diff options
author | Dimitry Andric <dim@FreeBSD.org> | 2019-12-20 19:53:05 +0000 |
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committer | Dimitry Andric <dim@FreeBSD.org> | 2019-12-20 19:53:05 +0000 |
commit | 0b57cec536236d46e3dba9bd041533462f33dbb7 (patch) | |
tree | 56229dbdbbf76d18580f72f789003db17246c8d9 /contrib/llvm/lib/Support/MemoryBuffer.cpp | |
parent | 718ef55ec7785aae63f98f8ca05dc07ed399c16d (diff) |
Notes
Diffstat (limited to 'contrib/llvm/lib/Support/MemoryBuffer.cpp')
-rw-r--r-- | contrib/llvm/lib/Support/MemoryBuffer.cpp | 510 |
1 files changed, 0 insertions, 510 deletions
diff --git a/contrib/llvm/lib/Support/MemoryBuffer.cpp b/contrib/llvm/lib/Support/MemoryBuffer.cpp deleted file mode 100644 index d0e5bb154c1a..000000000000 --- a/contrib/llvm/lib/Support/MemoryBuffer.cpp +++ /dev/null @@ -1,510 +0,0 @@ -//===--- MemoryBuffer.cpp - Memory Buffer implementation ------------------===// -// -// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. -// See https://llvm.org/LICENSE.txt for license information. -// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception -// -//===----------------------------------------------------------------------===// -// -// This file implements the MemoryBuffer interface. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Support/MemoryBuffer.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/SmallVectorMemoryBuffer.h" -#include <cassert> -#include <cerrno> -#include <cstring> -#include <new> -#include <sys/types.h> -#include <system_error> -#if !defined(_MSC_VER) && !defined(__MINGW32__) -#include <unistd.h> -#else -#include <io.h> -#endif -using namespace llvm; - -//===----------------------------------------------------------------------===// -// MemoryBuffer implementation itself. -//===----------------------------------------------------------------------===// - -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, - bool RequiresNullTerminator) { - assert((!RequiresNullTerminator || BufEnd[0] == 0) && - "Buffer is not null terminated!"); - BufferStart = BufStart; - BufferEnd = BufEnd; -} - -//===----------------------------------------------------------------------===// -// MemoryBufferMem implementation. -//===----------------------------------------------------------------------===// - -/// CopyStringRef - Copies contents of a StringRef into a block of memory and -/// null-terminates it. -static void CopyStringRef(char *Memory, StringRef Data) { - if (!Data.empty()) - memcpy(Memory, Data.data(), Data.size()); - Memory[Data.size()] = 0; // Null terminate string. -} - -namespace { -struct NamedBufferAlloc { - const Twine &Name; - NamedBufferAlloc(const Twine &Name) : Name(Name) {} -}; -} - -void *operator new(size_t N, const NamedBufferAlloc &Alloc) { - SmallString<256> NameBuf; - StringRef NameRef = Alloc.Name.toStringRef(NameBuf); - - char *Mem = static_cast<char *>(operator new(N + NameRef.size() + 1)); - CopyStringRef(Mem + N, NameRef); - return Mem; -} - -namespace { -/// MemoryBufferMem - Named MemoryBuffer pointing to a block of memory. -template<typename MB> -class MemoryBufferMem : public MB { -public: - MemoryBufferMem(StringRef InputData, bool RequiresNullTerminator) { - MemoryBuffer::init(InputData.begin(), InputData.end(), - RequiresNullTerminator); - } - - /// Disable sized deallocation for MemoryBufferMem, because it has - /// tail-allocated data. - void operator delete(void *p) { ::operator delete(p); } - - StringRef getBufferIdentifier() const override { - // The name is stored after the class itself. - return StringRef(reinterpret_cast<const char *>(this + 1)); - } - - MemoryBuffer::BufferKind getBufferKind() const override { - return MemoryBuffer::MemoryBuffer_Malloc; - } -}; -} - -template <typename MB> -static ErrorOr<std::unique_ptr<MB>> -getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, - uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile); - -std::unique_ptr<MemoryBuffer> -MemoryBuffer::getMemBuffer(StringRef InputData, StringRef BufferName, - bool RequiresNullTerminator) { - auto *Ret = new (NamedBufferAlloc(BufferName)) - MemoryBufferMem<MemoryBuffer>(InputData, RequiresNullTerminator); - return std::unique_ptr<MemoryBuffer>(Ret); -} - -std::unique_ptr<MemoryBuffer> -MemoryBuffer::getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator) { - return std::unique_ptr<MemoryBuffer>(getMemBuffer( - Ref.getBuffer(), Ref.getBufferIdentifier(), RequiresNullTerminator)); -} - -static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> -getMemBufferCopyImpl(StringRef InputData, const Twine &BufferName) { - auto Buf = WritableMemoryBuffer::getNewUninitMemBuffer(InputData.size(), BufferName); - if (!Buf) - return make_error_code(errc::not_enough_memory); - memcpy(Buf->getBufferStart(), InputData.data(), InputData.size()); - return std::move(Buf); -} - -std::unique_ptr<MemoryBuffer> -MemoryBuffer::getMemBufferCopy(StringRef InputData, const Twine &BufferName) { - auto Buf = getMemBufferCopyImpl(InputData, BufferName); - if (Buf) - return std::move(*Buf); - return nullptr; -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getFileOrSTDIN(const Twine &Filename, int64_t FileSize, - bool RequiresNullTerminator) { - SmallString<256> NameBuf; - StringRef NameRef = Filename.toStringRef(NameBuf); - - if (NameRef == "-") - return getSTDIN(); - return getFile(Filename, FileSize, RequiresNullTerminator); -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getFileSlice(const Twine &FilePath, uint64_t MapSize, - uint64_t Offset, bool IsVolatile) { - return getFileAux<MemoryBuffer>(FilePath, -1, MapSize, Offset, false, - IsVolatile); -} - -//===----------------------------------------------------------------------===// -// MemoryBuffer::getFile implementation. -//===----------------------------------------------------------------------===// - -namespace { -/// Memory maps a file descriptor using sys::fs::mapped_file_region. -/// -/// This handles converting the offset into a legal offset on the platform. -template<typename MB> -class MemoryBufferMMapFile : public MB { - 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 RequiresNullTerminator, sys::fs::file_t FD, uint64_t Len, - uint64_t Offset, std::error_code &EC) - : MFR(FD, MB::Mapmode, getLegalMapSize(Len, Offset), - getLegalMapOffset(Offset), EC) { - if (!EC) { - const char *Start = getStart(Len, Offset); - MemoryBuffer::init(Start, Start + Len, RequiresNullTerminator); - } - } - - /// Disable sized deallocation for MemoryBufferMMapFile, because it has - /// tail-allocated data. - void operator delete(void *p) { ::operator delete(p); } - - StringRef getBufferIdentifier() const override { - // The name is stored after the class itself. - return StringRef(reinterpret_cast<const char *>(this + 1)); - } - - MemoryBuffer::BufferKind getBufferKind() const override { - return MemoryBuffer::MemoryBuffer_MMap; - } -}; -} - -static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> -getMemoryBufferForStream(sys::fs::file_t FD, const Twine &BufferName) { - const ssize_t ChunkSize = 4096*4; - SmallString<ChunkSize> Buffer; - size_t ReadBytes; - // Read into Buffer until we hit EOF. - do { - Buffer.reserve(Buffer.size() + ChunkSize); - if (auto EC = sys::fs::readNativeFile( - FD, makeMutableArrayRef(Buffer.end(), ChunkSize), &ReadBytes)) - return EC; - Buffer.set_size(Buffer.size() + ReadBytes); - } while (ReadBytes != 0); - - return getMemBufferCopyImpl(Buffer, BufferName); -} - - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getFile(const Twine &Filename, int64_t FileSize, - bool RequiresNullTerminator, bool IsVolatile) { - return getFileAux<MemoryBuffer>(Filename, FileSize, FileSize, 0, - RequiresNullTerminator, IsVolatile); -} - -template <typename MB> -static ErrorOr<std::unique_ptr<MB>> -getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, - uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, - bool IsVolatile); - -template <typename MB> -static ErrorOr<std::unique_ptr<MB>> -getFileAux(const Twine &Filename, int64_t FileSize, uint64_t MapSize, - uint64_t Offset, bool RequiresNullTerminator, bool IsVolatile) { - Expected<sys::fs::file_t> FDOrErr = - sys::fs::openNativeFileForRead(Filename, sys::fs::OF_None); - if (!FDOrErr) - return errorToErrorCode(FDOrErr.takeError()); - sys::fs::file_t FD = *FDOrErr; - auto Ret = getOpenFileImpl<MB>(FD, Filename, FileSize, MapSize, Offset, - RequiresNullTerminator, IsVolatile); - sys::fs::closeFile(FD); - return Ret; -} - -ErrorOr<std::unique_ptr<WritableMemoryBuffer>> -WritableMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize, - bool IsVolatile) { - return getFileAux<WritableMemoryBuffer>(Filename, FileSize, FileSize, 0, - /*RequiresNullTerminator*/ false, - IsVolatile); -} - -ErrorOr<std::unique_ptr<WritableMemoryBuffer>> -WritableMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize, - uint64_t Offset, bool IsVolatile) { - return getFileAux<WritableMemoryBuffer>(Filename, -1, MapSize, Offset, false, - IsVolatile); -} - -std::unique_ptr<WritableMemoryBuffer> -WritableMemoryBuffer::getNewUninitMemBuffer(size_t Size, const Twine &BufferName) { - using MemBuffer = MemoryBufferMem<WritableMemoryBuffer>; - // 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. - SmallString<256> NameBuf; - StringRef NameRef = BufferName.toStringRef(NameBuf); - size_t AlignedStringLen = alignTo(sizeof(MemBuffer) + NameRef.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(MemBuffer), NameRef); - - // The buffer begins after the name and must be aligned. - char *Buf = Mem + AlignedStringLen; - Buf[Size] = 0; // Null terminate buffer. - - auto *Ret = new (Mem) MemBuffer(StringRef(Buf, Size), true); - return std::unique_ptr<WritableMemoryBuffer>(Ret); -} - -std::unique_ptr<WritableMemoryBuffer> -WritableMemoryBuffer::getNewMemBuffer(size_t Size, const Twine &BufferName) { - auto SB = WritableMemoryBuffer::getNewUninitMemBuffer(Size, BufferName); - if (!SB) - return nullptr; - memset(SB->getBufferStart(), 0, Size); - return SB; -} - -static bool shouldUseMmap(sys::fs::file_t FD, - size_t FileSize, - size_t MapSize, - off_t Offset, - bool RequiresNullTerminator, - int PageSize, - bool IsVolatile) { - // 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 (IsVolatile) - 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; - - // 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(); - } - - // 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; - -#if defined(__CYGWIN__) - // Don't try to map files that are exactly a multiple of the physical page size - // if we need a null terminator. - // FIXME: We should reorganize again getPageSize() on Win32. - if ((FileSize & (4096 - 1)) == 0) - return false; -#endif - - return true; -} - -static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> -getReadWriteFile(const Twine &Filename, uint64_t FileSize, uint64_t MapSize, - uint64_t Offset) { - Expected<sys::fs::file_t> FDOrErr = sys::fs::openNativeFileForReadWrite( - Filename, sys::fs::CD_OpenExisting, sys::fs::OF_None); - if (!FDOrErr) - return