Add r127409 back now that the windows file was updated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127417 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2011-03-10 18:33:29 +00:00
parent b78e2ae4ca
commit f7fdad15d9
4 changed files with 86 additions and 32 deletions

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@ -40,7 +40,8 @@ class MemoryBuffer {
MemoryBuffer &operator=(const MemoryBuffer &); // DO NOT IMPLEMENT
protected:
MemoryBuffer() {}
void init(const char *BufStart, const char *BufEnd);
void init(const char *BufStart, const char *BufEnd,
bool RequiresNullTerminator);
public:
virtual ~MemoryBuffer();
@ -72,7 +73,10 @@ public:
/// return a MemoryBuffer.
static error_code getOpenFile(int FD, const char *Filename,
OwningPtr<MemoryBuffer> &result,
int64_t FileSize = -1);
size_t FileSize = -1,
size_t MapSize = -1,
off_t Offset = 0,
bool RequiresNullTerminator = true);
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
/// that InputData must be null terminated.

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@ -608,14 +608,15 @@ namespace sys {
///
/// This API is not intended for general use, clients should use
/// MemoryBuffer::getFile instead.
static const char *MapInFilePages(int FD, uint64_t FileSize);
static const char *MapInFilePages(int FD, size_t FileSize,
off_t Offset);
/// UnMapFilePages - Free pages mapped into the current process by
/// MapInFilePages.
///
/// This API is not intended for general use, clients should use
/// MemoryBuffer::getFile instead.
static void UnMapFilePages(const char *Base, uint64_t FileSize);
static void UnMapFilePages(const char *Base, size_t FileSize);
/// @}
/// @name Data

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@ -46,8 +46,10 @@ 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) {
assert(BufEnd[0] == 0 && "Buffer is not null terminated!");
void MemoryBuffer::init(const char *BufStart, const char *BufEnd,
bool RequiresNullTerminator) {
assert((BufEnd[0] == 0 || !RequiresNullTerminator) &&
"Buffer is not null terminated!");
BufferStart = BufStart;
BufferEnd = BufEnd;
}
@ -65,18 +67,19 @@ static void CopyStringRef(char *Memory, StringRef Data) {
/// 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 {
@ -90,7 +93,7 @@ public:
/// that EndPtr[0] must be a null byte and be accessible!
MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
StringRef BufferName) {
return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName);
return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName, true);
}
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
@ -127,7 +130,7 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
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
@ -172,11 +175,19 @@ namespace {
/// 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);
}
};
}
@ -205,12 +216,44 @@ error_code MemoryBuffer::getFile(const char *Filename,
return ret;
}
static bool shouldUseMmap(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 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,
int64_t FileSize) {
size_t FileSize, size_t MapSize,
off_t Offset,
bool RequiresNullTerminator) {
static int PageSize = sys::Process::GetPageSize();
// 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) {
if (FileSize == size_t(-1)) {
struct stat FileInfo;
// TODO: This should use fstat64 when available.
if (fstat(FD, &FileInfo) == -1) {
@ -219,23 +262,26 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
FileSize = FileInfo.st_size;
}
// Default is to map the full file.
if (MapSize == size_t(-1))
MapSize = FileSize;
// 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)) {
if (shouldUseMmap(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));
StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator));
return 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.
@ -245,7 +291,10 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
OwningPtr<MemoryBuffer> SB(Buf);
char *BufPtr = const_cast<char*>(SB->getBufferStart());
size_t BytesLeft = FileSize;
size_t BytesLeft = MapSize;
if (lseek(FD, Offset, SEEK_SET) == -1)
return error_code(errno, posix_category());
while (BytesLeft) {
ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
if (NumRead == -1) {

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@ -869,18 +869,18 @@ Path::makeUnique(bool reuse_current, std::string* ErrMsg) {
return false;
}
const char *Path::MapInFilePages(int FD, uint64_t FileSize) {
const char *Path::MapInFilePages(int FD, size_t FileSize, off_t Offset) {
int Flags = MAP_PRIVATE;
#ifdef MAP_FILE
Flags |= MAP_FILE;
#endif
void *BasePtr = ::mmap(0, FileSize, PROT_READ, Flags, FD, 0);
void *BasePtr = ::mmap(0, FileSize, PROT_READ, Flags, FD, Offset);
if (BasePtr == MAP_FAILED)
return 0;
return (const char*)BasePtr;
}
void Path::UnMapFilePages(const char *BasePtr, uint64_t FileSize) {
void Path::UnMapFilePages(const char *BasePtr, size_t FileSize) {
::munmap((void*)BasePtr, FileSize);
}