ARMBaseRegisterInfo.cpp revision 6c7d3a16b3321c527e35322e869c73d47dba719d 
1//===- ARMBaseRegisterInfo.cpp - ARM Register Information -------*- C++ -*-===//
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 base ARM implementation of TargetRegisterInfo class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "ARM.h"
15#include "ARMAddressingModes.h"
16#include "ARMBaseInstrInfo.h"
17#include "ARMBaseRegisterInfo.h"
18#include "ARMInstrInfo.h"
19#include "ARMMachineFunctionInfo.h"
20#include "ARMSubtarget.h"
21#include "llvm/Constants.h"
22#include "llvm/DerivedTypes.h"
23#include "llvm/Function.h"
24#include "llvm/LLVMContext.h"
25#include "llvm/CodeGen/MachineConstantPool.h"
26#include "llvm/CodeGen/MachineFrameInfo.h"
27#include "llvm/CodeGen/MachineFunction.h"
28#include "llvm/CodeGen/MachineInstrBuilder.h"
29#include "llvm/CodeGen/MachineLocation.h"
30#include "llvm/CodeGen/MachineRegisterInfo.h"
31#include "llvm/CodeGen/RegisterScavenging.h"
32#include "llvm/Support/Debug.h"
33#include "llvm/Support/ErrorHandling.h"
34#include "llvm/Support/raw_ostream.h"
35#include "llvm/Target/TargetFrameInfo.h"
36#include "llvm/Target/TargetMachine.h"
37#include "llvm/Target/TargetOptions.h"
38#include "llvm/ADT/BitVector.h"
39#include "llvm/ADT/SmallVector.h"
40#include "llvm/Support/CommandLine.h"
41
42namespace llvm {
43cl::opt<bool>
44ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
45          cl::desc("Reuse repeated frame index values"));
46}
47
48using namespace llvm;
49
50unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
51                                                   bool *isSPVFP) {
52  if (isSPVFP)
53    *isSPVFP = false;
54
55  using namespace ARM;
56  switch (RegEnum) {
57  default:
58    llvm_unreachable("Unknown ARM register!");
59  case R0:  case D0:  case Q0:  return 0;
60  case R1:  case D1:  case Q1:  return 1;
61  case R2:  case D2:  case Q2:  return 2;
62  case R3:  case D3:  case Q3:  return 3;
63  case R4:  case D4:  case Q4:  return 4;
64  case R5:  case D5:  case Q5:  return 5;
65  case R6:  case D6:  case Q6:  return 6;
66  case R7:  case D7:  case Q7:  return 7;
67  case R8:  case D8:  case Q8:  return 8;
68  case R9:  case D9:  case Q9:  return 9;
69  case R10: case D10: case Q10: return 10;
70  case R11: case D11: case Q11: return 11;
71  case R12: case D12: case Q12: return 12;
72  case SP:  case D13: case Q13: return 13;
73  case LR:  case D14: case Q14: return 14;
74  case PC:  case D15: case Q15: return 15;
75
76  case D16: return 16;
77  case D17: return 17;
78  case D18: return 18;
79  case D19: return 19;
80  case D20: return 20;
81  case D21: return 21;
82  case D22: return 22;
83  case D23: return 23;
84  case D24: return 24;
85  case D25: return 25;
86  case D26: return 26;
87  case D27: return 27;
88  case D28: return 28;
89  case D29: return 29;
90  case D30: return 30;
91  case D31: return 31;
92
93  case S0: case S1: case S2: case S3:
94  case S4: case S5: case S6: case S7:
95  case S8: case S9: case S10: case S11:
96  case S12: case S13: case S14: case S15:
97  case S16: case S17: case S18: case S19:
98  case S20: case S21: case S22: case S23:
99  case S24: case S25: case S26: case S27:
100  case S28: case S29: case S30: case S31: {
101    if (isSPVFP)
102      *isSPVFP = true;
103    switch (RegEnum) {
104    default: return 0; // Avoid compile time warning.
105    case S0: return 0;
106    case S1: return 1;
107    case S2: return 2;
108    case S3: return 3;
109    case S4: return 4;
110    case S5: return 5;
111    case S6: return 6;
112    case S7: return 7;
113    case S8: return 8;
114    case S9: return 9;
115    case S10: return 10;
116    case S11: return 11;
117    case S12: return 12;
118    case S13: return 13;
119    case S14: return 14;
120    case S15: return 15;
121    case S16: return 16;
122    case S17: return 17;
123    case S18: return 18;
124    case S19: return 19;
125    case S20: return 20;
126    case S21: return 21;
127    case S22: return 22;
128    case S23: return 23;
129    case S24: return 24;
130    case S25: return 25;
131    case S26: return 26;
132    case S27: return 27;
133    case S28: return 28;
134    case S29: return 29;
135    case S30: return 30;
136    case S31: return 31;
137    }
138  }
139  }
140}
141
142ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
143                                         const ARMSubtarget &sti)
144  : ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
145    TII(tii), STI(sti),
146    FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
147}
148
149const unsigned*
150ARMBaseRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
151  static const unsigned CalleeSavedRegs[] = {
152    ARM::LR, ARM::R11, ARM::R10, ARM::R9, ARM::R8,
153    ARM::R7, ARM::R6,  ARM::R5,  ARM::R4,
154
155    ARM::D15, ARM::D14, ARM::D13, ARM::D12,
156    ARM::D11, ARM::D10, ARM::D9,  ARM::D8,
157    0
158  };
159
160  static const unsigned DarwinCalleeSavedRegs[] = {
161    // Darwin ABI deviates from ARM standard ABI. R9 is not a callee-saved
162    // register.
163    ARM::LR,  ARM::R7,  ARM::R6, ARM::R5, ARM::R4,
164    ARM::R11, ARM::R10, ARM::R8,
165
166    ARM::D15, ARM::D14, ARM::D13, ARM::D12,
167    ARM::D11, ARM::D10, ARM::D9,  ARM::D8,
168    0
169  };
170  return STI.isTargetDarwin() ? DarwinCalleeSavedRegs : CalleeSavedRegs;
171}
172
173BitVector ARMBaseRegisterInfo::
174getReservedRegs(const MachineFunction &MF) const {
175  // FIXME: avoid re-calculating this everytime.
176  BitVector Reserved(getNumRegs());
177  Reserved.set(ARM::SP);
178  Reserved.set(ARM::PC);
179  if (STI.isTargetDarwin() || hasFP(MF))
180    Reserved.set(FramePtr);
181  // Some targets reserve R9.
182  if (STI.isR9Reserved())
183    Reserved.set(ARM::R9);
184  return Reserved;
185}
186
187bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
188                                        unsigned Reg) const {
189  switch (Reg) {
190  default: break;
191  case ARM::SP:
192  case ARM::PC:
193    return true;
194  case ARM::R7:
195  case ARM::R11:
196    if (FramePtr == Reg && (STI.isTargetDarwin() || hasFP(MF)))
197      return true;
198    break;
199  case ARM::R9:
200    return STI.isR9Reserved();
201  }
202
203  return false;
204}
205
206const TargetRegisterClass *
207ARMBaseRegisterInfo::getMatchingSuperRegClass(const TargetRegisterClass *A,
208                                              const TargetRegisterClass *B,
209                                              unsigned SubIdx) const {
210  switch (SubIdx) {
211  default: return 0;
212  case ARM::ssub_0:
213  case ARM::ssub_1:
214  case ARM::ssub_2:
215  case ARM::ssub_3: {
216    // S sub-registers.
217    if (A->getSize() == 8) {
218      if (B == &ARM::SPR_8RegClass)
219        return &ARM::DPR_8RegClass;
220      assert(B == &ARM::SPRRegClass && "Expecting SPR register class!");
221      if (A == &ARM::DPR_8RegClass)
222        return A;
223      return &ARM::DPR_VFP2RegClass;
224    }
225
226    if (A->getSize() == 16) {
227      if (B == &ARM::SPR_8RegClass)
228        return &ARM::QPR_8RegClass;
229      return &ARM::QPR_VFP2RegClass;
230    }
231
232    if (A->getSize() == 32) {
233      if (B == &ARM::SPR_8RegClass)
234        return 0;  // Do not allow coalescing!
