ObjectBuffer.h revision 263508
1//===---- ObjectBuffer.h - Utility class to wrap object image memory -----===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file declares a wrapper class to hold the memory into which an 11// object will be generated. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_EXECUTIONENGINE_OBJECTBUFFER_H 16#define LLVM_EXECUTIONENGINE_OBJECTBUFFER_H 17 18#include "llvm/ADT/OwningPtr.h" 19#include "llvm/ADT/SmallVector.h" 20#include "llvm/Support/MemoryBuffer.h" 21#include "llvm/Support/raw_ostream.h" 22 23namespace llvm { 24 25/// ObjectBuffer - This class acts as a container for the memory buffer used during 26/// generation and loading of executable objects using MCJIT and RuntimeDyld. The 27/// underlying memory for the object will be owned by the ObjectBuffer instance 28/// throughout its lifetime. The getMemBuffer() method provides a way to create a 29/// MemoryBuffer wrapper object instance to be owned by other classes (such as 30/// ObjectFile) as needed, but the MemoryBuffer instance returned does not own the 31/// actual memory it points to. 32class ObjectBuffer { 33 virtual void anchor(); 34public: 35 ObjectBuffer() {} 36 ObjectBuffer(MemoryBuffer* Buf) : Buffer(Buf) {} 37 virtual ~ObjectBuffer() {} 38 39 /// getMemBuffer - Like MemoryBuffer::getMemBuffer() this function 40 /// returns a pointer to an object that is owned by the caller. However, 41 /// the caller does not take ownership of the underlying memory. 42 MemoryBuffer *getMemBuffer() const { 43 return MemoryBuffer::getMemBuffer(Buffer->getBuffer(), "", false); 44 } 45 46 const char *getBufferStart() const { return Buffer->getBufferStart(); } 47 size_t getBufferSize() const { return Buffer->getBufferSize(); } 48 StringRef getBuffer() const { return Buffer->getBuffer(); } 49 50protected: 51 // The memory contained in an ObjectBuffer 52 OwningPtr<MemoryBuffer> Buffer; 53}; 54 55/// ObjectBufferStream - This class encapsulates the SmallVector and 56/// raw_svector_ostream needed to generate an object using MC code emission 57/// while providing a common ObjectBuffer interface for access to the 58/// memory once the object has been generated. 59class ObjectBufferStream : public ObjectBuffer { 60 virtual void anchor(); 61public: 62 ObjectBufferStream() : OS(SV) {} 63 virtual ~ObjectBufferStream() {} 64 65 raw_ostream &getOStream() { return OS; } 66 void flush() 67 { 68 OS.flush(); 69 70 // Make the data accessible via the ObjectBuffer::Buffer 71 Buffer.reset(MemoryBuffer::getMemBuffer(StringRef(SV.data(), SV.size()), 72 "", 73 false)); 74 } 75 76protected: 77 SmallVector<char, 4096> SV; // Working buffer into which we JIT. 78 raw_svector_ostream OS; // streaming wrapper 79}; 80 81} // namespace llvm 82 83#endif 84