1 //===-- SystemZFrameLowering.h - Frame lowering for SystemZ -----*- 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_SYSTEMZ_SYSTEMZFRAMELOWERING_H
10 #define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZFRAMELOWERING_H
11 
12 #include "MCTargetDesc/SystemZMCTargetDesc.h"
13 #include "llvm/ADT/IndexedMap.h"
14 #include "llvm/CodeGen/TargetFrameLowering.h"
15 #include "llvm/Support/TypeSize.h"
16 
17 namespace llvm {
18 class SystemZTargetMachine;
19 class SystemZSubtarget;
20 
21 class SystemZFrameLowering : public TargetFrameLowering {
22   IndexedMap<unsigned> RegSpillOffsets;
23 
24 public:
25   SystemZFrameLowering();
26 
27   // Override TargetFrameLowering.
isFPCloseToIncomingSP()28   bool isFPCloseToIncomingSP() const override { return false; }
29   bool
30   assignCalleeSavedSpillSlots(MachineFunction &MF,
31                               const TargetRegisterInfo *TRI,
32                               std::vector<CalleeSavedInfo> &CSI) const override;
33   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
34                             RegScavenger *RS) const override;
35   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
36                                  MachineBasicBlock::iterator MBBI,
37                                  ArrayRef<CalleeSavedInfo> CSI,
38                                  const TargetRegisterInfo *TRI) const override;
39   bool
40   restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
41                               MachineBasicBlock::iterator MBBII,
42                               MutableArrayRef<CalleeSavedInfo> CSI,
43                               const TargetRegisterInfo *TRI) const override;
44   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
45                                            RegScavenger *RS) const override;
46   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
47   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
48   void inlineStackProbe(MachineFunction &MF,
49                         MachineBasicBlock &PrologMBB) const override;
50   bool hasFP(const MachineFunction &MF) const override;
51   bool hasReservedCallFrame(const MachineFunction &MF) const override;
52   StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
53                                      Register &FrameReg) const override;
54   MachineBasicBlock::iterator
55   eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
56                                 MachineBasicBlock::iterator MI) const override;
57 
58   // Return the byte offset from the incoming stack pointer of Reg's
59   // ABI-defined save slot.  Return 0 if no slot is defined for Reg.  Adjust
60   // the offset in case MF has packed-stack.
61   unsigned getRegSpillOffset(MachineFunction &MF, Register Reg) const;
62 
63   // Get or create the frame index of where the old frame pointer is stored.
64   int getOrCreateFramePointerSaveIndex(MachineFunction &MF) const;
65 
66   bool usePackedStack(MachineFunction &MF) const;
67 
68   // Return the offset of the backchain.
getBackchainOffset(MachineFunction & MF)69   unsigned getBackchainOffset(MachineFunction &MF) const {
70     // The back chain is stored topmost with packed-stack.
71     return usePackedStack(MF) ? SystemZMC::ELFCallFrameSize - 8 : 0;
72   }
73 };
74 } // end namespace llvm
75 
76 #endif
77