lib/Target/ARM/ARMFrameLowering.h

   1 //===- ARMTargetFrameLowering.h - Define frame lowering for ARM -*- 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_ARM_ARMFRAMELOWERING_H
  10 #define LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H
  11
  12 #include "llvm/CodeGen/MachineBasicBlock.h"
  13 #include "llvm/CodeGen/TargetFrameLowering.h"
  14 #include <vector>
  15
  16 namespace llvm {
  17
  18 class ARMSubtarget;
  19 class CalleeSavedInfo;
  20 class MachineFunction;
  21
  22 class ARMFrameLowering : public TargetFrameLowering {
  23 protected:
  24   const ARMSubtarget &STI;
  25
  26 public:
  27   explicit ARMFrameLowering(const ARMSubtarget &sti);
  28
  29   /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
  30   /// the function.
  31   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
  32   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
  33
  34   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
  35                                  MachineBasicBlock::iterator MI,
  36                                  const std::vector<CalleeSavedInfo> &CSI,
  37                                  const TargetRegisterInfo *TRI) const override;
  38
  39   bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
  40                                   MachineBasicBlock::iterator MI,
  41                                   std::vector<CalleeSavedInfo> &CSI,
  42                                   const TargetRegisterInfo *TRI) const override;
  43
  44   bool keepFramePointer(const MachineFunction &MF) const override;
  45
  46   bool enableCalleeSaveSkip(const MachineFunction &MF) const override;
  47
  48   bool hasFP(const MachineFunction &MF) const override;
  49   bool hasReservedCallFrame(const MachineFunction &MF) const override;
  50   bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
  51   int getFrameIndexReference(const MachineFunction &MF, int FI,
  52                              unsigned &FrameReg) const override;
  53   int ResolveFrameIndexReference(const MachineFunction &MF, int FI,
  54                                  unsigned &FrameReg, int SPAdj) const;
  55
  56   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
  57                             RegScavenger *RS) const override;
  58
  59   void adjustForSegmentedStacks(MachineFunction &MF,
  60                                 MachineBasicBlock &MBB) const override;
  61
  62   /// Returns true if the target will correctly handle shrink wrapping.
  63   bool enableShrinkWrapping(const MachineFunction &MF) const override {
  64     return true;
  65   }
  66   bool isProfitableForNoCSROpt(const Function &F) const override {
  67     // The no-CSR optimisation is bad for code size on ARM, because we can save
  68     // many registers with a single PUSH/POP pair.
  69     return false;
  70   }
  71
  72 private:
  73   void emitPushInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
  74                     const std::vector<CalleeSavedInfo> &CSI, unsigned StmOpc,
  75                     unsigned StrOpc, bool NoGap,
  76                     bool(*Func)(unsigned, bool), unsigned NumAlignedDPRCS2Regs,
  77                     unsigned MIFlags = 0) const;
  78   void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
  79                    std::vector<CalleeSavedInfo> &CSI, unsigned LdmOpc,
  80                    unsigned LdrOpc, bool isVarArg, bool NoGap,
  81                    bool(*Func)(unsigned, bool),
  82                    unsigned NumAlignedDPRCS2Regs) const;
  83
  84   MachineBasicBlock::iterator
  85   eliminateCallFramePseudoInstr(MachineFunction &MF,
  86                                 MachineBasicBlock &MBB,
  87                                 MachineBasicBlock::iterator MI) const override;
  88 };
  89
  90 } // end namespace llvm
  91
  92 #endif // LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H