[llvm-commits] [llvm] r127417 - in /llvm/trunk: include/llvm/Support/MemoryBuffer.h include/llvm/Support/PathV1.h lib/Support/MemoryBuffer.cpp lib/Support/Unix/Path.inc
Rafael Espindola
rafael.espindola at gmail.com
Thu Mar 10 10:33:29 PST 2011
Author: rafael
Date: Thu Mar 10 12:33:29 2011
New Revision: 127417
URL: http://llvm.org/viewvc/llvm-project?rev=127417&view=rev
Log:
Add r127409 back now that the windows file was updated.
Modified:
llvm/trunk/include/llvm/Support/MemoryBuffer.h
llvm/trunk/include/llvm/Support/PathV1.h
llvm/trunk/lib/Support/MemoryBuffer.cpp
llvm/trunk/lib/Support/Unix/Path.inc
Modified: llvm/trunk/include/llvm/Support/MemoryBuffer.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/MemoryBuffer.h?rev=127417&r1=127416&r2=127417&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/MemoryBuffer.h (original)
+++ llvm/trunk/include/llvm/Support/MemoryBuffer.h Thu Mar 10 12:33:29 2011
@@ -40,7 +40,8 @@
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 @@
/// 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.
Modified: llvm/trunk/include/llvm/Support/PathV1.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/PathV1.h?rev=127417&r1=127416&r2=127417&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/PathV1.h (original)
+++ llvm/trunk/include/llvm/Support/PathV1.h Thu Mar 10 12:33:29 2011
@@ -608,14 +608,15 @@
///
/// 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
Modified: llvm/trunk/lib/Support/MemoryBuffer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/MemoryBuffer.cpp?rev=127417&r1=127416&r2=127417&view=diff
==============================================================================
--- llvm/trunk/lib/Support/MemoryBuffer.cpp (original)
+++ llvm/trunk/lib/Support/MemoryBuffer.cpp Thu Mar 10 12:33:29 2011
@@ -46,8 +46,10 @@
/// 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 @@
/// 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 @@
/// 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 @@
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 @@
/// 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 @@
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 @@
FileSize = FileInfo.st_size;
}
-
- // 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)) {
+ // Default is to map the full file.
+ if (MapSize == size_t(-1))
+ MapSize = 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 @@
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) {
Modified: llvm/trunk/lib/Support/Unix/Path.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Path.inc?rev=127417&r1=127416&r2=127417&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc (original)
+++ llvm/trunk/lib/Support/Unix/Path.inc Thu Mar 10 12:33:29 2011
@@ -869,18 +869,18 @@
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);
}
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