lib/Target/Hexagon/HexagonFrameLowering.h

   1 //==- HexagonFrameLowering.h - Define frame lowering for Hexagon -*- C++ -*-==//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIB_TARGET_HEXAGON_HEXAGONFRAMELOWERING_H
  10 #define LLVM_LIB_TARGET_HEXAGON_HEXAGONFRAMELOWERING_H
  11
  12 #include "Hexagon.h"
  13 #include "HexagonBlockRanges.h"
  14 #include "llvm/ADT/STLExtras.h"
  15 #include "llvm/CodeGen/MachineBasicBlock.h"
  16 #include "llvm/CodeGen/MachineFrameInfo.h"
  17 #include "llvm/CodeGen/TargetFrameLowering.h"
  18 #include <vector>
  19
  20 namespace llvm {
  21
  22 class BitVector;
  23 class HexagonInstrInfo;
  24 class HexagonRegisterInfo;
  25 class MachineFunction;
  26 class MachineInstr;
  27 class MachineRegisterInfo;
  28 class TargetRegisterClass;
  29
  30 class HexagonFrameLowering : public TargetFrameLowering {
  31 public:
  32   explicit HexagonFrameLowering()
  33       : TargetFrameLowering(StackGrowsDown, 8, 0, 1, true) {}
  34
  35   // All of the prolog/epilog functionality, including saving and restoring
  36   // callee-saved registers is handled in emitPrologue. This is to have the
  37   // logic for shrink-wrapping in one place.
  38   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const
  39       override;
  40   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const
  41       override {}
  42
  43   bool enableCalleeSaveSkip(const MachineFunction &MF) const override;
  44
  45   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
  46       MachineBasicBlock::iterator MI, const std::vector<CalleeSavedInfo> &CSI,
  47       const TargetRegisterInfo *TRI) const override {
  48     return true;
  49   }
  50
  51   bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
  52       MachineBasicBlock::iterator MI, std::vector<CalleeSavedInfo> &CSI,
  53       const TargetRegisterInfo *TRI) const override {
  54     return true;
  55   }
  56
  57   bool hasReservedCallFrame(const MachineFunction &MF) const override {
  58     // We always reserve call frame as a part of the initial stack allocation.
  59     return true;
  60   }
  61
  62   bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override {
  63     // Override this function to avoid calling hasFP before CSI is set
  64     // (the default implementation calls hasFP).
  65     return true;
  66   }
  67
  68   MachineBasicBlock::iterator
  69   eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
  70                                 MachineBasicBlock::iterator I) const override;
  71   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
  72       RegScavenger *RS = nullptr) const override;
  73   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
  74       RegScavenger *RS) const override;
  75
  76   bool targetHandlesStackFrameRounding() const override {
  77     return true;
  78   }
  79
  80   int getFrameIndexReference(const MachineFunction &MF, int FI,
  81       unsigned &FrameReg) const override;
  82   bool hasFP(const MachineFunction &MF) const override;
  83
  84   const SpillSlot *getCalleeSavedSpillSlots(unsigned &NumEntries)
  85       const override {
  86     static const SpillSlot Offsets[] = {
  87       { Hexagon::R17, -4 }, { Hexagon::R16, -8 }, { Hexagon::D8, -8 },
  88       { Hexagon::R19, -12 }, { Hexagon::R18, -16 }, { Hexagon::D9, -16 },
  89       { Hexagon::R21, -20 }, { Hexagon::R20, -24 }, { Hexagon::D10, -24 },
  90       { Hexagon::R23, -28 }, { Hexagon::R22, -32 }, { Hexagon::D11, -32 },
  91       { Hexagon::R25, -36 }, { Hexagon::R24, -40 }, { Hexagon::D12, -40 },
  92       { Hexagon::R27, -44 }, { Hexagon::R26, -48 }, { Hexagon::D13, -48 }
  93     };
  94     NumEntries = array_lengthof(Offsets);
  95     return Offsets;
  96   }
  97
  98   bool assignCalleeSavedSpillSlots(MachineFunction &MF,
  99       const TargetRegisterInfo *TRI, std::vector<CalleeSavedInfo> &CSI)
 100       const override;
 101
 102   bool needsAligna(const MachineFunction &MF) const;
 103   const MachineInstr *getAlignaInstr(const MachineFunction &MF) const;
 104
 105   void insertCFIInstructions(MachineFunction &MF) const;
