reset(GetNamedBuffer<MemoryBufferMMapFile>(
+          StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator));
+      return error_code::success();
+    }
+  }
+
+  MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(MapSize, Filename);
+  if (!Buf) {
+    // Failed to create a buffer. The only way it can fail is if
+    // new(std::nothrow) returns 0.
+    return make_error_code(errc::not_enough_memory);
+  }
+
+  OwningPtr<MemoryBuffer> SB(Buf);
+  char *BufPtr = const_cast<char*>(SB->getBufferStart());
+
+  size_t BytesLeft = MapSize;
+#ifndef HAVE_PREAD
+  if (lseek(FD, Offset, SEEK_SET) == -1)
+    return error_code(errno, posix_category());
+#endif
+
+  while (BytesLeft) {
+#ifdef HAVE_PREAD
+    ssize_t NumRead = ::pread(FD, BufPtr, BytesLeft, MapSize-BytesLeft+Offset);
+#else
+    ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
+#endif
+    if (NumRead == -1) {
+      if (errno == EINTR)
+        continue;
+      // Error while reading.
+      return error_code(errno, posix_category());
+    }
+    if (NumRead == 0) {
+      assert(0 && "We got inaccurate FileSize value or fstat reported an "
+                   "invalid file size.");
+      *BufPtr = '\0'; // null-terminate at the actual size.
+      break;
+    }
+    BytesLeft -= NumRead;
+    BufPtr += NumRead;
+  }
+
+  result.swap(SB);
+  return error_code::success();
+}
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer::getSTDIN implementation.
+//===----------------------------------------------------------------------===//
+
+error_code MemoryBuffer::getSTDIN(OwningPtr<MemoryBuffer> &result) {
+  // Read in all of the data from stdin, we cannot mmap stdin.
+  //
+  // FIXME: That isn't necessarily true, we should try to mmap stdin and
+  // fallback if it fails.
+  sys::Program::ChangeStdinToBinary();
+
+  const ssize_t ChunkSize = 4096*4;
+  SmallString<ChunkSize> Buffer;
+  ssize_t ReadBytes;
+  // Read into Buffer until we hit EOF.
+  do {
+    Buffer.reserve(Buffer.size() + ChunkSize);
+    ReadBytes = read(0, Buffer.end(), ChunkSize);
+    if (ReadBytes == -1) {
+      if (errno == EINTR) continue;
+      return error_code(errno, posix_category());
+    }
+    Buffer.set_size(Buffer.size() + ReadBytes);
+  } while (ReadBytes != 0);
+
+  result.reset(getMemBufferCopy(Buffer, "<stdin>"));
+  return error_code::success();
+}