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
15namespace llvm {
16
17class ARMSubtarget;
18class CalleeSavedInfo;
19class MachineFunction;
20
21class ARMFrameLowering : public TargetFrameLowering {
22protected:
23 const ARMSubtarget &STI;
24
25public:
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
89protected:
90 bool hasFPImpl(const MachineFunction &MF) const override;
91
92private:
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 void emitFPStatusSaves(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
103 ArrayRef<CalleeSavedInfo> CSI,
104 unsigned PushOneOpc) const;
105
106 void emitFPStatusRestores(MachineBasicBlock &MBB,
107 MachineBasicBlock::iterator MI,
108 MutableArrayRef<CalleeSavedInfo> CSI,
109 unsigned LdrOpc) const;
110
111 MachineBasicBlock::iterator
112 eliminateCallFramePseudoInstr(MachineFunction &MF,
113 MachineBasicBlock &MBB,
114 MachineBasicBlock::iterator MI) const override;
115};
116
117} // end namespace llvm
118
119#endif // LLVM_LIB_TARGET_ARM_ARMFRAMELOWERING_H
120