summaryrefslogtreecommitdiff
path: root/lib/Basic/TargetInfo.cpp
blob: db20ec33e88504572137041589188bb321fda75d (plain)
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
//===--- TargetInfo.cpp - Information about Target machine ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file implements the TargetInfo and TargetInfoImpl interfaces.
//
//===----------------------------------------------------------------------===//

#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/CharInfo.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/LangOptions.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetParser.h"
#include <cstdlib>
using namespace clang;

static const LangASMap DefaultAddrSpaceMap = {0};

// TargetInfo Constructor.
TargetInfo::TargetInfo(const llvm::Triple &T) : TargetOpts(), Triple(T) {
  // Set defaults.  Defaults are set for a 32-bit RISC platform, like PPC or
  // SPARC.  These should be overridden by concrete targets as needed.
  BigEndian = !T.isLittleEndian();
  TLSSupported = true;
  VLASupported = true;
  NoAsmVariants = false;
  HasLegalHalfType = false;
  HasFloat128 = false;
  PointerWidth = PointerAlign = 32;
  BoolWidth = BoolAlign = 8;
  IntWidth = IntAlign = 32;
  LongWidth = LongAlign = 32;
  LongLongWidth = LongLongAlign = 64;

  // Fixed point default bit widths
  ShortAccumWidth = ShortAccumAlign = 16;
  AccumWidth = AccumAlign = 32;
  LongAccumWidth = LongAccumAlign = 64;
  ShortFractWidth = ShortFractAlign = 8;
  FractWidth = FractAlign = 16;
  LongFractWidth = LongFractAlign = 32;

  // Fixed point default integral and fractional bit sizes
  // We give the _Accum 1 fewer fractional bits than their corresponding _Fract
  // types by default to have the same number of fractional bits between _Accum
  // and _Fract types.
  PaddingOnUnsignedFixedPoint = false;
  ShortAccumScale = 7;
  AccumScale = 15;
  LongAccumScale = 31;

  SuitableAlign = 64;
  DefaultAlignForAttributeAligned = 128;
  MinGlobalAlign = 0;
  // From the glibc documentation, on GNU systems, malloc guarantees 16-byte
  // alignment on 64-bit systems and 8-byte alignment on 32-bit systems. See
  // https://www.gnu.org/software/libc/manual/html_node/Malloc-Examples.html.
  // This alignment guarantee also applies to Windows and Android.
  if (T.isGNUEnvironment() || T.isWindowsMSVCEnvironment() || T.isAndroid())
    NewAlign = Triple.isArch64Bit() ? 128 : Triple.isArch32Bit() ? 64 : 0;
  else
    NewAlign = 0; // Infer from basic type alignment.
  HalfWidth = 16;
  HalfAlign = 16;
  FloatWidth = 32;
  FloatAlign = 32;
  DoubleWidth = 64;
  DoubleAlign = 64;
  LongDoubleWidth = 64;
  LongDoubleAlign = 64;
  Float128Align = 128;
  LargeArrayMinWidth = 0;
  LargeArrayAlign = 0;
  MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
  MaxVectorAlign = 0;
  MaxTLSAlign = 0;
  SimdDefaultAlign = 0;
  SizeType = UnsignedLong;
  PtrDiffType = SignedLong;
  IntMaxType = SignedLongLong;
  IntPtrType = SignedLong;
  WCharType = SignedInt;
  WIntType = SignedInt;
  Char16Type = UnsignedShort;
  Char32Type = UnsignedInt;
  Int64Type = SignedLongLong;
  SigAtomicType = SignedInt;
  ProcessIDType = SignedInt;
  UseSignedCharForObjCBool = true;
  UseBitFieldTypeAlignment = true;
  UseZeroLengthBitfieldAlignment = false;
  UseExplicitBitFieldAlignment = true;
  ZeroLengthBitfieldBoundary = 0;
  HalfFormat = &llvm::APFloat::IEEEhalf();
  FloatFormat = &llvm::APFloat::IEEEsingle();
  DoubleFormat = &llvm::APFloat::IEEEdouble();
  LongDoubleFormat = &llvm::APFloat::IEEEdouble();
  Float128Format = &llvm::APFloat::IEEEquad();
  MCountName = "mcount";
  RegParmMax = 0;
  SSERegParmMax = 0;
  HasAlignMac68kSupport = false;
  HasBuiltinMSVaList = false;
  IsRenderScriptTarget = false;

