1 //===-- MipsRegisterInfo.cpp - MIPS Register Information -== --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the MIPS implementation of the TargetRegisterInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #define DEBUG_TYPE "mips-reg-info"
15 
16 #include "MipsRegisterInfo.h"
17 #include "Mips.h"
18 #include "MipsAnalyzeImmediate.h"
19 #include "MipsInstrInfo.h"
20 #include "MipsMachineFunction.h"
21 #include "MipsSubtarget.h"
22 #include "llvm/ADT/BitVector.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/CodeGen/MachineFrameInfo.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineInstrBuilder.h"
27 #include "llvm/CodeGen/ValueTypes.h"
28 #include "llvm/DebugInfo.h"
29 #include "llvm/IR/Constants.h"
30 #include "llvm/IR/Function.h"
31 #include "llvm/IR/Type.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Target/TargetFrameLowering.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include "llvm/Target/TargetOptions.h"
40 
41 #define GET_REGINFO_TARGET_DESC
42 #include "MipsGenRegisterInfo.inc"
43 
44 using namespace llvm;
45 
46 MipsRegisterInfo::MipsRegisterInfo(const MipsSubtarget &ST)
47   : MipsGenRegisterInfo(Mips::RA), Subtarget(ST) {}
48 
49 unsigned MipsRegisterInfo::getPICCallReg() { return Mips::T9; }
50 
51 const TargetRegisterClass *
52 MipsRegisterInfo::getPointerRegClass(const MachineFunction &MF,
53                                      unsigned Kind) const {
54   return Subtarget.isABI_N64() ? &Mips::GPR64RegClass : &Mips::GPR32RegClass;
55 }
56 
57 unsigned
58 MipsRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
59                                       MachineFunction &MF) const {
60   switch (RC->getID()) {
61   default:
62     return 0;
63   case Mips::GPR32RegClassID:
64   case Mips::GPR64RegClassID:
65   case Mips::DSPRRegClassID: {
66     const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
67     return 28 - TFI->hasFP(MF);
68   }
69   case Mips::FGR32RegClassID:
70     return 32;
71   case Mips::AFGR64RegClassID:
72     return 16;
73   case Mips::FGR64RegClassID:
74     return 32;
75   }
76 }
77 
78 //===----------------------------------------------------------------------===//
79 // Callee Saved Registers methods
80 //===----------------------------------------------------------------------===//
81 
82 /// Mips Callee Saved Registers
83 const uint16_t* MipsRegisterInfo::
84 getCalleeSavedRegs(const MachineFunction *MF) const {
85   if (Subtarget.isSingleFloat())
86     return CSR_SingleFloatOnly_SaveList;
87 
88   if (Subtarget.isABI_N64())
89     return CSR_N64_SaveList;
90 
91   if (Subtarget.isABI_N32())
92     return CSR_N32_SaveList;
93 
94   if (Subtarget.isFP64bit())
95     return CSR_O32_FP64_SaveList;
96 
97   return CSR_O32_SaveList;
98 }
99 
100 const uint32_t*
101 MipsRegisterInfo::getCallPreservedMask(CallingConv::ID) const {
102   if (Subtarget.isSingleFloat())
103     return CSR_SingleFloatOnly_RegMask;
104 
105   if (Subtarget.isABI_N64())
106     return CSR_N64_RegMask;
107 
108   if (Subtarget.isABI_N32())
109     return CSR_N32_RegMask;
110 
111   if (Subtarget.isFP64bit())
112     return CSR_O32_FP64_RegMask;
113 
114   return CSR_O32_RegMask;
115 }
116 
117 const uint32_t *MipsRegisterInfo::getMips16RetHelperMask() {
118   return CSR_Mips16RetHelper_RegMask;
119 }
120 
121 BitVector MipsRegisterInfo::
122 getReservedRegs(const MachineFunction &MF) const {
123   static const uint16_t ReservedGPR32[] = {
124     Mips::ZERO, Mips::K0, Mips::K1, Mips::SP
125   };
126 
127   static const uint16_t ReservedGPR64[] = {
128     Mips::ZERO_64, Mips::K0_64, Mips::K1_64, Mips::SP_64
129   };
130 
131   BitVector Reserved(getNumRegs());
132   typedef TargetRegisterClass::const_iterator RegIter;
133 
134   for (unsigned I = 0; I < array_lengthof(ReservedGPR32); ++I)
135     Reserved.set(ReservedGPR32[I]);
136 
137   // Reserve registers for the NaCl sandbox.
