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1 //===-- ARMBaseRegisterInfo.h - ARM Register Information Impl ---*- 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 base ARM implementation of TargetRegisterInfo class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_ARM_ARMBASEREGISTERINFO_H
14 #define LLVM_LIB_TARGET_ARM_ARMBASEREGISTERINFO_H
15 
16 #include "MCTargetDesc/ARMBaseInfo.h"
17 #include "llvm/CodeGen/MachineBasicBlock.h"
18 #include "llvm/CodeGen/MachineInstr.h"
19 #include "llvm/CodeGen/TargetRegisterInfo.h"
20 #include "llvm/IR/CallingConv.h"
21 #include "llvm/MC/MCRegisterInfo.h"
22 #include <cstdint>
23 
24 #define GET_REGINFO_HEADER
25 #include "ARMGenRegisterInfo.inc"
26 
27 namespace llvm {
28 
29 class LiveIntervals;
30 
31 /// Register allocation hints.
32 namespace ARMRI {
33 
34   enum {
35     RegPairOdd  = 1,
36     RegPairEven = 2
37   };
38 
39 } // end namespace ARMRI
40 
41 /// isARMArea1Register - Returns true if the register is a low register (r0-r7)
42 /// or a stack/pc register that we should push/pop.
isARMArea1Register(unsigned Reg,bool isIOS)43 static inline bool isARMArea1Register(unsigned Reg, bool isIOS) {
44   using namespace ARM;
45 
46   switch (Reg) {
47     case R0:  case R1:  case R2:  case R3:
48     case R4:  case R5:  case R6:  case R7:
49     case LR:  case SP:  case PC:
50       return true;
51     case R8:  case R9:  case R10: case R11: case R12:
52       // For iOS we want r7 and lr to be next to each other.
53       return !isIOS;
54     default:
55       return false;
56   }
57 }
58 
isARMArea2Register(unsigned Reg,bool isIOS)59 static inline bool isARMArea2Register(unsigned Reg, bool isIOS) {
60   using namespace ARM;
61 
62   switch (Reg) {
63     case R8: case R9: case R10: case R11: case R12:
64       // iOS has this second area.
65       return isIOS;
66     default:
67       return false;
68   }
69 }
70 
isARMArea3Register(unsigned Reg,bool isIOS)71 static inline bool isARMArea3Register(unsigned Reg, bool isIOS) {
72   using namespace ARM;
73 
74   switch (Reg) {
75     case D15: case D14: case D13: case D12:
76     case D11: case D10: case D9:  case D8:
77     case D7:  case D6:  case D5:  case D4:
78     case D3:  case D2:  case D1:  case D0:
79     case D31: case D30: case D29: case D28:
80     case D27: case D26: case D25: case D24:
81     case D23: case D22: case D21: case D20:
82     case D19: case D18: case D17: case D16:
83       return true;
84     default:
85       return false;
86   }
87 }
88 
isCalleeSavedRegister(unsigned Reg,const MCPhysReg * CSRegs)89 static inline bool isCalleeSavedRegister(unsigned Reg,
90                                          const MCPhysReg *CSRegs) {
91   for (unsigned i = 0; CSRegs[i]; ++i)
92     if (Reg == CSRegs[i])
93       return true;
94   return false;
95 }
96 
97 class ARMBaseRegisterInfo : public ARMGenRegisterInfo {
98 protected:
99   /// BasePtr - ARM physical register used as a base ptr in complex stack
100   /// frames. I.e., when we need a 3rd base, not just SP and FP, due to
101   /// variable size stack objects.
102   unsigned BasePtr = ARM::R6;
103 
104   // Can be only subclassed.
105   explicit ARMBaseRegisterInfo();
106 
107   // Return the opcode that implements 'Op', or 0 if no opcode
108   unsigned getOpcode(int Op) const;
109 
110 public:
111   /// Code Generation virtual methods...
