reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
  165
  166
  167
  168
  169
  170
  171
  172
  173
  174
  175
  176
  177
  178
//==- HexagonFrameLowering.h - Define frame lowering for Hexagon -*- 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_HEXAGON_HEXAGONFRAMELOWERING_H
#define LLVM_LIB_TARGET_HEXAGON_HEXAGONFRAMELOWERING_H

#include "Hexagon.h"
#include "HexagonBlockRanges.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include <vector>

namespace llvm {

class BitVector;
class HexagonInstrInfo;
class HexagonRegisterInfo;
class MachineFunction;
class MachineInstr;
class MachineRegisterInfo;
class TargetRegisterClass;

class HexagonFrameLowering : public TargetFrameLowering {
public:
  explicit HexagonFrameLowering()
      : TargetFrameLowering(StackGrowsDown, Align(8), 0, Align::None(), true) {}

  // All of the prolog/epilog functionality, including saving and restoring
  // callee-saved registers is handled in emitPrologue. This is to have the
  // logic for shrink-wrapping in one place.
  void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const
      override;
  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const
      override {}

  bool enableCalleeSaveSkip(const MachineFunction &MF) const override;

  bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
      MachineBasicBlock::iterator MI, const std::vector<CalleeSavedInfo> &CSI,
      const TargetRegisterInfo *TRI) const override {
    return true;
  }

  bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
      MachineBasicBlock::iterator MI, std::vector<CalleeSavedInfo> &CSI,
      const TargetRegisterInfo *TRI) const override {
    return true;
  }

  bool hasReservedCallFrame(const MachineFunction &MF) const override {
    // We always reserve call frame as a part of the initial stack allocation.
    return true;
  }

  bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override {
    // Override this function to avoid calling hasFP before CSI is set
    // (the default implementation calls hasFP).
    return true;
  }

  MachineBasicBlock::iterator
  eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
                                MachineBasicBlock::iterator I) const override;
  void processFunctionBeforeFrameFinalized(MachineFunction &MF,
      RegScavenger *RS = nullptr) const override;
  void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
      RegScavenger *RS) const override;

  bool targetHandlesStackFrameRounding() const override {
    return true;
  }

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

  const SpillSlot *getCalleeSavedSpillSlots(unsigned &NumEntries)
      const override {
    static const SpillSlot Offsets[] = {
      { Hexagon::R17, -4 }, { Hexagon::R16, -8 }, { Hexagon::D8, -8 },
      { Hexagon::R19, -12 }, { Hexagon::R18, -16 }, { Hexagon::D9, -16 },
      { Hexagon::R21, -20 }, { Hexagon::R20, -24 }, { Hexagon::D10, -24 },
      { Hexagon::R23, -28 }, { Hexagon::R22, -32 }, { Hexagon::D11, -32 },
      { Hexagon::R25, -36 }, { Hexagon::R24, -40 }, { Hexagon::D12, -40 },
      { Hexagon::R27, -44 }, { Hexagon::R26, -48 }, { Hexagon::D13, -48 }
    };
    NumEntries = array_lengthof(Offsets);
    return Offsets;
  }

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

  bool needsAligna(const MachineFunction &MF) const;
  const MachineInstr *getAlignaInstr(const MachineFunction &MF) const;

  void insertCFIInstructions(MachineFunction &MF) const;

private:
  using CSIVect = std::vector<CalleeSavedInfo>;

  void expandAlloca(MachineInstr *AI, const HexagonInstrInfo &TII,
      unsigned SP, unsigned CF) const;
  void insertPrologueInBlock(MachineBasicBlock &MBB, bool PrologueStubs) const;
  void insertEpilogueInBlock(MachineBasicBlock &MBB) const;
  void insertAllocframe(MachineBasicBlock &MBB,
      MachineBasicBlock::iterator InsertPt, unsigned NumBytes) const;
  bool insertCSRSpillsInBlock(MachineBasicBlock &MBB, const CSIVect &CSI,
      const HexagonRegisterInfo &HRI, bool &PrologueStubs) const;
  bool insertCSRRestoresInBlock(MachineBasicBlock &MBB, const CSIVect &CSI,
      const HexagonRegisterInfo &HRI) const;
  void updateEntryPaths(MachineFunction &MF, MachineBasicBlock &SaveB) const;
  bool updateExitPaths(MachineBasicBlock &MBB, MachineBasicBlock &RestoreB,
      BitVector &DoneT, BitVector &DoneF, BitVector &Path) const;
  void insertCFIInstructionsAt(MachineBasicBlock &MBB,
      MachineBasicBlock::iterator At) const;

  void adjustForCalleeSavedRegsSpillCall(MachineFunction &MF) const;

  bool expandCopy(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandStoreInt(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandLoadInt(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandStoreVecPred(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandLoadVecPred(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandStoreVec2(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandLoadVec2(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandStoreVec(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandLoadVec(MachineBasicBlock &B, MachineBasicBlock::iterator It,
      MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
      SmallVectorImpl<unsigned> &NewRegs) const;
  bool expandSpillMacros(MachineFunction &MF,
      SmallVectorImpl<unsigned> &NewRegs) const;

  unsigned findPhysReg(MachineFunction &MF, HexagonBlockRanges::IndexRange &FIR,
      HexagonBlockRanges::InstrIndexMap &IndexMap,
      HexagonBlockRanges::RegToRangeMap &DeadMap,
      const TargetRegisterClass *RC) const;
  void optimizeSpillSlots(MachineFunction &MF,
      SmallVectorImpl<unsigned> &VRegs) const;

  void findShrunkPrologEpilog(MachineFunction &MF, MachineBasicBlock *&PrologB,
      MachineBasicBlock *&EpilogB) const;

  void addCalleeSaveRegistersAsImpOperand(MachineInstr *MI, const CSIVect &CSI,
      bool IsDef, bool IsKill) const;
  bool shouldInlineCSR(const MachineFunction &MF, const CSIVect &CSI) const;
  bool useSpillFunction(const MachineFunction &MF, const CSIVect &CSI) const;
  bool useRestoreFunction(const MachineFunction &MF, const CSIVect &CSI) const;
  bool mayOverflowFrameOffset(MachineFunction &MF) const;
};

} // end namespace llvm

#endif // LLVM_LIB_TARGET_HEXAGON_HEXAGONFRAMELOWERING_H