llvm/lib/CodeGen/RegAlloc/PhyRegAlloc.h

//===-- PhyRegAlloc.h - Graph Coloring Register Allocator -------*- c++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//   
// This is the main entry point for register allocation.
//
// Notes:
// * RegisterClasses: Each RegClass accepts a 
//   TargetRegClass which contains machine specific info about that register
//   class. The code in the RegClass is machine independent and they use
//   access functions in the TargetRegClass object passed into it to get
//   machine specific info.
//
// * Machine dependent work: All parts of the register coloring algorithm
//   except coloring of an individual node are machine independent.
//
//===----------------------------------------------------------------------===//

#ifndef PHYREGALLOC_H
#define PHYREGALLOC_H

#include "LiveRangeInfo.h"
#include "llvm/Pass.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/Target/TargetMachine.h" 
#include "llvm/Target/TargetRegInfo.h"
#include <map>

class MachineFunction;
class FunctionLiveVarInfo;
class MachineInstr;
class LoopInfo;
class RegClass;
class Constant;

//----------------------------------------------------------------------------
// Class AddedInstrns:
// When register allocator inserts new instructions in to the existing 
// instruction stream, it does NOT directly modify the instruction stream.
// Rather, it creates an object of AddedInstrns and stick it in the 
// AddedInstrMap for an existing instruction. This class contains two vectors
// to store such instructions added before and after an existing instruction.
//----------------------------------------------------------------------------

struct AddedInstrns {
  std::vector<MachineInstr*> InstrnsBefore;//Insts added BEFORE an existing inst
  std::vector<MachineInstr*> InstrnsAfter; //Insts added AFTER an existing inst
  inline void clear () { InstrnsBefore.clear (); InstrnsAfter.clear (); }
};

//----------------------------------------------------------------------------
// class PhyRegAlloc:
// Main class the register allocator. Call runOnFunction() to allocate
// registers for a Function.
//----------------------------------------------------------------------------

class PhyRegAlloc : public FunctionPass {
  std::vector<RegClass *> RegClassList; // vector of register classes
  const TargetMachine &TM;              // target machine
  const Function *Fn;                   // name of the function we work on
  MachineFunction *MF;                  // descriptor for method's native code
  FunctionLiveVarInfo *LVI;             // LV information for this method 
                                        // (already computed for BBs) 
  LiveRangeInfo *LRI;                   // LR info  (will be computed)
  const TargetRegInfo &MRI;             // Machine Register information
  const unsigned NumOfRegClasses;       // recorded here for efficiency

  // Map to indicate whether operands of each MachineInstr have been
  // updated according to their assigned colors.  This is only used in
  // assertion checking (debug builds).
  std::map<const MachineInstr *, bool> OperandsColoredMap;
  
  // AddedInstrMap - Used to store instrns added in this phase
  std::map<const MachineInstr *, AddedInstrns> AddedInstrMap;

  // ScratchRegsUsed - Contains scratch register uses for a particular MI.
  typedef std::multimap<const MachineInstr*, int> ScratchRegsUsedTy;
  ScratchRegsUsedTy ScratchRegsUsed;

  AddedInstrns AddedInstrAtEntry;       // to store instrns added at entry
  const LoopInfo *LoopDepthCalc;        // to calculate loop depths 

  std::map<const Function *, std::vector<Constant *> > FnAllocState;

  PhyRegAlloc(const PhyRegAlloc&);     // DO NOT IMPLEMENT
  void operator=(const PhyRegAlloc&);  // DO NOT IMPLEMENT
public:
  inline PhyRegAlloc (const TargetMachine &TM_) :
    TM (TM_), MRI (TM.getRegInfo ()),
    NumOfRegClasses (MRI.getNumOfRegClasses ()) { }
  virtual ~PhyRegAlloc() { }

  /// runOnFunction - Main method called for allocating registers.
  ///
  virtual bool runOnFunction (Function &F);

  virtual bool doFinalization (Module &M);

  virtual void getAnalysisUsage (AnalysisUsage &AU) const;

  const char *getPassName () const {
    return "Traditional graph-coloring reg. allocator";
  }

  inline const RegClass* getRegClassByID(unsigned id) const {
    return RegClassList[id];
  }
  inline RegClass *getRegClassByID(unsigned id) { return RegClassList[id]; }

private:
  void addInterference(const Value *Def, const ValueSet *LVSet, 
		       bool isCallInst);
  bool markAllocatedRegs(MachineInstr* MInst);

  void addInterferencesForArgs();
  void createIGNodeListsAndIGs();
  void buildInterferenceGraphs();
  void saveState();
  void verifySavedState();

  void setCallInterferences(const MachineInstr *MI, 
			    const ValueSet *LVSetAft);

  void move2DelayedInstr(const MachineInstr *OrigMI, 
			 const MachineInstr *DelayedMI);

  void markUnusableSugColors();
  void allocateStackSpace4SpilledLRs();

  void insertCode4SpilledLR(const LiveRange *LR, 
                            MachineBasicBlock::iterator& MII,
                            MachineBasicBlock &MBB, unsigned OpNum);

  /// Method for inserting caller saving code. The caller must save all the
  /// volatile registers live across a call.
  ///
  void insertCallerSavingCode(std::vector<MachineInstr*>& instrnsBefore,
                              std::vector<MachineInstr*>& instrnsAfter,
                              MachineInstr *CallMI,
                              const BasicBlock *BB);

  void colorIncomingArgs();
  void colorCallRetArgs();
  void updateMachineCode();
  void updateInstruction(MachineBasicBlock::iterator& MII,
                         MachineBasicBlock &MBB);

  int getUsableUniRegAtMI(int RegType, const ValueSet *LVSetBef,
			  MachineInstr *MI,
                          std::vector<MachineInstr*>& MIBef,
                          std::vector<MachineInstr*>& MIAft);
  
  /// Callback method used to find unused registers. 
  /// LVSetBef is the live variable set to search for an unused register.
  /// If it is not specified, the LV set before the current MI is used.
  /// This is sufficient as long as no new copy instructions are generated
  /// to copy the free register to memory.
  /// 
  int getUnusedUniRegAtMI(RegClass *RC, int RegType,
                          const MachineInstr *MI,
                          const ValueSet *LVSetBef = 0);
  
  void setRelRegsUsedByThisInst(RegClass *RC, int RegType,
                                const MachineInstr *MI);

  int getUniRegNotUsedByThisInst(RegClass *RC, int RegType,
                                 const MachineInstr *MI);

  void addInterf4PseudoInstr(const MachineInstr *MI);
};

#endif