//===-- llvm/CodeGen/InstrSelection.h ---------------------------*- C++ -*-===//
//
// External interface to instruction selection.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_INSTR_SELECTION_H
#define LLVM_CODEGEN_INSTR_SELECTION_H

#include "llvm/Instruction.h"

class Function;
class InstrForest;
class MachineInstr;
class InstructionNode;
class TargetMachine;
class MachineCodeForInstruction;
class FunctionPass;

//===--------------------- Required Functions ---------------------------------
// Target-dependent functions that MUST be implemented for each target.
//

extern void	GetInstructionsByRule	(InstructionNode* subtreeRoot,
					 int ruleForNode,
					 short* nts,
					 TargetMachine &Target,
                                         std::vector<MachineInstr*>& mvec);

extern bool	ThisIsAChainRule	(int eruleno);


//************************ Exported Functions ******************************/


//---------------------------------------------------------------------------
// Function: createInstructionSelectionPass
// 
// Purpose:
//   Entry point for instruction selection using BURG.
//   Return a pass that performs machine dependent instruction selection.
//---------------------------------------------------------------------------

FunctionPass *createInstructionSelectionPass(TargetMachine &Target);


//************************ Exported Data Types *****************************/


//---------------------------------------------------------------------------
// class TmpInstruction
//
//   This class represents temporary intermediate values
//   used within the machine code for a VM instruction
//---------------------------------------------------------------------------

class TmpInstruction : public Instruction {
  TmpInstruction(const TmpInstruction &TI)
    : Instruction(TI.getType(), TI.getOpcode()) {
    if (!TI.Operands.empty()) {
      Operands.push_back(Use(TI.Operands[0], this));
      if (TI.Operands.size() == 2)
        Operands.push_back(Use(TI.Operands[1], this));
      else
        assert(0 && "Bad # operands to TmpInstruction!");
    }
  }
public:
  // Constructor that uses the type of S1 as the type of the temporary.
  // s1 must be a valid value.  s2 may be NULL.
  TmpInstruction(MachineCodeForInstruction& mcfi,
                 Value *s1, Value *s2 = 0, const std::string &name = "");
  
  // Constructor that requires the type of the temporary to be specified.
  // Both S1 and S2 may be NULL.
  TmpInstruction(MachineCodeForInstruction& mcfi,
                 const Type *Ty, Value *s1 = 0, Value* s2 = 0,
                 const std::string &name = "");
  
  virtual Instruction *clone() const {
    assert(0 && "Cannot clone TmpInstructions!");
    return 0;
  }
  virtual const char *getOpcodeName() const {
    return "TempValueForMachineInstr";
  }
  
  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const TmpInstruction *) { return true; }
  static inline bool classof(const Instruction *I) {
    return (I->getOpcode() == Instruction::UserOp1);
  }
  static inline bool classof(const Value *V) {
    return isa<Instruction>(V) && classof(cast<Instruction>(V));
  }
};

#endif