235      return &ARM::QQPR_VFP2RegClass;
236    }
237
238    assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
239    return 0;  // Do not allow coalescing!
240  }
241  case ARM::dsub_0:
242  case ARM::dsub_1:
243  case ARM::dsub_2:
244  case ARM::dsub_3: {
245    // D sub-registers.
246    if (A->getSize() == 16) {
247      if (B == &ARM::DPR_VFP2RegClass)
248        return &ARM::QPR_VFP2RegClass;
249      if (B == &ARM::DPR_8RegClass)
250        return 0;  // Do not allow coalescing!
251      return A;
252    }
253
254    if (A->getSize() == 32) {
255      if (B == &ARM::DPR_VFP2RegClass)
256        return &ARM::QQPR_VFP2RegClass;
257      if (B == &ARM::DPR_8RegClass)
258        return 0;  // Do not allow coalescing!
259      return A;
260    }
261
262    assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
263    if (B != &ARM::DPRRegClass)
264      return 0;  // Do not allow coalescing!
265    return A;
266  }
267  case ARM::dsub_4:
268  case ARM::dsub_5:
269  case ARM::dsub_6:
270  case ARM::dsub_7: {
271    // D sub-registers of QQQQ registers.
272    if (A->getSize() == 64 && B == &ARM::DPRRegClass)
273      return A;
274    return 0;  // Do not allow coalescing!
275  }
276
277  case ARM::qsub_0:
278  case ARM::qsub_1: {
279    // Q sub-registers.
280    if (A->getSize() == 32) {
281      if (B == &ARM::QPR_VFP2RegClass)
282        return &ARM::QQPR_VFP2RegClass;
283      if (B == &ARM::QPR_8RegClass)
284        return 0;  // Do not allow coalescing!
285      return A;
286    }
287
288    assert(A->getSize() == 64 && "Expecting a QQQQ register class!");
289    if (B == &ARM::QPRRegClass)
290      return A;
291    return 0;  // Do not allow coalescing!
292  }
293  case ARM::qsub_2:
294  case ARM::qsub_3: {
295    // Q sub-registers of QQQQ registers.
296    if (A->getSize() == 64 && B == &ARM::QPRRegClass)
297      return A;
298    return 0;  // Do not allow coalescing!
299  }
300  }
301  return 0;
302}
303
304bool
305ARMBaseRegisterInfo::canCombineSubRegIndices(const TargetRegisterClass *RC,
306                                          SmallVectorImpl<unsigned> &SubIndices,
307                                          unsigned &NewSubIdx) const {
308
309  unsigned Size = RC->getSize() * 8;
310  if (Size < 6)
311    return 0;
312
313  NewSubIdx = 0;  // Whole register.
314  unsigned NumRegs = SubIndices.size();
315  if (NumRegs == 8) {
316    // 8 D registers -> 1 QQQQ register.
317    return (Size == 512 &&
318            SubIndices[0] == ARM::dsub_0 &&
319            SubIndices[1] == ARM::dsub_1 &&
320            SubIndices[2] == ARM::dsub_2 &&
321            SubIndices[3] == ARM::dsub_3 &&
322            SubIndices[4] == ARM::dsub_4 &&
323            SubIndices[5] == ARM::dsub_5 &&
324            SubIndices[6] == ARM::dsub_6 &&
325            SubIndices[7] == ARM::dsub_7);
326  } else if (NumRegs == 4) {
327    if (SubIndices[0] == ARM::qsub_0) {
328      // 4 Q registers -> 1 QQQQ register.
329      return (Size == 512 &&
330              SubIndices[1] == ARM::qsub_1 &&
331              SubIndices[2] == ARM::qsub_2 &&
332              SubIndices[3] == ARM::qsub_3);
333    } else if (SubIndices[0] == ARM::dsub_0) {
334      // 4 D registers -> 1 QQ register.
335      if (Size >= 256 &&
336          SubIndices[1] == ARM::dsub_1 &&
337          SubIndices[2] == ARM::dsub_2 &&
338          SubIndices[3] == ARM::dsub_3) {
339        if (Size == 512)
340          NewSubIdx = ARM::qqsub_0;
341        return true;
342      }
343    } else if (SubIndices[0] == ARM::dsub_4) {
344      // 4 D registers -> 1 QQ register (2nd).
345      if (Size == 512 &&
346          SubIndices[1] == ARM::dsub_5 &&
347          SubIndices[2] == ARM::dsub_6 &&
348          SubIndices[3] == ARM::dsub_7) {
349        NewSubIdx = ARM::qqsub_1;
350        return true;
351      }
352    } else if (SubIndices[0] == ARM::ssub_0) {
353      // 4 S registers -> 1 Q register.
354      if (Size >= 128 &&
355          SubIndices[1] == ARM::ssub_1 &&
356          SubIndices[2] == ARM::ssub_2 &&
357          SubIndices[3] == ARM::ssub_3) {
358        if (Size >= 256)
359          NewSubIdx = ARM::qsub_0;
360        return true;
361      }
362    }
363  } else if (NumRegs == 2) {
364    if (SubIndices[0] == ARM::qsub_0) {
365      // 2 Q registers -> 1 QQ register.
366      if (Size >= 256 && SubIndices[1] == ARM::qsub_1) {
367        if (Size == 512)
368          NewSubIdx = ARM::qqsub_0;
369        return true;
370      }
371    } else if (SubIndices[0] == ARM::qsub_2) {
372      // 2 Q registers -> 1 QQ register (2nd).
373      if (Size == 512 && SubIndices[1] == ARM::qsub_3) {
374        NewSubIdx = ARM::qqsub_1;
375        return true;
376      }
377    } else if (SubIndices[0] == ARM::dsub_0) {
378      // 2 D registers -> 1 Q register.
379      if (Size >= 128 && SubIndices[1] == ARM::dsub_1) {
380        if (Size >= 256)
381          NewSubIdx = ARM::qsub_0;
382        return true;
383      }
384    } else if (SubIndices[0] == ARM::dsub_2) {
385      // 2 D registers -> 1 Q register (2nd).
386      if (Size >= 256 && SubIndices[1] == ARM::dsub_3) {
387        NewSubIdx = ARM::qsub_1;
388        return true;
389      }
390    } else if (SubIndices[0] == ARM::dsub_4) {
391      // 2 D registers -> 1 Q register (3rd).
392      if (Size == 512 && SubIndices[1] == ARM::dsub_5) {
393        NewSubIdx = ARM::qsub_2;
394        return true;
395      }
396    } else if (SubIndices[0] == ARM::dsub_6) {
397      // 2 D registers -> 1 Q register (3rd).
398      if (Size == 512 && SubIndices[1] == ARM::dsub_7) {
399        NewSubIdx = ARM::qsub_3;
400        return true;
401      }
402    } else if (SubIndices[0] == ARM::ssub_0) {
403      // 2 S registers -> 1 D register.
404      if (SubIndices[1] == ARM::ssub_1) {
405        if (Size >= 128)
406          NewSubIdx = ARM::dsub_0;
407        return true;
408      }
409    } else if (SubIndices[0] == ARM::ssub_2) {
410      // 2 S registers -> 1 D register (2nd).
411      if (Size >= 128 && SubIndices[1] == ARM::ssub_3) {
412        NewSubIdx = ARM::dsub_1;
413        return true;
414      }
415    }
416  }
417  return false;
418}
419
420
421const TargetRegisterClass *
422ARMBaseRegisterInfo::getPointerRegClass(unsigned Kind) const {
423  return ARM::GPRRegisterClass;
424}
425
426/// getAllocationOrder - Returns the register allocation order for a specified
427/// register class in the form of a pair of TargetRegisterClass iterators.
428std::pair<TargetRegisterClass::iterator,TargetRegisterClass::iterator>
429ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
430                                        unsigned HintType, unsigned HintReg,
431                                        const MachineFunction &MF) const {
432  // Alternative register allocation orders when favoring even / odd registers
433  // of register pairs.
