X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FMemoryBuffer.cpp;h=5f4b7daae53d162affc9dd71d9cccaba140b4312;hb=03ac7db89d5df4cb7bb63cf53ba299d8cb3459c9;hp=cb587d59c9291adb8fc1228525303bdc6167ce40;hpb=d04a8d4b33ff316ca4cf961e06c9e312eff8e64f;p=oota-llvm.git diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp index cb587d59c92..5f4b7daae53 100644 --- a/lib/Support/MemoryBuffer.cpp +++ b/lib/Support/MemoryBuffer.cpp @@ -12,32 +12,27 @@ //===----------------------------------------------------------------------===// #include "llvm/Support/MemoryBuffer.h" -#include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/SmallString.h" #include "llvm/Config/config.h" +#include "llvm/Support/Errc.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 #include #include #include #include -#include #include +#include #if !defined(_MSC_VER) && !defined(__MINGW32__) #include #else #include -#ifndef S_ISFIFO -#define S_ISFIFO(x) (0) #endif -#endif -#include using namespace llvm; //===----------------------------------------------------------------------===// @@ -67,13 +62,17 @@ static void CopyStringRef(char *Memory, StringRef Data) { Memory[Data.size()] = 0; // Null terminate string. } -/// GetNamedBuffer - Allocates a new MemoryBuffer with Name copied after it. -template -static T *GetNamedBuffer(StringRef Buffer, StringRef Name, - bool RequiresNullTerminator) { - char *Mem = static_cast(operator new(sizeof(T) + Name.size() + 1)); - CopyStringRef(Mem + sizeof(T), Name); - return new (Mem) T(Buffer, RequiresNullTerminator); +namespace { +struct NamedBufferAlloc { + StringRef Name; + NamedBufferAlloc(StringRef Name) : Name(Name) {} +}; +} + +void *operator new(size_t N, const NamedBufferAlloc &Alloc) { + char *Mem = static_cast(operator new(N + Alloc.Name.size() + 1)); + CopyStringRef(Mem + N, Alloc.Name); + return Mem; } namespace { @@ -84,12 +83,12 @@ public: init(InputData.begin(), InputData.end(), RequiresNullTerminator); } - virtual const char *getBufferIdentifier() const LLVM_OVERRIDE { + const char *getBufferIdentifier() const override { // The name is stored after the class itself. return reinterpret_cast(this + 1); } - virtual BufferKind getBufferKind() const LLVM_OVERRIDE { + BufferKind getBufferKind() const override { return MemoryBuffer_Malloc; } }; @@ -100,8 +99,8 @@ public: MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData, StringRef BufferName, bool RequiresNullTerminator) { - return GetNamedBuffer(InputData, BufferName, - RequiresNullTerminator); + return new (NamedBufferAlloc(BufferName)) + MemoryBufferMem(InputData, RequiresNullTerminator); } /// getMemBufferCopy - Open the specified memory range as a MemoryBuffer, @@ -110,7 +109,7 @@ MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData, MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData, StringRef BufferName) { MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName); - if (!Buf) return 0; + if (!Buf) return nullptr; memcpy(const_cast(Buf->getBufferStart()), InputData.data(), InputData.size()); return Buf; @@ -124,12 +123,13 @@ 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, - sizeof(void*)); // TODO: Is sizeof(void*) enough? + RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1, 16); size_t RealLen = AlignedStringLen + Size + 1; char *Mem = static_cast(operator new(RealLen, std::nothrow)); - if (!Mem) return 0; + if (!Mem) return nullptr; // The name is stored after the class itself. CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName); @@ -147,66 +147,66 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size, /// the MemoryBuffer object. MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) { MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName); - if (!SB) return 0; + if (!SB) return nullptr; memset(const_cast(SB->getBufferStart()), 0, Size); 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. -error_code MemoryBuffer::getFileOrSTDIN(StringRef Filename, - OwningPtr &result, - int64_t FileSize) { +ErrorOr> +MemoryBuffer::getFileOrSTDIN(StringRef Filename, int64_t FileSize) { if (Filename == "-") - return getSTDIN(result); - return getFile(Filename, result, FileSize); + return getSTDIN(); + return getFile(Filename, FileSize); } -error_code MemoryBuffer::getFileOrSTDIN(const char *Filename, - OwningPtr &result, - int64_t FileSize) { - if (strcmp(Filename, "-") == 0) - return getSTDIN(result); - return getFile(Filename, result, FileSize); -} //===----------------------------------------------------------------------===// // 