llvm.org GIT mirror llvm / 15c435a lib / IR / DataLayout.cpp
15c435a

Tree @15c435a (Download .tar.gz)

DataLayout.cpp @15c435araw · history · blame

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
//===-- DataLayout.cpp - Data size & alignment routines --------------------==//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines layout properties related to datatype size/offset/alignment
// information.
//
// This structure should be created once, filled in if the defaults are not
// correct and then passed around by const&.  None of the members functions
// require modification to the object.
//
//===----------------------------------------------------------------------===//

#include "llvm/IR/DataLayout.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cstdlib>
using namespace llvm;

// Handle the Pass registration stuff necessary to use DataLayout's.

INITIALIZE_PASS(DataLayoutPass, "datalayout", "Data Layout", false, true)
char DataLayoutPass::ID = 0;

//===----------------------------------------------------------------------===//
// Support for StructLayout
//===----------------------------------------------------------------------===//

StructLayout::StructLayout(StructType *ST, const DataLayout &DL) {
  assert(!ST->isOpaque() && "Cannot get layout of opaque structs");
  StructAlignment = 0;
  StructSize = 0;
  NumElements = ST->getNumElements();

  // Loop over each of the elements, placing them in memory.
  for (unsigned i = 0, e = NumElements; i != e; ++i) {
    Type *Ty = ST->getElementType(i);
    unsigned TyAlign = ST->isPacked() ? 1 : DL.getABITypeAlignment(Ty);

    // Add padding if necessary to align the data element properly.
    if ((StructSize & (TyAlign-1)) != 0)
      StructSize = DataLayout::RoundUpAlignment(StructSize, TyAlign);

    // Keep track of maximum alignment constraint.
    StructAlignment = std::max(TyAlign, StructAlignment);

    MemberOffsets[i] = StructSize;
    StructSize += DL.getTypeAllocSize(Ty); // Consume space for this data item
  }

  // Empty structures have alignment of 1 byte.
  if (StructAlignment == 0) StructAlignment = 1;

  // Add padding to the end of the struct so that it could be put in an array
  // and all array elements would be aligned correctly.
  if ((StructSize & (StructAlignment-1)) != 0)
    StructSize = DataLayout::RoundUpAlignment(StructSize, StructAlignment);
}


/// getElementContainingOffset - Given a valid offset into the structure,
/// return the structure index that contains it.
unsigned StructLayout::getElementContainingOffset(uint64_t Offset) const {
  const uint64_t *SI =
    std::upper_bound(&MemberOffsets[0], &MemberOffsets[NumElements], Offset);
  assert(SI != &MemberOffsets[0] && "Offset not in structure type!");
  --SI;
  assert(*SI <= Offset && "upper_bound didn't work");
  assert((SI == &MemberOffsets[0] || *(SI-1) <= Offset) &&
         (SI+1 == &MemberOffsets[NumElements] || *(SI+1) > Offset) &&
         "Upper bound didn't work!");

  // Multiple fields can have the same offset if any of them are zero sized.
  // For example, in { i32, [0 x i32], i32 }, searching for offset 4 will stop
  // at the i32 element, because it is the last element at that offset.  This is
  // the right one to return, because anything after it will have a higher
  // offset, implying that this element is non-empty.
  return SI-&MemberOffsets[0];
}

//===----------------------------------------------------------------------===//
// LayoutAlignElem, LayoutAlign support
//===----------------------------------------------------------------------===//

LayoutAlignElem
LayoutAlignElem::get(AlignTypeEnum align_type, unsigned abi_align,
                     unsigned pref_align, uint32_t bit_width) {
  assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
  LayoutAlignElem retval;
  retval.AlignType = align_type;
  retval.ABIAlign = abi_align;
  retval.PrefAlign = pref_align;
  retval.TypeBitWidth = bit_width;
  return retval;
}

bool
LayoutAlignElem::operator==(const LayoutAlignElem &rhs) const {
  return (AlignType == rhs.AlignType
          && ABIAlign == rhs.ABIAlign
          && PrefAlign == rhs.PrefAlign
          && TypeBitWidth == rhs.TypeBitWidth);
}

const LayoutAlignElem
DataLayout::InvalidAlignmentElem = { INVALID_ALIGN, 0, 0, 0 };