434
435  // No FP, R9 is available.
436  static const unsigned GPREven1[] = {
437    ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8, ARM::R10,
438    ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7,
439    ARM::R9, ARM::R11
440  };
441  static const unsigned GPROdd1[] = {
442    ARM::R1, ARM::R3, ARM::R5, ARM::R7, ARM::R9, ARM::R11,
443    ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
444    ARM::R8, ARM::R10
445  };
446
447  // FP is R7, R9 is available.
448  static const unsigned GPREven2[] = {
449    ARM::R0, ARM::R2, ARM::R4,          ARM::R8, ARM::R10,
450    ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6,
451    ARM::R9, ARM::R11
452  };
453  static const unsigned GPROdd2[] = {
454    ARM::R1, ARM::R3, ARM::R5,          ARM::R9, ARM::R11,
455    ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6,
456    ARM::R8, ARM::R10
457  };
458
459  // FP is R11, R9 is available.
460  static const unsigned GPREven3[] = {
461    ARM::R0, ARM::R2, ARM::R4, ARM::R6, ARM::R8,
462    ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7,
463    ARM::R9
464  };
465  static const unsigned GPROdd3[] = {
466    ARM::R1, ARM::R3, ARM::R5, ARM::R6, ARM::R9,
467    ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R7,
468    ARM::R8
469  };
470
471  // No FP, R9 is not available.
472  static const unsigned GPREven4[] = {
473    ARM::R0, ARM::R2, ARM::R4, ARM::R6,          ARM::R10,
474    ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8,
475    ARM::R11
476  };
477  static const unsigned GPROdd4[] = {
478    ARM::R1, ARM::R3, ARM::R5, ARM::R7,          ARM::R11,
479    ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
480    ARM::R10
481  };
482
483  // FP is R7, R9 is not available.
484  static const unsigned GPREven5[] = {
485    ARM::R0, ARM::R2, ARM::R4,                   ARM::R10,
486    ARM::R1, ARM::R3, ARM::R12,ARM::LR, ARM::R5, ARM::R6, ARM::R8,
487    ARM::R11
488  };
489  static const unsigned GPROdd5[] = {
490    ARM::R1, ARM::R3, ARM::R5,                   ARM::R11,
491    ARM::R0, ARM::R2, ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8,
492    ARM::R10
493  };
494
495  // FP is R11, R9 is not available.
496  static const unsigned GPREven6[] = {
497    ARM::R0, ARM::R2, ARM::R4, ARM::R6,
498    ARM::R1, ARM::R3, ARM::R10,ARM::R12,ARM::LR, ARM::R5, ARM::R7, ARM::R8
499  };
500  static const unsigned GPROdd6[] = {
501    ARM::R1, ARM::R3, ARM::R5, ARM::R7,
502    ARM::R0, ARM::R2, ARM::R10,ARM::R12,ARM::LR, ARM::R4, ARM::R6, ARM::R8
503  };
504
505
506  if (HintType == ARMRI::RegPairEven) {
507    if (isPhysicalRegister(HintReg) && getRegisterPairEven(HintReg, MF) == 0)
508      // It's no longer possible to fulfill this hint. Return the default
509      // allocation order.
510      return std::make_pair(RC->allocation_order_begin(MF),
511                            RC->allocation_order_end(MF));
512
513    if (!STI.isTargetDarwin() && !hasFP(MF)) {
514      if (!STI.isR9Reserved())
515        return std::make_pair(GPREven1,
516                              GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
517      else
518        return std::make_pair(GPREven4,
519                              GPREven4 + (sizeof(GPREven4)/sizeof(unsigned)));
520    } else if (FramePtr == ARM::R7) {
521      if (!STI.isR9Reserved())
522        return std::make_pair(GPREven2,
523                              GPREven2 + (sizeof(GPREven2)/sizeof(unsigned)));
524      else
525        return std::make_pair(GPREven5,
526                              GPREven5 + (sizeof(GPREven5)/sizeof(unsigned)));
527    } else { // FramePtr == ARM::R11
528      if (!STI.isR9Reserved())
529        return std::make_pair(GPREven3,
530                              GPREven3 + (sizeof(GPREven3)/sizeof(unsigned)));
531      else
532        return std::make_pair(GPREven6,
533                              GPREven6 + (sizeof(GPREven6)/sizeof(unsigned)));
534    }
535  } else if (HintType == ARMRI::RegPairOdd) {
536    if (isPhysicalRegister(HintReg) && getRegisterPairOdd(HintReg, MF) == 0)
537      // It's no longer possible to fulfill this hint. Return the default
538      // allocation order.
539      return std::make_pair(RC->allocation_order_begin(MF),
540                            RC->allocation_order_end(MF));
541
542    if (!STI.isTargetDarwin() && !hasFP(MF)) {
543      if (!STI.isR9Reserved())
544        return std::make_pair(GPROdd1,
545                              GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
546      else
547        return std::make_pair(GPROdd4,
548                              GPROdd4 + (sizeof(GPROdd4)/sizeof(unsigned)));
549    } else if (FramePtr == ARM::R7) {
550      if (!STI.isR9Reserved())
551        return std::make_pair(GPROdd2,
552                              GPROdd2 + (sizeof(GPROdd2)/sizeof(unsigned)));
553      else
554        return std::make_pair(GPROdd5,
555                              GPROdd5 + (sizeof(GPROdd5)/sizeof(unsigned)));
556    } else { // FramePtr == ARM::R11
557      if (!STI.isR9Reserved())
558        return std::make_pair(GPROdd3,
559                              GPROdd3 + (sizeof(GPROdd3)/sizeof(unsigned)));
560      else
561        return std::make_pair(GPROdd6,
562                              GPROdd6 + (sizeof(GPROdd6)/sizeof(unsigned)));
563    }
564  }
565  return std::make_pair(RC->allocation_order_begin(MF),
566                        RC->allocation_order_end(MF));
567}
568
569/// ResolveRegAllocHint - Resolves the specified register allocation hint
570/// to a physical register. Returns the physical register if it is successful.
571unsigned
572ARMBaseRegisterInfo::ResolveRegAllocHint(unsigned Type, unsigned Reg,
573                                         const MachineFunction &MF) const {
574  if (Reg == 0 || !isPhysicalRegister(Reg))
575    return 0;
576  if (Type == 0)
577    return Reg;
578  else if (Type == (unsigned)ARMRI::RegPairOdd)
579    // Odd register.
580    return getRegisterPairOdd(Reg, MF);
581  else if (Type == (unsigned)ARMRI::RegPairEven)
582    // Even register.
583    return getRegisterPairEven(Reg, MF);
584  return 0;
585}
586
587void
588ARMBaseRegisterInfo::UpdateRegAllocHint(unsigned Reg, unsigned NewReg,
589                                        MachineFunction &MF) const {
590  MachineRegisterInfo *MRI = &MF.getRegInfo();
591  std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(Reg);
592  if ((Hint.first == (unsigned)ARMRI::RegPairOdd ||
593       Hint.first == (unsigned)ARMRI::RegPairEven) &&
594      Hint.second && TargetRegisterInfo::isVirtualRegister(Hint.second)) {
595    // If 'Reg' is one of the even / odd register pair and it's now changed
596    // (e.g. coalesced) into a different register. The other register of the
597    // pair allocation hint must be updated to reflect the relationship
598    // change.
599    unsigned OtherReg = Hint.second;
600    Hint = MRI->getRegAllocationHint(OtherReg);
601    if (Hint.second == Reg)
602      // Make sure the pair has not already divorced.
603      MRI->setRegAllocationHint(OtherReg, Hint.first, NewReg);
604  }
605}
606
607/// hasFP - Return true if the specified function should have a dedicated frame
608/// pointer register.  This is true if the function has variable sized allocas
609/// or if frame pointer elimination is disabled.
