/* Title:   RegClass.h   -*- C++ -*-
   Author:  Ruchira Sasanka
   Date:    Aug 20, 01
   Purpose: Contains machine independent methods for register coloring.

*/

#ifndef REG_CLASS_H
#define REG_CLASS_H

#include "llvm/CodeGen/IGNode.h"
#include "llvm/CodeGen/InterferenceGraph.h"
#include "llvm/Target/MachineRegInfo.h"
#include <stack>
#include <iostream>
class MachineRegClassInfo;

typedef std::vector<unsigned> ReservedColorListType;


//-----------------------------------------------------------------------------
// Class RegClass
//
//   Implements a machine independant register class. 
//
//   This is the class that contains all data structures and common algos
//   for coloring a particular register class (e.g., int class, fp class).  
//   This class is hardware independent. This class accepts a hardware 
//   dependent description of machine registers (MachineRegInfo class) to 
//   get hardware specific info and to color an individual IG node.
//
//   This class contains the InterferenceGraph (IG).
//   Also it contains an IGNode stack that can be used for coloring. 
//   The class provides some easy access methods to the IG methods, since these
//   methods are called thru a register class.
//
//-----------------------------------------------------------------------------
class RegClass {
  const Function *const Meth;           // Function we are working on
  const MachineRegClassInfo *const MRC; // corresponding MRC
  const unsigned RegClassID;            // my int ID

  InterferenceGraph IG;                 // Interference graph - constructed by
                                        // buildInterferenceGraph
  std::stack<IGNode *> IGNodeStack;     // the stack used for coloring

  const ReservedColorListType *const ReservedColorList;
  //
  // for passing registers that are pre-allocated and cannot be used by the
  // register allocator for this function.
  
  bool *IsColorUsedArr;
  //
  // An array used for coloring each node. This array must be of size 
  // MRC->getNumOfAllRegs(). Allocated once in the constructor
  // for efficiency.


  //--------------------------- private methods ------------------------------

  void pushAllIGNodes();

  bool  pushUnconstrainedIGNodes();

  IGNode * getIGNodeWithMinSpillCost();

  void colorIGNode(IGNode *const Node);


 public:

  RegClass(const Function *M,
	   const MachineRegClassInfo *MRC,
	   const ReservedColorListType *RCL = 0);

  ~RegClass() { delete[] IsColorUsedArr; }

  inline void createInterferenceGraph() { IG.createGraph(); }

  inline InterferenceGraph &getIG() { return IG; }

  inline const unsigned getID() const { return RegClassID; }

  // main method called for coloring regs
  //
  void colorAllRegs();                 

  inline unsigned getNumOfAvailRegs() const 
    { return MRC->getNumOfAvailRegs(); }


  // --- following methods are provided to access the IG contained within this
  // ---- RegClass easilly.

  inline void addLRToIG(LiveRange *const LR) 
    { IG.addLRToIG(LR); }

  inline void setInterference(const LiveRange *const LR1,
			      const LiveRange *const LR2)  
    { IG.setInterference(LR1, LR2); }

  inline unsigned getInterference(const LiveRange *const LR1,
			      const LiveRange *const LR2) const 
    { return IG.getInterference(LR1, LR2); }

  inline void mergeIGNodesOfLRs(const LiveRange *const LR1,
				LiveRange *const LR2) 
    { IG.mergeIGNodesOfLRs(LR1, LR2); }


  inline bool * getIsColorUsedArr() { return IsColorUsedArr; }


  inline void printIGNodeList() const {
    std::cerr << "IG Nodes for Register Class " << RegClassID << ":" << "\n";
    IG.printIGNodeList(); 
  }

  inline void printIG() {  
    std::cerr << "IG for Register Class " << RegClassID << ":" << "\n";
    IG.printIG(); 
  }
};

#endif