ffd1746d03
This commit merges the latest LLVM sources from the vendor space. It also updates the build glue to match the new sources. Clang's version number is changed to match LLVM's, which means /usr/include/clang/2.0 has been renamed to /usr/include/clang/2.8. Obtained from: projects/clangbsd
298 lines
10 KiB
C++
298 lines
10 KiB
C++
//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the MemoryBuffer interface.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/MathExtras.h"
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#include "llvm/System/Errno.h"
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#include "llvm/System/Path.h"
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#include "llvm/System/Process.h"
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#include "llvm/System/Program.h"
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#include <cassert>
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#include <cstdio>
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#include <cstring>
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#include <cerrno>
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#include <sys/types.h>
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#include <sys/stat.h>
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#if !defined(_MSC_VER) && !defined(__MINGW32__)
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#include <unistd.h>
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#include <sys/uio.h>
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#else
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#include <io.h>
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#endif
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#include <fcntl.h>
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// MemoryBuffer implementation itself.
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//===----------------------------------------------------------------------===//
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MemoryBuffer::~MemoryBuffer() { }
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/// init - Initialize this MemoryBuffer as a reference to externally allocated
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/// memory, memory that we know is already null terminated.
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void MemoryBuffer::init(const char *BufStart, const char *BufEnd) {
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assert(BufEnd[0] == 0 && "Buffer is not null terminated!");
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BufferStart = BufStart;
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BufferEnd = BufEnd;
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}
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//===----------------------------------------------------------------------===//
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// MemoryBufferMem implementation.
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//===----------------------------------------------------------------------===//
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/// CopyStringRef - Copies contents of a StringRef into a block of memory and
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/// null-terminates it.
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static void CopyStringRef(char *Memory, StringRef Data) {
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memcpy(Memory, Data.data(), Data.size());
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Memory[Data.size()] = 0; // Null terminate string.
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}
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/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it.
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template <typename T>
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static T* GetNamedBuffer(StringRef Buffer, StringRef Name) {
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char *Mem = static_cast<char*>(operator new(sizeof(T) + Name.size() + 1));
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CopyStringRef(Mem + sizeof(T), Name);
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return new (Mem) T(Buffer);
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}
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namespace {
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/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory.
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class MemoryBufferMem : public MemoryBuffer {
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public:
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MemoryBufferMem(StringRef InputData) {
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init(InputData.begin(), InputData.end());
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}
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virtual const char *getBufferIdentifier() const {
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// The name is stored after the class itself.
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return reinterpret_cast<const char*>(this + 1);
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}
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};
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}
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/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note
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/// that EndPtr[0] must be a null byte and be accessible!
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MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
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StringRef BufferName) {
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return GetNamedBuffer<MemoryBufferMem>(InputData, BufferName);
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}
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/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer,
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/// copying the contents and taking ownership of it. This has no requirements
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/// on EndPtr[0].
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MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
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StringRef BufferName) {
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MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
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if (!Buf) return 0;
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memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
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InputData.size());
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return Buf;
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}
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/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size
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/// that is not initialized. Note that the caller should initialize the
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/// memory allocated by this method. The memory is owned by the MemoryBuffer
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/// object.
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MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
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StringRef BufferName) {
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// Allocate space for the MemoryBuffer, the data and the name. It is important
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// that MemoryBuffer and data are aligned so PointerIntPair works with them.
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size_t AlignedStringLen =
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RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1,
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sizeof(void*)); // TODO: Is sizeof(void*) enough?
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size_t RealLen = AlignedStringLen + Size + 1;
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char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
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if (!Mem) return 0;
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// The name is stored after the class itself.
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CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
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// The buffer begins after the name and must be aligned.
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char *Buf = Mem + AlignedStringLen;
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Buf[Size] = 0; // Null terminate buffer.
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return new (Mem) MemoryBufferMem(StringRef(Buf, Size));
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}
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/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that
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/// is completely initialized to zeros. Note that the caller should
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/// initialize the memory allocated by this method. The memory is owned by
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/// the MemoryBuffer object.
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MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
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MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
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if (!SB) return 0;
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memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
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return SB;
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}
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/// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin
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/// if the Filename is "-". If an error occurs, this returns null and fills
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/// in *ErrStr with a reason. If stdin is empty, this API (unlike getSTDIN)
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/// returns an empty buffer.
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MemoryBuffer *MemoryBuffer::getFileOrSTDIN(StringRef Filename,
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std::string *ErrStr,
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int64_t FileSize,
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struct stat *FileInfo) {
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if (Filename == "-")
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return getSTDIN(ErrStr);
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return getFile(Filename, ErrStr, FileSize, FileInfo);
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}
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MemoryBuffer *MemoryBuffer::getFileOrSTDIN(const char *Filename,
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std::string *ErrStr,
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int64_t FileSize,
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struct stat *FileInfo) {
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if (strcmp(Filename, "-") == 0)
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return getSTDIN(ErrStr);
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return getFile(Filename, ErrStr, FileSize, FileInfo);
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}
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//===----------------------------------------------------------------------===//
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// MemoryBuffer::getFile implementation.
