MipsRegisterInfo.cpp revision a2b2200ff8684ba23c64b24c0128a78f4b6e3c73 
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/Type.h"
31#include "llvm/Support/CommandLine.h"
32#include "llvm/Support/Debug.h"
33#include "llvm/Support/ErrorHandling.h"
34#include "llvm/Support/raw_ostream.h"
35#include "llvm/Target/TargetFrameLowering.h"
36#include "llvm/Target/TargetInstrInfo.h"
37#include "llvm/Target/TargetMachine.h"
38#include "llvm/Target/TargetOptions.h"
39
40#define GET_REGINFO_TARGET_DESC
41#include "MipsGenRegisterInfo.inc"
42
43using namespace llvm;
44
45MipsRegisterInfo::MipsRegisterInfo(const MipsSubtarget &ST)
46  : MipsGenRegisterInfo(Mips::RA), Subtarget(ST) {}
47
48unsigned MipsRegisterInfo::getPICCallReg() { return Mips::T9; }
49
50
51unsigned
52MipsRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
53                                      MachineFunction &MF) const {
54  switch (RC->getID()) {
55  default:
56    return 0;
57  case Mips::CPURegsRegClassID:
58  case Mips::CPU64RegsRegClassID:
59  case Mips::DSPRegsRegClassID: {
60    const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
61    return 28 - TFI->hasFP(MF);
62  }
63  case Mips::FGR32RegClassID:
64    return 32;
65  case Mips::AFGR64RegClassID:
66    return 16;
67  case Mips::FGR64RegClassID:
68    return 32;
69  }
70}
71
72//===----------------------------------------------------------------------===//
73// Callee Saved Registers methods
74//===----------------------------------------------------------------------===//
75
76/// Mips Callee Saved Registers
77const uint16_t* MipsRegisterInfo::
78getCalleeSavedRegs(const MachineFunction *MF) const {
79  if (Subtarget.isSingleFloat())
80    return CSR_SingleFloatOnly_SaveList;
81  else if (!Subtarget.hasMips64())
82    return CSR_O32_SaveList;
83  else if (Subtarget.isABI_N32())
84    return CSR_N32_SaveList;
85
86  assert(Subtarget.isABI_N64());
87  return CSR_N64_SaveList;
88}
89
90const uint32_t*
91MipsRegisterInfo::getCallPreservedMask(CallingConv::ID) const {
92  if (Subtarget.isSingleFloat())
93    return CSR_SingleFloatOnly_RegMask;
94  else if (!Subtarget.hasMips64())
95    return CSR_O32_RegMask;
96  else if (Subtarget.isABI_N32())
97    return CSR_N32_RegMask;
98
99  assert(Subtarget.isABI_N64());
100  return CSR_N64_RegMask;
101}
102
103BitVector MipsRegisterInfo::
104getReservedRegs(const MachineFunction &MF) const {
105  static const uint16_t ReservedCPURegs[] = {
106    Mips::ZERO, Mips::K0, Mips::K1, Mips::SP
107  };
108
109  static const uint16_t ReservedCPU64Regs[] = {
110    Mips::ZERO_64, Mips::K0_64, Mips::K1_64, Mips::SP_64
111  };
112
113  BitVector Reserved(getNumRegs());
114  typedef TargetRegisterClass::const_iterator RegIter;
115
116  for (unsigned I = 0; I < array_lengthof(ReservedCPURegs); ++I)
117    Reserved.set(ReservedCPURegs[I]);
118
119  for (unsigned I = 0; I < array_lengthof(ReservedCPU64Regs); ++I)
120    Reserved.set(ReservedCPU64Regs[I]);
121
122  if (Subtarget.hasMips64()) {
123    // Reserve all registers in AFGR64.
124    for (RegIter Reg = Mips::AFGR64RegClass.begin(),
125         EReg = Mips::AFGR64RegClass.end(); Reg != EReg; ++Reg)
126      Reserved.set(*Reg);
127  } else {
128    // Reserve all registers in FGR64.
129    for (RegIter Reg = Mips::FGR64RegClass.begin(),
130         EReg = Mips::FGR64RegClass.end(); Reg != EReg; ++Reg)
131      Reserved.set(*Reg);
132  }
133  // Reserve FP if this function should have a dedicated frame pointer register.
134  if (MF.getTarget().getFrameLowering()->hasFP(MF)) {
135    if (Subtarget.inMips16Mode())
136      Reserved.set(Mips::S0);
137    else {
138      Reserved.set(Mips::FP);
139      Reserved.set(Mips::FP_64);
140    }
141  }
142
143  // Reserve hardware registers.
144  Reserved.set(Mips::HWR29);
145  Reserved.set(Mips::HWR29_64);
146
147  // Reserve DSP control register.
148  Reserved.set(Mips::DSPPos);
149  Reserved.set(Mips::DSPSCount);
150  Reserved.set(Mips::DSPCarry);
151  Reserved.set(Mips::DSPEFI);
152  Reserved.set(Mips::DSPOutFlag);
153
154  // Reserve RA if in mips16 mode.
155  if (Subtarget.inMips16Mode()) {
156    Reserved.set(Mips::RA);
157    Reserved.set(Mips::RA_64);
158  }
159
160  // Reserve GP if small section is used.
161  if (Subtarget.useSmallSection()) {
162    Reserved.set(Mips::GP);
163    Reserved.set(Mips::GP_64);
164  }
165
166  return Reserved;
167}
168
169bool
170MipsRegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
171  return true;
172}
173
174bool
175MipsRegisterInfo::trackLivenessAfterRegAlloc(const MachineFunction &MF) const {
176  return true;
177}
178
179// FrameIndex represent objects inside a abstract stack.
180// We must replace FrameIndex with an stack/frame pointer
181// direct reference.
182void MipsRegisterInfo::
183eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
184                    unsigned FIOperandNum, RegScavenger *RS) const {
185  MachineInstr &MI = *II;
186  MachineFunction &MF = *MI.getParent()->getParent();
187
188  DEBUG(errs() << "\nFunction : " << MF.getName() << "\n";
189        errs() << "<--------->\n" << MI);
190
191  int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
192  uint64_t stackSize = MF.getFrameInfo()->getStackSize();
193  int64_t spOffset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
194
195  DEBUG(errs() << "FrameIndex : " << FrameIndex << "\n"
196               << "spOffset   : " << spOffset << "\n"
197               << "stackSize  : " << stackSize << "\n");
198
199  eliminateFI(MI, FIOperandNum, FrameIndex, stackSize, spOffset);
200}
201
202unsigned MipsRegisterInfo::
203getFrameRegister(const MachineFunction &MF) const {
204  const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
205  bool IsN64 = Subtarget.isABI_N64();
206
207  if (Subtarget.inMips16Mode())
208    return TFI->hasFP(MF) ? Mips::S0 : Mips::SP;
209  else
210    return TFI->hasFP(MF) ? (IsN64 ? Mips::FP_64 : Mips::FP) :
211                            (IsN64 ? Mips::SP_64 : Mips::SP);
212
213}
214
215unsigned MipsRegisterInfo::
216getEHExceptionRegister() const {
217  llvm_unreachable("What is the exception register");
218}
219
220unsigned MipsRegisterInfo::
221getEHHandlerRegister() const {
222  llvm_unreachable("What is the exception handler register");
223}
224