1 //===-- RISCVFrameLowering.h - Define frame lowering for RISCV -*- 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 // This class implements RISCV-specific bits of TargetFrameLowering class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H
14 #define LLVM_LIB_TARGET_RISCV_RISCVFRAMELOWERING_H
15 
16 #include "llvm/CodeGen/TargetFrameLowering.h"
17 #include "llvm/Support/TypeSize.h"
18 
19 namespace llvm {
20 class RISCVSubtarget;
21 
22 class RISCVFrameLowering : public TargetFrameLowering {
23 public:
24   explicit RISCVFrameLowering(const RISCVSubtarget &STI)
25       : TargetFrameLowering(StackGrowsDown,
26                             /*StackAlignment=*/Align(16),
27                             /*LocalAreaOffset=*/0),
28         STI(STI) {}
29 
30   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
31   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
32 
33   StackOffset getFrameIndexReference(const MachineFunction &MF, int FI,
34                                      Register &FrameReg) const override;
35 
36   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
37                             RegScavenger *RS) const override;
38 
39   void processFunctionBeforeFrameFinalized(MachineFunction &MF,
40                                            RegScavenger *RS) const override;
41 
42   bool hasFP(const MachineFunction &MF) const override;
43 
44   bool hasBP(const MachineFunction &MF) const;
45 
46   bool hasReservedCallFrame(const MachineFunction &MF) const override;
47   MachineBasicBlock::iterator
48   eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
49                                 MachineBasicBlock::iterator MI) const override;
50   bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
51                                  MachineBasicBlock::iterator MI,
52                                  ArrayRef<CalleeSavedInfo> CSI,
53                                  const TargetRegisterInfo *TRI) const override;
54   bool
55   restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
56                               MachineBasicBlock::iterator MI,
57                               MutableArrayRef<CalleeSavedInfo> CSI,
58                               const TargetRegisterInfo *TRI) const override;
59 
60   // Get the first stack adjustment amount for SplitSPAdjust.
61   // Return 0 if we don't want to to split the SP adjustment in prologue and
62   // epilogue.
63   uint64_t getFirstSPAdjustAmount(const MachineFunction &MF) const;
64 
65   bool canUseAsPrologue(const MachineBasicBlock &MBB) const override;
66   bool canUseAsEpilogue(const MachineBasicBlock &MBB) const override;
67 
68 protected:
69   const RISCVSubtarget &STI;
70 
71 private:
72   void determineFrameLayout(MachineFunction &MF) const;
73   void adjustReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
74                  const DebugLoc &DL, Register DestReg, Register SrcReg,
75                  int64_t Val, MachineInstr::MIFlag Flag) const;
76 };
77 }
78 #endif
79