diff options
| author | Stephen Hines <srhines@google.com> | 2019-07-02 16:25:20 -0700 |
|---|---|---|
| committer | Ali B <abittin@gmail.com> | 2019-07-05 19:33:16 +0300 |
| commit | 9afee4e65dc5f9f5eb371683729ff67b8df81d03 (patch) | |
| tree | 4cf241d6c9044f91ee8c06e6920174d06f8de0b6 /clang-r353983e/include/llvm/Support/MemoryBuffer.h | |
| parent | 2f19bd722c4c825320d1511c1ed83161b7f95d51 (diff) | |
clang 9.0.5 (based on r353983e) from build 5696680.
Bug: http://b/135931688
Bug: http://b/136008926
Test: N/A
Change-Id: I922d17410047d2e2df4625615352c588ee71b203
Diffstat (limited to 'clang-r353983e/include/llvm/Support/MemoryBuffer.h')
| -rw-r--r-- | clang-r353983e/include/llvm/Support/MemoryBuffer.h | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/clang-r353983e/include/llvm/Support/MemoryBuffer.h b/clang-r353983e/include/llvm/Support/MemoryBuffer.h new file mode 100644 index 00000000..44052697 --- /dev/null +++ b/clang-r353983e/include/llvm/Support/MemoryBuffer.h @@ -0,0 +1,286 @@ +//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===// +// +// 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 defines the MemoryBuffer interface. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_MEMORYBUFFER_H +#define LLVM_SUPPORT_MEMORYBUFFER_H + +#include "llvm-c/Types.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/Twine.h" +#include "llvm/Support/CBindingWrapping.h" +#include "llvm/Support/ErrorOr.h" +#include "llvm/Support/FileSystem.h" +#include <cstddef> +#include <cstdint> +#include <memory> + +namespace llvm { + +class MemoryBufferRef; + +/// This interface provides simple read-only access to a block of memory, and +/// provides simple methods for reading files and standard input into a memory +/// buffer. In addition to basic access to the characters in the file, this +/// interface guarantees you can read one character past the end of the file, +/// and that this character will read as '\0'. +/// +/// The '\0' guarantee is needed to support an optimization -- it's intended to +/// be more efficient for clients which are reading all the data to stop +/// reading when they encounter a '\0' than to continually check the file +/// position to see if it has reached the end of the file. +class MemoryBuffer { + const char *BufferStart; // Start of the buffer. + const char *BufferEnd; // End of the buffer. + +protected: + MemoryBuffer() = default; + + void init(const char *BufStart, const char *BufEnd, + bool RequiresNullTerminator); + + static constexpr sys::fs::mapped_file_region::mapmode Mapmode = + sys::fs::mapped_file_region::readonly; + +public: + MemoryBuffer(const MemoryBuffer &) = delete; + MemoryBuffer &operator=(const MemoryBuffer &) = delete; + virtual ~MemoryBuffer(); + + const char *getBufferStart() const { return BufferStart; } + const char *getBufferEnd() const { return BufferEnd; } + size_t getBufferSize() const { return BufferEnd-BufferStart; } + + StringRef getBuffer() const { + return StringRef(BufferStart, getBufferSize()); + } + + /// Return an identifier for this buffer, typically the filename it was read + /// from. + virtual StringRef getBufferIdentifier() const { return "Unknown buffer"; } + + /// Open the specified file as a MemoryBuffer, returning a new MemoryBuffer + /// if successful, otherwise returning null. If FileSize is specified, this + /// means that the client knows that the file exists and that it has the + /// specified size. + /// + /// \param IsVolatile Set to true to indicate that the contents of the file + /// can change outside the user's control, e.g. when libclang tries to parse + /// while the user is editing/updating the file or if the file is on an NFS. + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getFile(const Twine &Filename, int64_t FileSize = -1, + bool RequiresNullTerminator = true, bool IsVolatile = false); + + /// Read all of the specified file into a MemoryBuffer as a stream + /// (i.e. until EOF reached). This is useful for special