1 files changed, 437 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/MemoryBuffer.cpp b/contrib/llvm/lib/Support/MemoryBuffer.cpp
new file mode 100644
index 0000000..faee10b
--- /dev/null
+++ b/contrib/llvm/lib/Support/MemoryBuffer.cpp
@@ -0,0 +1,437 @@
+//===--- 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/SmallString.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/Errno.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Process.h"
+#include "llvm/Support/Program.h"
+#include <cassert>
+#include <cerrno>
+#include <cstring>
+#include <new>
+#include <sys/types.h>
+#include <system_error>
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
+#include <unistd.h>
+#else
+#include <io.h>
+#endif
+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) {
+  if (!Data.empty())
+    memcpy(Memory, Data.data(), Data.size());
+  Memory[Data.size()] = 0; // Null terminate string.
+}
+
+namespace {
+struct NamedBufferAlloc {
+  const Twine &Name;
+  NamedBufferAlloc(const Twine &Name) : Name(Name) {}
+};
+}
+
+void *operator new(size_t N, const NamedBufferAlloc &Alloc) {
+  SmallString<256> NameBuf;
+  StringRef NameRef = Alloc.Name.toStringRef(NameBuf);
+
+  char *Mem = static_cast<char *>(operator new(N + NameRef.size() + 1));
+  CopyStringRef(Mem + N, NameRef);
+  return Mem;
+}
+
+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);
+  }
+
+  const char *getBufferIdentifier() const override {
+     // The name is stored after the class itself.
+    return reinterpret_cast<const char*>(this + 1);
+  }
+
+  BufferKind getBufferKind() const override {
+    return MemoryBuffer_Malloc;
+  }
+};
+}
+
+static ErrorOr<std::unique_ptr<MemoryBuffer>>
+getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, 
+           uint64_t Offset, bool RequiresNullTerminator, bool IsVolatileSize);
+
+std::unique_ptr<MemoryBuffer>
+MemoryBuffer::getMemBuffer(StringRef InputData, StringRef BufferName,
+                           bool RequiresNullTerminator) {
+  auto *Ret = new (NamedBufferAlloc(BufferName))
+      MemoryBufferMem(InputData, RequiresNullTerminator);
+  return std::unique_ptr<MemoryBuffer>(Ret);
+}
+
+std::unique_ptr<MemoryBuffer>
+MemoryBuffer::getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator) {
+  return std::unique_ptr<MemoryBuffer>(getMemBuffer(
+      Ref.getBuffer(), Ref.getBufferIdentifier(), RequiresNullTerminator));
+}
+
+std::unique_ptr<MemoryBuffer>
+MemoryBuffer::getMemBufferCopy(StringRef InputData, const Twine &BufferName) {
+  std::unique_ptr<MemoryBuffer> Buf =
+      getNewUninitMemBuffer(InputData.size(), BufferName);
+  if (!Buf)
+    return nullptr;
+  memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
+         InputData.size());
+  return Buf;
+}
+
+std::unique_ptr<MemoryBuffer>
+MemoryBuffer::getNewUninitMemBuffer(size_t Size, const Twine &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.
+  // TODO: Is 16-byte alignment enough?  We copy small object files with large
+  // alignment expectations into this buffer.
+  SmallString<256> NameBuf;
+  StringRef NameRef = BufferName.toStringRef(NameBuf);
+  size_t AlignedStringLen =
+      RoundUpToAlignment(sizeof(MemoryBufferMem) + NameRef.size() + 1, 16);
+  size_t RealLen = AlignedStringLen + Size + 1;
+  char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
+  if (!Mem)
+    return nullptr;
+
+  // The name is stored after the class itself.
+  CopyStringRef(Mem + sizeof(MemoryBufferMem), NameRef);
+
+  // The buffer begins after the name and must be aligned.
+  char *Buf = Mem + AlignedStringLen;
+  Buf[Size] = 0; // Null terminate buffer.