138   if (Subtarget.isTargetNaCl()) {
139     Reserved.set(Mips::T6);   // Reserved for control flow mask.
140     Reserved.set(Mips::T7);   // Reserved for memory access mask.
141     Reserved.set(Mips::T8);   // Reserved for thread pointer.
142   }
143 
144   for (unsigned I = 0; I < array_lengthof(ReservedGPR64); ++I)
145     Reserved.set(ReservedGPR64[I]);
146 
147   if (Subtarget.isFP64bit()) {
148     // Reserve all registers in AFGR64.
149     for (RegIter Reg = Mips::AFGR64RegClass.begin(),
150          EReg = Mips::AFGR64RegClass.end(); Reg != EReg; ++Reg)
151       Reserved.set(*Reg);
152   } else {
153     // Reserve all registers in FGR64.
154     for (RegIter Reg = Mips::FGR64RegClass.begin(),
155          EReg = Mips::FGR64RegClass.end(); Reg != EReg; ++Reg)
156       Reserved.set(*Reg);
157   }
158   // Reserve FP if this function should have a dedicated frame pointer register.
159   if (MF.getTarget().getFrameLowering()->hasFP(MF)) {
160     if (Subtarget.inMips16Mode())
161       Reserved.set(Mips::S0);
162     else {
163       Reserved.set(Mips::FP);
164       Reserved.set(Mips::FP_64);
165     }
166   }
167 
168   // Reserve hardware registers.
169   Reserved.set(Mips::HWR29);
170 
171   // Reserve DSP control register.
172   Reserved.set(Mips::DSPPos);
173   Reserved.set(Mips::DSPSCount);
174   Reserved.set(Mips::DSPCarry);
175   Reserved.set(Mips::DSPEFI);
176   Reserved.set(Mips::DSPOutFlag);
177 
178   // Reserve MSA control registers.
179   Reserved.set(Mips::MSAIR);
180   Reserved.set(Mips::MSACSR);
181   Reserved.set(Mips::MSAAccess);
182   Reserved.set(Mips::MSASave);
183   Reserved.set(Mips::MSAModify);
184   Reserved.set(Mips::MSARequest);
185   Reserved.set(Mips::MSAMap);
186   Reserved.set(Mips::MSAUnmap);
187 
188   // Reserve RA if in mips16 mode.
189   if (Subtarget.inMips16Mode()) {
190     const MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
191     Reserved.set(Mips::RA);
192     Reserved.set(Mips::RA_64);
193     Reserved.set(Mips::T0);
194     Reserved.set(Mips::T1);
195     if (MF.getFunction()->hasFnAttribute("saveS2") || MipsFI->hasSaveS2())
196       Reserved.set(Mips::S2);
197   }
198 
199   // Reserve GP if small section is used.
200   if (Subtarget.useSmallSection()) {
201     Reserved.set(Mips::GP);
202     Reserved.set(Mips::GP_64);
203   }
204 
205   return Reserved;
206 }
207 
208 bool
209 MipsRegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
210   return true;
211 }
212 
213 bool
214 MipsRegisterInfo::trackLivenessAfterRegAlloc(const MachineFunction &MF) const {
215   return true;
216 }
217 
218 // FrameIndex represent objects inside a abstract stack.
219 // We must replace FrameIndex with an stack/frame pointer
220 // direct reference.
221 void MipsRegisterInfo::
222 eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
223                     unsigned FIOperandNum, RegScavenger *RS) const {
224   MachineInstr &MI = *II;
225   MachineFunction &MF = *MI.getParent()->getParent();
226 
227   DEBUG(errs() << "\nFunction : " << MF.getName() << "\n";
228         errs() << "<--------->\n" << MI);
229 
230   int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
231   uint64_t stackSize = MF.getFrameInfo()->getStackSize();
232   int64_t spOffset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
233 
234   DEBUG(errs() << "FrameIndex : " << FrameIndex << "\n"
235                << "spOffset   : " << spOffset << "\n"
236                << "stackSize  : " << stackSize << "\n");
237 
238   eliminateFI(MI, FIOperandNum, FrameIndex, stackSize, spOffset);
239 }
240 
241 unsigned MipsRegisterInfo::
242 getFrameRegister(const MachineFunction &MF) const {
243   const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
244   bool IsN64 = Subtarget.isABI_N64();
245 
246   if (Subtarget.inMips16Mode())
247     return TFI->hasFP(MF) ? Mips::S0 : Mips::SP;
248   else
249     return TFI->hasFP(MF) ? (IsN64 ? Mips::FP_64 : Mips::FP) :
250                             (IsN64 ? Mips::SP_64 : Mips::SP);
251 
252 }
253 
254