llvm/lib/Target/AMDGPU/SIFrameLowering.h

//===--------------------- SIFrameLowering.h --------------------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_AMDGPU_SIFRAMELOWERING_H
#define LLVM_LIB_TARGET_AMDGPU_SIFRAMELOWERING_H

#include "AMDGPUFrameLowering.h"
#include "SIRegisterInfo.h"

namespace llvm {

class SIInstrInfo;

class SIFrameLowering final : public AMDGPUFrameLowering {
public:
  SIFrameLowering(StackDirection D, Align StackAl, int LAO,
                  Align TransAl = Align(1))
      : AMDGPUFrameLowering(D, StackAl, LAO, TransAl) {}
  ~SIFrameLowering() override = default;

  void emitEntryFunctionPrologue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const;
  void emitPrologue(MachineFunction &MF,
                    MachineBasicBlock &MBB) const override;
  void emitEpilogue(MachineFunction &MF,
                    MachineBasicBlock &MBB) const override;
  StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
                                     Register &FrameReg) const override;

  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
                            RegScavenger *RS = nullptr) const override;
  void determineCalleeSavesSGPR(MachineFunction &MF, BitVector &SavedRegs,
                                RegScavenger *RS = nullptr) const;
  void determinePrologEpilogSGPRSaves(MachineFunction &MF, BitVector &SavedRegs,
                                      bool NeedExecCopyReservedReg) const;
  void emitCSRSpillStores(MachineFunction &MF, MachineBasicBlock &MBB,
                          MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
                          LiveRegUnits &LiveUnits, Register FrameReg,
                          Register FramePtrRegScratchCopy,
                          const bool NeedsFrameMoves) const;
  void emitCSRSpillRestores(MachineFunction &MF, MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MBBI,
                            const DebugLoc &DL, LiveRegUnits &LiveUnits,
                            Register FrameReg,
                            Register FramePtrRegScratchCopy) const;
  bool
  assignCalleeSavedSpillSlots(MachineFunction &MF,
                              const TargetRegisterInfo *TRI,
                              std::vector<CalleeSavedInfo> &CSI) const override;

  bool assignCalleeSavedSpillSlotsImpl(MachineFunction &MF,
                                       const TargetRegisterInfo *TRI,
                                       std::vector<CalleeSavedInfo> &CSI) const;

private:
  /// Spill a single CSR according to @p CS
  ///
  /// This is a separate method so it an be shared between the block-ops enabled
  /// and disabled paths. Even when block-ops are enabled we may not have a
  /// viable block for a specific register, so it will fall back to this
  /// implementation.
  ///
  /// @p LiveInRoots conveys whether we are tracking liveness, and if we are
  /// it captures the original live-ins before spilling in a way that can be
  /// (relatively) efficiently checked without enumerating all register aliases.
  /// See @c buildLiveInRoots in the implementation.
  void spillCalleeSavedRegisterWithoutBlockOps(
      MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
      const CalleeSavedInfo &CS, const SIInstrInfo *TII,
      const SIRegisterInfo &TRI,
      const std::optional<SparseBitVector<>> &LiveInRoots) const;

public:
  bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
                                 MachineBasicBlock::iterator MI,
                                 ArrayRef<CalleeSavedInfo> CSI,
                                 const TargetRegisterInfo *TRI) const override;

  bool
  restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
                              MachineBasicBlock::iterator MI,
                              MutableArrayRef<CalleeSavedInfo> CSI,
                              const TargetRegisterInfo *TRI) const override;

  bool allocateScavengingFrameIndexesNearIncomingSP(
    const MachineFunction &MF) const override;

  bool isSupportedStackID(TargetStackID::Value ID) const override;

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

  void processFunctionBeforeFrameIndicesReplaced(
      MachineFunction &MF, RegScavenger *RS = nullptr) const override;

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

protected:
  bool hasFPImpl(const MachineFunction &MF) const override;

private:
  void emitEntryFunctionFlatScratchInit(MachineFunction &MF,
                                        MachineBasicBlock &MBB,
                                        MachineBasicBlock::iterator I,
                                        const DebugLoc &DL,
                                        Register ScratchWaveOffsetReg) const;