+
+  auto *Ret = new (Mem) MemoryBufferMem(StringRef(Buf, Size), true);
+  return std::unique_ptr<MemoryBuffer>(Ret);
+}
+
+std::unique_ptr<MemoryBuffer>
+MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
+  std::unique_ptr<MemoryBuffer> SB = getNewUninitMemBuffer(Size, BufferName);
+  if (!SB)
+    return nullptr;
+  memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
+  return SB;
+}
+
+ErrorOr<std::unique_ptr<MemoryBuffer>>
+MemoryBuffer::getFileOrSTDIN(const Twine &Filename, int64_t FileSize,
+                             bool RequiresNullTerminator) {
+  SmallString<256> NameBuf;
+  StringRef NameRef = Filename.toStringRef(NameBuf);
+
+  if (NameRef == "-")
+    return getSTDIN();
+  return getFile(Filename, FileSize, RequiresNullTerminator);
+}
+
+ErrorOr<std::unique_ptr<MemoryBuffer>>
+MemoryBuffer::getFileSlice(const Twine &FilePath, uint64_t MapSize, 
+                           uint64_t Offset) {
+  return getFileAux(FilePath, -1, MapSize, Offset, false, false);
+}
+
+
+//===----------------------------------------------------------------------===//
+// MemoryBuffer::getFile implementation.
+//===----------------------------------------------------------------------===//
+
+namespace {
+/// \brief Memory maps a file descriptor using sys::fs::mapped_file_region.
+///
+/// This handles converting the offset into a legal offset on the platform.
+class MemoryBufferMMapFile : public MemoryBuffer {
+  sys::fs::mapped_file_region MFR;
+
+  static uint64_t getLegalMapOffset(uint64_t Offset) {
+    return Offset & ~(sys::fs::mapped_file_region::alignment() - 1);
+  }
+
+  static uint64_t getLegalMapSize(uint64_t Len, uint64_t Offset) {
+    return Len + (Offset - getLegalMapOffset(Offset));
+  }
+
+  const char *getStart(uint64_t Len, uint64_t Offset) {
+    return MFR.const_data() + (Offset - getLegalMapOffset(Offset));
+  }
+
+public:
+  MemoryBufferMMapFile(bool RequiresNullTerminator, int FD, uint64_t Len,
+                       uint64_t Offset, std::error_code &EC)
+      : MFR(FD, sys::fs::mapped_file_region::readonly,
+            getLegalMapSize(Len, Offset), getLegalMapOffset(Offset), EC) {
+    if (!EC) {
+      const char *Start = getStart(Len, Offset);
+      init(Start, Start + Len, RequiresNullTerminator);
+    }
+  }
+
+  const char *getBufferIdentifier() const override {
+    // The name is stored after the class itself.
+    return reinterpret_cast<const char *>(this + 1);
+  }
+
+  BufferKind getBufferKind() const override {
+    return MemoryBuffer_MMap;
+  }
+};
+}
+
+static ErrorOr<std::unique_ptr<MemoryBuffer>>
+getMemoryBufferForStream(int FD, const Twine &BufferName) {
+  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(FD, Buffer.end(), ChunkSize);
+    if (ReadBytes == -1) {
+      if (errno == EINTR) continue;
+      return std::error_code(errno, std::generic_category());
+    }
+    Buffer.set_size(Buffer.size() + ReadBytes);
+  } while (ReadBytes != 0);
+
+  return MemoryBuffer::getMemBufferCopy(Buffer, BufferName);
+}
+
+
+ErrorOr<std::unique_ptr<MemoryBuffer>>
+MemoryBuffer::getFile(const Twine &Filename, int64_t FileSize,
+                      bool RequiresNullTerminator, bool IsVolatileSize) {
+  return getFileAux(Filename, FileSize, FileSize, 0,
+                    RequiresNullTerminator, IsVolatileSize);
+}
+
+static ErrorOr<std::unique_ptr<MemoryBuffer>>
+getOpenFileImpl(int FD, const Twine &Filename, uint64_t FileSize,
+                uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator,
+                bool IsVolatileSize);
+
+static ErrorOr<std::unique_ptr<MemoryBuffer>>
+getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize,
+           uint64_t Offset, bool RequiresNullTerminator, bool IsVolatileSize) {
+  int FD;
+  std::error_code EC = sys::fs::openFileForRead(Filename, FD);
+  if (EC)
+    return EC;
+
+  ErrorOr<std::unique_ptr<MemoryBuffer>> Ret =
+      getOpenFileImpl(FD, Filename, FileSize, MapSize, Offset,
+                      RequiresNullTerminator, IsVolatileSize);
+  close(FD);
+  return Ret;
+}
+
+static bool shouldUseMmap(int FD,
+                          size_t FileSize,
+                          size_t MapSize,
+                          off_t Offset,
+                          bool RequiresNullTerminator,
+                          int PageSize,
+                          bool IsVolatileSize) {
+  // mmap may leave the buffer without null terminator if the file size changed
+  // by the time the last page is mapped in, so avoid it if the file size is
+  // likely to change.
