1193323Sed//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===// 2193323Sed// 3193323Sed// The LLVM Compiler Infrastructure 4193323Sed// 5193323Sed// This file is distributed under the University of Illinois Open Source 6193323Sed// License. See LICENSE.TXT for details. 7193323Sed// 8193323Sed//===----------------------------------------------------------------------===// 9193323Sed// 10193323Sed// This file implements the MemoryBuffer interface. 11193323Sed// 12193323Sed//===----------------------------------------------------------------------===// 13193323Sed 14193323Sed#include "llvm/Support/MemoryBuffer.h" 15193323Sed#include "llvm/ADT/OwningPtr.h" 16193323Sed#include "llvm/ADT/SmallString.h" 17234353Sdim#include "llvm/Config/config.h" 18218893Sdim#include "llvm/Support/Errno.h" 19239462Sdim#include "llvm/Support/FileSystem.h" 20249423Sdim#include "llvm/Support/MathExtras.h" 21218893Sdim#include "llvm/Support/Path.h" 22218893Sdim#include "llvm/Support/Process.h" 23218893Sdim#include "llvm/Support/Program.h" 24218893Sdim#include "llvm/Support/system_error.h" 25193323Sed#include <cassert> 26249423Sdim#include <cerrno> 27193323Sed#include <cstdio> 28193323Sed#include <cstring> 29218893Sdim#include <new> 30249423Sdim#include <sys/stat.h> 31193323Sed#include <sys/types.h> 32193323Sed#if !defined(_MSC_VER) && !defined(__MINGW32__) 33193323Sed#include <unistd.h> 34193323Sed#else 35193323Sed#include <io.h> 36263508Sdim// Simplistic definitinos of these macros for use in getOpenFile. 37249423Sdim#ifndef S_ISREG 38249423Sdim#define S_ISREG(x) (1) 39193323Sed#endif 40249423Sdim#ifndef S_ISBLK 41249423Sdim#define S_ISBLK(x) (0) 42243830Sdim#endif 43249423Sdim#endif 44193323Sedusing namespace llvm; 45193323Sed 46193323Sed//===----------------------------------------------------------------------===// 47193323Sed// MemoryBuffer implementation itself. 48193323Sed//===----------------------------------------------------------------------===// 49193323Sed 50210299SedMemoryBuffer::~MemoryBuffer() { } 51193323Sed 52193323Sed/// init - Initialize this MemoryBuffer as a reference to externally allocated 53193323Sed/// memory, memory that we know is already null terminated. 54221345Sdimvoid MemoryBuffer::init(const char *BufStart, const char *BufEnd, 55221345Sdim bool RequiresNullTerminator) { 56221345Sdim assert((!RequiresNullTerminator || BufEnd[0] == 0) && 57221345Sdim "Buffer is not null terminated!"); 58193323Sed BufferStart = BufStart; 59193323Sed BufferEnd = BufEnd; 60193323Sed} 61193323Sed 62193323Sed//===----------------------------------------------------------------------===// 63193323Sed// MemoryBufferMem implementation. 64193323Sed//===----------------------------------------------------------------------===// 65193323Sed 66210299Sed/// CopyStringRef - Copies contents of a StringRef into a block of memory and 67210299Sed/// null-terminates it. 68210299Sedstatic void CopyStringRef(char *Memory, StringRef Data) { 69210299Sed memcpy(Memory, Data.data(), Data.size()); 70210299Sed Memory[Data.size()] = 0; // Null terminate string. 71210299Sed} 72210299Sed 73249423Sdimnamespace { 74249423Sdimstruct NamedBufferAlloc { 75249423Sdim StringRef Name; 76249423Sdim NamedBufferAlloc(StringRef Name) : Name(Name) {} 77249423Sdim}; 78210299Sed} 79210299Sed 80249423Sdimvoid *operator new(size_t N, const NamedBufferAlloc &Alloc) { 81249423Sdim char *Mem = static_cast<char *>(operator new(N + Alloc.Name.size() + 1)); 82249423Sdim CopyStringRef(Mem + N, Alloc.Name); 83249423Sdim return Mem; 84249423Sdim} 85249423Sdim 86193323Sednamespace { 87210299Sed/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory. 88193323Sedclass MemoryBufferMem : public MemoryBuffer { 89193323Sedpublic: 90221345Sdim MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) { 91221345Sdim init(InputData.begin(), InputData.end(), RequiresNullTerminator); 92193323Sed } 93210299Sed 94243830Sdim virtual const char *getBufferIdentifier() const LLVM_OVERRIDE { 95210299Sed // The name is stored after the class itself. 