  // Default to no types using fpret.
  RealTypeUsesObjCFPRet = 0;

  // Default to not using fp2ret for __Complex long double
  ComplexLongDoubleUsesFP2Ret = false;

  // Set the C++ ABI based on the triple.
  TheCXXABI.set(Triple.isKnownWindowsMSVCEnvironment()
                    ? TargetCXXABI::Microsoft
                    : TargetCXXABI::GenericItanium);

  // Default to an empty address space map.
  AddrSpaceMap = &DefaultAddrSpaceMap;
  UseAddrSpaceMapMangling = false;

  // Default to an unknown platform name.
  PlatformName = "unknown";
  PlatformMinVersion = VersionTuple();
}

// Out of line virtual dtor for TargetInfo.
TargetInfo::~TargetInfo() {}

bool
TargetInfo::checkCFProtectionBranchSupported(DiagnosticsEngine &Diags) const {
  Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=branch";
  return false;
}

bool
TargetInfo::checkCFProtectionReturnSupported(DiagnosticsEngine &Diags) const {
  Diags.Report(diag::err_opt_not_valid_on_target) << "cf-protection=return";
  return false;
}

/// getTypeName - Return the user string for the specified integer type enum.
/// For example, SignedShort -> "short".
const char *TargetInfo::getTypeName(IntType T) {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:       return "signed char";
  case UnsignedChar:     return "unsigned char";
  case SignedShort:      return "short";
  case UnsignedShort:    return "unsigned short";
  case SignedInt:        return "int";
  case UnsignedInt:      return "unsigned int";
  case SignedLong:       return "long int";
  case UnsignedLong:     return "long unsigned int";
  case SignedLongLong:   return "long long int";
  case UnsignedLongLong: return "long long unsigned int";
  }
}

/// getTypeConstantSuffix - Return the constant suffix for the specified
/// integer type enum. For example, SignedLong -> "L".
const char *TargetInfo::getTypeConstantSuffix(IntType T) const {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:
  case SignedShort:
  case SignedInt:        return "";
  case SignedLong:       return "L";
  case SignedLongLong:   return "LL";
  case UnsignedChar:
    if (getCharWidth() < getIntWidth())
      return "";
    LLVM_FALLTHROUGH;
  case UnsignedShort:
    if (getShortWidth() < getIntWidth())
      return "";
    LLVM_FALLTHROUGH;
  case UnsignedInt:      return "U";
  case UnsignedLong:     return "UL";
  case UnsignedLongLong: return "ULL";
  }
}

/// getTypeFormatModifier - Return the printf format modifier for the
/// specified integer type enum. For example, SignedLong -> "l".

const char *TargetInfo::getTypeFormatModifier(IntType T) {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:
  case UnsignedChar:     return "hh";
  case SignedShort:
  case UnsignedShort:    return "h";
  case SignedInt:
  case UnsignedInt:      return "";
  case SignedLong:
  case UnsignedLong:     return "l";
  case SignedLongLong:
  case UnsignedLongLong: return "ll";
  }
}

/// getTypeWidth - Return the width (in bits) of the specified integer type
/// enum. For example, SignedInt -> getIntWidth().
unsigned TargetInfo::getTypeWidth(IntType T) const {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:
  case UnsignedChar:     return getCharWidth();
  case SignedShort:
  case UnsignedShort:    return getShortWidth();
  case SignedInt:
  case UnsignedInt:      return getIntWidth();
  case SignedLong:
  case UnsignedLong:     return getLongWidth();
  case SignedLongLong:
  case UnsignedLongLong: return getLongLongWidth();
  };
}

