RISCVFrameLowering.h

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//===-- RISCVFrameLowering.h - Define frame lowering for RISCV -*- 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 class implements RISCV-specific bits of TargetFrameLowering class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H
#define LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H

#include "llvm/CodeGen/TargetFrameLowering.h"

namespace llvm {
class RISCVSubtarget;

class RISCVFrameLowering : public TargetFrameLowering {
public:
  explicit RISCVFrameLowering(const RISCVSubtarget &STI)
      : TargetFrameLowering(StackGrowsDown,
                            /*StackAlignment=*/Align(16),
                            /*LocalAreaOffset=*/0),
        STI(STI) {}

  void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;

  int getFrameIndexReference(const MachineFunction &MF, int FI,
                             unsigned &FrameReg) const override;

  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
                            RegScavenger *RS) const override;

  void processFunctionBeforeFrameFinalized(MachineFunction &MF,
                                           RegScavenger *RS) const override;

  bool hasFP(const MachineFunction &MF) const override;

  bool hasReservedCallFrame(const MachineFunction &MF) const override;
  MachineBasicBlock::iterator
  eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                                MachineBasicBlock::iterator MI) const override;

  // Get the first stack adjustment amount for SplitSPAdjust.
  // Return 0 if we don't want to to split the SP adjustment in prologue and
  // epilogue.
  uint64_t getFirstSPAdjustAmount(const MachineFunction &MF) const;

protected:
  const RISCVSubtarget &STI;

private:
  void determineFrameLayout(MachineFunction &MF) const;
  void adjustReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
                 const DebugLoc &DL, Register DestReg, Register SrcReg,
                 int64_t Val, MachineInstr::MIFlag Flag) const;
};
}
#endif