 106
 107 private:
 108   using CSIVect = std::vector<CalleeSavedInfo>;
 109
 110   void expandAlloca(MachineInstr *AI, const HexagonInstrInfo &TII,
 111       unsigned SP, unsigned CF) const;
 112   void insertPrologueInBlock(MachineBasicBlock &MBB, bool PrologueStubs) const;
 113   void insertEpilogueInBlock(MachineBasicBlock &MBB) const;
 114   void insertAllocframe(MachineBasicBlock &MBB,
 115       MachineBasicBlock::iterator InsertPt, unsigned NumBytes) const;
 116   bool insertCSRSpillsInBlock(MachineBasicBlock &MBB, const CSIVect &CSI,
 117       const HexagonRegisterInfo &HRI, bool &PrologueStubs) const;
 118   bool insertCSRRestoresInBlock(MachineBasicBlock &MBB, const CSIVect &CSI,
 119       const HexagonRegisterInfo &HRI) const;
 120   void updateEntryPaths(MachineFunction &MF, MachineBasicBlock &SaveB) const;
 121   bool updateExitPaths(MachineBasicBlock &MBB, MachineBasicBlock &RestoreB,
 122       BitVector &DoneT, BitVector &DoneF, BitVector &Path) const;
 123   void insertCFIInstructionsAt(MachineBasicBlock &MBB,
 124       MachineBasicBlock::iterator At) const;
 125
 126   void adjustForCalleeSavedRegsSpillCall(MachineFunction &MF) const;
 127
 128   bool expandCopy(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 129       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 130       SmallVectorImpl<unsigned> &NewRegs) const;
 131   bool expandStoreInt(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 132       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 133       SmallVectorImpl<unsigned> &NewRegs) const;
 134   bool expandLoadInt(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 135       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 136       SmallVectorImpl<unsigned> &NewRegs) const;
 137   bool expandStoreVecPred(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 138       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 139       SmallVectorImpl<unsigned> &NewRegs) const;
 140   bool expandLoadVecPred(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 141       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 142       SmallVectorImpl<unsigned> &NewRegs) const;
 143   bool expandStoreVec2(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 144       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 145       SmallVectorImpl<unsigned> &NewRegs) const;
 146   bool expandLoadVec2(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 147       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 148       SmallVectorImpl<unsigned> &NewRegs) const;
 149   bool expandStoreVec(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 150       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 151       SmallVectorImpl<unsigned> &NewRegs) const;
 152   bool expandLoadVec(MachineBasicBlock &B, MachineBasicBlock::iterator It,
 153       MachineRegisterInfo &MRI, const HexagonInstrInfo &HII,
 154       SmallVectorImpl<unsigned> &NewRegs) const;
 155   bool expandSpillMacros(MachineFunction &MF,
 156       SmallVectorImpl<unsigned> &NewRegs) const;
 157
 158   unsigned findPhysReg(MachineFunction &MF, HexagonBlockRanges::IndexRange &FIR,
 159       HexagonBlockRanges::InstrIndexMap &IndexMap,
 160       HexagonBlockRanges::RegToRangeMap &DeadMap,
 161       const TargetRegisterClass *RC) const;
 162   void optimizeSpillSlots(MachineFunction &MF,
 163       SmallVectorImpl<unsigned> &VRegs) const;
 164
 165   void findShrunkPrologEpilog(MachineFunction &MF, MachineBasicBlock *&PrologB,
 166       MachineBasicBlock *&EpilogB) const;
 167
 168   void addCalleeSaveRegistersAsImpOperand(MachineInstr *MI, const CSIVect &CSI,
 169       bool IsDef, bool IsKill) const;
 170   bool shouldInlineCSR(const MachineFunction &MF, const CSIVect &CSI) const;
 171   bool useSpillFunction(const MachineFunction &MF, const CSIVect &CSI) const;
 172   bool useRestoreFunction(const MachineFunction &MF, const CSIVect &CSI) const;
 173   bool mayOverflowFrameOffset(MachineFunction &MF) const;
 174 };
 175
 176 } // end namespace llvm
 177
 178 #endif // LLVM_LIB_TARGET_HEXAGON_HEXAGONFRAMELOWERING_H