610///
611bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
612  const MachineFrameInfo *MFI = MF.getFrameInfo();
613  return ((DisableFramePointerElim(MF) && MFI->adjustsStack())||
614          needsStackRealignment(MF) ||
615          MFI->hasVarSizedObjects() ||
616          MFI->isFrameAddressTaken());
617}
618
619bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
620  const MachineFrameInfo *MFI = MF.getFrameInfo();
621  const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
622  return (RealignStack &&
623          !AFI->isThumb1OnlyFunction() &&
624          !MFI->hasVarSizedObjects());
625}
626
627bool ARMBaseRegisterInfo::
628needsStackRealignment(const MachineFunction &MF) const {
629  const MachineFrameInfo *MFI = MF.getFrameInfo();
630  const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
631  unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
632  return (RealignStack &&
633          !AFI->isThumb1OnlyFunction() &&
634          (MFI->getMaxAlignment() > StackAlign) &&
635          !MFI->hasVarSizedObjects());
636}
637
638bool ARMBaseRegisterInfo::
639cannotEliminateFrame(const MachineFunction &MF) const {
640  const MachineFrameInfo *MFI = MF.getFrameInfo();
641  if (DisableFramePointerElim(MF) && MFI->adjustsStack())
642    return true;
643  return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken()
644    || needsStackRealignment(MF);
645}
646
647/// estimateStackSize - Estimate and return the size of the frame.
648static unsigned estimateStackSize(MachineFunction &MF) {
649  const MachineFrameInfo *FFI = MF.getFrameInfo();
650  int Offset = 0;
651  for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
652    int FixedOff = -FFI->getObjectOffset(i);
653    if (FixedOff > Offset) Offset = FixedOff;
654  }
655  for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
656    if (FFI->isDeadObjectIndex(i))
657      continue;
658    Offset += FFI->getObjectSize(i);
659    unsigned Align = FFI->getObjectAlignment(i);
660    // Adjust to alignment boundary
661    Offset = (Offset+Align-1)/Align*Align;
662  }
663  return (unsigned)Offset;
664}
665
666/// estimateRSStackSizeLimit - Look at each instruction that references stack
667/// frames and return the stack size limit beyond which some of these
668/// instructions will require a scratch register during their expansion later.
669unsigned
670ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
671  unsigned Limit = (1 << 12) - 1;
672  for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
673    for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
674         I != E; ++I) {
675      for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
676        if (!I->getOperand(i).isFI()) continue;
677
678        // When using ADDri to get the address of a stack object, 255 is the
679        // largest offset guaranteed to fit in the immediate offset.
680        if (I->getOpcode() == ARM::ADDri) {
681          Limit = std::min(Limit, (1U << 8) - 1);
682          break;
683        }
684
685        // Otherwise check the addressing mode.
686        switch (I->getDesc().TSFlags & ARMII::AddrModeMask) {
687        case ARMII::AddrMode3:
688        case ARMII::AddrModeT2_i8:
689          Limit = std::min(Limit, (1U << 8) - 1);
690          break;
691        case ARMII::AddrMode5:
692        case ARMII::AddrModeT2_i8s4:
693          Limit = std::min(Limit, ((1U << 8) - 1) * 4);
694          break;
695        case ARMII::AddrModeT2_i12:
696          if (hasFP(MF)) Limit = std::min(Limit, (1U << 8) - 1);
697          break;
698        case ARMII::AddrMode6:
699          // Addressing mode 6 (load/store) instructions can't encode an
700          // immediate offset for stack references.
701          return 0;
702        default:
703          break;
704        }
705        break; // At most one FI per instruction
706      }
707    }
708  }
709
710  return Limit;
711}
712
713void
714ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
715                                                       RegScavenger *RS) const {
716  // This tells PEI to spill the FP as if it is any other callee-save register
717  // to take advantage the eliminateFrameIndex machinery. This also ensures it
718  // is spilled in the order specified by getCalleeSavedRegs() to make it easier
719  // to combine multiple loads / stores.
720  bool CanEliminateFrame = true;
721  bool CS1Spilled = false;
722  bool LRSpilled = false;
723  unsigned NumGPRSpills = 0;
724  SmallVector<unsigned, 4> UnspilledCS1GPRs;
725  SmallVector<unsigned, 4> UnspilledCS2GPRs;
726  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
727  MachineFrameInfo *MFI = MF.getFrameInfo();
728
729  // Spill R4 if Thumb2 function requires stack realignment - it will be used as
730  // scratch register.
731  // FIXME: It will be better just to find spare register here.
732  if (needsStackRealignment(MF) &&
733      AFI->isThumb2Function())
734    MF.getRegInfo().setPhysRegUsed(ARM::R4);
735
736  // Spill LR if Thumb1 function uses variable length argument lists.
737  if (AFI->isThumb1OnlyFunction() && AFI->getVarArgsRegSaveSize() > 0)
738    MF.getRegInfo().setPhysRegUsed(ARM::LR);
739
740  // Don't spill FP if the frame can be eliminated. This is determined
741  // by scanning the callee-save registers to see if any is used.
742  const unsigned *CSRegs = getCalleeSavedRegs();
743  for (unsigned i = 0; CSRegs[i]; ++i) {
744    unsigned Reg = CSRegs[i];
745    bool Spilled = false;
746    if (MF.getRegInfo().isPhysRegUsed(Reg)) {
747      AFI->setCSRegisterIsSpilled(Reg);
748      Spilled = true;
749      CanEliminateFrame = false;
750    } else {
751      // Check alias registers too.
752      for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
753        if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
754          Spilled = true;
755          CanEliminateFrame = false;
756        }
757      }
758    }
759
760    if (!ARM::GPRRegisterClass->contains(Reg))
761      continue;
762
763    if (Spilled) {
764      NumGPRSpills++;
765
766      if (!STI.isTargetDarwin()) {
767        if (Reg == ARM::LR)
768          LRSpilled = true;
769        CS1Spilled = true;
770        continue;
771      }
772
773      // Keep track if LR and any of R4, R5, R6, and R7 is spilled.
774      switch (Reg) {
775      case ARM::LR:
776        LRSpilled = true;
777        // Fallthrough
778      case ARM::R4:
779      case ARM::R5:
780      case ARM::R6:
781      case ARM::R7:
782        CS1Spilled = true;
783        break;
784      default:
785        break;
786      }
787    } else {
788      if (!STI.isTargetDarwin()) {
789        UnspilledCS1GPRs.push_back(Reg);
790        continue;
791      }
792
793      switch (Reg) {
794      case ARM::R4:
795      case ARM::R5:
796      case ARM::R6:
797      case ARM::R7:
798      case ARM::LR:
799        UnspilledCS1GPRs.push_back(Reg);
800        break;
801      default:
802        UnspilledCS2GPRs.push_back(Reg);
803        break;
804      }
805    }
806  }
807
808  bool ForceLRSpill = false;
809  if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
810    unsigned FnSize = TII.GetFunctionSizeInBytes(MF);
811    // Force LR to be spilled if the Thumb function size is > 2048. This enables
812    // use of BL to implement far jump. If it turns out that it's not needed
813    // then the branch fix up path will undo it.
814    if (FnSize >= (1 << 11)) {
815      CanEliminateFrame = false;
816      ForceLRSpill = true;
817    }
818  }
819
820  // If any of the stack slot references may be out of range of an immediate
821  // offset, make sure a register (or a spill slot) is available for the
822  // register scavenger. Note that if we're indexing off the frame pointer, the
823  // effective stack size is 4 bytes larger since the FP points to the stack
824  // slot of the previous FP. Also, if we have variable sized objects in the
825  // function, stack slot references will often be negative, and some of
826  // our instructions are positive-offset only, so conservatively consider
827  // that case to want a spill slot (or register) as well.
828  // FIXME: We could add logic to be more precise about negative offsets
829  //        and which instructions will need a scratch register for them. Is it
830  //        worth the effort and added fragility?
831  bool BigStack = RS &&
832    (estimateStackSize(MF) + (hasFP(MF) ? 4:0) >= estimateRSStackSizeLimit(MF))
833    || MFI->hasVarSizedObjects();
834
835  bool ExtraCSSpill = false;
836  if (BigStack || !CanEliminateFrame || cannotEliminateFrame(MF)) {
837    AFI->setHasStackFrame(true);
838
839    // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
840    // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
841    if (!LRSpilled && CS1Spilled) {
842      MF.getRegInfo().setPhysRegUsed(ARM::LR);
843      AFI->setCSRegisterIsSpilled(ARM::LR);
844      NumGPRSpills++;
845      UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
846                                    UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
847      ForceLRSpill = false;
848      ExtraCSSpill = true;
849    }
850
851    // Darwin ABI requires FP to point to the stack slot that contains the
852    // previous FP.