112   const MCPhysReg *getCalleeSavedRegs(const MachineFunction *MF) const override;
113   const MCPhysReg *
114   getCalleeSavedRegsViaCopy(const MachineFunction *MF) const;
115   const uint32_t *getCallPreservedMask(const MachineFunction &MF,
116                                        CallingConv::ID) const override;
117   const uint32_t *getNoPreservedMask() const override;
118   const uint32_t *getTLSCallPreservedMask(const MachineFunction &MF) const;
119   const uint32_t *getSjLjDispatchPreservedMask(const MachineFunction &MF) const;
120 
121   /// getThisReturnPreservedMask - Returns a call preserved mask specific to the
122   /// case that 'returned' is on an i32 first argument if the calling convention
123   /// is one that can (partially) model this attribute with a preserved mask
124   /// (i.e. it is a calling convention that uses the same register for the first
125   /// i32 argument and an i32 return value)
126   ///
127   /// Should return NULL in the case that the calling convention does not have
128   /// this property
129   const uint32_t *getThisReturnPreservedMask(const MachineFunction &MF,
130                                              CallingConv::ID) const;
131 
132   ArrayRef<MCPhysReg>
133   getIntraCallClobberedRegs(const MachineFunction *MF) const override;
134 
135   BitVector getReservedRegs(const MachineFunction &MF) const override;
136   bool isAsmClobberable(const MachineFunction &MF,
137                        unsigned PhysReg) const override;
138 
139   const TargetRegisterClass *
140   getPointerRegClass(const MachineFunction &MF,
141                      unsigned Kind = 0) const override;
142   const TargetRegisterClass *
143   getCrossCopyRegClass(const TargetRegisterClass *RC) const override;
144 
145   const TargetRegisterClass *
146   getLargestLegalSuperClass(const TargetRegisterClass *RC,
147                             const MachineFunction &MF) const override;
148 
149   unsigned getRegPressureLimit(const TargetRegisterClass *RC,
150                                MachineFunction &MF) const override;
151 
152   bool getRegAllocationHints(unsigned VirtReg,
153                              ArrayRef<MCPhysReg> Order,
154                              SmallVectorImpl<MCPhysReg> &Hints,
155                              const MachineFunction &MF,
156                              const VirtRegMap *VRM,
157                              const LiveRegMatrix *Matrix) const override;
158 
159   void updateRegAllocHint(unsigned Reg, unsigned NewReg,
160                           MachineFunction &MF) const override;
161 
162   bool hasBasePointer(const MachineFunction &MF) const;
163 
164   bool canRealignStack(const MachineFunction &MF) const override;
165   int64_t getFrameIndexInstrOffset(const MachineInstr *MI,
166                                    int Idx) const override;
167   bool needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const override;
168   void materializeFrameBaseRegister(MachineBasicBlock *MBB,
169                                     unsigned BaseReg, int FrameIdx,
170                                     int64_t Offset) const override;
171   void resolveFrameIndex(MachineInstr &MI, unsigned BaseReg,
172                          int64_t Offset) const override;
173   bool isFrameOffsetLegal(const MachineInstr *MI, unsigned BaseReg,
174                           int64_t Offset) const override;
175 
176   bool cannotEliminateFrame(const MachineFunction &MF) const;
177 
178   // Debug information queries.
179   Register getFrameRegister(const MachineFunction &MF) const override;
getBaseRegister()180   unsigned getBaseRegister() const { return BasePtr; }
181 
182 
183   /// emitLoadConstPool - Emits a load from constpool to materialize the
184   /// specified immediate.
185   virtual void
186   emitLoadConstPool(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
187                     const DebugLoc &dl, unsigned DestReg, unsigned SubIdx,
188                     int Val, ARMCC::CondCodes Pred = ARMCC::AL,
189                     unsigned PredReg = 0,
190                     unsigned MIFlags = MachineInstr::NoFlags) const;
191 
192   /// Code Generation virtual methods...
193   bool requiresRegisterScavenging(const MachineFunction &MF) const override;
194 
195   bool trackLivenessAfterRegAlloc(const MachineFunction &MF) const override;
196 
197   bool requiresFrameIndexScavenging(const MachineFunction &MF) const override;
198 
199   bool requiresVirtualBaseRegisters(const MachineFunction &MF) const override;
200 
201   void eliminateFrameIndex(MachineBasicBlock::iterator II,
202                            int SPAdj, unsigned FIOperandNum,
203                            RegScavenger *RS = nullptr) const override;
204 
205   /// SrcRC and DstRC will be morphed into NewRC if this returns true
206   bool shouldCoalesce(MachineInstr *MI,
207                       const TargetRegisterClass *SrcRC,
208                       unsigned SubReg,
209                       const TargetRegisterClass *DstRC,
210                       unsigned DstSubReg,
211                       const TargetRegisterClass *NewRC,
212                       LiveIntervals &LIS) const override;
213 };
214 
215 } // end namespace llvm
216 
217 #endif // LLVM_LIB_TARGET_ARM_ARMBASEREGISTERINFO_H
218