files that + /// look like a regular file but have 0 size (e.g. /proc/cpuinfo on Linux). + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getFileAsStream(const Twine &Filename); + + /// Given an already-open file descriptor, map some slice of it into a + /// MemoryBuffer. The slice is specified by an \p Offset and \p MapSize. + /// Since this is in the middle of a file, the buffer is not null terminated. + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getOpenFileSlice(int FD, const Twine &Filename, uint64_t MapSize, + int64_t Offset, bool IsVolatile = false); + + /// Given an already-open file descriptor, read the file and return a + /// MemoryBuffer. + /// + /// \param IsVolatile Set to true to indicate that the contents of the file + /// can change outside the user's control, e.g. when libclang tries to parse + /// while the user is editing/updating the file or if the file is on an NFS. + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getOpenFile(int FD, const Twine &Filename, uint64_t FileSize, + bool RequiresNullTerminator = true, bool IsVolatile = false); + + /// Open the specified memory range as a MemoryBuffer. Note that InputData + /// must be null terminated if RequiresNullTerminator is true. + static std::unique_ptr<MemoryBuffer> + getMemBuffer(StringRef InputData, StringRef BufferName = "", + bool RequiresNullTerminator = true); + + static std::unique_ptr<MemoryBuffer> + getMemBuffer(MemoryBufferRef Ref, bool RequiresNullTerminator = true); + + /// Open the specified memory range as a MemoryBuffer, copying the contents + /// and taking ownership of it. InputData does not have to be null terminated. + static std::unique_ptr<MemoryBuffer> + getMemBufferCopy(StringRef InputData, const Twine &BufferName = ""); + + /// Read all of stdin into a file buffer, and return it. + static ErrorOr<std::unique_ptr<MemoryBuffer>> getSTDIN(); + + /// Open the specified file as a MemoryBuffer, or open stdin if the Filename + /// is "-". + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getFileOrSTDIN(const Twine &Filename, int64_t FileSize = -1, + bool RequiresNullTerminator = true); + + /// Map a subrange of the specified file as a MemoryBuffer. + static ErrorOr<std::unique_ptr<MemoryBuffer>> + getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset, + bool IsVolatile = false); + + //===--------------------------------------------------------------------===// + // Provided for performance analysis. + //===--------------------------------------------------------------------===// + + /// The kind of memory backing used to support the MemoryBuffer. + enum BufferKind { + MemoryBuffer_Malloc, + MemoryBuffer_MMap + }; + + /// Return information on the memory mechanism used to support the + /// MemoryBuffer. + virtual BufferKind getBufferKind() const = 0; + + MemoryBufferRef getMemBufferRef() const; +}; + +/// This class is an extension of MemoryBuffer, which allows copy-on-write +/// access to the underlying contents. It only supports creation methods that +/// are guaranteed to produce a writable buffer. For example, mapping a file +/// read-only is not supported. +class WritableMemoryBuffer : public MemoryBuffer { +protected: + WritableMemoryBuffer() = default; + + static constexpr sys::fs::mapped_file_region::mapmode Mapmode = + sys::fs::mapped_file_region::priv; + +public: + using MemoryBuffer::getBuffer; + using MemoryBuffer::getBufferEnd; + using MemoryBuffer::getBufferStart; + + // const_cast is well-defined here, because the underlying buffer is + // guaranteed to have been initialized with a mutable buffer. + char *getBufferStart() { + return const_cast<char *>(MemoryBuffer::getBufferStart()); + } + char *getBufferEnd() { + return const_cast<char *>(MemoryBuffer::getBufferEnd()); + } + MutableArrayRef<char> getBuffer() { + return {getBufferStart(), getBufferEnd()}; + } + + static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> + getFile(const Twine &Filename, int64_t FileSize = -1, + bool