//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the MemoryBuffer interface. // //===----------------------------------------------------------------------===// #include "llvm/Support/MemoryBuffer.h" #include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/SmallString.h" #include "llvm/System/Errno.h" #include "llvm/System/Path.h" #include "llvm/System/Process.h" #include "llvm/System/Program.h" #include #include #include #include #include #include #if !defined(_MSC_VER) && !defined(__MINGW32__) #include #include #else #include #endif #include using namespace llvm; //===----------------------------------------------------------------------===// // MemoryBuffer implementation itself. //===----------------------------------------------------------------------===// MemoryBuffer::~MemoryBuffer() { if (MustDeleteBuffer) free((void*)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 = (char *)malloc(Size+1); BufferEnd = BufferStart+Size; memcpy(const_cast(BufferStart), BufStart, Size); *const_cast(BufferEnd) = 0; // Null terminate buffer. MustDeleteBuffer = true; } /// 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!"); BufferStart = BufStart; BufferEnd = BufEnd; MustDeleteBuffer = false; } //===----------------------------------------------------------------------===// // MemoryBufferMem implementation. //===----------------------------------------------------------------------===// namespace { class MemoryBufferMem : public MemoryBuffer { std::string FileID; public: MemoryBufferMem(StringRef InputData, StringRef FID, bool Copy = false) : FileID(FID) { if (!Copy) init(InputData.data(), InputData.data()+InputData.size()); else initCopyOf(InputData.data(), InputData.data()+InputData.size()); } virtual const char *getBufferIdentifier() const { return FileID.c_str(); } }; } /// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note /// that EndPtr[0] must be a null byte and be accessible! MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData, const char *BufferName) { return new MemoryBufferMem(InputData, BufferName); } /// 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(StringRef InputData, const char *BufferName) { return new MemoryBufferMem(InputData, BufferName, true); } /// 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(size_t Size, StringRef BufferName) { char *Buf = (char *)malloc(Size+1); if (!Buf) return 0; Buf[Size] = 0; MemoryBufferMem *SB = new MemoryBufferMem(StringRef(Buf, Size), BufferName); // The memory for this buffer is owned by the MemoryBuffer. SB->MustDeleteBuffer = true; return SB; } /// 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(size_t Size, const char *BufferName) { MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName); if (!SB) return 0; memset(const_cast(SB->getBufferStart()), 0, Size+1); return SB; } /// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin /// 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(StringRef Filename, std::string *ErrStr, int64_t FileSize, struct stat *FileInfo) { if (Filename == "-") return getSTDIN(ErrStr); return getFile(Filename, ErrStr, FileSize, FileInfo); } //===----------------------------------------------------------------------===// // MemoryBuffer::getFile implementation. //===----------------------------------------------------------------------===// namespace { /// MemoryBufferMMapFile - This represents a file that was mapped in with the /// sys::Path::MapInFilePages method. When destroyed, it calls the /// sys::Path::UnMapFilePages method. class MemoryBufferMMapFile : public MemoryBuffer { std::string Filename; public: MemoryBufferMMapFile(StringRef filename, const char *Pages, uint64_t Size) : Filename(filename) { init(Pages, Pages+Size); } virtual const char *getBufferIdentifier() const { return Filename.c_str(); } ~MemoryBufferMMapFile() { sys::Path::UnMapFilePages(getBufferStart(), getBufferSize()); } }; /// FileCloser - RAII object to make sure an FD gets closed properly. class FileCloser { int FD; public: FileCloser(int FD) : FD(FD) {} ~FileCloser() { ::close(FD); } }; } MemoryBuffer *MemoryBuffer::getFile(StringRef Filename, std::string *ErrStr, int64_t FileSize, struct stat *FileInfo) { int OpenFlags = 0; #ifdef O_BINARY OpenFlags |= O_BINARY; // Open input file in binary mode on win32. #endif SmallString<256> PathBuf(Filename.begin(), Filename.end()); int FD = ::open(PathBuf.c_str(), O_RDONLY|OpenFlags); if (FD == -1) { if (ErrStr) *ErrStr = sys::StrError(); return 0; } FileCloser FC(FD); // Close FD on return. // 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 || FileInfo) { struct stat MyFileInfo; struct stat *FileInfoPtr = FileInfo? FileInfo : &MyFileInfo; // TODO: This should use fstat64 when available. if (fstat(FD, FileInfoPtr) == -1) { if (ErrStr) *ErrStr = sys::StrError(); return 0; } FileSize = FileInfoPtr->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)) { // Close the file descriptor, now that the whole file is in memory. return new MemoryBufferMMapFile(Filename, Pages, FileSize); } } MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(FileSize, Filename); if (!Buf) { // Failed to create a buffer. if (ErrStr) *ErrStr = "could not allocate buffer"; return 0; } OwningPtr SB(Buf); char *BufPtr = const_cast(SB->getBufferStart()); size_t BytesLeft = FileSize; while (BytesLeft) { ssize_t NumRead = ::read(FD, BufPtr, BytesLeft); if (NumRead == -1) { if (errno == EINTR) continue; // Error while reading. if (ErrStr) *ErrStr = sys::StrError(); return 0; } else if (NumRead == 0) { // We hit EOF early, truncate and terminate buffer. Buf->BufferEnd = BufPtr; *BufPtr = 0; return SB.take(); } BytesLeft -= NumRead; BufPtr += NumRead; } return SB.take(); } //===----------------------------------------------------------------------===// // MemoryBuffer::getSTDIN implementation. //===----------------------------------------------------------------------===// namespace { class STDINBufferFile : public MemoryBuffer { public: virtual const char *getBufferIdentifier() const { return ""; } }; } MemoryBuffer *MemoryBuffer::getSTDIN(std::string *ErrStr) { char Buffer[4096*4]; std::vector FileData; // Read in all of the data from stdin, we cannot mmap stdin. // // FIXME: That isn't necessarily true, we should try to mmap stdin and // fallback if it fails. sys::Program::ChangeStdinToBinary(); size_t ReadBytes; do { ReadBytes = fread(Buffer, sizeof(char), sizeof(Buffer), stdin); FileData.insert(FileData.end(), Buffer, Buffer+ReadBytes); } while (ReadBytes == sizeof(Buffer)); if (!feof(stdin)) { if (ErrStr) *ErrStr = "error reading from stdin"; return 0; } FileData.push_back(0); // &FileData[Size] is invalid. So is &*FileData.end(). size_t Size = FileData.size(); MemoryBuffer *B = new STDINBufferFile(); B->initCopyOf(&FileData[0], &FileData[Size-1]); return B; }