LLVM 17.0.0git
Thumb1FrameLowering.h
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1//===- Thumb1FrameLowering.h - Thumb1-specific frame info stuff ---*- 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_THUMB1FRAMELOWERING_H
10#define LLVM_LIB_TARGET_ARM_THUMB1FRAMELOWERING_H
11
12#include "ARMFrameLowering.h"
13
14namespace llvm {
15
16class ARMSubtarget;
17class MachineFunction;
18
20public:
21 explicit Thumb1FrameLowering(const ARMSubtarget &sti);
22
23 /// emitProlog/emitEpilog - These methods insert prolog and epilog code into
24 /// the function.
25 void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
26 void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
27
31 const TargetRegisterInfo *TRI) const override;
32 bool
36 const TargetRegisterInfo *TRI) const override;
37
38 bool hasReservedCallFrame(const MachineFunction &MF) const override;
39
43 MachineBasicBlock::iterator MI) const override;
44
45 /// Check whether or not the given \p MBB can be used as a epilogue
46 /// for the target.
47 /// The epilogue will be inserted before the first terminator of that block.
48 /// This method is used by the shrink-wrapping pass to decide if
49 /// \p MBB will be correctly handled by the target.
50 bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
51
52 /// Disable shrink wrap as tBfar/BL will be used to adjust for long jumps.
53 bool enableShrinkWrapping(const MachineFunction &MF) const override {
54 return false;
55 }
56
57private:
58 /// Check if the frame lowering of \p MF needs a special fixup
59 /// code sequence for the epilogue.
60 /// Unlike T2 and ARM mode, the T1 pop instruction cannot restore
61 /// to LR, and we can't pop the value directly to the PC when
62 /// we need to update the SP after popping the value. So instead
63 /// we have to emit:
64 /// POP {r3}
65 /// ADD sp, #offset
66 /// BX r3
67 /// If this would clobber a return value, then generate this sequence instead:
68 /// MOV ip, r3
69 /// POP {r3}
70 /// ADD sp, #offset
71 /// MOV lr, r3
72 /// MOV r3, ip
73 /// BX lr
74 bool needPopSpecialFixUp(const MachineFunction &MF) const;
75
76 /// Emit the special fixup code sequence for the epilogue.
77 /// \see needPopSpecialFixUp for more details.
78 /// \p DoIt, tells this method whether or not to actually insert
79 /// the code sequence in \p MBB. I.e., when \p DoIt is false,
80 /// \p MBB is left untouched.
81 /// \returns For \p DoIt == true: True when the emission succeeded
82 /// false otherwise. For \p DoIt == false: True when the emission
83 /// would have been possible, false otherwise.
84 bool emitPopSpecialFixUp(MachineBasicBlock &MBB, bool DoIt) const;
85};
86
87} // end namespace llvm
88
89#endif // LLVM_LIB_TARGET_ARM_THUMB1FRAMELOWERING_H
MachineBasicBlock & MBB
IRTranslator LLVM IR MI
unsigned const TargetRegisterInfo * TRI
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
MutableArrayRef - Represent a mutable reference to an array (0 or more elements consecutively in memo...
Definition: ArrayRef.h:305
TargetRegisterInfo base class - We assume that the target defines a static array of TargetRegisterDes...
MachineBasicBlock::iterator eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const override
This method is called during prolog/epilog code insertion to eliminate call frame setup and destroy p...
void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override
emitProlog/emitEpilog - These methods insert prolog and epilog code into the function.
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override
bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override
Check whether or not the given MBB can be used as a epilogue for the target.
bool hasReservedCallFrame(const MachineFunction &MF) const override
hasReservedCallFrame - Under normal circumstances, when a frame pointer is not required,...
bool enableShrinkWrapping(const MachineFunction &MF) const override
Disable shrink wrap as tBfar/BL will be used to adjust for long jumps.
bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, MutableArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee saved registers and returns...
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, ArrayRef< CalleeSavedInfo > CSI, const TargetRegisterInfo *TRI) const override
spillCalleeSavedRegisters - Issues instruction(s) to spill all callee saved registers and returns tru...
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18