+  if (IsVolatileSize)
+    return false;
+
+  // We don't use mmap for small files because this can severely fragment our
+  // address space.
+  if (MapSize < 4 * 4096 || MapSize < (unsigned)PageSize)
+    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)) {
+    sys::fs::file_status Status;
+    if (sys::fs::status(FD, Status))
+      return false;
+    FileSize = Status.getSize();
+  }
+
+  // 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;
+
+#if defined(__CYGWIN__)
+  // Don't try to map files that are exactly a multiple of the physical page size
+  // if we need a null terminator.
+  // FIXME: We should reorganize again getPageSize() on Win32.
+  if ((FileSize & (4096 - 1)) == 0)
+    return false;
+#endif
+
+  return true;
+}
+
+static ErrorOr<std::unique_ptr<MemoryBuffer>>
+getOpenFileImpl(int FD, const Twine &Filename, uint64_t FileSize,
+                uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator,
+                bool IsVolatileSize) {
+  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)) {
+      sys::fs::file_status Status;
+      std::error_code EC = sys::fs::status(FD, Status);
+      if (EC)
+        return EC;
+
+      // If this not a file or a block device (e.g. it's a named pipe
+      // or character device), we can't trust the size. Create the memory
+      // buffer by copying off the stream.
+      sys::fs::file_type Type = Status.type();
+      if (Type != sys::fs::file_type::regular_file &&
+          Type != sys::fs::file_type::block_file)
+        return getMemoryBufferForStream(FD, Filename);
+
+      FileSize = Status.getSize();
+    }
+    MapSize = FileSize;
+  }
+
+  if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
+                    PageSize, IsVolatileSize)) {
+    std::error_code EC;
+    std::unique_ptr<MemoryBuffer> Result(
+        new (NamedBufferAlloc(Filename))
+        MemoryBufferMMapFile(RequiresNullTerminator, FD, MapSize, Offset, EC));
+    if (!EC)
+      return std::move(Result);
+  }
+
+  std::unique_ptr<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);
+  }
+
+  char *BufPtr = const_cast<char *>(Buf->getBufferStart());
+
+  size_t BytesLeft = MapSize;
+#ifndef HAVE_PREAD
+  if (lseek(FD, Offset, SEEK_SET) == -1)
+    return std::error_code(errno, std::generic_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 std::error_code(errno, std::generic_category());
+    }
+    if (NumRead == 0) {
+      memset(BufPtr, 0, BytesLeft); // zero-initialize rest of the buffer.
+      break;
+    }
+    BytesLeft -= NumRead;
+    BufPtr += NumRead;
+  }
+
+  return std::move(Buf);
+}
+
+ErrorOr<std::unique_ptr<MemoryBuffer>>
+MemoryBuffer::getOpenFile(int FD, const Twine &Filename, uint64_t FileSize,
+                          bool RequiresNullTerminator, bool IsVolatileSize) {
+  return getOpenFileImpl(FD, Filename, FileSize, FileSize, 0,
+                         RequiresNullTerminator, IsVolatileSize);
+}
+
+ErrorOr<std::unique_ptr<MemoryBuffer>>
+MemoryBuffer::getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize,
+                               int64_t Offset) {
+  assert(MapSize != uint64_t(-1));
+  return getOpenFileImpl(FD, Filename, -1, MapSize, Offset, false,
+                         /*IsVolatileSize*/ false);
+}
+
+ErrorOr<std::unique_ptr<MemoryBuffer>> MemoryBuffer::getSTDIN() {
+  // 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::ChangeStdinToBinary();
+
+  return getMemoryBufferForStream(0, "<stdin>");
+}
+
+MemoryBufferRef MemoryBuffer::getMemBufferRef() const {
+  StringRef Data = getBuffer();
+  StringRef Identifier = getBufferIdentifier();
+  return MemoryBufferRef(Data, Identifier);
+}