errorToErrorCode(FDOrErr.takeError()); - sys::fs::file_t FD = *FDOrErr; - - // 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; - std::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 mmap it, so error out. - sys::fs::file_type Type = Status.type(); - if (Type != sys::fs::file_type::regular_file && - Type != sys::fs::file_type::block_file) - return make_error_code(errc::invalid_argument); - - FileSize = Status.getSize(); - } - MapSize = FileSize; - } - - std::error_code EC; - std::unique_ptr<WriteThroughMemoryBuffer> Result( - new (NamedBufferAlloc(Filename)) - MemoryBufferMMapFile<WriteThroughMemoryBuffer>(false, FD, MapSize, - Offset, EC)); - if (EC) - return EC; - return std::move(Result); -} - -ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> -WriteThroughMemoryBuffer::getFile(const Twine &Filename, int64_t FileSize) { - return getReadWriteFile(Filename, FileSize, FileSize, 0); -} - -/// Map a subrange of the specified file as a WritableMemoryBuffer. -ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> -WriteThroughMemoryBuffer::getFileSlice(const Twine &Filename, uint64_t MapSize, - uint64_t Offset) { - return getReadWriteFile(Filename, -1, MapSize, Offset); -} - -template <typename MB> -static ErrorOr<std::unique_ptr<MB>> -getOpenFileImpl(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, - uint64_t MapSize, int64_t Offset, bool RequiresNullTerminator, - bool IsVolatile) { - static int PageSize = sys::Process::getPageSizeEstimate(); - - // 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; - std::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); - - FileSize = Status.getSize(); - } - MapSize = FileSize; - } - - if (shouldUseMmap(FD, FileSize, MapSize, Offset, RequiresNullTerminator, - PageSize, IsVolatile)) { - std::error_code EC; - std::unique_ptr<MB> Result( - new (NamedBufferAlloc(Filename)) MemoryBufferMMapFile<MB>( - RequiresNullTerminator, FD, MapSize, Offset, EC)); - if (!EC) - return std::move(Result); - } - - auto Buf = WritableMemoryBuffer::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(errc::not_enough_memory); - } - - sys::fs::readNativeFileSlice(FD, Buf->getBuffer(), Offset); - - return std::move(Buf); -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getOpenFile(sys::fs::file_t FD, const Twine &Filename, uint64_t FileSize, - bool RequiresNullTerminator, bool IsVolatile) { - return getOpenFileImpl<MemoryBuffer>(FD, Filename, FileSize, FileSize, 0, - RequiresNullTerminator, IsVolatile); -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getOpenFileSlice(sys::fs::file_t FD, const Twine &Filename, uint64_t MapSize, - int64_t Offset, bool IsVolatile) { - assert(MapSize != uint64_t(-1)); - return getOpenFileImpl<MemoryBuffer>(FD, Filename, -1, MapSize, Offset, false, - IsVolatile); -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> 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::ChangeStdinToBinary(); - - return getMemoryBufferForStream(sys::fs::getStdinHandle(), "<stdin>"); -} - -ErrorOr<std::unique_ptr<MemoryBuffer>> -MemoryBuffer::getFileAsStream(const Twine &Filename) { - Expected<sys::fs::file_t> FDOrErr = - sys::fs::openNativeFileForRead(Filename, sys::fs::OF_None); - if (!FDOrErr) - return errorToErrorCode(FDOrErr.takeError()); - sys::fs::file_t FD = *FDOrErr; - ErrorOr<std::unique_ptr<MemoryBuffer>> Ret = - getMemoryBufferForStream(FD, Filename); - sys::fs::closeFile(FD); - return Ret; -} - -MemoryBufferRef MemoryBuffer::getMemBufferRef() const { - StringRef Data = getBuffer(); - StringRef Identifier = getBufferIdentifier(); - return MemoryBufferRef(Data, Identifier); -} - -SmallVectorMemoryBuffer::~SmallVectorMemoryBuffer() {} |