//===----------------------------------------------------------------------===//
// PointerAlignElem, PointerAlign support
//===----------------------------------------------------------------------===//

PointerAlignElem
PointerAlignElem::get(uint32_t AddressSpace, unsigned ABIAlign,
                      unsigned PrefAlign, uint32_t TypeByteWidth) {
  assert(ABIAlign <= PrefAlign && "Preferred alignment worse than ABI!");
  PointerAlignElem retval;
  retval.AddressSpace = AddressSpace;
  retval.ABIAlign = ABIAlign;
  retval.PrefAlign = PrefAlign;
  retval.TypeByteWidth = TypeByteWidth;
  return retval;
}

bool
PointerAlignElem::operator==(const PointerAlignElem &rhs) const {
  return (ABIAlign == rhs.ABIAlign
          && AddressSpace == rhs.AddressSpace
          && PrefAlign == rhs.PrefAlign
          && TypeByteWidth == rhs.TypeByteWidth);
}

const PointerAlignElem
DataLayout::InvalidPointerElem = { 0U, 0U, 0U, ~0U };

//===----------------------------------------------------------------------===//
//                       DataLayout Class Implementation
//===----------------------------------------------------------------------===//

const char *DataLayout::getManglingComponent(const Triple &T) {
  if (T.isOSBinFormatMachO())
    return "-m:o";
  if (T.isOSWindows() && T.getArch() == Triple::x86 && T.isOSBinFormatCOFF())
    return "-m:w";
  return "-m:e";
}

static const LayoutAlignElem DefaultAlignments[] = {
  { INTEGER_ALIGN, 1, 1, 1 },    // i1
  { INTEGER_ALIGN, 8, 1, 1 },    // i8
  { INTEGER_ALIGN, 16, 2, 2 },   // i16
  { INTEGER_ALIGN, 32, 4, 4 },   // i32
  { INTEGER_ALIGN, 64, 4, 8 },   // i64
  { FLOAT_ALIGN, 16, 2, 2 },     // half
  { FLOAT_ALIGN, 32, 4, 4 },     // float
  { FLOAT_ALIGN, 64, 8, 8 },     // double
  { FLOAT_ALIGN, 128, 16, 16 },  // ppcf128, quad, ...
  { VECTOR_ALIGN, 64, 8, 8 },    // v2i32, v1i64, ...
  { VECTOR_ALIGN, 128, 16, 16 }, // v16i8, v8i16, v4i32, ...
  { AGGREGATE_ALIGN, 0, 0, 8 }   // struct
};

void DataLayout::reset(StringRef Desc) {
  clear();

  LayoutMap = nullptr;
  LittleEndian = false;
  StackNaturalAlign = 0;
  ManglingMode = MM_None;

  // Default alignments
  for (const LayoutAlignElem &E : DefaultAlignments) {
    setAlignment((AlignTypeEnum)E.AlignType, E.ABIAlign, E.PrefAlign,
                 E.TypeBitWidth);
  }
  setPointerAlignment(0, 8, 8, 8);

  parseSpecifier(Desc);
}

/// Checked version of split, to ensure mandatory subparts.
static std::pair<StringRef, StringRef> split(StringRef Str, char Separator) {
  assert(!Str.empty() && "parse error, string can't be empty here");
  std::pair<StringRef, StringRef> Split = Str.split(Separator);
  assert((!Split.second.empty() || Split.first == Str) &&
         "a trailing separator is not allowed");
  return Split;
}

/// Get an unsigned integer, including error checks.
static unsigned getInt(StringRef R) {
  unsigned Result;
  bool error = R.getAsInteger(10, Result); (void)error;
  if (error)
    report_fatal_error("not a number, or does not fit in an unsigned int");
  return Result;
}

/// Convert bits into bytes. Assert if not a byte width multiple.
static unsigned inBytes(unsigned Bits) {
  assert(Bits % 8 == 0 && "number of bits must be a byte width multiple");
  return Bits / 8;
}

void DataLayout::parseSpecifier(StringRef Desc) {
  while (!Desc.empty()) {
    // Split at '-'.
    std::pair<StringRef, StringRef> Split = split(Desc, '-');
    Desc = Split.second;

    // Split at ':'.
    Split = split(Split.first, ':');