TargetInfo::IntType TargetInfo::getIntTypeByWidth(
    unsigned BitWidth, bool IsSigned) const {
  if (getCharWidth() == BitWidth)
    return IsSigned ? SignedChar : UnsignedChar;
  if (getShortWidth() == BitWidth)
    return IsSigned ? SignedShort : UnsignedShort;
  if (getIntWidth() == BitWidth)
    return IsSigned ? SignedInt : UnsignedInt;
  if (getLongWidth() == BitWidth)
    return IsSigned ? SignedLong : UnsignedLong;
  if (getLongLongWidth() == BitWidth)
    return IsSigned ? SignedLongLong : UnsignedLongLong;
  return NoInt;
}

TargetInfo::IntType TargetInfo::getLeastIntTypeByWidth(unsigned BitWidth,
                                                       bool IsSigned) const {
  if (getCharWidth() >= BitWidth)
    return IsSigned ? SignedChar : UnsignedChar;
  if (getShortWidth() >= BitWidth)
    return IsSigned ? SignedShort : UnsignedShort;
  if (getIntWidth() >= BitWidth)
    return IsSigned ? SignedInt : UnsignedInt;
  if (getLongWidth() >= BitWidth)
    return IsSigned ? SignedLong : UnsignedLong;
  if (getLongLongWidth() >= BitWidth)
    return IsSigned ? SignedLongLong : UnsignedLongLong;
  return NoInt;
}

TargetInfo::RealType TargetInfo::getRealTypeByWidth(unsigned BitWidth) const {
  if (getFloatWidth() == BitWidth)
    return Float;
  if (getDoubleWidth() == BitWidth)
    return Double;

  switch (BitWidth) {
  case 96:
    if (&getLongDoubleFormat() == &llvm::APFloat::x87DoubleExtended())
      return LongDouble;
    break;
  case 128:
    if (&getLongDoubleFormat() == &llvm::APFloat::PPCDoubleDouble() ||
        &getLongDoubleFormat() == &llvm::APFloat::IEEEquad())
      return LongDouble;
    if (hasFloat128Type())
      return Float128;
    break;
  }

  return NoFloat;
}

/// getTypeAlign - Return the alignment (in bits) of the specified integer type
/// enum. For example, SignedInt -> getIntAlign().
unsigned TargetInfo::getTypeAlign(IntType T) const {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:
  case UnsignedChar:     return getCharAlign();
  case SignedShort:
  case UnsignedShort:    return getShortAlign();
  case SignedInt:
  case UnsignedInt:      return getIntAlign();
  case SignedLong:
  case UnsignedLong:     return getLongAlign();
  case SignedLongLong:
  case UnsignedLongLong: return getLongLongAlign();
  };
}

/// isTypeSigned - Return whether an integer types is signed. Returns true if
/// the type is signed; false otherwise.
bool TargetInfo::isTypeSigned(IntType T) {
  switch (T) {
  default: llvm_unreachable("not an integer!");
  case SignedChar:
  case SignedShort:
  case SignedInt:
  case SignedLong:
  case SignedLongLong:
    return true;
  case UnsignedChar:
  case UnsignedShort:
  case UnsignedInt:
  case UnsignedLong:
  case UnsignedLongLong:
    return false;
  };
}

/// adjust - Set forced language options.
/// Apply changes to the target information with respect to certain
/// language options which change the target configuration and adjust
/// the language based on the target options where applicable.
void TargetInfo::adjust(LangOptions &Opts) {
  if (Opts.NoBitFieldTypeAlign)
    UseBitFieldTypeAlignment = false;

  switch (Opts.WCharSize) {
  default: llvm_unreachable("invalid wchar_t width");
  case 0: break;
  case 1: WCharType = Opts.WCharIsSigned ? SignedChar : UnsignedChar; break;
  case 2: WCharType = Opts.WCharIsSigned ? SignedShort : UnsignedShort; break;
  case 4: WCharType = Opts.WCharIsSigned ? SignedInt : UnsignedInt; break;
  }

  if (Opts.AlignDouble) {
    DoubleAlign = LongLongAlign = 64;
    LongDoubleAlign = 64;
  }

  if (Opts.OpenCL) {
    // OpenCL C requires specific widths for types, irrespective of
    // what these normally are for the target.
    // We also define long long and long double here, although the
    // OpenCL standard only mentions these as "reserved".
    IntWidth = IntAlign = 32;
    LongWidth = LongAlign = 64;
    LongLongWidth = LongLongAlign = 128;
    HalfWidth = HalfAlign = 16;
    FloatWidth = FloatAlign = 32;

