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                                  ArrayRef<CalleeSavedInfo> CSI,
37                                  const TargetRegisterInfo *TRI) const override;
38 
39   bool
40   restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
41                               MachineBasicBlock::iterator MI,
42                               MutableArrayRef<CalleeSavedInfo> CSI,
43                               const TargetRegisterInfo *TRI) const override;
44 
45   bool keepFramePointer(const MachineFunction &MF) const override;
46 
47   bool enableCalleeSaveSkip(const MachineFunction &MF) const override;
48 
49   bool hasFP(const MachineFunction &MF) const override;
50   bool hasReservedCallFrame(const MachineFunction &MF) const override;
51   bool canSimplifyCallFramePseudos(const MachineFunction &MF) const override;
52   int getFrameIndexReference(const MachineFunction &MF, int FI,
53                              unsigned &FrameReg) const override;
54   int ResolveFrameIndexReference(const MachineFunction &MF, int FI,
55                                  unsigned &FrameReg, int SPAdj) const;
56 
57   void getCalleeSaves(const MachineFunction &MF,
58                       BitVector &SavedRegs) const override;
59   void findRegDefsOutsideSaveRestore(MachineFunction &MF,
60                                      BitVector &Regs) const;
61   unsigned spillExtraRegsForIPRA(MachineFunction &MF, BitVector &SavedRegs,
62                                  bool HasFPRegSaves) const;
63   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
64                             RegScavenger *RS) const override;
65 
66   void adjustForSegmentedStacks(MachineFunction &MF,
67                                 MachineBasicBlock &MBB) const override;
68 
69   /// Returns true if the target will correctly handle shrink wrapping.
70   bool enableShrinkWrapping(const MachineFunction &MF) const override;
71 
72   bool isProfitableForNoCSROpt(const Function &F) const override {
73     // The no-CSR optimisation is bad for code size on ARM, because we can save
74     // many registers with a single PUSH/POP pair.
75     return false;
76   }
77 
78 private:
79   void emitPushInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
80                     ArrayRef<CalleeSavedInfo> CSI, unsigned StmOpc,
81                     unsigned StrOpc, bool NoGap, bool (*Func)(unsigned, bool),
82                     unsigned NumAlignedDPRCS2Regs, unsigned MIFlags = 0) const;
83   void emitPopInst(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
84                    MutableArrayRef<CalleeSavedInfo> CSI, unsigned LdmOpc,
85                    unsigned LdrOpc, bool isVarArg, bool NoGap,
86                    bool (*Func)(unsigned, bool),
87                    unsigned NumAlignedDPRCS2Regs) const;
88 
89   MachineBasicBlock::iterator
90   eliminateCallFramePseudoInstr(MachineFunction &MF,
91                                 MachineBasicBlock &MBB,
92                                 MachineBasicBlock::iterator MI) const override;
93 };
94 
95 } // end namespace llvm
96 
97 #endif // LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H
98