| //===- Thumb1FrameLowering.h - Thumb1-specific frame info stuff ---*- C++ -*-=// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_LIB_TARGET_ARM_THUMB1FRAMELOWERING_H |
| #define LLVM_LIB_TARGET_ARM_THUMB1FRAMELOWERING_H |
| |
| #include "ARMFrameLowering.h" |
| |
| namespace llvm { |
| |
| class ARMSubtarget; |
| class MachineFunction; |
| |
| class Thumb1FrameLowering : public ARMFrameLowering { |
| public: |
| explicit Thumb1FrameLowering(const ARMSubtarget &sti); |
| |
| /// emitProlog/emitEpilog - These methods insert prolog and epilog code into |
| /// the function. |
| void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override; |
| void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override; |
| |
| bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| const std::vector<CalleeSavedInfo> &CSI, |
| const TargetRegisterInfo *TRI) const override; |
| bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| std::vector<CalleeSavedInfo> &CSI, |
| const TargetRegisterInfo *TRI) const override; |
| |
| bool hasReservedCallFrame(const MachineFunction &MF) const override; |
| |
| MachineBasicBlock::iterator |
| eliminateCallFramePseudoInstr(MachineFunction &MF, |
| MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI) const override; |
| |
| /// Check whether or not the given \p MBB can be used as a epilogue |
| /// for the target. |
| /// The epilogue will be inserted before the first terminator of that block. |
| /// This method is used by the shrink-wrapping pass to decide if |
| /// \p MBB will be correctly handled by the target. |
| bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override; |
| |
| /// Disable shrink wrap as tBfar/BL will be used to adjust for long jumps. |
| bool enableShrinkWrapping(const MachineFunction &MF) const override { |
| return false; |
| } |
| |
| private: |
| /// Check if the frame lowering of \p MF needs a special fixup |
| /// code sequence for the epilogue. |
| /// Unlike T2 and ARM mode, the T1 pop instruction cannot restore |
| /// to LR, and we can't pop the value directly to the PC when |
| /// we need to update the SP after popping the value. So instead |
| /// we have to emit: |
| /// POP {r3} |
| /// ADD sp, #offset |
| /// BX r3 |
| /// If this would clobber a return value, then generate this sequence instead: |
| /// MOV ip, r3 |
| /// POP {r3} |
| /// ADD sp, #offset |
| /// MOV lr, r3 |
| /// MOV r3, ip |
| /// BX lr |
| bool needPopSpecialFixUp(const MachineFunction &MF) const; |
| |
| /// Emit the special fixup code sequence for the epilogue. |
| /// \see needPopSpecialFixUp for more details. |
| /// \p DoIt, tells this method whether or not to actually insert |
| /// the code sequence in \p MBB. I.e., when \p DoIt is false, |
| /// \p MBB is left untouched. |
| /// \returns For \p DoIt == true: True when the emission succeeded |
| /// false otherwise. For \p DoIt == false: True when the emission |
| /// would have been possible, false otherwise. |
| bool emitPopSpecialFixUp(MachineBasicBlock &MBB, bool DoIt) const; |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_LIB_TARGET_ARM_THUMB1FRAMELOWERING_H |