96210299Sed return reinterpret_cast<const char*>(this + 1); 97193323Sed } 98243830Sdim 99243830Sdim virtual BufferKind getBufferKind() const LLVM_OVERRIDE { 100221345Sdim return MemoryBuffer_Malloc; 101221345Sdim } 102193323Sed}; 103193323Sed} 104193323Sed 105193323Sed/// getMemBuffer - Open the specified memory range as a MemoryBuffer. Note 106223017Sdim/// that InputData must be a null terminated if RequiresNullTerminator is true! 107206274SrdivackyMemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData, 108221345Sdim StringRef BufferName, 109221345Sdim bool RequiresNullTerminator) { 110249423Sdim return new (NamedBufferAlloc(BufferName)) 111249423Sdim MemoryBufferMem(InputData, RequiresNullTerminator); 112193323Sed} 113193323Sed 114193323Sed/// getMemBufferCopy - Open the specified memory range as a MemoryBuffer, 115193323Sed/// copying the contents and taking ownership of it. This has no requirements 116193323Sed/// on EndPtr[0]. 117206274SrdivackyMemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData, 118210299Sed StringRef BufferName) { 119210299Sed MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName); 120210299Sed if (!Buf) return 0; 121210299Sed memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(), 122210299Sed InputData.size()); 123210299Sed return Buf; 124193323Sed} 125193323Sed 126193323Sed/// getNewUninitMemBuffer - Allocate a new MemoryBuffer of the specified size 127210299Sed/// that is not initialized. Note that the caller should initialize the 128210299Sed/// memory allocated by this method. The memory is owned by the MemoryBuffer 129210299Sed/// object. 130193323SedMemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size, 131199481Srdivacky StringRef BufferName) { 132210299Sed // Allocate space for the MemoryBuffer, the data and the name. It is important 133210299Sed // that MemoryBuffer and data are aligned so PointerIntPair works with them. 134210299Sed size_t AlignedStringLen = 135210299Sed RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1, 136210299Sed sizeof(void*)); // TODO: Is sizeof(void*) enough? 137210299Sed size_t RealLen = AlignedStringLen + Size + 1; 138210299Sed char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow)); 139210299Sed if (!Mem) return 0; 140210299Sed 141210299Sed // The name is stored after the class itself. 142210299Sed CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName); 143210299Sed 144210299Sed // The buffer begins after the name and must be aligned. 145210299Sed char *Buf = Mem + AlignedStringLen; 146210299Sed Buf[Size] = 0; // Null terminate buffer. 147210299Sed 148221345Sdim return new (Mem) MemoryBufferMem(StringRef(Buf, Size), true); 149193323Sed} 150193323Sed 151193323Sed/// getNewMemBuffer - Allocate a new MemoryBuffer of the specified size that 152193323Sed/// is completely initialized to zeros. Note that the caller should 153193323Sed/// initialize the memory allocated by this method. The memory is owned by 154193323Sed/// the MemoryBuffer object. 155210299SedMemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) { 156193323Sed MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName); 157193323Sed if (!SB) return 0; 158210299Sed memset(const_cast<char*>(SB->getBufferStart()), 0, Size); 159193323Sed return SB; 160193323Sed} 161193323Sed 162193323Sed 163193323Sed/// getFileOrSTDIN - Open the specified file as a MemoryBuffer, or open stdin 164193323Sed/// if the Filename is "-". If an error occurs, this returns null and fills 165193323Sed/// in *ErrStr with a reason. If stdin is empty, this API (unlike getSTDIN) 166193323Sed/// returns an empty buffer. 