    // Aliases used below.
    StringRef &Tok  = Split.first;  // Current token.
    StringRef &Rest = Split.second; // The rest of the string.

    char Specifier = Tok.front();
    Tok = Tok.substr(1);

    switch (Specifier) {
    case 's':
      // Ignored for backward compatibility.
      // FIXME: remove this on LLVM 4.0.
      break;
    case 'E':
      LittleEndian = false;
      break;
    case 'e':
      LittleEndian = true;
      break;
    case 'p': {
      // Address space.
      unsigned AddrSpace = Tok.empty() ? 0 : getInt(Tok);
      assert(AddrSpace < 1 << 24 &&
             "Invalid address space, must be a 24bit integer");

      // Size.
      Split = split(Rest, ':');
      unsigned PointerMemSize = inBytes(getInt(Tok));

      // ABI alignment.
      Split = split(Rest, ':');
      unsigned PointerABIAlign = inBytes(getInt(Tok));

      // Preferred alignment.
      unsigned PointerPrefAlign = PointerABIAlign;
      if (!Rest.empty()) {
        Split = split(Rest, ':');
        PointerPrefAlign = inBytes(getInt(Tok));
      }

      setPointerAlignment(AddrSpace, PointerABIAlign, PointerPrefAlign,
                          PointerMemSize);
      break;
    }
    case 'i':
    case 'v':
    case 'f':
    case 'a': {
      AlignTypeEnum AlignType;
      switch (Specifier) {
      default:
      case 'i': AlignType = INTEGER_ALIGN; break;
      case 'v': AlignType = VECTOR_ALIGN; break;
      case 'f': AlignType = FLOAT_ALIGN; break;
      case 'a': AlignType = AGGREGATE_ALIGN; break;
      }

      // Bit size.
      unsigned Size = Tok.empty() ? 0 : getInt(Tok);

      assert((AlignType != AGGREGATE_ALIGN || Size == 0) &&
             "These specifications don't have a size");

      // ABI alignment.
      Split = split(Rest, ':');
      unsigned ABIAlign = inBytes(getInt(Tok));

      // Preferred alignment.
      unsigned PrefAlign = ABIAlign;
      if (!Rest.empty()) {
        Split = split(Rest, ':');
        PrefAlign = inBytes(getInt(Tok));
      }

      setAlignment(AlignType, ABIAlign, PrefAlign, Size);

      break;
    }
    case 'n':  // Native integer types.
      for (;;) {
        unsigned Width = getInt(Tok);
        assert(Width != 0 && "width must be non-zero");
        LegalIntWidths.push_back(Width);
        if (Rest.empty())
          break;
        Split = split(Rest, ':');
      }
      break;
    case 'S': { // Stack natural alignment.
      StackNaturalAlign = inBytes(getInt(Tok));
      break;
    }
    case 'm':
      assert(Tok.empty());
      assert(Rest.size() == 1);
      switch(Rest[0]) {
      default:
        llvm_unreachable("Unknown mangling in datalayout string");
      case 'e':
        ManglingMode = MM_ELF;
        break;
      case 'o':
        ManglingMode = MM_MachO;
        break;
      case 'm':
        ManglingMode = MM_Mips;
        break;
      case 'w':
        ManglingMode = MM_WINCOFF;
        break;
      }
      break;
    default:
      llvm_unreachable("Unknown specifier in datalayout string");
      break;
    }
  }
}

DataLayout::DataLayout(const Module *M) : LayoutMap(nullptr) {
  const DataLayout *Other = M->getDataLayout();
  if (Other)
    *this = *Other;
  else
    reset("");
}

bool DataLayout::operator==(const DataLayout &Other) const {
  bool Ret = LittleEndian == Other.LittleEndian &&
             StackNaturalAlign == Other.StackNaturalAlign &&
             ManglingMode == Other.ManglingMode &&
             LegalIntWidths == Other.LegalIntWidths &&
             Alignments == Other.Alignments && Pointers == Pointers;
  assert(Ret == (getStringRepresentation() == Other.getStringRepresentation()));
  return Ret;
}

void
DataLayout::setAlignment(AlignTypeEnum align_type, unsigned abi_align,
                         unsigned pref_align, uint32_t bit_width) {
  assert(abi_align <= pref_align && "Preferred alignment worse than ABI!");
  assert(pref_align < (1 << 16) && "Alignment doesn't fit in bitfield");
  assert(bit_width < (1 << 24) && "Bit width doesn't fit in bitfield");
  for (LayoutAlignElem &Elem : Alignments) {
    if (Elem.AlignType == (unsigned)align_type &&
        Elem.TypeBitWidth == bit_width) {
      // Update the abi, preferred alignments.
      Elem.ABIAlign = abi_align;
      Elem.PrefAlign = pref_align;
      return;
    }
  }

