//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Chris Lattner and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/MemoryBuffer.h"
-#include "llvm/System/MappedFile.h"
-#include "llvm/System/Process.h"
-#include "llvm/System/Program.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Config/config.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 "llvm/Support/system_error.h"
#include <cassert>
+#include <cerrno>
#include <cstdio>
#include <cstring>
-#include <cerrno>
+#include <new>
+#include <sys/types.h>
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
+#include <unistd.h>
+#else
+#include <io.h>
+#endif
using namespace llvm;
//===----------------------------------------------------------------------===//
// MemoryBuffer implementation itself.
//===----------------------------------------------------------------------===//
-MemoryBuffer::~MemoryBuffer() {
- if (MustDeleteBuffer)
- delete [] BufferStart;
-}
-
-/// initCopyOf - Initialize this source buffer with a copy of the specified
-/// memory range. We make the copy so that we can null terminate it
-/// successfully.
-void MemoryBuffer::initCopyOf(const char *BufStart, const char *BufEnd) {
- size_t Size = BufEnd-BufStart;
- BufferStart = new char[Size+1];
- BufferEnd = BufferStart+Size;
- memcpy(const_cast<char*>(BufferStart), BufStart, Size);
- *const_cast<char*>(BufferEnd) = 0; // Null terminate buffer.
- MustDeleteBuffer = true;
-}
+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((!RequiresNullTerminator || BufEnd[0] == 0) &&
+ "Buffer is not null terminated!");
BufferStart = BufStart;
BufferEnd = BufEnd;
- MustDeleteBuffer = false;
}
//===----------------------------------------------------------------------===//
// MemoryBufferMem implementation.
//===----------------------------------------------------------------------===//
+/// CopyStringRef - Copies contents of a StringRef into a block of memory and
+/// null-terminates it.
+static void CopyStringRef(char *Memory, StringRef Data) {
+ memcpy(Memory, Data.data(), Data.size());
+ Memory[Data.size()] = 0; // Null terminate string.
+}
+
namespace {
+struct NamedBufferAlloc {
+ StringRef Name;
+ NamedBufferAlloc(StringRef Name) : Name(Name) {}
+};
+}
+
+void *operator new(size_t N, const NamedBufferAlloc &Alloc) {
+ char *Mem = static_cast<char *>(operator new(N + Alloc.Name.size() + 1));
+ CopyStringRef(Mem + N, Alloc.Name);
+ return Mem;
+}
+
+namespace {
+/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
class MemoryBufferMem : public MemoryBuffer {
- std::string FileID;
public:
- MemoryBufferMem(const char *Start, const char *End, const char *FID,
- bool Copy = false)
- : FileID(FID) {
- if (!Copy)
- init(Start, End);
- else
- initCopyOf(Start, End);
+ MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) {
+ init(InputData.begin(), InputData.end(), RequiresNullTerminator);
}
-
- virtual const char *getBufferIdentifier() const {
- return FileID.c_str();
+
+ 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;
}
};
}
/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
-/// that EndPtr[0] must be a null byte and be accessible!
-MemoryBuffer *MemoryBuffer::getMemBuffer(const char *StartPtr,
- const char *EndPtr,
- const char *BufferName) {
- return new MemoryBufferMem(StartPtr, EndPtr, BufferName);
+/// that InputData must be a null terminated if RequiresNullTerminator is true!
+MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
+ StringRef BufferName,
+ bool RequiresNullTerminator) {
+ return new (NamedBufferAlloc(BufferName))
+ MemoryBufferMem(InputData, RequiresNullTerminator);
}
/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
/// copying the contents and taking ownership of it. This has no requirements
/// on EndPtr[0].
-MemoryBuffer *MemoryBuffer::getMemBufferCopy(const char *StartPtr,
- const char *EndPtr,
- const char *BufferName) {
- return new MemoryBufferMem(StartPtr, EndPtr, BufferName, true);
+MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
+ StringRef BufferName) {
+ MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
+ if (!Buf) return nullptr;
+ memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
+ InputData.size());
+ return Buf;
}
/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
-/// that is completely initialized to zeros. Note that the caller should
-/// initialize the memory allocated by this method. The memory is owned by
-/// the MemoryBuffer object.
-MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(unsigned Size,
- const char *BufferName) {
- char *Buf = new char[Size+1];
- Buf[Size] = 0;
- MemoryBufferMem *SB = new MemoryBufferMem(Buf, Buf+Size, BufferName);
- // The memory for this buffer is owned by the MemoryBuffer.
- SB->MustDeleteBuffer = true;
- return SB;
+/// that is not initialized. Note that the caller should initialize the
+/// memory allocated by this method. The memory is owned by the MemoryBuffer
+/// object.
+MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
+ StringRef 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.
+ size_t AlignedStringLen =
+ RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.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), BufferName);
+
+ // The buffer begins after the name and must be aligned.
+ char *Buf = Mem + AlignedStringLen;
+ Buf[Size] = 0; // Null terminate buffer.