853    if (STI.isTargetDarwin() || hasFP(MF)) {
854      MF.getRegInfo().setPhysRegUsed(FramePtr);
855      NumGPRSpills++;
856    }
857
858    // If stack and double are 8-byte aligned and we are spilling an odd number
859    // of GPRs. Spill one extra callee save GPR so we won't have to pad between
860    // the integer and double callee save areas.
861    unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
862    if (TargetAlign == 8 && (NumGPRSpills & 1)) {
863      if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
864        for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
865          unsigned Reg = UnspilledCS1GPRs[i];
866          // Don't spill high register if the function is thumb1
867          if (!AFI->isThumb1OnlyFunction() ||
868              isARMLowRegister(Reg) || Reg == ARM::LR) {
869            MF.getRegInfo().setPhysRegUsed(Reg);
870            AFI->setCSRegisterIsSpilled(Reg);
871            if (!isReservedReg(MF, Reg))
872              ExtraCSSpill = true;
873            break;
874          }
875        }
876      } else if (!UnspilledCS2GPRs.empty() &&
877                 !AFI->isThumb1OnlyFunction()) {
878        unsigned Reg = UnspilledCS2GPRs.front();
879        MF.getRegInfo().setPhysRegUsed(Reg);
880        AFI->setCSRegisterIsSpilled(Reg);
881        if (!isReservedReg(MF, Reg))
882          ExtraCSSpill = true;
883      }
884    }
885
886    // Estimate if we might need to scavenge a register at some point in order
887    // to materialize a stack offset. If so, either spill one additional
888    // callee-saved register or reserve a special spill slot to facilitate
889    // register scavenging. Thumb1 needs a spill slot for stack pointer
890    // adjustments also, even when the frame itself is small.
891    if (BigStack && !ExtraCSSpill) {
892      // If any non-reserved CS register isn't spilled, just spill one or two
893      // extra. That should take care of it!
894      unsigned NumExtras = TargetAlign / 4;
895      SmallVector<unsigned, 2> Extras;
896      while (NumExtras && !UnspilledCS1GPRs.empty()) {
897        unsigned Reg = UnspilledCS1GPRs.back();
898        UnspilledCS1GPRs.pop_back();
899        if (!isReservedReg(MF, Reg) &&
900            (!AFI->isThumb1OnlyFunction() || isARMLowRegister(Reg) ||
901             Reg == ARM::LR)) {
902          Extras.push_back(Reg);
903          NumExtras--;
904        }
905      }
906      // For non-Thumb1 functions, also check for hi-reg CS registers
907      if (!AFI->isThumb1OnlyFunction()) {
908        while (NumExtras && !UnspilledCS2GPRs.empty()) {
909          unsigned Reg = UnspilledCS2GPRs.back();
910          UnspilledCS2GPRs.pop_back();
911          if (!isReservedReg(MF, Reg)) {
912            Extras.push_back(Reg);
913            NumExtras--;
914          }
915        }
916      }
917      if (Extras.size() && NumExtras == 0) {
918        for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
919          MF.getRegInfo().setPhysRegUsed(Extras[i]);
920          AFI->setCSRegisterIsSpilled(Extras[i]);
921        }
922      } else if (!AFI->isThumb1OnlyFunction()) {
923        // note: Thumb1 functions spill to R12, not the stack.  Reserve a slot
924        // closest to SP or frame pointer.
925        const TargetRegisterClass *RC = ARM::GPRRegisterClass;
926        RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
927                                                           RC->getAlignment(),
928                                                           false));
929      }
930    }
931  }
932
933  if (ForceLRSpill) {
934    MF.getRegInfo().setPhysRegUsed(ARM::LR);
935    AFI->setCSRegisterIsSpilled(ARM::LR);
936    AFI->setLRIsSpilledForFarJump(true);
937  }
938}
939
940unsigned ARMBaseRegisterInfo::getRARegister() const {
941  return ARM::LR;
942}
943
944unsigned
945ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
946  if (STI.isTargetDarwin() || hasFP(MF))
947    return FramePtr;
948  return ARM::SP;
949}
950
951int
952ARMBaseRegisterInfo::getFrameIndexReference(const MachineFunction &MF, int FI,
953                                            unsigned &FrameReg) const {
954  const MachineFrameInfo *MFI = MF.getFrameInfo();
955  const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
956  int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize();
957  bool isFixed = MFI->isFixedObjectIndex(FI);
958
959  FrameReg = ARM::SP;
960  if (AFI->isGPRCalleeSavedArea1Frame(FI))
961    Offset -= AFI->getGPRCalleeSavedArea1Offset();
962  else if (AFI->isGPRCalleeSavedArea2Frame(FI))
963    Offset -= AFI->getGPRCalleeSavedArea2Offset();
964  else if (AFI->isDPRCalleeSavedAreaFrame(FI))
965    Offset -= AFI->getDPRCalleeSavedAreaOffset();
966  else if (needsStackRealignment(MF)) {
967    // When dynamically realigning the stack, use the frame pointer for
968    // parameters, and the stack pointer for locals.
969    assert (hasFP(MF) && "dynamic stack realignment without a FP!");
970    if (isFixed) {
971      FrameReg = getFrameRegister(MF);
972      Offset -= AFI->getFramePtrSpillOffset();
973    }
974  } else if (hasFP(MF) && AFI->hasStackFrame()) {
975    if (isFixed || MFI->hasVarSizedObjects()) {
976      // Use frame pointer to reference fixed objects unless this is a
977      // frameless function.
978      FrameReg = getFrameRegister(MF);
979      Offset -= AFI->getFramePtrSpillOffset();
980    } else if (AFI->isThumb2Function()) {
981      // In Thumb2 mode, the negative offset is very limited.
982      int FPOffset = Offset - AFI->getFramePtrSpillOffset();
983      if (FPOffset >= -255 && FPOffset < 0) {
984        FrameReg = getFrameRegister(MF);
985        Offset = FPOffset;
986      }
987    }
988  }
989  return Offset;
990}
991
992
993int
994ARMBaseRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
995                                         int FI) const {
996  unsigned FrameReg;
997  return getFrameIndexReference(MF, FI, FrameReg);
998}
999
1000unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
1001  llvm_unreachable("What is the exception register");
1002  return 0;
1003}
1004
1005unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
1006  llvm_unreachable("What is the exception handler register");
1007  return 0;
1008}
1009
1010int ARMBaseRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
1011  return ARMGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
1012}
1013
1014unsigned ARMBaseRegisterInfo::getRegisterPairEven(unsigned Reg,
1015                                              const MachineFunction &MF) const {
1016  switch (Reg) {
1017  default: break;
1018  // Return 0 if either register of the pair is a special register.
1019  // So no R12, etc.