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 MemoryBufferMem { -public: - MemoryBufferMMapFile(StringRef Buffer, bool RequiresNullTerminator) - : MemoryBufferMem(Buffer, RequiresNullTerminator) { } +/// \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::fs::mapped_file_region MFR; + + static uint64_t getLegalMapOffset(uint64_t Offset) { + return Offset & ~(sys::fs::mapped_file_region::alignment() - 1); + } - ~MemoryBufferMMapFile() { - static int PageSize = sys::Process::GetPageSize(); + static uint64_t getLegalMapSize(uint64_t Len, uint64_t Offset) { + return Len + (Offset - getLegalMapOffset(Offset)); + } - uintptr_t Start = reinterpret_cast(getBufferStart()); - size_t Size = getBufferSize(); - uintptr_t RealStart = Start & ~(PageSize - 1); - size_t RealSize = Size + (Start - RealStart); + const char *getStart(uint64_t Len, uint64_t Offset) { + return MFR.const_data() + (Offset - getLegalMapOffset(Offset)); + } - sys::Path::UnMapFilePages(reinterpret_cast(RealStart), - RealSize); +public: + MemoryBufferMMapFile(bool RequiresNullTerminator, int FD, uint64_t Len, + uint64_t Offset, std::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); + } } - virtual BufferKind getBufferKind() const LLVM_OVERRIDE { + const char *getBufferIdentifier() const override { + // The name is stored after the class itself. + return reinterpret_cast(this + 1); + } + + BufferKind getBufferKind() const override { return MemoryBuffer_MMap; } }; } -static error_code getMemoryBufferForStream(int FD, - StringRef BufferName, - OwningPtr &result) { +static ErrorOr> +getMemoryBufferForStream(int FD, StringRef BufferName) { const ssize_t ChunkSize = 4096*4; SmallString Buffer; ssize_t ReadBytes; @@ -216,49 +216,48 @@ static error_code getMemoryBufferForStream(int FD, ReadBytes = read(FD, Buffer.end(), ChunkSize); if (ReadBytes == -1) { if (errno == EINTR) continue; - return error_code(errno, posix_category()); + return std::error_code(errno, std::generic_category()); } Buffer.set_size(Buffer.size() + ReadBytes); } while (ReadBytes != 0); - result.reset(MemoryBuffer::getMemBufferCopy(Buffer, BufferName)); - return error_code::success(); + std::unique_ptr Ret( + MemoryBuffer::getMemBufferCopy(Buffer, BufferName)); + return std::move(Ret); } -error_code MemoryBuffer::getFile(StringRef Filename, - OwningPtr &result, - int64_t FileSize, - bool RequiresNullTerminator) { +static ErrorOr> +getFileAux(const char *Filename, int64_t FileSize, bool RequiresNullTerminator, + bool IsVolatileSize); + +ErrorOr> +MemoryBuffer::getFile(Twine Filename, int64_t FileSize, + bool RequiresNullTerminator, bool IsVolatileSize) { // Ensure the path is null terminated. - SmallString<256> PathBuf(Filename.begin(), Filename.end()); - return MemoryBuffer::getFile(PathBuf.c_str(), result, FileSize, - RequiresNullTerminator); + SmallString<256> PathBuf; + StringRef NullTerminatedName = Filename.toNullTerminatedStringRef(PathBuf); + return getFileAux(NullTerminatedName.data(), FileSize, RequiresNullTerminator, + IsVolatileSize); } -error_code MemoryBuffer::getFile(const char *Filename, - OwningPtr &result, - int64_t FileSize, - bool RequiresNullTerminator) { - // First check that the "file" is not a directory - bool is_dir = false; - error_code err = sys::fs::is_directory(Filename, is_dir); - if (err) - return err; - if (is_dir) - return make_error_code(errc::is_a_directory); - - int OpenFlags = O_RDONLY; -#ifdef O_BINARY - OpenFlags |= O_BINARY; // Open input file in binary mode on win32. -#endif - int FD = ::open(Filename, OpenFlags); - if (FD == -1) - return error_code(errno, posix_category()); - - error_code ret = getOpenFile(FD, Filename, result, FileSize, FileSize, - 0, RequiresNullTerminator); +static ErrorOr> +getOpenFileImpl(int FD, const char *Filename, uint64_t FileSize, + uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, + bool IsVolatileSize); + +static ErrorOr> +getFileAux(const char *Filename, int64_t FileSize, bool RequiresNullTerminator, + bool IsVolatileSize) { + int FD; + std::error_code EC = sys::fs::openFileForRead(Filename, FD); + if (EC) + return EC; + + ErrorOr> Ret = + getOpenFileImpl(FD, Filename, FileSize, FileSize, 0, + RequiresNullTerminator, IsVolatileSize); close(FD); - return ret; + return Ret; } static bool shouldUseMmap(int FD, @@ -266,10 +265,17 @@ static bool shouldUseMmap(int FD, size_t MapSize, off_t Offset, bool RequiresNullTerminator, - int PageSize) { + 