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//===----------------------------------------------------------------------===//
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namespace {
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/// MemoryBufferMMapFile - This represents a file that was mapped in with the
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/// sys::Path::MapInFilePages method. When destroyed, it calls the
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/// sys::Path::UnMapFilePages method.
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class MemoryBufferMMapFile : public MemoryBufferMem {
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public:
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MemoryBufferMMapFile(StringRef Buffer)
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: MemoryBufferMem(Buffer) { }
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~MemoryBufferMMapFile() {
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sys::Path::UnMapFilePages(getBufferStart(), getBufferSize());
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}
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};
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/// FileCloser - RAII object to make sure an FD gets closed properly.
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class FileCloser {
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int FD;
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public:
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explicit FileCloser(int FD) : FD(FD) {}
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~FileCloser() { ::close(FD); }
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};
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}
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MemoryBuffer *MemoryBuffer::getFile(StringRef Filename, std::string *ErrStr,
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int64_t FileSize, struct stat *FileInfo) {
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SmallString<256> PathBuf(Filename.begin(), Filename.end());
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return MemoryBuffer::getFile(PathBuf.c_str(), ErrStr, FileSize, FileInfo);
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}
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MemoryBuffer *MemoryBuffer::getFile(const char *Filename, std::string *ErrStr,
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int64_t FileSize, struct stat *FileInfo) {
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int OpenFlags = O_RDONLY;
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#ifdef O_BINARY
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OpenFlags |= O_BINARY; // Open input file in binary mode on win32.
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#endif
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int FD = ::open(Filename, OpenFlags);
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if (FD == -1) {
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if (ErrStr) *ErrStr = sys::StrError();
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return 0;
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}
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FileCloser FC(FD); // Close FD on return.
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// If we don't know the file size, use fstat to find out. fstat on an open
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// file descriptor is cheaper than stat on a random path.
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if (FileSize == -1 || FileInfo) {
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struct stat MyFileInfo;
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struct stat *FileInfoPtr = FileInfo? FileInfo : &MyFileInfo;
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// TODO: This should use fstat64 when available.
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if (fstat(FD, FileInfoPtr) == -1) {
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if (ErrStr) *ErrStr = sys::StrError();
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return 0;
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}
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FileSize = FileInfoPtr->st_size;
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}
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// If the file is large, try to use mmap to read it in. We don't use mmap
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// for small files, because this can severely fragment our address space. Also
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// don't try to map files that are exactly a multiple of the system page size,
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// as the file would not have the required null terminator.
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//
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// FIXME: Can we just mmap an extra page in the latter case?
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if (FileSize >= 4096*4 &&
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(FileSize & (sys::Process::GetPageSize()-1)) != 0) {
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if (const char *Pages = sys::Path::MapInFilePages(FD, FileSize)) {
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return GetNamedBuffer<MemoryBufferMMapFile>(StringRef(Pages, FileSize),
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Filename);
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}
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}
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MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(FileSize, Filename);
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if (!Buf) {
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// Failed to create a buffer.
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if (ErrStr) *ErrStr = "could not allocate buffer";
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return 0;
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}
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OwningPtr<MemoryBuffer> SB(Buf);
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char *BufPtr = const_cast<char*>(SB->getBufferStart());
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size_t BytesLeft = FileSize;
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while (BytesLeft) {
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ssize_t NumRead = ::read(FD, BufPtr, BytesLeft);
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if (NumRead == -1) {
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if (errno == EINTR)
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continue;
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// Error while reading.
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if (ErrStr) *ErrStr = sys::StrError();
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return 0;
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} else if (NumRead == 0) {
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// We hit EOF early, truncate and terminate buffer.
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Buf->BufferEnd = BufPtr;
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*BufPtr = 0;
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return SB.take();
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}
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BytesLeft -= NumRead;
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BufPtr += NumRead;
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}
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return SB.take();
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}
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//===----------------------------------------------------------------------===//
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// MemoryBuffer::getSTDIN implementation.
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//===----------------------------------------------------------------------===//
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MemoryBuffer *MemoryBuffer::getSTDIN(std::string *ErrStr) {
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// Read in all of the data from stdin, we cannot mmap stdin.
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//
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// FIXME: That isn't necessarily true, we should try to mmap stdin and
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// fallback if it fails.
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sys::Program::ChangeStdinToBinary();
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const ssize_t ChunkSize = 4096*4;
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SmallString<ChunkSize> Buffer;
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ssize_t ReadBytes;
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// Read into Buffer until we hit EOF.
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do {
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Buffer.reserve(Buffer.size() + ChunkSize);
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ReadBytes = read(0, Buffer.end(), ChunkSize);
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if (ReadBytes == -1) {
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if (errno == EINTR) continue;
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if (ErrStr) *ErrStr = sys::StrError();
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return 0;
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}
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Buffer.set_size(Buffer.size() + ReadBytes);
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} while (ReadBytes != 0);
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return getMemBufferCopy(Buffer, "<stdin>");
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}
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