1020  case ARM::R1:
1021    return ARM::R0;
1022  case ARM::R3:
1023    return ARM::R2;
1024  case ARM::R5:
1025    return ARM::R4;
1026  case ARM::R7:
1027    return isReservedReg(MF, ARM::R7)  ? 0 : ARM::R6;
1028  case ARM::R9:
1029    return isReservedReg(MF, ARM::R9)  ? 0 :ARM::R8;
1030  case ARM::R11:
1031    return isReservedReg(MF, ARM::R11) ? 0 : ARM::R10;
1032
1033  case ARM::S1:
1034    return ARM::S0;
1035  case ARM::S3:
1036    return ARM::S2;
1037  case ARM::S5:
1038    return ARM::S4;
1039  case ARM::S7:
1040    return ARM::S6;
1041  case ARM::S9:
1042    return ARM::S8;
1043  case ARM::S11:
1044    return ARM::S10;
1045  case ARM::S13:
1046    return ARM::S12;
1047  case ARM::S15:
1048    return ARM::S14;
1049  case ARM::S17:
1050    return ARM::S16;
1051  case ARM::S19:
1052    return ARM::S18;
1053  case ARM::S21:
1054    return ARM::S20;
1055  case ARM::S23:
1056    return ARM::S22;
1057  case ARM::S25:
1058    return ARM::S24;
1059  case ARM::S27:
1060    return ARM::S26;
1061  case ARM::S29:
1062    return ARM::S28;
1063  case ARM::S31:
1064    return ARM::S30;
1065
1066  case ARM::D1:
1067    return ARM::D0;
1068  case ARM::D3:
1069    return ARM::D2;
1070  case ARM::D5:
1071    return ARM::D4;
1072  case ARM::D7:
1073    return ARM::D6;
1074  case ARM::D9:
1075    return ARM::D8;
1076  case ARM::D11:
1077    return ARM::D10;
1078  case ARM::D13:
1079    return ARM::D12;
1080  case ARM::D15:
1081    return ARM::D14;
1082  case ARM::D17:
1083    return ARM::D16;
1084  case ARM::D19:
1085    return ARM::D18;
1086  case ARM::D21:
1087    return ARM::D20;
1088  case ARM::D23:
1089    return ARM::D22;
1090  case ARM::D25:
1091    return ARM::D24;
1092  case ARM::D27:
1093    return ARM::D26;
1094  case ARM::D29:
1095    return ARM::D28;
1096  case ARM::D31:
1097    return ARM::D30;
1098  }
1099
1100  return 0;
1101}
1102
1103unsigned ARMBaseRegisterInfo::getRegisterPairOdd(unsigned Reg,
1104                                             const MachineFunction &MF) const {
1105  switch (Reg) {
1106  default: break;
1107  // Return 0 if either register of the pair is a special register.
1108  // So no R12, etc.
1109  case ARM::R0:
1110    return ARM::R1;
1111  case ARM::R2:
1112    return ARM::R3;
1113  case ARM::R4:
1114    return ARM::R5;
1115  case ARM::R6:
1116    return isReservedReg(MF, ARM::R7)  ? 0 : ARM::R7;
1117  case ARM::R8:
1118    return isReservedReg(MF, ARM::R9)  ? 0 :ARM::R9;
1119  case ARM::R10:
1120    return isReservedReg(MF, ARM::R11) ? 0 : ARM::R11;
1121
1122  case ARM::S0:
1123    return ARM::S1;
1124  case ARM::S2:
1125    return ARM::S3;
1126  case ARM::S4:
1127    return ARM::S5;
1128  case ARM::S6:
1129    return ARM::S7;
1130  case ARM::S8:
1131    return ARM::S9;
1132  case ARM::S10:
1133    return ARM::S11;
1134  case ARM::S12:
1135    return ARM::S13;
1136  case ARM::S14:
1137    return ARM::S15;
1138  case ARM::S16:
1139    return ARM::S17;
1140  case ARM::S18:
1141    return ARM::S19;
1142  case ARM::S20:
1143    return ARM::S21;
1144  case ARM::S22:
1145    return ARM::S23;
1146  case ARM::S24:
1147    return ARM::S25;
1148  case ARM::S26:
1149    return ARM::S27;
1150  case ARM::S28:
1151    return ARM::S29;
1152  case ARM::S30:
1153    return ARM::S31;
1154
1155  case ARM::D0:
1156    return ARM::D1;
1157  case ARM::D2:
1158    return ARM::D3;
1159  case ARM::D4:
1160    return ARM::D5;
1161  case ARM::D6:
1162    return ARM::D7;
1163  case ARM::D8:
1164    return ARM::D9;
1165  case ARM::D10:
1166    return ARM::D11;
1167  case ARM::D12:
1168    return ARM::D13;
1169  case ARM::D14:
1170    return ARM::D15;
1171  case ARM::D16:
1172    return ARM::D17;
1173  case ARM::D18:
1174    return ARM::D19;
1175  case ARM::D20:
1176    return ARM::D21;
1177  case ARM::D22:
1178    return ARM::D23;
1179  case ARM::D24:
1180    return ARM::D25;
1181  case ARM::D26:
1182    return ARM::D27;
1183  case ARM::D28:
1184    return ARM::D29;
1185  case ARM::D30:
1186    return ARM::D31;
1187  }
1188
1189  return 0;
1190}
1191
1192/// emitLoadConstPool - Emits a load from constpool to materialize the
1193/// specified immediate.
1194void ARMBaseRegisterInfo::
1195emitLoadConstPool(MachineBasicBlock &MBB,
1196                  MachineBasicBlock::iterator &MBBI,
1197                  DebugLoc dl,
1198                  unsigned DestReg, unsigned SubIdx, int Val,
1199                  ARMCC::CondCodes Pred,
1200                  unsigned PredReg) const {
1201  MachineFunction &MF = *MBB.getParent();
1202  MachineConstantPool *ConstantPool = MF.getConstantPool();
1203  const Constant *C =
1204        ConstantInt::get(Type::getInt32Ty(MF.getFunction()->getContext()), Val);
1205  unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
1206
1207  BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
1208    .addReg(DestReg, getDefRegState(true), SubIdx)
1209    .addConstantPoolIndex(Idx)
1210    .addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
1211}
1212
1213bool ARMBaseRegisterInfo::
1214requiresRegisterScavenging(const MachineFunction &MF) const {
1215  return true;
1216}
1217
1218bool ARMBaseRegisterInfo::
1219requiresFrameIndexScavenging(const MachineFunction &MF) const {
1220  return true;
1221}
1222
1223// hasReservedCallFrame - Under normal circumstances, when a frame pointer is
1224// not required, we reserve argument space for call sites in the function
1225// immediately on entry to the current function. This eliminates the need for
1226// add/sub sp brackets around call sites. Returns true if the call frame is
1227// included as part of the stack frame.
1228bool ARMBaseRegisterInfo::
1229hasReservedCallFrame(MachineFunction &MF) const {
1230  const MachineFrameInfo *FFI = MF.getFrameInfo();
1231  unsigned CFSize = FFI->getMaxCallFrameSize();
1232  // It's not always a good idea to include the call frame as part of the
1233  // stack frame. ARM (especially Thumb) has small immediate offset to
1234  // address the stack frame. So a large call frame can cause poor codegen
1235  // and may even makes it impossible to scavenge a register.
1236  if (CFSize >= ((1 << 12) - 1) / 2)  // Half of imm12
1237    return false;
1238
1239  return !MF.getFrameInfo()->hasVarSizedObjects();
1240}
1241
1242// canSimplifyCallFramePseudos - If there is a reserved call frame, the
1243// call frame pseudos can be simplified. Unlike most targets, having a FP
1244// is not sufficient here since we still may reference some objects via SP
1245// even when FP is available in Thumb2 mode.
1246bool ARMBaseRegisterInfo::
1247canSimplifyCallFramePseudos(MachineFunction &MF) const {
1248  return hasReservedCallFrame(MF) || MF.getFrameInfo()->hasVarSizedObjects();
1249}
1250
1251static void
1252emitSPUpdate(bool isARM,
1253             MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
1254             DebugLoc dl, const ARMBaseInstrInfo &TII,
1255             int NumBytes,
1256             ARMCC::CondCodes Pred = ARMCC::AL, unsigned PredReg = 0) {
1257  if (isARM)
1258    emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1259                            Pred, PredReg, TII);
1260  else
1261    emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, ARM::SP, NumBytes,
1262                           Pred, PredReg, TII);
1263}
1264
1265
1266void ARMBaseRegisterInfo::
1267eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
1268                              MachineBasicBlock::iterator I) const {
1269  if (!hasReservedCallFrame(MF)) {
1270    // If we have alloca, convert as follows:
1271    // ADJCALLSTACKDOWN -> sub, sp, sp, amount
1272    // ADJCALLSTACKUP   -> add, sp, sp, amount
1273    MachineInstr *Old = I;
1274    DebugLoc dl = Old->getDebugLoc();
1275    unsigned Amount = Old->getOperand(0).getImm();
1276    if (Amount != 0) {
1277      // We need to keep the stack aligned properly.  To do this, we round the
1278      // amount of space needed for the outgoing arguments up to the next
1279      // alignment boundary.
