1 //===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission -------*- C++ -*-===//
3 // This file defines an abstract interface that is used by the machine code
4 // emission framework to output the code. This allows machine code emission to
5 // be seperated from concerns such as resolution of call targets, and where the
6 // machine code will be written (memory or disk, f.e.).
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_CODEGEN_MACHINE_CODE_EMITTER_H
11 #define LLVM_CODEGEN_MACHINE_CODE_EMITTER_H
13 class MachineFunction;
14 class MachineBasicBlock;
18 struct MachineCodeEmitter {
19 virtual ~MachineCodeEmitter() {}
21 /// startFunction - This callback is invoked when the specified function is
22 /// about to be code generated.
24 virtual void startFunction(MachineFunction &F) {}
26 /// finishFunction - This callback is invoked when the specified function has
27 /// finished code generation.
29 virtual void finishFunction(MachineFunction &F) {}
31 /// startBasicBlock - This callback is invoked when a new basic block is about
34 virtual void startBasicBlock(MachineBasicBlock &BB) {}
36 /// emitByte - This callback is invoked when a byte needs to be written to the
39 virtual void emitByte(unsigned char B) {}
41 /// emitPCRelativeDisp - This callback is invoked when we need to write out a
42 /// PC relative displacement for the specified Value*. This is used for call
43 /// and jump instructions typically.
45 virtual void emitPCRelativeDisp(Value *V) {}
47 /// emitGlobalAddress - This callback is invoked when we need to write out the
48 /// address of a global value to machine code. This is important for indirect
49 /// calls as well as accessing global variables.
51 virtual void emitGlobalAddress(GlobalValue *V) {}
54 /// createDebugMachineCodeEmitter - Return a dynamically allocated machine
55 /// code emitter, which just prints the opcodes and fields out the cout. This
56 /// can be used for debugging users of the MachineCodeEmitter interface.
58 static MachineCodeEmitter *createDebugMachineCodeEmitter();