diff --git a/include/llvm/CodeGen/MachineCodeEmitter.h b/include/llvm/CodeGen/MachineCodeEmitter.h
index 2e8908343c9..69eea5c972d 100644
--- a/include/llvm/CodeGen/MachineCodeEmitter.h
+++ b/include/llvm/CodeGen/MachineCodeEmitter.h
@@ -10,11 +10,29 @@
 #ifndef LLVM_CODEGEN_MACHINE_CODE_EMITTER_H
 #define LLVM_CODEGEN_MACHINE_CODE_EMITTER_H
 
+class MachineFunction;
+class MachineBasicBlock;
+
 struct MachineCodeEmitter {
 
-
+  /// startFunction - This callback is invoked when the specified function is
+  /// about to be code generated.
+  ///
+  virtual void startFunction(MachineFunction &F) {}
   
+  /// finishFunction - This callback is invoked when the specified function has
+  /// finished code generation.
+  ///
+  virtual void finishFunction(MachineFunction &F) {}
 
+  /// startBasicBlock - This callback is invoked when a new basic block is about
+  /// to be emitted.
+  ///
+  virtual void startBasicBlock(MachineBasicBlock &BB) {}
+
+  /// emitByte - This callback is invoked when a byte needs to be written to the
+  /// output stream.
+  virtual void emitByte(unsigned char B) {}
 };
 
 #endif