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https://github.com/c64scene-ar/llvm-6502.git
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d4d1f85aa7
buffer in the same chunk of memory. 2 less mallocs for every uninitialized MemoryBuffer and 1 less malloc for every MemoryBuffer pointing to a memory range translate into 20% less mallocs on clang -cc1 -Eonly Cocoa_h.m. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106839 91177308-0d34-0410-b5e6-96231b3b80d8
118 lines
5.0 KiB
C++
118 lines
5.0 KiB
C++
//===--- MemoryBuffer.h - Memory Buffer Interface ---------------*- C++ -*-===//
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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 defines the MemoryBuffer interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_MEMORYBUFFER_H
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#define LLVM_SUPPORT_MEMORYBUFFER_H
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#include "llvm/ADT/StringRef.h"
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#include "llvm/System/DataTypes.h"
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#include <string>
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#include <sys/stat.h>
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namespace llvm {
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/// MemoryBuffer - This interface provides simple read-only access to a block
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/// of memory, and provides simple methods for reading files and standard input
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/// into a memory buffer. In addition to basic access to the characters in the
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/// file, this interface guarantees you can read one character past the end of
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/// the file, and that this character will read as '\0'.
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///
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/// The '\0' guarantee is needed to support an optimization -- it's intended to
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/// be more efficient for clients which are reading all the data to stop
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/// reading when they encounter a '\0' than to continually check the file
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/// position to see if it has reached the end of the file.
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class MemoryBuffer {
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const char *BufferStart; // Start of the buffer.
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const char *BufferEnd; // End of the buffer.
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MemoryBuffer(const MemoryBuffer &); // DO NOT IMPLEMENT
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MemoryBuffer &operator=(const MemoryBuffer &); // DO NOT IMPLEMENT
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protected:
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MemoryBuffer() {}
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void init(const char *BufStart, const char *BufEnd);
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public:
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virtual ~MemoryBuffer();
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const char *getBufferStart() const { return BufferStart; }
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const char *getBufferEnd() const { return BufferEnd; }
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size_t getBufferSize() const { return BufferEnd-BufferStart; }
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StringRef getBuffer() const {
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return StringRef(BufferStart, getBufferSize());
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}
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/// getBufferIdentifier - Return an identifier for this buffer, typically the
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/// filename it was read from.
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virtual const char *getBufferIdentifier() const {
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return "Unknown buffer";
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}
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/// getFile - Open the specified file as a MemoryBuffer, returning a new
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/// MemoryBuffer if successful, otherwise returning null. If FileSize is
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/// specified, this means that the client knows that the file exists and that
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/// it has the specified size.
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static MemoryBuffer *getFile(StringRef Filename,
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std::string *ErrStr = 0,
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int64_t FileSize = -1,
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struct stat *FileInfo = 0);
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static MemoryBuffer *getFile(const char *Filename,
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std::string *ErrStr = 0,
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int64_t FileSize = -1,
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struct stat *FileInfo = 0);
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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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static MemoryBuffer *getMemBuffer(StringRef InputData,
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StringRef BufferName = "");
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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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static MemoryBuffer *getMemBufferCopy(StringRef InputData,
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StringRef BufferName = "");
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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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static MemoryBuffer *getNewMemBuffer(size_t Size, StringRef BufferName = "");
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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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static MemoryBuffer *getNewUninitMemBuffer(size_t Size,
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StringRef BufferName = "");
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/// getSTDIN - Read all of stdin into a file buffer, and return it.
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/// If an error occurs, this returns null and fills in *ErrStr with a reason.
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static MemoryBuffer *getSTDIN(std::string *ErrStr = 0);
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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.
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static MemoryBuffer *getFileOrSTDIN(StringRef Filename,
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std::string *ErrStr = 0,
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int64_t FileSize = -1,
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struct stat *FileInfo = 0);
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static MemoryBuffer *getFileOrSTDIN(const char *Filename,
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std::string *ErrStr = 0,
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int64_t FileSize = -1,
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struct stat *FileInfo = 0);
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};
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} // end namespace llvm
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#endif
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