+
+ return new (Mem) MemoryBufferMem(StringRef(Buf, Size), true);
}
/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
/// is completely initialized to zeros. Note that the caller should
/// initialize the memory allocated by this method. The memory is owned by
/// the MemoryBuffer object.
-MemoryBuffer *MemoryBuffer::getNewMemBuffer(unsigned Size,
- const char *BufferName) {
+MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
- memset(const_cast<char*>(SB->getBufferStart()), 0, Size+1);
+ if (!SB) return nullptr;
+ memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
return SB;
}
/// if the Filename is "-". If an error occurs, this returns null and fills
/// in *ErrStr with a reason. If stdin is empty, this API (unlike getSTDIN)
/// returns an empty buffer.
-MemoryBuffer *MemoryBuffer::getFileOrSTDIN(const char *FilenameStart,
- unsigned FnSize,
- std::string *ErrStr,
- int64_t FileSize) {
- if (FnSize != 1 || FilenameStart[0] != '-')
- return getFile(FilenameStart, FnSize, ErrStr, FileSize);
- MemoryBuffer *M = getSTDIN();
- if (M) return M;
-
- // If stdin was empty, M is null. Cons up an empty memory buffer now.
- const char *EmptyStr = "";
- return MemoryBuffer::getMemBuffer(EmptyStr, EmptyStr, "<stdin>");
+error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ int64_t FileSize) {
+ if (Filename == "-")
+ return getSTDIN(Result);
+ return getFile(Filename, Result, FileSize);
}
+
//===----------------------------------------------------------------------===//
-// MemoryBufferMMapFile implementation.
+// 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::MappedFile File;
+ 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 open(const sys::Path &Filename, std::string *ErrStr);
-
- virtual const char *getBufferIdentifier() const {
- return File.path().c_str();
+ MemoryBufferMMapFile(bool RequiresNullTerminator, int FD, uint64_t Len,
+ uint64_t Offset, error_code EC)
+ : MFR(FD, false, 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;
}
-
- ~MemoryBufferMMapFile();
};
}
-bool MemoryBufferMMapFile::open(const sys::Path &Filename,
- std::string *ErrStr) {
- // FIXME: This does an extra stat syscall to figure out the size, but we
- // already know the size!
- bool Failure = File.open(Filename, sys::MappedFile::READ_ACCESS, ErrStr);
- if (Failure) return true;
-
- if (!File.map(ErrStr))
+static error_code getMemoryBufferForStream(int FD,
+ StringRef BufferName,
+ std::unique_ptr<MemoryBuffer> &Result) {
+ 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 error_code(errno, std::generic_category());
+ }
+ Buffer.set_size(Buffer.size() + ReadBytes);
+ } while (ReadBytes != 0);
+
+ Result.reset(MemoryBuffer::getMemBufferCopy(Buffer, BufferName));
+ return error_code();
+}
+
+static error_code getFileAux(const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ int64_t FileSize,
+ bool RequiresNullTerminator,
+ bool IsVolatileSize);
+
+error_code MemoryBuffer::getFile(Twine Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ int64_t FileSize,
+ bool RequiresNullTerminator,
+ bool IsVolatileSize) {
+ // Ensure the path is null terminated.
+ SmallString<256> PathBuf;
+ StringRef NullTerminatedName = Filename.toNullTerminatedStringRef(PathBuf);
+ return getFileAux(NullTerminatedName.data(), Result, FileSize,
+ RequiresNullTerminator, IsVolatileSize);
+}
+
+static error_code getOpenFileImpl(int FD, const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ uint64_t FileSize, uint64_t MapSize,
+ int64_t Offset, bool RequiresNullTerminator,
+ bool IsVolatileSize);
+
+static error_code getFileAux(const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result, int64_t FileSize,
+ bool RequiresNullTerminator,
+ bool IsVolatileSize) {
+ int FD;
+ error_code EC = sys::fs::openFileForRead(Filename, FD);
+ if (EC)
+ return EC;
+
+ error_code ret = getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0,
+ 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;
-
- size_t Size = File.size();
-
- static unsigned PageSize = sys::Process::GetPageSize();
- assert(((PageSize & (PageSize-1)) == 0) && PageSize &&
- "Page size is not a power of 2!");
-
- // If this file is not an exact multiple of the system page size (common
- // case), then the OS has zero terminated the buffer for us.
- if ((Size & (PageSize-1))) {
- init(File.charBase(), File.charBase()+Size);
- } else {
- // Otherwise, we allocate a new memory buffer and copy the data over
- initCopyOf(File.charBase(), File.charBase()+Size);
-
- // No need to keep the file mapped any longer.
- File.unmap();
+
+
+ // 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();
}
- return false;
-}
-MemoryBufferMMapFile::~MemoryBufferMMapFile() {
- if (File.isMapped())
- File.unmap();
+ // 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;
}
-//===----------------------------------------------------------------------===//
-// MemoryBuffer::getFile implementation.