  Register getEntryFunctionReservedScratchRsrcReg(MachineFunction &MF) const;

  void emitEntryFunctionScratchRsrcRegSetup(
      MachineFunction &MF, MachineBasicBlock &MBB,
      MachineBasicBlock::iterator I, const DebugLoc &DL,
      Register PreloadedPrivateBufferReg, Register ScratchRsrcReg,
      Register ScratchWaveOffsetReg) const;

  void emitPrologueEntryCFI(MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MBBI,
                            const DebugLoc &DL) const;

  void emitDefCFA(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
                  DebugLoc const &DL, MCRegister StackPtrReg,
                  bool AspaceAlreadyDefined,
                  MachineInstr::MIFlag Flags = MachineInstr::NoFlags) const;

public:
  bool requiresStackPointerReference(const MachineFunction &MF) const;

  /// Create a CFI index for CFIInst and build a MachineInstr around it.
  MachineInstr *
  buildCFI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
           const DebugLoc &DL, const MCCFIInstruction &CFIInst,
           MachineInstr::MIFlag flag = MachineInstr::FrameSetup) const;

  /// Create a CFI index describing a spill of the VGPR/AGPR \p Reg to another
  /// VGPR/AGPR \p RegCopy and build a MachineInstr around it.
  MachineInstr *buildCFIForVRegToVRegSpill(MachineBasicBlock &MBB,
                                           MachineBasicBlock::iterator MBBI,
                                           const DebugLoc &DL,
                                           const MCRegister Reg,
                                           const MCRegister RegCopy) const;
  /// Create a CFI index describing a spill of an SGPR to a single lane of
  /// a VGPR and build a MachineInstr around it.
  MachineInstr *buildCFIForSGPRToVGPRSpill(MachineBasicBlock &MBB,
                                           MachineBasicBlock::iterator MBBI,
                                           const DebugLoc &DL,
                                           const MCRegister SGPR,
                                           const MCRegister VGPR,
                                           const int Lane) const;
  /// Create a CFI index describing a spill of an SGPR to multiple lanes of
  /// VGPRs and build a MachineInstr around it.
  MachineInstr *buildCFIForSGPRToVGPRSpill(
      MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
      const DebugLoc &DL, MCRegister SGPR,
      ArrayRef<SIRegisterInfo::SpilledReg> VGPRSpills) const;
  /// Create a CFI index describing a spill of a SGPR to VMEM and
  /// build a MachineInstr around it.
  MachineInstr *buildCFIForSGPRToVMEMSpill(MachineBasicBlock &MBB,
                                           MachineBasicBlock::iterator MBBI,
                                           const DebugLoc &DL, MCRegister SGPR,
                                           int64_t Offset) const;
  /// Create a CFI index describing a spill of a VGPR to VMEM and
  /// build a MachineInstr around it.
  MachineInstr *buildCFIForVGPRToVMEMSpill(MachineBasicBlock &MBB,
                                           MachineBasicBlock::iterator MBBI,
                                           const DebugLoc &DL, MCRegister VGPR,
                                           int64_t Offset) const;
  MachineInstr *buildCFIForRegToSGPRPairSpill(MachineBasicBlock &MBB,
                                              MachineBasicBlock::iterator MBBI,
                                              const DebugLoc &DL,
                                              MCRegister Reg,
                                              MCRegister SGPRPair) const;
  MachineInstr *buildCFIForSameValue(MachineBasicBlock &MBB,
                                     MachineBasicBlock::iterator MBBI,
                                     const DebugLoc &DL, MCRegister Reg) const;
  // Returns true if the function may need to reserve space on the stack for the
  // CWSR trap handler.
  bool mayReserveScratchForCWSR(const MachineFunction &MF) const;
};

} // end namespace llvm

#endif // LLVM_LIB_TARGET_AMDGPU_SIFRAMELOWERING_H