1280      unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
1281      Amount = (Amount+Align-1)/Align*Align;
1282
1283      ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1284      assert(!AFI->isThumb1OnlyFunction() &&
1285             "This eliminateCallFramePseudoInstr does not support Thumb1!");
1286      bool isARM = !AFI->isThumbFunction();
1287
1288      // Replace the pseudo instruction with a new instruction...
1289      unsigned Opc = Old->getOpcode();
1290      int PIdx = Old->findFirstPredOperandIdx();
1291      ARMCC::CondCodes Pred = (PIdx == -1)
1292        ? ARMCC::AL : (ARMCC::CondCodes)Old->getOperand(PIdx).getImm();
1293      if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
1294        // Note: PredReg is operand 2 for ADJCALLSTACKDOWN.
1295        unsigned PredReg = Old->getOperand(2).getReg();
1296        emitSPUpdate(isARM, MBB, I, dl, TII, -Amount, Pred, PredReg);
1297      } else {
1298        // Note: PredReg is operand 3 for ADJCALLSTACKUP.
1299        unsigned PredReg = Old->getOperand(3).getReg();
1300        assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
1301        emitSPUpdate(isARM, MBB, I, dl, TII, Amount, Pred, PredReg);
1302      }
1303    }
1304  }
1305  MBB.erase(I);
1306}
1307
1308unsigned
1309ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
1310                                         int SPAdj, FrameIndexValue *Value,
1311                                         RegScavenger *RS) const {
1312  unsigned i = 0;
1313  MachineInstr &MI = *II;
1314  MachineBasicBlock &MBB = *MI.getParent();
1315  MachineFunction &MF = *MBB.getParent();
1316  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1317  assert(!AFI->isThumb1OnlyFunction() &&
1318         "This eliminateFrameIndex does not support Thumb1!");
1319
1320  while (!MI.getOperand(i).isFI()) {
1321    ++i;
1322    assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
1323  }
1324
1325  int FrameIndex = MI.getOperand(i).getIndex();
1326  unsigned FrameReg;
1327
1328  int Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
1329  if (FrameReg != ARM::SP)
1330    SPAdj = 0;
1331  Offset += SPAdj;
1332
1333  // Special handling of dbg_value instructions.
1334  if (MI.isDebugValue()) {
1335    MI.getOperand(i).  ChangeToRegister(FrameReg, false /*isDef*/);
1336    MI.getOperand(i+1).ChangeToImmediate(Offset);
1337    return 0;
1338  }
1339
1340  // Modify MI as necessary to handle as much of 'Offset' as possible
1341  bool Done = false;
1342  if (!AFI->isThumbFunction())
1343    Done = rewriteARMFrameIndex(MI, i, FrameReg, Offset, TII);
1344  else {
1345    assert(AFI->isThumb2Function());
1346    Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
1347  }
1348  if (Done)
1349    return 0;
1350
1351  // If we get here, the immediate doesn't fit into the instruction.  We folded
1352  // as much as possible above, handle the rest, providing a register that is
1353  // SP+LargeImm.
1354  assert((Offset ||
1355          (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode4 ||
1356          (MI.getDesc().TSFlags & ARMII::AddrModeMask) == ARMII::AddrMode6) &&
1357         "This code isn't needed if offset already handled!");
1358
1359  unsigned ScratchReg = 0;
1360  int PIdx = MI.findFirstPredOperandIdx();
1361  ARMCC::CondCodes Pred = (PIdx == -1)
1362    ? ARMCC::AL : (ARMCC::CondCodes)MI.getOperand(PIdx).getImm();
1363  unsigned PredReg = (PIdx == -1) ? 0 : MI.getOperand(PIdx+1).getReg();
1364  if (Offset == 0)
1365    // Must be addrmode4/6.
1366    MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
1367  else {
1368    ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
1369    if (Value) {
1370      Value->first = FrameReg; // use the frame register as a kind indicator
1371      Value->second = Offset;
1372    }
1373    if (!AFI->isThumbFunction())
1374      emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1375                              Offset, Pred, PredReg, TII);
1376    else {
1377      assert(AFI->isThumb2Function());
1378      emitT2RegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
1379                             Offset, Pred, PredReg, TII);
1380    }
1381    MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
1382    if (!ReuseFrameIndexVals)
1383      ScratchReg = 0;
1384  }
1385  return ScratchReg;
1386}
1387
1388/// Move iterator past the next bunch of callee save load / store ops for
1389/// the particular spill area (1: integer area 1, 2: integer area 2,
1390/// 3: fp area, 0: don't care).
1391static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
1392                                   MachineBasicBlock::iterator &MBBI,
1393                                   int Opc1, int Opc2, unsigned Area,
1394                                   const ARMSubtarget &STI) {
1395  while (MBBI != MBB.end() &&
1396         ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
1397         MBBI->getOperand(1).isFI()) {
1398    if (Area != 0) {
1399      bool Done = false;
1400      unsigned Category = 0;
1401      switch (MBBI->getOperand(0).getReg()) {
1402      case ARM::R4:  case ARM::R5:  case ARM::R6: case ARM::R7:
1403      case ARM::LR:
1404        Category = 1;
1405        break;
1406      case ARM::R8:  case ARM::R9:  case ARM::R10: case ARM::R11:
1407        Category = STI.isTargetDarwin() ? 2 : 1;
1408        break;
1409      case ARM::D8:  case ARM::D9:  case ARM::D10: case ARM::D11:
1410      case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
1411        Category = 3;
1412        break;
1413      default:
1414        Done = true;
1415        break;
1416      }
1417      if (Done || Category != Area)
1418        break;
1419    }
1420
1421    ++MBBI;
1422  }
1423}
1424
1425void ARMBaseRegisterInfo::
1426emitPrologue(MachineFunction &MF) const {
1427  MachineBasicBlock &MBB = MF.front();
1428  MachineBasicBlock::iterator MBBI = MBB.begin();
1429  MachineFrameInfo  *MFI = MF.getFrameInfo();
1430  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1431  assert(!AFI->isThumb1OnlyFunction() &&
1432         "This emitPrologue does not support Thumb1!");
1433  bool isARM = !AFI->isThumbFunction();
1434  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1435  unsigned NumBytes = MFI->getStackSize();
1436  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
1437  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
1438
1439  // Determine the sizes of each callee-save spill areas and record which frame
1440  // belongs to which callee-save spill areas.
1441  unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
1442  int FramePtrSpillFI = 0;
1443
1444  // Allocate the vararg register save area. This is not counted in NumBytes.
1445  if (VARegSaveSize)
1446    emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
1447
1448  if (!AFI->hasStackFrame()) {
1449    if (NumBytes != 0)
1450      emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1451    return;
1452  }
1453
1454  for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
1455    unsigned Reg = CSI[i].getReg();
1456    int FI = CSI[i].getFrameIdx();
1457    switch (Reg) {
1458    case ARM::R4:
1459    case ARM::R5:
1460    case ARM::R6:
1461    case ARM::R7:
1462    case ARM::LR:
1463      if (Reg == FramePtr)
1464        FramePtrSpillFI = FI;
1465      AFI->addGPRCalleeSavedArea1Frame(FI);
1466      GPRCS1Size += 4;
1467      break;
1468    case ARM::R8:
1469    case ARM::R9:
1470    case ARM::R10:
1471    case ARM::R11:
1472      if (Reg == FramePtr)
1473        FramePtrSpillFI = FI;
1474      if (STI.isTargetDarwin()) {
1475        AFI->addGPRCalleeSavedArea2Frame(FI);
1476        GPRCS2Size += 4;
1477      } else {
1478        AFI->addGPRCalleeSavedArea1Frame(FI);
1479        GPRCS1Size += 4;
1480      }
1481      break;
1482    default:
1483      AFI->addDPRCalleeSavedAreaFrame(FI);
1484      DPRCSSize += 8;
1485    }
1486  }
1487
1488  // Build the new SUBri to adjust SP for integer callee-save spill area 1.
