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1 //===- MipsInstrInfo.h - Mips Instruction Information -----------*- 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 file contains the Mips implementation of the TargetInstrInfo class.
10 //
11 // FIXME: We need to override TargetInstrInfo::getInlineAsmLength method in
12 // order for MipsLongBranch pass to work correctly when the code has inline
13 // assembly.  The returned value doesn't have to be the asm instruction's exact
14 // size in bytes; MipsLongBranch only expects it to be the correct upper bound.
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef LLVM_LIB_TARGET_MIPS_MIPSINSTRINFO_H
18 #define LLVM_LIB_TARGET_MIPS_MIPSINSTRINFO_H
19 
20 #include "MCTargetDesc/MipsMCTargetDesc.h"
21 #include "Mips.h"
22 #include "MipsRegisterInfo.h"
23 #include "llvm/ADT/ArrayRef.h"
24 #include "llvm/CodeGen/MachineBasicBlock.h"
25 #include "llvm/CodeGen/MachineInstrBuilder.h"
26 #include "llvm/CodeGen/MachineMemOperand.h"
27 #include "llvm/CodeGen/TargetInstrInfo.h"
28 #include <cstdint>
29 
30 #define GET_INSTRINFO_HEADER
31 #include "MipsGenInstrInfo.inc"
32 
33 namespace llvm {
34 
35 class MachineInstr;
36 class MachineOperand;
37 class MipsSubtarget;
38 class TargetRegisterClass;
39 class TargetRegisterInfo;
40 
41 class MipsInstrInfo : public MipsGenInstrInfo {
42   virtual void anchor();
43 
44 protected:
45   const MipsSubtarget &Subtarget;
46   unsigned UncondBrOpc;
47 
48 public:
49   enum BranchType {
50     BT_None,       // Couldn't analyze branch.
51     BT_NoBranch,   // No branches found.
52     BT_Uncond,     // One unconditional branch.
53     BT_Cond,       // One conditional branch.
54     BT_CondUncond, // A conditional branch followed by an unconditional branch.
55     BT_Indirect    // One indirct branch.
56   };
57 
58   explicit MipsInstrInfo(const MipsSubtarget &STI, unsigned UncondBrOpc);
59 
60   static const MipsInstrInfo *create(MipsSubtarget &STI);
61 
62   /// Branch Analysis
63   bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
64                      MachineBasicBlock *&FBB,
65                      SmallVectorImpl<MachineOperand> &Cond,
66                      bool AllowModify) const override;
67 
68   unsigned removeBranch(MachineBasicBlock &MBB,
69                         int *BytesRemoved = nullptr) const override;
70 
71   unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
72                         MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
73                         const DebugLoc &DL,
74                         int *BytesAdded = nullptr) const override;
75 
76   bool
77   reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
78 
79   BranchType analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
80                            MachineBasicBlock *&FBB,
81                            SmallVectorImpl<MachineOperand> &Cond,
82                            bool AllowModify,
83                            SmallVectorImpl<MachineInstr *> &BranchInstrs) const;
84 
85   /// Determine the opcode of a non-delay slot form for a branch if one exists.
86   unsigned getEquivalentCompactForm(const MachineBasicBlock::iterator I) const;
87 
88   /// Determine if the branch target is in range.
89   bool isBranchOffsetInRange(unsigned BranchOpc,
90                              int64_t BrOffset) const override;
91 
92   /// Predicate to determine if an instruction can go in a forbidden slot.
93   bool SafeInForbiddenSlot(const MachineInstr &MI) const;
94 
95   /// Predicate to determine if an instruction has a forbidden slot.
96   bool HasForbiddenSlot(const MachineInstr &MI) const;
97 
98   /// Insert nop instruction when hazard condition is found
99   void insertNoop(MachineBasicBlock &MBB,
100                   MachineBasicBlock::iterator MI) const override;
101 
102   /// getRegisterInfo - TargetInstrInfo is a superset of MRegister info.  As
103   /// such, whenever a client has an instance of instruction info, it should
104   /// always be able to get register info as well (through this method).
105   virtual const MipsRegisterInfo &getRegisterInfo() const = 0;
106 
107   virtual unsigned getOppositeBranchOpc(unsigned Opc) const = 0;
108 
109   /// Return the number of bytes of code the specified instruction may be.
