//==-- SystemZISelLowering.h - SystemZ DAG Lowering Interface ----*- C++ -*-==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that SystemZ uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TARGET_SystemZ_ISELLOWERING_H
#define LLVM_TARGET_SystemZ_ISELLOWERING_H

#include "SystemZ.h"
#include "SystemZRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/Target/TargetLowering.h"

namespace llvm {
  namespace SystemZISD {
    enum {
      FIRST_NUMBER = ISD::BUILTIN_OP_END,

      /// Return with a flag operand. Operand 0 is the chain operand.
      RET_FLAG,

      /// CALL - These operations represent an abstract call
      /// instruction, which includes a bunch of information.
      CALL,

      /// PCRelativeWrapper - PC relative address
      PCRelativeWrapper,

      /// CMP, UCMP - Compare instruction
      CMP,
      UCMP,

      /// BRCOND - Conditional branch. Operand 0 is chain operand, operand 1 is
      /// the block to branch if condition is true, operand 2 is condition code
      /// and operand 3 is the flag operand produced by a CMP instruction.
      BRCOND,

      /// SELECT - Operands 0 and 1 are selection variables, operand 2 is
      /// condition code and operand 3 is the flag operand.
      SELECT
    };
  }

  class SystemZSubtarget;
  class SystemZTargetMachine;

  class SystemZTargetLowering : public TargetLowering {
  public:
    explicit SystemZTargetLowering(SystemZTargetMachine &TM);

    virtual MVT getShiftAmountTy(EVT LHSTy) const { return MVT::i64; }

    /// LowerOperation - Provide custom lowering hooks for some operations.
    virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;

    /// getTargetNodeName - This method returns the name of a target specific
    /// DAG node.
    virtual const char *getTargetNodeName(unsigned Opcode) const;

    /// getFunctionAlignment - Return the Log2 alignment of this function.
    virtual unsigned getFunctionAlignment(const Function *F) const {
      return 1;
    }

    std::pair<unsigned, const TargetRegisterClass*>
    getRegForInlineAsmConstraint(const std::string &Constraint, EVT VT) const;
    TargetLowering::ConstraintType
    getConstraintType(const std::string &Constraint) const;

    SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;

    SDValue EmitCmp(SDValue LHS, SDValue RHS,
                    ISD::CondCode CC, SDValue &SystemZCC,
                    SelectionDAG &DAG) const;


    MachineBasicBlock* EmitInstrWithCustomInserter(MachineInstr *MI,
                                                   MachineBasicBlock *BB) const;

    /// isFPImmLegal - Returns true if the target can instruction select the
    /// specified FP immediate natively. If false, the legalizer will
    /// materialize the FP immediate as a load from a constant pool.
    virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const;

  private:
    SDValue LowerCCCCallTo(SDValue Chain, SDValue Callee,
                           CallingConv::ID CallConv, bool isVarArg,
                           bool isTailCall,
                           const SmallVectorImpl<ISD::OutputArg> &Outs,
                           const SmallVectorImpl<SDValue> &OutVals,
                           const SmallVectorImpl<ISD::InputArg> &Ins,
                           DebugLoc dl, SelectionDAG &DAG,
                           SmallVectorImpl<SDValue> &InVals) const;

    SDValue LowerCCCArguments(SDValue Chain,
                              CallingConv::ID CallConv,
                              bool isVarArg,
                              const SmallVectorImpl<ISD::InputArg> &Ins,
                              DebugLoc dl,
                              SelectionDAG &DAG,
                              SmallVectorImpl<SDValue> &InVals) const;

    SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
                            CallingConv::ID CallConv, bool isVarArg,
                            const SmallVectorImpl<ISD::InputArg> &Ins,
                            DebugLoc dl, SelectionDAG &DAG,
                            SmallVectorImpl<SDValue> &InVals) const;

    virtual SDValue
      LowerFormalArguments(SDValue Chain,
                           CallingConv::ID CallConv, bool isVarArg,
                           const SmallVectorImpl<ISD::InputArg> &Ins,
                           DebugLoc dl, SelectionDAG &DAG,
                           SmallVectorImpl<SDValue> &InVals) const;
    virtual SDValue
      LowerCall(SDValue Chain, SDValue Callee,
                CallingConv::ID CallConv, bool isVarArg, bool &isTailCall,
                const SmallVectorImpl<ISD::OutputArg> &Outs,
                const SmallVectorImpl<SDValue> &OutVals,
                const SmallVectorImpl<ISD::InputArg> &Ins,
                DebugLoc dl, SelectionDAG &DAG,
                SmallVectorImpl<SDValue> &InVals) const;

    virtual SDValue
      LowerReturn(SDValue Chain,
                  CallingConv::ID CallConv, bool isVarArg,
                  const SmallVectorImpl<ISD::OutputArg> &Outs,
                  const SmallVectorImpl<SDValue> &OutVals,
                  DebugLoc dl, SelectionDAG &DAG) const;

    const SystemZSubtarget &Subtarget;
    const SystemZTargetMachine &TM;
    const SystemZRegisterInfo *RegInfo;
  };
} // namespace llvm

#endif // LLVM_TARGET_SystemZ_ISELLOWERING_H