+#ifndef LLVM_CODEGEN_MACHINECODEEMITTER_H
+#define LLVM_CODEGEN_MACHINECODEEMITTER_H
+
+#include "llvm/Support/DataTypes.h"
+#include <vector>
+
+namespace llvm {
+
+class MachineBasicBlock;
+class MachineConstantPool;
+class MachineJumpTableInfo;
+class MachineFunction;
+class MachineRelocation;
+class Value;
+class GlobalValue;
+class Function;
+
+/// MachineCodeEmitter - This class defines two sorts of methods: those for
+/// emitting the actual bytes of machine code, and those for emitting auxillary
+/// structures, such as jump tables, relocations, etc.
+///
+/// Emission of machine code is complicated by the fact that we don't (in
+/// general) know the size of the machine code that we're about to emit before
+/// we emit it. As such, we preallocate a certain amount of memory, and set the
+/// BufferBegin/BufferEnd pointers to the start and end of the buffer. As we
+/// emit machine instructions, we advance the CurBufferPtr to indicate the
+/// location of the next byte to emit. In the case of a buffer overflow (we
+/// need to emit more machine code than we have allocated space for), the
+/// CurBufferPtr will saturate to BufferEnd and ignore stores. Once the entire
+/// function has been emitted, the overflow condition is checked, and if it has
+/// occurred, more memory is allocated, and we reemit the code into it.
+///
+class MachineCodeEmitter {
+protected:
+ /// BufferBegin/BufferEnd - Pointers to the start and end of the memory
+ /// allocated for this code buffer.
+ unsigned char *BufferBegin, *BufferEnd;
+
+ /// CurBufferPtr - Pointer to the next byte of memory to fill when emitting
+ /// code. This is guranteed to be in the range [BufferBegin,BufferEnd]. If
+ /// this pointer is at BufferEnd, it will never move due to code emission, and
+ /// all code emission requests will be ignored (this is the buffer overflow
+ /// condition).
+ unsigned char *CurBufferPtr;
+public:
+ virtual ~MachineCodeEmitter() {}
+
+ /// startFunction - This callback is invoked when the specified function is
+ /// about to be code generated. This initializes the BufferBegin/End/Ptr
+ /// fields.
+ ///
+ virtual void startFunction(MachineFunction &F) = 0;
+
+ /// finishFunction - This callback is invoked when the specified function has
+ /// finished code generation. If a buffer overflow has occurred, this method
+ /// returns true (the callee is required to try again), otherwise it returns
+ /// false.
+ ///
+ virtual bool finishFunction(MachineFunction &F) = 0;
+
+ /// startFunctionStub - This callback is invoked when the JIT needs the
+ /// address of a function that has not been code generated yet. The StubSize
+ /// specifies the total size required by the stub. Stubs are not allowed to
+ /// have constant pools, the can only use the other emitByte*/emitWord*
+ /// methods.
+ ///
+ virtual void startFunctionStub(unsigned StubSize, unsigned Alignment = 1) = 0;