110   unsigned getInstSizeInBytes(const MachineInstr &MI) const override;
111 
storeRegToStackSlot(MachineBasicBlock & MBB,MachineBasicBlock::iterator MBBI,unsigned SrcReg,bool isKill,int FrameIndex,const TargetRegisterClass * RC,const TargetRegisterInfo * TRI)112   void storeRegToStackSlot(MachineBasicBlock &MBB,
113                            MachineBasicBlock::iterator MBBI,
114                            unsigned SrcReg, bool isKill, int FrameIndex,
115                            const TargetRegisterClass *RC,
116                            const TargetRegisterInfo *TRI) const override {
117     storeRegToStack(MBB, MBBI, SrcReg, isKill, FrameIndex, RC, TRI, 0);
118   }
119 
loadRegFromStackSlot(MachineBasicBlock & MBB,MachineBasicBlock::iterator MBBI,unsigned DestReg,int FrameIndex,const TargetRegisterClass * RC,const TargetRegisterInfo * TRI)120   void loadRegFromStackSlot(MachineBasicBlock &MBB,
121                             MachineBasicBlock::iterator MBBI,
122                             unsigned DestReg, int FrameIndex,
123                             const TargetRegisterClass *RC,
124                             const TargetRegisterInfo *TRI) const override {
125     loadRegFromStack(MBB, MBBI, DestReg, FrameIndex, RC, TRI, 0);
126   }
127 
128   virtual void storeRegToStack(MachineBasicBlock &MBB,
129                                MachineBasicBlock::iterator MI,
130                                unsigned SrcReg, bool isKill, int FrameIndex,
131                                const TargetRegisterClass *RC,
132                                const TargetRegisterInfo *TRI,
133                                int64_t Offset) const = 0;
134 
135   virtual void loadRegFromStack(MachineBasicBlock &MBB,
136                                 MachineBasicBlock::iterator MI,
137                                 unsigned DestReg, int FrameIndex,
138                                 const TargetRegisterClass *RC,
139                                 const TargetRegisterInfo *TRI,
140                                 int64_t Offset) const = 0;
141 
142   virtual void adjustStackPtr(unsigned SP, int64_t Amount,
143                               MachineBasicBlock &MBB,
144                               MachineBasicBlock::iterator I) const = 0;
145 
146   /// Create an instruction which has the same operands and memory operands
147   /// as MI but has a new opcode.
148   MachineInstrBuilder genInstrWithNewOpc(unsigned NewOpc,
149                                          MachineBasicBlock::iterator I) const;
150 
151   bool findCommutedOpIndices(const MachineInstr &MI, unsigned &SrcOpIdx1,
152                              unsigned &SrcOpIdx2) const override;
153 
154   /// Perform target specific instruction verification.
155   bool verifyInstruction(const MachineInstr &MI,
156                          StringRef &ErrInfo) const override;
157 
158   std::pair<unsigned, unsigned>
159   decomposeMachineOperandsTargetFlags(unsigned TF) const override;
160 
161   ArrayRef<std::pair<unsigned, const char *>>
162   getSerializableDirectMachineOperandTargetFlags() const override;
163 
164 protected:
165   bool isZeroImm(const MachineOperand &op) const;
166 
167   MachineMemOperand *GetMemOperand(MachineBasicBlock &MBB, int FI,
168                                    MachineMemOperand::Flags Flags) const;
169 
170 private:
171   virtual unsigned getAnalyzableBrOpc(unsigned Opc) const = 0;
172 
173   void AnalyzeCondBr(const MachineInstr *Inst, unsigned Opc,
174                      MachineBasicBlock *&BB,
175                      SmallVectorImpl<MachineOperand> &Cond) const;
176 
177   void BuildCondBr(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
178                    const DebugLoc &DL, ArrayRef<MachineOperand> Cond) const;
179 };
180 
181 /// Create MipsInstrInfo objects.
182 const MipsInstrInfo *createMips16InstrInfo(const MipsSubtarget &STI);
183 const MipsInstrInfo *createMipsSEInstrInfo(const MipsSubtarget &STI);
184 
185 } // end namespace llvm
186 
187 #endif // LLVM_LIB_TARGET_MIPS_MIPSINSTRINFO_H
188