-//===----------------------------------------------------------------------===//
+static error_code getOpenFileImpl(int FD, const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ uint64_t FileSize, uint64_t MapSize,
+ int64_t Offset, bool RequiresNullTerminator,
+ bool IsVolatileSize) {
+ static int PageSize = sys::process::get_self()->page_size();
-MemoryBuffer *MemoryBuffer::getFile(const char *FilenameStart, unsigned FnSize,
- std::string *ErrStr, int64_t FileSize){
- // FIXME: it would be nice if PathWithStatus didn't copy the filename into a
- // temporary string. :(
- sys::PathWithStatus P(FilenameStart, FnSize);
-#if 1
- MemoryBufferMMapFile *M = new MemoryBufferMMapFile();
- if (!M->open(P, ErrStr))
- return M;
- delete M;
- return 0;
-#else
- // FIXME: We need an efficient and portable method to open a file and then use
- // 'read' to copy the bits out. The unix implementation is below. This is
- // an important optimization for clients that want to open large numbers of
- // small files (using mmap on everything can easily exhaust address space!).
-
- // If the user didn't specify a filesize, do a stat to find it.
- if (FileSize == -1) {
- const sys::FileStatus *FS = P.getFileStatus();
- if (FS == 0) return 0; // Error stat'ing file.
-
- FileSize = FS->fileSize;
+ // 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;
+ 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, Result);
+
+ FileSize = Status.getSize();
+ }
+ MapSize = FileSize;
}
-
- // If the file is larger than some threshold, use mmap, otherwise use 'read'.
- if (FileSize >= 4096*4) {
- MemoryBufferMMapFile *M = new MemoryBufferMMapFile();
- if (!M->open(P, ErrStr))
- return M;
- delete M;
- return 0;
+
+ if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator,
+ PageSize, IsVolatileSize)) {
+ error_code EC;
+ Result.reset(new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile(
+ RequiresNullTerminator, FD, MapSize, Offset, EC));
+ if (!EC)
+ return error_code();
}
-
- MemoryBuffer *SB = getNewUninitMemBuffer(FileSize, FilenameStart);
- char *BufPtr = const_cast<char*>(SB->getBufferStart());
-
- int FD = ::open(FilenameStart, O_RDONLY);
- if (FD == -1) {
- delete SB;
- return 0;
+
+ 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(std::errc::not_enough_memory);
}
-
- unsigned BytesLeft = FileSize;
+
+ std::unique_ptr<MemoryBuffer> SB(Buf);
+ char *BufPtr = const_cast<char*>(SB->getBufferStart());
+
+ size_t BytesLeft = MapSize;
+#ifndef HAVE_PREAD
+ if (lseek(FD, Offset, SEEK_SET) == -1)
+ return 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);
- if (NumRead != -1) {
- BytesLeft -= NumRead;
- BufPtr += NumRead;
- } else if (errno == EINTR) {
- // try again
- } else {
- // error reading.
- close(FD);
- delete SB;
- return 0;
+#endif
+ if (NumRead == -1) {
+ if (errno == EINTR)
+ continue;
+ // Error while reading.
+ return error_code(errno, std::generic_category());
+ }
+ if (NumRead == 0) {
+ memset(BufPtr, 0, BytesLeft); // zero-initialize rest of the buffer.
+ break;
}
+ BytesLeft -= NumRead;
+ BufPtr += NumRead;
}
- close(FD);
-
- return SB;
-#endif
+
+ Result.swap(SB);
+ return error_code();
+}
+
+error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ uint64_t FileSize,
+ bool RequiresNullTerminator,
+ bool IsVolatileSize) {
+ return getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0,
+ RequiresNullTerminator, IsVolatileSize);
}
+error_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename,
+ std::unique_ptr<MemoryBuffer> &Result,
+ uint64_t MapSize, int64_t Offset,
+ bool IsVolatileSize) {
+ return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false,
+ IsVolatileSize);
+}
//===----------------------------------------------------------------------===//
// MemoryBuffer::getSTDIN implementation.
//===----------------------------------------------------------------------===//
-namespace {
-class STDINBufferFile : public MemoryBuffer {
-public:
- virtual const char *getBufferIdentifier() const {
- return "<stdin>";
- }
-};
-}
-
-MemoryBuffer *MemoryBuffer::getSTDIN() {
- char Buffer[4096*4];
-
- std::vector<char> FileData;
-
+error_code MemoryBuffer::getSTDIN(std::unique_ptr<MemoryBuffer> &Result) {
// Read in all of the data from stdin, we cannot mmap stdin.
- sys::Program::ChangeStdinToBinary();
- while (size_t ReadBytes = fread(Buffer, sizeof(char), 4096*4, stdin))
- FileData.insert(FileData.end(), Buffer, Buffer+ReadBytes);
-
- FileData.push_back(0); // &FileData[Size] is invalid. So is &*FileData.end().
- size_t Size = FileData.size();
- if (Size <= 1)
- return 0;
- MemoryBuffer *B = new STDINBufferFile();
- B->initCopyOf(&FileData[0], &FileData[Size-1]);
- return B;
+ //
+ // FIXME: That isn't necessarily true, we should try to mmap stdin and
+ // fallback if it fails.
+ sys::ChangeStdinToBinary();
+
+ return getMemoryBufferForStream(0, "<stdin>", Result);
}
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