    // Embedded 32-bit targets (OpenCL EP) might have double C type
    // defined as float. Let's not override this as it might lead
    // to generating illegal code that uses 64bit doubles.
    if (DoubleWidth != FloatWidth) {
      DoubleWidth = DoubleAlign = 64;
      DoubleFormat = &llvm::APFloat::IEEEdouble();
    }
    LongDoubleWidth = LongDoubleAlign = 128;

    unsigned MaxPointerWidth = getMaxPointerWidth();
    assert(MaxPointerWidth == 32 || MaxPointerWidth == 64);
    bool Is32BitArch = MaxPointerWidth == 32;
    SizeType = Is32BitArch ? UnsignedInt : UnsignedLong;
    PtrDiffType = Is32BitArch ? SignedInt : SignedLong;
    IntPtrType = Is32BitArch ? SignedInt : SignedLong;

    IntMaxType = SignedLongLong;
    Int64Type = SignedLong;

    HalfFormat = &llvm::APFloat::IEEEhalf();
    FloatFormat = &llvm::APFloat::IEEEsingle();
    LongDoubleFormat = &llvm::APFloat::IEEEquad();
  }

  if (Opts.NewAlignOverride)
    NewAlign = Opts.NewAlignOverride * getCharWidth();

  // Each unsigned fixed point type has the same number of fractional bits as
  // its corresponding signed type.
  PaddingOnUnsignedFixedPoint |= Opts.PaddingOnUnsignedFixedPoint;
  CheckFixedPointBits();
}

bool TargetInfo::initFeatureMap(
    llvm::StringMap<bool> &Features, DiagnosticsEngine &Diags, StringRef CPU,
    const std::vector<std::string> &FeatureVec) const {
  for (const auto &F : FeatureVec) {
    StringRef Name = F;
    // Apply the feature via the target.
    bool Enabled = Name[0] == '+';
    setFeatureEnabled(Features, Name.substr(1), Enabled);
  }
  return true;
}

TargetInfo::CallingConvKind
TargetInfo::getCallingConvKind(bool ClangABICompat4) const {
  if (getCXXABI() != TargetCXXABI::Microsoft &&
      (ClangABICompat4 || getTriple().getOS() == llvm::Triple::PS4))
    return CCK_ClangABI4OrPS4;
  return CCK_Default;
}

LangAS TargetInfo::getOpenCLTypeAddrSpace(OpenCLTypeKind TK) const {
  switch (TK) {
  case OCLTK_Image:
  case OCLTK_Pipe:
    return LangAS::opencl_global;

  case OCLTK_Sampler:
    return LangAS::opencl_constant;

  default:
    return LangAS::Default;
  }
}

//===----------------------------------------------------------------------===//


static StringRef removeGCCRegisterPrefix(StringRef Name) {
  if (Name[0] == '%' || Name[0] == '#')
    Name = Name.substr(1);

  return Name;
}

/// isValidClobber - Returns whether the passed in string is
/// a valid clobber in an inline asm statement. This is used by
/// Sema.
bool TargetInfo::isValidClobber(StringRef Name) const {
  return (isValidGCCRegisterName(Name) ||
          Name == "memory" || Name == "cc");
}

/// isValidGCCRegisterName - Returns whether the passed in string
/// is a valid register name according to GCC. This is used by Sema for
/// inline asm statements.
bool TargetInfo::isValidGCCRegisterName(StringRef Name) const {
  if (Name.empty())
    return false;

  // Get rid of any register prefix.
  Name = removeGCCRegisterPrefix(Name);
  if (Name.empty())
    return false;

  ArrayRef<const char *> Names = getGCCRegNames();

  // If we have a number it maps to an entry in the register name array.
  if (isDigit(Name[0])) {
    unsigned n;
    if (!Name.getAsInteger(0, n))
      return n < Names.size();
  }