  Alignments.push_back(LayoutAlignElem::get(align_type, abi_align,
                                            pref_align, bit_width));
}

DataLayout::PointersTy::iterator
DataLayout::findPointerLowerBound(uint32_t AddressSpace) {
  return std::lower_bound(Pointers.begin(), Pointers.end(), AddressSpace,
                          [](const PointerAlignElem &A, uint32_t AddressSpace) {
    return A.AddressSpace < AddressSpace;
  });
}

void DataLayout::setPointerAlignment(uint32_t AddrSpace, unsigned ABIAlign,
                                     unsigned PrefAlign,
                                     uint32_t TypeByteWidth) {
  assert(ABIAlign <= PrefAlign && "Preferred alignment worse than ABI!");
  PointersTy::iterator I = findPointerLowerBound(AddrSpace);
  if (I == Pointers.end() || I->AddressSpace != AddrSpace) {
    Pointers.insert(I, PointerAlignElem::get(AddrSpace, ABIAlign, PrefAlign,
                                             TypeByteWidth));
  } else {
    I->ABIAlign = ABIAlign;
    I->PrefAlign = PrefAlign;
    I->TypeByteWidth = TypeByteWidth;
  }
}

/// getAlignmentInfo - Return the alignment (either ABI if ABIInfo = true or
/// preferred if ABIInfo = false) the layout wants for the specified datatype.
unsigned DataLayout::getAlignmentInfo(AlignTypeEnum AlignType,
                                      uint32_t BitWidth, bool ABIInfo,
                                      Type *Ty) const {
  // Check to see if we have an exact match and remember the best match we see.
  int BestMatchIdx = -1;
  int LargestInt = -1;
  for (unsigned i = 0, e = Alignments.size(); i != e; ++i) {
    if (Alignments[i].AlignType == (unsigned)AlignType &&
        Alignments[i].TypeBitWidth == BitWidth)
      return ABIInfo ? Alignments[i].ABIAlign : Alignments[i].PrefAlign;

    // The best match so far depends on what we're looking for.
     if (AlignType == INTEGER_ALIGN &&
         Alignments[i].AlignType == INTEGER_ALIGN) {
      // The "best match" for integers is the smallest size that is larger than
      // the BitWidth requested.
      if (Alignments[i].TypeBitWidth > BitWidth && (BestMatchIdx == -1 ||
          Alignments[i].TypeBitWidth < Alignments[BestMatchIdx].TypeBitWidth))
        BestMatchIdx = i;
      // However, if there isn't one that's larger, then we must use the
      // largest one we have (see below)
      if (LargestInt == -1 ||
          Alignments[i].TypeBitWidth > Alignments[LargestInt].TypeBitWidth)
        LargestInt = i;
    }
  }

  // Okay, we didn't find an exact solution.  Fall back here depending on what
  // is being looked for.
  if (BestMatchIdx == -1) {
    // If we didn't find an integer alignment, fall back on most conservative.
    if (AlignType == INTEGER_ALIGN) {
      BestMatchIdx = LargestInt;
    } else {
      assert(AlignType == VECTOR_ALIGN && "Unknown alignment type!");

      // By default, use natural alignment for vector types. This is consistent
      // with what clang and llvm-gcc do.
      unsigned Align = getTypeAllocSize(cast<VectorType>(Ty)->getElementType());
      Align *= cast<VectorType>(Ty)->getNumElements();
      // If the alignment is not a power of 2, round up to the next power of 2.
      // This happens for non-power-of-2 length vectors.
      if (Align & (Align-1))
        Align = NextPowerOf2(Align);
      return Align;
    }
  }