IsVolatile = false); + + /// Map a subrange of the specified file as a WritableMemoryBuffer. + static ErrorOr<std::unique_ptr<WritableMemoryBuffer>> + getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset, + bool IsVolatile = false); + + /// Allocate a new MemoryBuffer of the specified size that is not initialized. + /// Note that the caller should initialize the memory allocated by this + /// method. The memory is owned by the MemoryBuffer object. + static std::unique_ptr<WritableMemoryBuffer> + getNewUninitMemBuffer(size_t Size, const Twine &BufferName = ""); + + /// Allocate a new zero-initialized MemoryBuffer of the specified size. Note + /// that the caller need not initialize the memory allocated by this method. + /// The memory is owned by the MemoryBuffer object. + static std::unique_ptr<WritableMemoryBuffer> + getNewMemBuffer(size_t Size, const Twine &BufferName = ""); + +private: + // Hide these base class factory function so one can't write + // WritableMemoryBuffer::getXXX() + // and be surprised that he got a read-only Buffer. + using MemoryBuffer::getFileAsStream; + using MemoryBuffer::getFileOrSTDIN; + using MemoryBuffer::getMemBuffer; + using MemoryBuffer::getMemBufferCopy; + using MemoryBuffer::getOpenFile; + using MemoryBuffer::getOpenFileSlice; + using MemoryBuffer::getSTDIN; +}; + +/// This class is an extension of MemoryBuffer, which allows write access to +/// the underlying contents and committing those changes to the original source. +/// It only supports creation methods that are guaranteed to produce a writable +/// buffer. For example, mapping a file read-only is not supported. +class WriteThroughMemoryBuffer : public MemoryBuffer { +protected: + WriteThroughMemoryBuffer() = default; + + static constexpr sys::fs::mapped_file_region::mapmode Mapmode = + sys::fs::mapped_file_region::readwrite; + +public: + using MemoryBuffer::getBuffer; + using MemoryBuffer::getBufferEnd; + using MemoryBuffer::getBufferStart; + + // const_cast is well-defined here, because the underlying buffer is + // guaranteed to have been initialized with a mutable buffer. + char *getBufferStart() { + return const_cast<char *>(MemoryBuffer::getBufferStart()); + } + char *getBufferEnd() { + return const_cast<char *>(MemoryBuffer::getBufferEnd()); + } + MutableArrayRef<char> getBuffer() { + return {getBufferStart(), getBufferEnd()}; + } + + static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> + getFile(const Twine &Filename, int64_t FileSize = -1); + + /// Map a subrange of the specified file as a ReadWriteMemoryBuffer. + static ErrorOr<std::unique_ptr<WriteThroughMemoryBuffer>> + getFileSlice(const Twine &Filename, uint64_t MapSize, uint64_t Offset); + +private: + // Hide these base class factory function so one can't write + // WritableMemoryBuffer::getXXX() + // and be surprised that he got a read-only Buffer. + using MemoryBuffer::getFileAsStream; + using MemoryBuffer::getFileOrSTDIN; + using MemoryBuffer::getMemBuffer; + using MemoryBuffer::getMemBufferCopy; + using MemoryBuffer::getOpenFile; + using MemoryBuffer::getOpenFileSlice; + using MemoryBuffer::getSTDIN; +}; + +class MemoryBufferRef { + StringRef Buffer; + StringRef Identifier; + +public: + MemoryBufferRef() = default; + MemoryBufferRef(MemoryBuffer& Buffer) + : Buffer(Buffer.getBuffer()), Identifier(Buffer.getBufferIdentifier()) {} + MemoryBufferRef(StringRef Buffer, StringRef Identifier) + : Buffer(Buffer), Identifier(Identifier) {} + + StringRef getBuffer() const { return Buffer; } + + StringRef getBufferIdentifier() const { return Identifier; } + + const char *getBufferStart() const { return Buffer.begin(); } + const char *getBufferEnd() const { return Buffer.end(); } + size_t getBufferSize() const { return Buffer.size(); } +}; + +// Create wrappers for C Binding types (see CBindingWrapping.h). +DEFINE_SIMPLE_CONVERSION_FUNCTIONS(MemoryBuffer, LLVMMemoryBufferRef) + +} // end namespace llvm + +#endif // LLVM_SUPPORT_MEMORYBUFFER_H |