1489  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
1490  movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
1491
1492  // Set FP to point to the stack slot that contains the previous FP.
1493  // For Darwin, FP is R7, which has now been stored in spill area 1.
1494  // Otherwise, if this is not Darwin, all the callee-saved registers go
1495  // into spill area 1, including the FP in R11.  In either case, it is
1496  // now safe to emit this assignment.
1497  if (STI.isTargetDarwin() || hasFP(MF)) {
1498    unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
1499    MachineInstrBuilder MIB =
1500      BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
1501      .addFrameIndex(FramePtrSpillFI).addImm(0);
1502    AddDefaultCC(AddDefaultPred(MIB));
1503  }
1504
1505  // Build the new SUBri to adjust SP for integer callee-save spill area 2.
1506  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
1507
1508  // Build the new SUBri to adjust SP for FP callee-save spill area.
1509  movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
1510  emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
1511
1512  // Determine starting offsets of spill areas.
1513  unsigned DPRCSOffset  = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
1514  unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
1515  unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
1516  if (STI.isTargetDarwin() || hasFP(MF))
1517    AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) +
1518                                NumBytes);
1519  AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
1520  AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
1521  AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
1522
1523  movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
1524  NumBytes = DPRCSOffset;
1525  if (NumBytes) {
1526    // Adjust SP after all the callee-save spills.
1527    emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
1528  }
1529
1530  if (STI.isTargetELF() && hasFP(MF)) {
1531    MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
1532                             AFI->getFramePtrSpillOffset());
1533  }
1534
1535  AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
1536  AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
1537  AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
1538
1539  // If we need dynamic stack realignment, do it here.
1540  if (needsStackRealignment(MF)) {
1541    unsigned MaxAlign = MFI->getMaxAlignment();
1542    assert (!AFI->isThumb1OnlyFunction());
1543    if (!AFI->isThumbFunction()) {
1544      // Emit bic sp, sp, MaxAlign
1545      AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
1546                                          TII.get(ARM::BICri), ARM::SP)
1547                                  .addReg(ARM::SP, RegState::Kill)
1548                                  .addImm(MaxAlign-1)));
1549    } else {
1550      // We cannot use sp as source/dest register here, thus we're emitting the
1551      // following sequence:
1552      // mov r4, sp
1553      // bic r4, r4, MaxAlign
1554      // mov sp, r4
1555      // FIXME: It will be better just to find spare register here.
1556      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2tgpr), ARM::R4)
1557        .addReg(ARM::SP, RegState::Kill);
1558      AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
1559                                          TII.get(ARM::t2BICri), ARM::R4)
1560                                  .addReg(ARM::R4, RegState::Kill)
1561                                  .addImm(MaxAlign-1)));
1562      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
1563        .addReg(ARM::R4, RegState::Kill);
1564    }
1565  }
1566}
1567
1568static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
1569  for (unsigned i = 0; CSRegs[i]; ++i)
1570    if (Reg == CSRegs[i])
1571      return true;
1572  return false;
1573}
1574
1575static bool isCSRestore(MachineInstr *MI,
1576                        const ARMBaseInstrInfo &TII,
1577                        const unsigned *CSRegs) {
1578  return ((MI->getOpcode() == (int)ARM::VLDRD ||
1579           MI->getOpcode() == (int)ARM::LDR ||
1580           MI->getOpcode() == (int)ARM::t2LDRi12) &&
1581          MI->getOperand(1).isFI() &&
1582          isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
1583}
1584
1585void ARMBaseRegisterInfo::
1586emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
1587  MachineBasicBlock::iterator MBBI = prior(MBB.end());
1588  assert(MBBI->getDesc().isReturn() &&
1589         "Can only insert epilog into returning blocks");
1590  unsigned RetOpcode = MBBI->getOpcode();
1591  DebugLoc dl = MBBI->getDebugLoc();
1592  MachineFrameInfo *MFI = MF.getFrameInfo();
1593  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
1594  assert(!AFI->isThumb1OnlyFunction() &&
1595         "This emitEpilogue does not support Thumb1!");
1596  bool isARM = !AFI->isThumbFunction();
1597
1598  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
1599  int NumBytes = (int)MFI->getStackSize();
1600
1601  if (!AFI->hasStackFrame()) {
1602    if (NumBytes != 0)
1603      emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1604  } else {
1605    // Unwind MBBI to point to first LDR / VLDRD.
1606    const unsigned *CSRegs = getCalleeSavedRegs();
1607    if (MBBI != MBB.begin()) {
1608      do
1609        --MBBI;
1610      while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
1611      if (!isCSRestore(MBBI, TII, CSRegs))
1612        ++MBBI;
1613    }
1614
1615    // Move SP to start of FP callee save spill area.
1616    NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
1617                 AFI->getGPRCalleeSavedArea2Size() +
1618                 AFI->getDPRCalleeSavedAreaSize());
1619
1620    // Darwin ABI requires FP to point to the stack slot that contains the
1621    // previous FP.
1622    bool HasFP = hasFP(MF);
1623    if ((STI.isTargetDarwin() && NumBytes) || HasFP) {
1624      NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
1625      // Reset SP based on frame pointer only if the stack frame extends beyond
1626      // frame pointer stack slot or target is ELF and the function has FP.
1627      if (HasFP ||
1628          AFI->getGPRCalleeSavedArea2Size() ||
1629          AFI->getDPRCalleeSavedAreaSize()  ||
1630          AFI->getDPRCalleeSavedAreaOffset()) {
1631        if (NumBytes) {
1632          if (isARM)
1633            emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1634                                    ARMCC::AL, 0, TII);
1635          else
1636            emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
1637                                    ARMCC::AL, 0, TII);
1638        } else {
1639          // Thumb2 or ARM.
1640          if (isARM)
1641            BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
1642              .addReg(FramePtr)
1643              .addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
1644          else
1645            BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
1646              .addReg(FramePtr);
1647        }
1648      }
1649    } else if (NumBytes)
1650      emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
1651
1652    // Move SP to start of integer callee save spill area 2.
1653    movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
1654    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
1655
1656    // Move SP to start of integer callee save spill area 1.
1657    movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
1658    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
1659
1660    // Move SP to SP upon entry to the function.
1661    movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
1662    emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
1663  }
1664
1665  if (RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNdiND ||
1666      RetOpcode == ARM::TCRETURNri || RetOpcode == ARM::TCRETURNriND) {
1667    // Tail call return: adjust the stack pointer and jump to callee.
1668    MBBI = prior(MBB.end());
1669    MachineOperand &JumpTarget = MBBI->getOperand(0);
1670
1671    // Jump to label or value in register.
1672    if (RetOpcode == ARM::TCRETURNdi) {
1673      BuildMI(MBB, MBBI, dl,
1674            TII.get(STI.isThumb() ? ARM::TAILJMPdt : ARM::TAILJMPd)).
1675        addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
1676                         JumpTarget.getTargetFlags());
1677    } else if (RetOpcode == ARM::TCRETURNdiND) {
1678      BuildMI(MBB, MBBI, dl,
1679            TII.get(STI.isThumb() ? ARM::TAILJMPdNDt : ARM::TAILJMPdND)).
1680        addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
1681                         JumpTarget.getTargetFlags());
1682    } else if (RetOpcode == ARM::TCRETURNri) {
1683      BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPr)).
1684        addReg(JumpTarget.getReg(), RegState::Kill);
1685    } else if (RetOpcode == ARM::TCRETURNriND) {
1686      BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPrND)).
1687        addReg(JumpTarget.getReg(), RegState::Kill);
1688    }
1689
1690    MachineInstr *NewMI = prior(MBBI);
1691    for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i)
1692      NewMI->addOperand(MBBI->getOperand(i));
1693
1694    // Delete the pseudo instruction TCRETURN.
1695    MBB.erase(MBBI);
1696  }
1697
1698  if (VARegSaveSize)
1699    emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
1700}
1701
1702#include "ARMGenRegisterInfo.inc"
1703