  // Since we got a "best match" index, just return it.
  return ABIInfo ? Alignments[BestMatchIdx].ABIAlign
                 : Alignments[BestMatchIdx].PrefAlign;
}

namespace {

class StructLayoutMap {
  typedef DenseMap<StructType*, StructLayout*> LayoutInfoTy;
  LayoutInfoTy LayoutInfo;

public:
  ~StructLayoutMap() {
    // Remove any layouts.
    for (const auto &I : LayoutInfo) {
      StructLayout *Value = I.second;
      Value->~StructLayout();
      free(Value);
    }
  }

  StructLayout *&operator[](StructType *STy) {
    return LayoutInfo[STy];
  }
};

} // end anonymous namespace

void DataLayout::clear() {
  LegalIntWidths.clear();
  Alignments.clear();
  Pointers.clear();
  delete static_cast<StructLayoutMap *>(LayoutMap);
  LayoutMap = nullptr;
}

DataLayout::~DataLayout() {
  clear();
}

const StructLayout *DataLayout::getStructLayout(StructType *Ty) const {
  if (!LayoutMap)
    LayoutMap = new StructLayoutMap();

  StructLayoutMap *STM = static_cast<StructLayoutMap*>(LayoutMap);
  StructLayout *&SL = (*STM)[Ty];
  if (SL) return SL;

  // Otherwise, create the struct layout.  Because it is variable length, we
  // malloc it, then use placement new.
  int NumElts = Ty->getNumElements();
  StructLayout *L =
    (StructLayout *)malloc(sizeof(StructLayout)+(NumElts-1) * sizeof(uint64_t));

  // Set SL before calling StructLayout's ctor.  The ctor could cause other
  // entries to be added to TheMap, invalidating our reference.
  SL = L;

  new (L) StructLayout(Ty, *this);

  return L;
}

std::string DataLayout::getStringRepresentation() const {
  std::string Result;
  raw_string_ostream OS(Result);

  OS << (LittleEndian ? "e" : "E");

  switch (ManglingMode) {
  case MM_None:
    break;
  case MM_ELF:
    OS << "-m:e";
    break;
  case MM_MachO:
    OS << "-m:o";
    break;
  case MM_WINCOFF:
    OS << "-m:w";
    break;
  case MM_Mips:
    OS << "-m:m";
    break;
  }

  for (const PointerAlignElem &PI : Pointers) {
    // Skip default.
    if (PI.AddressSpace == 0 && PI.ABIAlign == 8 && PI.PrefAlign == 8 &&
        PI.TypeByteWidth == 8)
      continue;

    OS << "-p";
    if (PI.AddressSpace) {
      OS << PI.AddressSpace;
    }
    OS << ":" << PI.TypeByteWidth*8 << ':' << PI.ABIAlign*8;
    if (PI.PrefAlign != PI.ABIAlign)
      OS << ':' << PI.PrefAlign*8;
  }

  for (const LayoutAlignElem &AI : Alignments) {
    if (std::find(std::begin(DefaultAlignments), std::end(DefaultAlignments),
                  AI) != std::end(DefaultAlignments))
      continue;
    OS << '-' << (char)AI.AlignType;
    if (AI.TypeBitWidth)
      OS << AI.TypeBitWidth;
    OS << ':' << AI.ABIAlign*8;
    if (AI.ABIAlign != AI.PrefAlign)
      OS << ':' << AI.PrefAlign*8;
  }

  if (!LegalIntWidths.empty()) {
    OS << "-n" << (unsigned)LegalIntWidths[0];

    for (unsigned i = 1, e = LegalIntWidths.size(); i != e; ++i)
      OS << ':' << (unsigned)LegalIntWidths[i];
  }

  if (StackNaturalAlign)
    OS << "-S" << StackNaturalAlign*8;

  return OS.str();
}

unsigned DataLayout::getPointerABIAlignment(unsigned AS) const {
  PointersTy::const_iterator I = findPointerLowerBound(AS);
  if (I == Pointers.end() || I->AddressSpace != AS) {
    I = findPointerLowerBound(0);
    assert(I->AddressSpace == 0);
  }
  return I->ABIAlign;
}

unsigned DataLayout::getPointerPrefAlignment(unsigned AS) const {
  PointersTy::const_iterator I = findPointerLowerBound(AS);
  if (I == Pointers.end() || I->AddressSpace != AS) {
    I = findPointerLowerBound(0);
    assert(I->AddressSpace == 0);
  }
  return I->PrefAlign;
}

