ARCISelLowering.h

//===- ARCISelLowering.h - ARC DAG Lowering Interface -----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that ARC uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_ARC_ARCISELLOWERING_H
#define LLVM_LIB_TARGET_ARC_ARCISELLOWERING_H

#include "ARC.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/TargetLowering.h"

namespace llvm {

// Forward delcarations
class ARCSubtarget;
class ARCTargetMachine;

namespace ARCISD {

enum NodeType : unsigned {
  // Start the numbering where the builtin ops and target ops leave off.
  FIRST_NUMBER = ISD::BUILTIN_OP_END,

  // Branch and link (call)
  BL,

  // Jump and link (indirect call)
  JL,

  // CMP
  CMP,

  // CMOV
  CMOV,

  // BRcc
  BRcc,

  // Global Address Wrapper
  GAWRAPPER,

  // return, (j_s [blink])
  RET
};

} // end namespace ARCISD

//===--------------------------------------------------------------------===//
// TargetLowering Implementation
//===--------------------------------------------------------------------===//
class ARCTargetLowering : public TargetLowering {
public:
  explicit ARCTargetLowering(const TargetMachine &TM,
                             const ARCSubtarget &Subtarget);

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

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

  /// Return true if the addressing mode represented by AM is legal for this
  /// target, for a load/store of the specified type.
  bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
                             unsigned AS,
                             Instruction *I = nullptr) const override;

private:
  const ARCSubtarget &Subtarget;

  void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
                          SelectionDAG &DAG) const override;

  // Lower Operand helpers
  SDValue LowerCallArguments(SDValue Chain, CallingConv::ID CallConv,
                             bool isVarArg,
                             const SmallVectorImpl<ISD::InputArg> &Ins,
                             SDLoc dl, SelectionDAG &DAG,
                             SmallVectorImpl<SDValue> &InVals) const;
  // Lower Operand specifics
  SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const;
  SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
  SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
  SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
  SDValue LowerSIGN_EXTEND_INREG(SDValue Op, SelectionDAG &DAG) const;
  SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
  SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;

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

  SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
                    SmallVectorImpl<SDValue> &InVals) const override;

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

  bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
                      bool isVarArg,
                      const SmallVectorImpl<ISD::OutputArg> &ArgsFlags,
                      LLVMContext &Context) const override;

  bool mayBeEmittedAsTailCall(const CallInst *CI) const override;
};

} // end namespace llvm

#endif // LLVM_LIB_TARGET_ARC_ARCISELLOWERING_H