llvm/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/TargetFrameLowering.h"
  13 #include "llvm/Support/TypeSize.h"
  14
  15 namespace llvm {
  16
  17 class ARMSubtarget;
  18 class CalleeSavedInfo;
  19 class MachineFunction;
  20
  21 class ARMFrameLowering : public TargetFrameLowering {
  22 protected:
  23   const ARMSubtarget &STI;
  24
  25 public:
  26   explicit ARMFrameLowering(const ARMSubtarget &sti);
  27
  28   /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
  29   /// the function.
  30   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
  31   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
  32
  33   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
  34                                  MachineBasicBlock::iterator MI,
  35                                  ArrayRef<CalleeSavedInfo> CSI,
  36                                  const TargetRegisterInfo *TRI) const override;
  37
  38   bool
  39   restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
  40                               MachineBasicBlock::iterator MI,
  41                               MutableArrayRef<CalleeSavedInfo> CSI,
  42                               const TargetRegisterInfo *TRI) const override;
  43
  44   bool keepFramePointer(const MachineFunction &MF) const;
  45
  46   bool enableCalleeSaveSkip(const MachineFunction &MF) const override;
  47
  48   bool isFPReserved(const MachineFunction &MF) const;
  49   bool requiresAAPCSFrameRecord(const MachineFunction &MF) const;
  50   bool hasReservedCallFrame(const MachineFunction &MF) const override;
  51   bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
  52   StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
  53                                      Register &FrameReg) const override;
  54   int ResolveFrameIndexReference(const MachineFunction &MF, int FI,
  55                                  Register &FrameReg, int SPAdj) const;
  56
  57   void getCalleeSaves(const MachineFunction &MF,
  58                       BitVector &SavedRegs) const override;
  59   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
  60                             RegScavenger *RS) const override;
  61
  62   /// Update the IsRestored flag on LR if it is spilled, based on the return
  63   /// instructions.
  64   static void updateLRRestored(MachineFunction &MF);
  65
  66   void processFunctionBeforeFrameFinalized(
  67       MachineFunction &MF, RegScavenger *RS = nullptr) const override;
  68
  69   void adjustForSegmentedStacks(MachineFunction &MF,
  70                                 MachineBasicBlock &MBB) const override;
  71
  72   /// Returns true if the target will correctly handle shrink wrapping.
  73   bool enableShrinkWrapping(const MachineFunction &MF) const override;
  74
  75   bool isProfitableForNoCSROpt(const Function &F) const override {
  76     // The no-CSR optimisation is bad for code size on ARM, because we can save
  77     // many registers with a single PUSH/POP pair.
  78     return false;
  79   }
  80
  81   bool
  82   assignCalleeSavedSpillSlots(MachineFunction &MF,
  83                               const TargetRegisterInfo *TRI,
  84                               std::vector<CalleeSavedInfo> &CSI) const override;
  85
  86   const SpillSlot *
  87   getCalleeSavedSpillSlots(unsigned &NumEntries) const override;
  88
  89 protected:
  90   bool hasFPImpl(const MachineFunction &MF) const override;
  91
  92 private:
  93   void emitPushInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
  94                     ArrayRef<CalleeSavedInfo> CSI, unsigned StmOpc,
  95                     unsigned StrOpc, bool NoGap,
  96                     function_ref<bool(unsigned)> Func) const;
  97   void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
  98                    MutableArrayRef<CalleeSavedInfo> CSI, unsigned LdmOpc,
  99                    unsigned LdrOpc, bool isVarArg, bool NoGap,
 100                    function_ref<bool(unsigned)> Func) const;
 101
 102   MachineBasicBlock::iterator
 103   eliminateCallFramePseudoInstr(MachineFunction &MF,
 104                                 MachineBasicBlock &MBB,
 105                                 MachineBasicBlock::iterator MI) const override;
 106 };
 107
 108 } // end namespace llvm
 109
 110 #endif // LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H