unsigned DataLayout::getPointerSize(unsigned AS) const {
  PointersTy::const_iterator I = findPointerLowerBound(AS);
  if (I == Pointers.end() || I->AddressSpace != AS) {
    I = findPointerLowerBound(0);
    assert(I->AddressSpace == 0);
  }
  return I->TypeByteWidth;
}

unsigned DataLayout::getPointerTypeSizeInBits(Type *Ty) const {
  assert(Ty->isPtrOrPtrVectorTy() &&
         "This should only be called with a pointer or pointer vector type");

  if (Ty->isPointerTy())
    return getTypeSizeInBits(Ty);

  return getTypeSizeInBits(Ty->getScalarType());
}

/*!
  \param abi_or_pref Flag that determines which alignment is returned. true
  returns the ABI alignment, false returns the preferred alignment.
  \param Ty The underlying type for which alignment is determined.

  Get the ABI (\a abi_or_pref == true) or preferred alignment (\a abi_or_pref
  == false) for the requested type \a Ty.
 */
unsigned DataLayout::getAlignment(Type *Ty, bool abi_or_pref) const {
  int AlignType = -1;

  assert(Ty->isSized() && "Cannot getTypeInfo() on a type that is unsized!");
  switch (Ty->getTypeID()) {
  // Early escape for the non-numeric types.
  case Type::LabelTyID:
    return (abi_or_pref
            ? getPointerABIAlignment(0)
            : getPointerPrefAlignment(0));
  case Type::PointerTyID: {
    unsigned AS = dyn_cast<PointerType>(Ty)->getAddressSpace();
    return (abi_or_pref
            ? getPointerABIAlignment(AS)
            : getPointerPrefAlignment(AS));
    }
  case Type::ArrayTyID:
    return getAlignment(cast<ArrayType>(Ty)->getElementType(), abi_or_pref);

  case Type::StructTyID: {
    // Packed structure types always have an ABI alignment of one.
    if (cast<StructType>(Ty)->isPacked() && abi_or_pref)
      return 1;

    // Get the layout annotation... which is lazily created on demand.
    const StructLayout *Layout = getStructLayout(cast<StructType>(Ty));
    unsigned Align = getAlignmentInfo(AGGREGATE_ALIGN, 0, abi_or_pref, Ty);
    return std::max(Align, Layout->getAlignment());
  }
  case Type::IntegerTyID:
    AlignType = INTEGER_ALIGN;
    break;
  case Type::HalfTyID:
  case Type::FloatTyID:
  case Type::DoubleTyID:
  // PPC_FP128TyID and FP128TyID have different data contents, but the
  // same size and alignment, so they look the same here.
  case Type::PPC_FP128TyID:
  case Type::FP128TyID:
  case Type::X86_FP80TyID:
    AlignType = FLOAT_ALIGN;
    break;
  case Type::X86_MMXTyID:
  case Type::VectorTyID:
    AlignType = VECTOR_ALIGN;
    break;
  default:
    llvm_unreachable("Bad type for getAlignment!!!");
  }

  return getAlignmentInfo((AlignTypeEnum)AlignType, getTypeSizeInBits(Ty),
                          abi_or_pref, Ty);
}

unsigned DataLayout::getABITypeAlignment(Type *Ty) const {
  return getAlignment(Ty, true);
}

/// getABIIntegerTypeAlignment - Return the minimum ABI-required alignment for
/// an integer type of the specified bitwidth.
unsigned DataLayout::getABIIntegerTypeAlignment(unsigned BitWidth) const {
  return getAlignmentInfo(INTEGER_ALIGN, BitWidth, true, nullptr);
}

unsigned DataLayout::getPrefTypeAlignment(Type *Ty) const {
  return getAlignment(Ty, false);
}

unsigned DataLayout::getPreferredTypeAlignmentShift(Type *Ty) const {
  unsigned Align = getPrefTypeAlignment(Ty);
  assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
  return Log2_32(Align);
}

IntegerType *DataLayout::getIntPtrType(LLVMContext &C,
                                       unsigned AddressSpace) const {
  return IntegerType::get(C, getPointerSizeInBits(AddressSpace));
}