167218893Sdimerror_code MemoryBuffer::getFileOrSTDIN(StringRef Filename, 168218893Sdim OwningPtr<MemoryBuffer> &result, 169218893Sdim int64_t FileSize) { 170199481Srdivacky if (Filename == "-") 171218893Sdim return getSTDIN(result); 172218893Sdim return getFile(Filename, result, FileSize); 173193323Sed} 174193323Sed 175193323Sed//===----------------------------------------------------------------------===// 176193323Sed// MemoryBuffer::getFile implementation. 177193323Sed//===----------------------------------------------------------------------===// 178193323Sed 179193323Sednamespace { 180263508Sdim/// \brief Memory maps a file descriptor using sys::fs::mapped_file_region. 181249423Sdim/// 182249423Sdim/// This handles converting the offset into a legal offset on the platform. 183249423Sdimclass MemoryBufferMMapFile : public MemoryBuffer { 184249423Sdim sys::fs::mapped_file_region MFR; 185210299Sed 186249423Sdim static uint64_t getLegalMapOffset(uint64_t Offset) { 187249423Sdim return Offset & ~(sys::fs::mapped_file_region::alignment() - 1); 188249423Sdim } 189221345Sdim 190249423Sdim static uint64_t getLegalMapSize(uint64_t Len, uint64_t Offset) { 191249423Sdim return Len + (Offset - getLegalMapOffset(Offset)); 192249423Sdim } 193221345Sdim 194249423Sdim const char *getStart(uint64_t Len, uint64_t Offset) { 195249423Sdim return MFR.const_data() + (Offset - getLegalMapOffset(Offset)); 196193323Sed } 197243830Sdim 198249423Sdimpublic: 199249423Sdim MemoryBufferMMapFile(bool RequiresNullTerminator, int FD, uint64_t Len, 200249423Sdim uint64_t Offset, error_code EC) 201249423Sdim : MFR(FD, false, sys::fs::mapped_file_region::readonly, 202249423Sdim getLegalMapSize(Len, Offset), getLegalMapOffset(Offset), EC) { 203249423Sdim if (!EC) { 204249423Sdim const char *Start = getStart(Len, Offset); 205249423Sdim init(Start, Start + Len, RequiresNullTerminator); 206249423Sdim } 207249423Sdim } 208249423Sdim 209249423Sdim virtual const char *getBufferIdentifier() const LLVM_OVERRIDE { 210249423Sdim // The name is stored after the class itself. 211249423Sdim return reinterpret_cast<const char *>(this + 1); 212249423Sdim } 213249423Sdim 214243830Sdim virtual BufferKind getBufferKind() const LLVM_OVERRIDE { 215221345Sdim return MemoryBuffer_MMap; 216221345Sdim } 217193323Sed}; 218193323Sed} 219193323Sed 220263508Sdimstatic error_code getMemoryBufferForStream(int FD, 221243830Sdim StringRef BufferName, 222243830Sdim OwningPtr<MemoryBuffer> &result) { 223243830Sdim const ssize_t ChunkSize = 4096*4; 224243830Sdim SmallString<ChunkSize> Buffer; 225243830Sdim ssize_t ReadBytes; 226243830Sdim // Read into Buffer until we hit EOF. 227243830Sdim do { 228243830Sdim Buffer.reserve(Buffer.size() + ChunkSize); 229243830Sdim ReadBytes = read(FD, Buffer.end(), ChunkSize); 230243830Sdim if (ReadBytes == -1) { 231243830Sdim if (errno == EINTR) continue; 232243830Sdim return error_code(errno, posix_category()); 233243830Sdim } 234243830Sdim Buffer.set_size(Buffer.size() + ReadBytes); 235243830Sdim } while (ReadBytes != 0); 236243830Sdim 237243830Sdim result.reset(MemoryBuffer::getMemBufferCopy(Buffer, BufferName)); 238243830Sdim return error_code::success(); 239243830Sdim} 240243830Sdim 241263508Sdimstatic error_code getFileAux(const char *Filename, 242263508Sdim OwningPtr<MemoryBuffer> &result, int64_t FileSize, 243263508Sdim bool RequiresNullTerminator); 244263508Sdim 245263508Sdimerror_code MemoryBuffer::getFile(Twine Filename, 246218893Sdim OwningPtr<MemoryBuffer> &result, 247221345Sdim int64_t FileSize, 248221345Sdim bool RequiresNullTerminator) { 249218893Sdim // Ensure the path is null terminated. 