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 23 namespace 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. 32 class ObjectBuffer { 33 public: ObjectBuffer()34 ObjectBuffer() {} ObjectBuffer(MemoryBuffer * Buf)35 ObjectBuffer(MemoryBuffer* Buf) : Buffer(Buf) {} ~ObjectBuffer()36 virtual ~ObjectBuffer() {} 37 38 /// getMemBuffer - Like MemoryBuffer::getMemBuffer() this function 39 /// returns a pointer to an object that is owned by the caller. However, 40 /// the caller does not take ownership of the underlying memory. getMemBuffer()41 MemoryBuffer *getMemBuffer() const { 42 return MemoryBuffer::getMemBuffer(Buffer->getBuffer(), "", false); 43 } 44 getBufferStart()45 const char *getBufferStart() const { return Buffer->getBufferStart(); } getBufferSize()46 size_t getBufferSize() const { return Buffer->getBufferSize(); } 47 48 protected: 49 // The memory contained in an ObjectBuffer 50 OwningPtr<MemoryBuffer> Buffer; 51 }; 52 53 /// ObjectBufferStream - This class encapsulates the SmallVector and 54 /// raw_svector_ostream needed to generate an object using MC code emission 55 /// while providing a common ObjectBuffer interface for access to the 56 /// memory once the object has been generated. 57 class ObjectBufferStream : public ObjectBuffer { 58 public: ObjectBufferStream()59 ObjectBufferStream() : OS(SV) {} ~ObjectBufferStream()60 virtual ~ObjectBufferStream() {} 61 getOStream()62 raw_ostream &getOStream() { return OS; } flush()63 void flush() 64 { 65 OS.flush(); 66 67 // Make the data accessible via the ObjectBuffer::Buffer 68 Buffer.reset(MemoryBuffer::getMemBuffer(StringRef(SV.data(), SV.size()), 69 "", 70 false)); 71 } 72 73 protected: 74 SmallVector<char, 4096> SV; // Working buffer into which we JIT. 75 raw_svector_ostream OS; // streaming wrapper 76 }; 77 78 } // namespace llvm 79 80 #endif 81