Type *DataLayout::getIntPtrType(Type *Ty) const {
  assert(Ty->isPtrOrPtrVectorTy() &&
         "Expected a pointer or pointer vector type.");
  unsigned NumBits = getTypeSizeInBits(Ty->getScalarType());
  IntegerType *IntTy = IntegerType::get(Ty->getContext(), NumBits);
  if (VectorType *VecTy = dyn_cast<VectorType>(Ty))
    return VectorType::get(IntTy, VecTy->getNumElements());
  return IntTy;
}

Type *DataLayout::getSmallestLegalIntType(LLVMContext &C, unsigned Width) const {
  for (unsigned LegalIntWidth : LegalIntWidths)
    if (Width <= LegalIntWidth)
      return Type::getIntNTy(C, LegalIntWidth);
  return nullptr;
}

unsigned DataLayout::getLargestLegalIntTypeSize() const {
  auto Max = std::max_element(LegalIntWidths.begin(), LegalIntWidths.end());
  return Max != LegalIntWidths.end() ? *Max : 0;
}

uint64_t DataLayout::getIndexedOffset(Type *ptrTy,
                                      ArrayRef<Value *> Indices) const {
  Type *Ty = ptrTy;
  assert(Ty->isPointerTy() && "Illegal argument for getIndexedOffset()");
  uint64_t Result = 0;

  generic_gep_type_iterator<Value* const*>
    TI = gep_type_begin(ptrTy, Indices);
  for (unsigned CurIDX = 0, EndIDX = Indices.size(); CurIDX != EndIDX;
       ++CurIDX, ++TI) {
    if (StructType *STy = dyn_cast<StructType>(*TI)) {
      assert(Indices[CurIDX]->getType() ==
             Type::getInt32Ty(ptrTy->getContext()) &&
             "Illegal struct idx");
      unsigned FieldNo = cast<ConstantInt>(Indices[CurIDX])->getZExtValue();

      // Get structure layout information...
      const StructLayout *Layout = getStructLayout(STy);

      // Add in the offset, as calculated by the structure layout info...
      Result += Layout->getElementOffset(FieldNo);

      // Update Ty to refer to current element
      Ty = STy->getElementType(FieldNo);
    } else {
      // Update Ty to refer to current element
      Ty = cast<SequentialType>(Ty)->getElementType();

      // Get the array index and the size of each array element.
      if (int64_t arrayIdx = cast<ConstantInt>(Indices[CurIDX])->getSExtValue())
        Result += (uint64_t)arrayIdx * getTypeAllocSize(Ty);
    }
  }

  return Result;
}

/// getPreferredAlignment - Return the preferred alignment of the specified
/// global.  This includes an explicitly requested alignment (if the global
/// has one).
unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
  Type *ElemType = GV->getType()->getElementType();
  unsigned Alignment = getPrefTypeAlignment(ElemType);
  unsigned GVAlignment = GV->getAlignment();
  if (GVAlignment >= Alignment) {
    Alignment = GVAlignment;
  } else if (GVAlignment != 0) {
    Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
  }

  if (GV->hasInitializer() && GVAlignment == 0) {
    if (Alignment < 16) {
      // If the global is not external, see if it is large.  If so, give it a
      // larger alignment.
      if (getTypeSizeInBits(ElemType) > 128)
        Alignment = 16;    // 16-byte alignment.
    }
  }
  return Alignment;
}

/// getPreferredAlignmentLog - Return the preferred alignment of the
/// specified global, returned in log form.  This includes an explicitly
/// requested alignment (if the global has one).
unsigned DataLayout::getPreferredAlignmentLog(const GlobalVariable *GV) const {
  return Log2_32(getPreferredAlignment(GV));
}

DataLayoutPass::DataLayoutPass() : ImmutablePass(ID), DL("") {
  report_fatal_error("Bad DataLayoutPass ctor used. Tool did not specify a "
                     "DataLayout to use?");
}

DataLayoutPass::~DataLayoutPass() {}

DataLayoutPass::DataLayoutPass(const DataLayout &DL)
    : ImmutablePass(ID), DL(DL) {
  initializeDataLayoutPassPass(*PassRegistry::getPassRegistry());
}

DataLayoutPass::DataLayoutPass(const Module *M) : ImmutablePass(ID), DL(M) {
  initializeDataLayoutPassPass(*PassRegistry::getPassRegistry());
}