llvm-6502/lib/System/Unix/MappedFile.inc
Chris Lattner 9ffd19af2e Implement Path::MapInFilePages/UnMapFilePages on unix, which
provides fast MappedFile::getFile for large files.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49034 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-01 06:16:24 +00:00

98 lines
2.2 KiB
C++

//===- Unix/MappedFile.inc - Unix MappedFile Implementation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the generic Unix implementation of the MappedFile concept.
//
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include "llvm/System/Process.h"
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
using namespace llvm;
using namespace sys;
namespace llvm {
namespace sys {
struct MappedFileInfo {
int FD;
off_t Size;
};
}
}
bool MappedFile::initialize(std::string* ErrMsg) {
int FD = ::open(Path.c_str(), O_RDONLY);
if (FD < 0) {
MakeErrMsg(ErrMsg, "can't open file '" + Path.toString() + "'");
return true;
}
const FileStatus *Status = Path.getFileStatus(false, ErrMsg);
if (!Status) {
::close(FD);
return true;
}
MapInfo = new MappedFileInfo();
MapInfo->FD = FD;
MapInfo->Size = Status->getSize();
return false;
}
void MappedFile::terminate() {
unmap();
assert(MapInfo && "MappedFile not initialized");
::close(MapInfo->FD);
delete MapInfo;
MapInfo = 0;
}
void MappedFile::unmap() {
assert(MapInfo && "MappedFile not initialized");
if (!isMapped()) return;
::munmap(BasePtr, MapInfo->Size);
BasePtr = 0; // Mark this as non-mapped.
}
const void* MappedFile::map(std::string* ErrMsg) {
assert(MapInfo && "MappedFile not initialized");
if (isMapped()) return BasePtr;
int flags = MAP_PRIVATE;
#ifdef MAP_FILE
flags |= MAP_FILE;
#endif
size_t PageSize = Process::GetPageSize();
size_t map_size = ((MapInfo->Size / PageSize)+1) * PageSize;
BasePtr = ::mmap(0, map_size, PROT_READ, flags, MapInfo->FD, 0);
if (BasePtr == MAP_FAILED) {
MakeErrMsg(ErrMsg, "Can't map file:" + Path.toString());
return 0;
}
return BasePtr;
}
size_t MappedFile::size() const {
assert(MapInfo && "MappedFile not initialized");
return MapInfo->Size;
}