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