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 < 4096*4) + if (MapSize < 4 * 4096 || MapSize < (unsigned)PageSize) return false; if (!RequiresNullTerminator) @@ -281,12 +287,10 @@ static bool shouldUseMmap(int FD, // FIXME: this chunk of code is duplicated, but it avoids a fstat when // RequiresNullTerminator = false and MapSize != -1. if (FileSize == size_t(-1)) { - struct stat FileInfo; - // TODO: This should use fstat64 when available. - if (fstat(FD, &FileInfo) == -1) { - return error_code(errno, posix_category()); - } - FileSize = FileInfo.st_size; + sys::fs::file_status Status; + if (sys::fs::status(FD, Status)) + return false; + FileSize = Status.getSize(); } // If we need a null terminator and the end of the map is inside the file, @@ -304,48 +308,43 @@ static bool shouldUseMmap(int FD, return true; } -error_code MemoryBuffer::getOpenFile(int FD, const char *Filename, - OwningPtr &result, - uint64_t FileSize, uint64_t MapSize, - int64_t Offset, - bool RequiresNullTerminator) { - static int PageSize = sys::Process::GetPageSize(); +static ErrorOr> +getOpenFileImpl(int FD, const char *Filename, uint64_t FileSize, + uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, + bool IsVolatileSize) { + static int PageSize = sys::process::get_self()->page_size(); // 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)) { - struct stat FileInfo; - // TODO: This should use fstat64 when available. - if (fstat(FD, &FileInfo) == -1) { - return error_code(errno, posix_category()); - } + sys::fs::file_status Status; + std::error_code EC = sys::fs::status(FD, Status); + if (EC) + return EC; - // If this is a named pipe, we can't trust the size. Create the memory + // 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. - if (S_ISFIFO(FileInfo.st_mode)) { - return getMemoryBufferForStream(FD, Filename, result); - } + 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); - FileSize = FileInfo.st_size; + FileSize = Status.getSize(); } MapSize = FileSize; } if (shouldUseMmap(FD, 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( - StringRef(Pages + Delta, MapSize), Filename, RequiresNullTerminator)); - return error_code::success(); - } + PageSize, IsVolatileSize)) { + std::error_code EC; + std::unique_ptr Result( + new (NamedBufferAlloc(Filename)) + MemoryBufferMMapFile(RequiresNullTerminator, FD, MapSize, Offset, EC)); + if (!EC) + return std::move(Result); } MemoryBuffer *Buf = MemoryBuffer::getNewUninitMemBuffer(MapSize, Filename); @@ -355,13 +354,13 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename, return make_error_code(errc::not_enough_memory); } - OwningPtr SB(Buf); + std::unique_ptr SB(Buf); char *BufPtr = const_cast(SB->getBufferStart()); size_t BytesLeft = MapSize; #ifndef HAVE_PREAD if (lseek(FD, Offset, SEEK_SET) == -1) - return error_code(errno, posix_category()); + return std::error_code(errno, std::generic_category()); #endif while (BytesLeft) { @@ -374,32 +373,39 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename, if (errno == EINTR) continue; // Error while reading. - return error_code(errno, posix_category()); + return std::error_code(errno, std::generic_category()); } if (NumRead == 0) { - assert(0 && "We got inaccurate FileSize value or fstat reported an " - "invalid file size."); - *BufPtr = '\0'; // null-terminate at the actual size. + memset(BufPtr, 0, BytesLeft); // zero-initialize rest of the buffer. break; } BytesLeft -= NumRead; BufPtr += NumRead; } - result.swap(SB); - return error_code::success(); + return std::move(SB); } -//===----------------------------------------------------------------------===// -// MemoryBuffer::getSTDIN implementation. -//===----------------------------------------------------------------------===// +ErrorOr> +MemoryBuffer::getOpenFile(int FD, const char *Filename, uint64_t FileSize, + bool RequiresNullTerminator, bool IsVolatileSize) { + return getOpenFileImpl(FD, Filename, FileSize, FileSize, 0, + RequiresNullTerminator, IsVolatileSize); +} + +ErrorOr> +MemoryBuffer::getOpenFileSlice(int FD, const char *Filename, uint64_t MapSize, + int64_t Offset, bool IsVolatileSize) { + return getOpenFileImpl(FD, Filename, -1, MapSize, Offset, false, + IsVolatileSize); +} -error_code MemoryBuffer::getSTDIN(OwningPtr &result) { +ErrorOr> MemoryBuffer::getSTDIN() { // 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(); + sys::ChangeStdinToBinary(); - return getMemoryBufferForStream(0, "", result); + return getMemoryBufferForStream(0, ""); }