#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/Path.h"
#include <sys/stat.h>
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
-#include <sys/uio.h>
#else
#include <io.h>
#endif
#include <fcntl.h>
using namespace llvm;
-namespace { const llvm::error_code success; }
-
//===----------------------------------------------------------------------===//
// MemoryBuffer implementation itself.
//===----------------------------------------------------------------------===//
/// 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) {
- assert(BufEnd[0] == 0 && "Buffer is not 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;
}
/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it.
template <typename T>
-static T* GetNamedBuffer(StringRef Buffer, StringRef Name) {
+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);
+ return new (Mem) T(Buffer, RequiresNullTerminator);
}
namespace {
/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
class MemoryBufferMem : public MemoryBuffer {
public:
- MemoryBufferMem(StringRef InputData) {
- init(InputData.begin(), InputData.end());
+ 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 EndPtr[0] must be a null byte and be accessible!
+/// that InputData must be a null terminated if RequiresNullTerminator is true!
MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
- StringRef BufferName) {
- return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName);
+ StringRef BufferName,
+ bool RequiresNullTerminator) {
+ return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName,
+ RequiresNullTerminator);
}
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
char *Buf = Mem + AlignedStringLen;
Buf[Size] = 0; // Null terminate buffer.
- return new (Mem) MemoryBufferMem(StringRef(Buf, Size));
+ return new (Mem) MemoryBufferMem(StringRef(Buf, Size), true);
}
/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
/// sys::Path::UnMapFilePages method.
class MemoryBufferMMapFile : public MemoryBufferMem {
public:
- MemoryBufferMMapFile(StringRef Buffer)
- : MemoryBufferMem(Buffer) { }
+ MemoryBufferMMapFile(StringRef Buffer, bool RequiresNullTerminator)
+ : MemoryBufferMem(Buffer, RequiresNullTerminator) { }
~MemoryBufferMMapFile() {
- sys::Path::UnMapFilePages(getBufferStart(), getBufferSize());
+ 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) {
+ 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);
+ return MemoryBuffer::getFile(PathBuf.c_str(), result, FileSize,
+ RequiresNullTerminator);
}
error_code MemoryBuffer::getFile(const char *Filename,
OwningPtr<MemoryBuffer> &result,
- int64_t FileSize) {
+ int64_t FileSize,
+ bool RequiresNullTerminator) {
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) {
+ if (FD == -1)
return error_code(errno, posix_category());
- }
- error_code ret = getOpenFile(FD, Filename, result, FileSize);
+
+ error_code ret = getOpenFile(FD, Filename, result, FileSize, FileSize,
+ 0, RequiresNullTerminator);
close(FD);
return ret;
}
-error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
- OwningPtr<MemoryBuffer> &result,
- int64_t FileSize) {
+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.
- if (FileSize == -1) {
+ // 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) {
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;
- // If the file is large, try to use mmap to read it in. We don't use mmap
- // for small files, because this can severely fragment our address space. Also
- // don't try to map files that are exactly a multiple of the system page size,
- // as the file would not have the required null terminator.
- //
- // FIXME: Can we just mmap an extra page in the latter case?
- if (FileSize >= 4096*4 &&
- (FileSize & (sys::Process::GetPageSize()-1)) != 0) {
- if (const char *Pages = sys::Path::MapInFilePages(FD, FileSize)) {
+ // 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, FileSize), Filename));
- return success;
+ StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator));
+ return error_code::success();
}
}
- MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(FileSize, Filename);
+ 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.
OwningPtr<MemoryBuffer> SB(Buf);
char *BufPtr = const_cast<char*>(SB->getBufferStart());
- size_t BytesLeft = FileSize;
+ 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());
- } else if (NumRead == 0) {
- // We hit EOF early, truncate and terminate buffer.
- Buf->BufferEnd = BufPtr;
- *BufPtr = 0;
- result.swap(SB);
- return success;
}
+ assert(NumRead != 0 && "fstat reported an invalid file size.");
BytesLeft -= NumRead;
BufPtr += NumRead;
}
result.swap(SB);
- return success;
+ return error_code::success();
}
//===----------------------------------------------------------------------===//
} while (ReadBytes != 0);
result.reset(getMemBufferCopy(Buffer, "<stdin>"));
- return success;
+ return error_code::success();
}
projects / oota-llvm.git / blobdiff