250263508Sdim SmallString<256> PathBuf; 251263508Sdim StringRef NullTerminatedName = Filename.toNullTerminatedStringRef(PathBuf); 252263508Sdim return getFileAux(NullTerminatedName.data(), result, FileSize, 253263508Sdim RequiresNullTerminator); 254210299Sed} 255210299Sed 256263508Sdimstatic error_code getOpenFileImpl(int FD, const char *Filename, 257263508Sdim OwningPtr<MemoryBuffer> &Result, 258263508Sdim uint64_t FileSize, uint64_t MapSize, 259263508Sdim int64_t Offset, bool RequiresNullTerminator); 260239462Sdim 261263508Sdimstatic error_code getFileAux(const char *Filename, 262263508Sdim OwningPtr<MemoryBuffer> &result, int64_t FileSize, 263263508Sdim bool RequiresNullTerminator) { 264263508Sdim int FD; 265263508Sdim error_code EC = sys::fs::openFileForRead(Filename, FD); 266263508Sdim if (EC) 267263508Sdim return EC; 268223017Sdim 269263508Sdim error_code ret = getOpenFileImpl(FD, Filename, result, FileSize, FileSize, 0, 270263508Sdim RequiresNullTerminator); 271218893Sdim close(FD); 272218893Sdim return ret; 273218893Sdim} 274218893Sdim 275221345Sdimstatic bool shouldUseMmap(int FD, 276221345Sdim size_t FileSize, 277221345Sdim size_t MapSize, 278221345Sdim off_t Offset, 279221345Sdim bool RequiresNullTerminator, 280221345Sdim int PageSize) { 281221345Sdim // We don't use mmap for small files because this can severely fragment our 282221345Sdim // address space. 283263508Sdim if (MapSize < 4 * 4096 || MapSize < (unsigned)PageSize) 284221345Sdim return false; 285221345Sdim 286221345Sdim if (!RequiresNullTerminator) 287221345Sdim return true; 288221345Sdim 289221345Sdim 290193323Sed // If we don't know the file size, use fstat to find out. fstat on an open 291193323Sed // file descriptor is cheaper than stat on a random path. 292221345Sdim // FIXME: this chunk of code is duplicated, but it avoids a fstat when 293221345Sdim // RequiresNullTerminator = false and MapSize != -1. 294221345Sdim if (FileSize == size_t(-1)) { 295263508Sdim sys::fs::file_status Status; 296263508Sdim error_code EC = sys::fs::status(FD, Status); 297263508Sdim if (EC) 298263508Sdim return EC; 299263508Sdim FileSize = Status.getSize(); 300193323Sed } 301218893Sdim 302221345Sdim // If we need a null terminator and the end of the map is inside the file, 303221345Sdim // we cannot use mmap. 304221345Sdim size_t End = Offset + MapSize; 305221345Sdim assert(End <= FileSize); 306221345Sdim if (End != FileSize) 307221345Sdim return false; 308218893Sdim 309263508Sdim#if defined(_WIN32) || defined(__CYGWIN__) 310263508Sdim // Don't peek the next page if file is multiple of *physical* pagesize(4k) 311263508Sdim // but is not multiple of AllocationGranularity(64k), 312263508Sdim // when a null terminator is required. 313263508Sdim // FIXME: It's not good to hardcode 4096 here. dwPageSize shows 4096. 314263508Sdim if ((FileSize & (4096 - 1)) == 0) 315263508Sdim return false; 316263508Sdim#endif 317263508Sdim 318221345Sdim // Don't try to map files that are exactly a multiple of the system page size 319221345Sdim // if we need a null terminator. 320221345Sdim if ((FileSize & (PageSize -1)) == 0) 321221345Sdim return false; 322221345Sdim 323221345Sdim return true; 324221345Sdim} 325221345Sdim 326263508Sdimstatic error_code getOpenFileImpl(int FD, const char *Filename, 327263508Sdim OwningPtr<MemoryBuffer> &result, 328263508Sdim uint64_t FileSize, uint64_t MapSize, 329263508Sdim int64_t Offset, bool RequiresNullTerminator) { 330249423Sdim static int PageSize = sys::process::get_self()->page_size(); 331221345Sdim 332221345Sdim // Default is to map the full file. 333226633Sdim if (MapSize == uint64_t(-1)) { 334221345Sdim // If we don't know the file size, use fstat to find out. fstat on an open 335221345Sdim // file descriptor is cheaper than stat on a random path. 336226633Sdim if (FileSize == uint64_t(-1)) { 337263508Sdim sys::fs::file_status Status; 338263508Sdim error_code EC = sys::fs::status(FD, Status); 339263508Sdim if (EC) 340263508Sdim return EC; 341243830Sdim 342249423Sdim // If this not a file or a block device (e.g. it's a named pipe 343249423Sdim // or character device), we can't trust the size. Create the memory 344243830Sdim // buffer by copying off the stream. 