//===-- llvm/CodeGen/MachineLocation.h --------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by James M. Laskey and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// The MachineLocation class is used to represent a simple location in a machine
// frame.  Locations will be one of two forms; a register or an address formed
// from a base address plus an offset.  Register indirection can be specified by
// using an offset of zero.
//
// The MachineMove class is used to represent abstract move operations in the 
// prolog/epilog of a compiled function.  A collection of these objects can be
// used by a debug consumer to track the location of values when unwinding stack
// frames.
//===----------------------------------------------------------------------===//


#ifndef LLVM_CODEGEN_MACHINELOCATION_H
#define LLVM_CODEGEN_MACHINELOCATION_H

namespace llvm {

class MachineLocation {
private:
  bool IsRegister;                      // True if location is a register.
  unsigned Register;                    // gcc/gdb register number.
  int Offset;                           // Displacement if not register.

public:
  enum {
    // The target register number for an abstract frame pointer. The value is
    // an arbitrary value greater than MRegisterInfo::FirstVirtualRegister.
    VirtualFP = ~0U
  };
  MachineLocation()
  : IsRegister(false)
  , Register(0)
  , Offset(0)
  {}
  explicit MachineLocation(unsigned R)
  : IsRegister(true)
  , Register(R)
  , Offset(0)
  {}
  MachineLocation(unsigned R, int O)
  : IsRegister(false)
  , Register(R)
  , Offset(O)
  {}
  
  // Accessors
  bool isRegister()      const { return IsRegister; }
  unsigned getRegister() const { return Register; }
  int getOffset()        const { return Offset; }
  void setIsRegister(bool Is)  { IsRegister = Is; }
  void setRegister(unsigned R) { Register = R; }
  void setOffset(int O)        { Offset = O; }
  void set(unsigned R) {
    IsRegister = true;
    Register = R;
    Offset = 0;
  }
  void set(unsigned R, int O) {
    IsRegister = false;
    Register = R;
    Offset = O;
  }

#ifndef NDEBUG
  void dump();
#endif
};

class MachineMove {
private:
  unsigned LabelID;                     // Label ID number for post-instruction
                                        // address when result of move takes
                                        // effect.
  MachineLocation Destination;          // Move to location.
  MachineLocation Source;               // Move from location.
  
public:
  MachineMove()
  : LabelID(0)
  , Destination()
  , Source()
  {}

  MachineMove(unsigned ID, MachineLocation &D, MachineLocation &S)
  : LabelID(ID)
  , Destination(D)
  , Source(S)
  {}
  
  // Accessors
  unsigned getLabelID()                   const { return LabelID; }
  const MachineLocation &getDestination() const { return Destination; }
  const MachineLocation &getSource()      const { return Source; }
};

} // End llvm namespace

#endif