345263508Sdim sys::fs::file_type Type = Status.type(); 346263508Sdim if (Type != sys::fs::file_type::regular_file && 347263508Sdim Type != sys::fs::file_type::block_file) 348243830Sdim return getMemoryBufferForStream(FD, Filename, result); 349243830Sdim 350263508Sdim FileSize = Status.getSize(); 351221345Sdim } 352221345Sdim MapSize = FileSize; 353221345Sdim } 354221345Sdim 355221345Sdim if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator, 356221345Sdim PageSize)) { 357249423Sdim error_code EC; 358249423Sdim result.reset(new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile( 359249423Sdim RequiresNullTerminator, FD, MapSize, Offset, EC)); 360249423Sdim if (!EC) 361234353Sdim return error_code::success(); 362193323Sed } 363193323Sed 364221345Sdim MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(MapSize, Filename); 365193323Sed if (!Buf) { 366218893Sdim // Failed to create a buffer. The only way it can fail is if 367218893Sdim // new(std::nothrow) returns 0. 368218893Sdim return make_error_code(errc::not_enough_memory); 369193323Sed } 370193323Sed 371193323Sed OwningPtr<MemoryBuffer> SB(Buf); 372193323Sed char *BufPtr = const_cast<char*>(SB->getBufferStart()); 373206083Srdivacky 374221345Sdim size_t BytesLeft = MapSize; 375234353Sdim#ifndef HAVE_PREAD 376221345Sdim if (lseek(FD, Offset, SEEK_SET) == -1) 377221345Sdim return error_code(errno, posix_category()); 378234353Sdim#endif 379221345Sdim 380193323Sed while (BytesLeft) { 381234353Sdim#ifdef HAVE_PREAD 382234353Sdim ssize_t NumRead = ::pread(FD, BufPtr, BytesLeft, MapSize-BytesLeft+Offset); 383234353Sdim#else 384193323Sed ssize_t NumRead = ::read(FD, BufPtr, BytesLeft); 385234353Sdim#endif 386206083Srdivacky if (NumRead == -1) { 387206083Srdivacky if (errno == EINTR) 388206083Srdivacky continue; 389206083Srdivacky // Error while reading. 390218893Sdim return error_code(errno, posix_category()); 391193323Sed } 392234353Sdim if (NumRead == 0) { 393234353Sdim assert(0 && "We got inaccurate FileSize value or fstat reported an " 394234353Sdim "invalid file size."); 395234353Sdim *BufPtr = '\0'; // null-terminate at the actual size. 396234353Sdim break; 397234353Sdim } 398206083Srdivacky BytesLeft -= NumRead; 399206083Srdivacky BufPtr += NumRead; 400193323Sed } 401206083Srdivacky 402218893Sdim result.swap(SB); 403234353Sdim return error_code::success(); 404193323Sed} 405193323Sed 406263508Sdimerror_code MemoryBuffer::getOpenFile(int FD, const char *Filename, 407263508Sdim OwningPtr<MemoryBuffer> &Result, 408263508Sdim uint64_t FileSize, 409263508Sdim bool RequiresNullTerminator) { 410263508Sdim return getOpenFileImpl(FD, Filename, Result, FileSize, FileSize, 0, 411263508Sdim RequiresNullTerminator); 412263508Sdim} 413263508Sdim 414263508Sdimerror_code MemoryBuffer::getOpenFileSlice(int FD, const char *Filename, 415263508Sdim OwningPtr<MemoryBuffer> &Result, 416263508Sdim uint64_t MapSize, int64_t Offset) { 417263508Sdim return getOpenFileImpl(FD, Filename, Result, -1, MapSize, Offset, false); 418263508Sdim} 419263508Sdim 420193323Sed//===----------------------------------------------------------------------===// 421193323Sed// MemoryBuffer::getSTDIN implementation. 422193323Sed//===----------------------------------------------------------------------===// 423193323Sed 424218893Sdimerror_code MemoryBuffer::getSTDIN(OwningPtr<MemoryBuffer> &result) { 425193323Sed // Read in all of the data from stdin, we cannot mmap stdin. 426199481Srdivacky // 427199481Srdivacky // FIXME: That isn't necessarily true, we should try to mmap stdin and 428199481Srdivacky // fallback if it fails. 429263508Sdim sys::ChangeStdinToBinary(); 430210299Sed 431243830Sdim return getMemoryBufferForStream(0, "<stdin>", result); 432193323Sed} 433