  // Check register names.
  if (std::find(Names.begin(), Names.end(), Name) != Names.end())
    return true;

  // Check any additional names that we have.
  for (const AddlRegName &ARN : getGCCAddlRegNames())
    for (const char *AN : ARN.Names) {
      if (!AN)
        break;
      // Make sure the register that the additional name is for is within
      // the bounds of the register names from above.
      if (AN == Name && ARN.RegNum < Names.size())
        return true;
    }

  // Now check aliases.
  for (const GCCRegAlias &GRA : getGCCRegAliases())
    for (const char *A : GRA.Aliases) {
      if (!A)
        break;
      if (A == Name)
        return true;
    }

  return false;
}

StringRef TargetInfo::getNormalizedGCCRegisterName(StringRef Name,
                                                   bool ReturnCanonical) const {
  assert(isValidGCCRegisterName(Name) && "Invalid register passed in");

  // Get rid of any register prefix.
  Name = removeGCCRegisterPrefix(Name);

  ArrayRef<const char *> Names = getGCCRegNames();

  // First, check if we have a number.
  if (isDigit(Name[0])) {
    unsigned n;
    if (!Name.getAsInteger(0, n)) {
      assert(n < Names.size() && "Out of bounds register number!");
      return Names[n];
    }
  }

  // Check any additional names that we have.
  for (const AddlRegName &ARN : getGCCAddlRegNames())
    for (const char *AN : ARN.Names) {
      if (!AN)
        break;
      // Make sure the register that the additional name is for is within
      // the bounds of the register names from above.
      if (AN == Name && ARN.RegNum < Names.size())
        return ReturnCanonical ? Names[ARN.RegNum] : Name;
    }

  // Now check aliases.
  for (const GCCRegAlias &RA : getGCCRegAliases())
    for (const char *A : RA.Aliases) {
      if (!A)
        break;
      if (A == Name)
        return RA.Register;
    }

  return Name;
}

bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const {
  const char *Name = Info.getConstraintStr().c_str();
  // An output constraint must start with '=' or '+'
  if (*Name != '=' && *Name != '+')
    return false;

  if (*Name == '+')
    Info.setIsReadWrite();

  Name++;
  while (*Name) {
    switch (*Name) {
    default:
      if (!validateAsmConstraint(Name, Info)) {
        // FIXME: We temporarily return false
        // so we can add more constraints as we hit it.
        // Eventually, an unknown constraint should just be treated as 'g'.
        return false;
      }
      break;
    case '&': // early clobber.
      Info.setEarlyClobber();
      break;
    case '%': // commutative.
      // FIXME: Check that there is a another register after this one.
      break;
    case 'r': // general register.
      Info.setAllowsRegister();
      break;
    case 'm': // memory operand.
    case 'o': // offsetable memory operand.
    case 'V': // non-offsetable memory operand.
    case '<': // autodecrement memory operand.
    case '>': // autoincrement memory operand.
      Info.setAllowsMemory();
      break;
    case 'g': // general register, memory operand or immediate integer.
    case 'X': // any operand.
      Info.setAllowsRegister();
      Info.setAllowsMemory();
      break;
    case ',': // multiple alternative constraint.  Pass it.
      // Handle additional optional '=' or '+' modifiers.
      if (Name[1] == '=' || Name[1] == '+')
        Name++;
      break;
    case '#': // Ignore as constraint.
      while (Name[1] && Name[1] != ',')
        Name++;
      break;
    case '?': // Disparage slightly code.
    case '!': // Disparage severely.
    case '*': // Ignore for choosing register preferences.
    case 'i': // Ignore i,n,E,F as output constraints (match from the other
              // chars)
    case 'n':
    case 'E':
    case 'F':
      break;  // Pass them.
    }

    Name++;
  }

  // Early clobber with a read-write constraint which doesn't permit registers
  // is invalid.
  if (Info.earlyClobber() && Info.isReadWrite() && !Info.allowsRegister())
    return false;

  // If a constraint allows neither memory nor register operands it contains
  // only modifiers. Reject it.
  return Info.allowsMemory() || Info.allowsRegister();
}

bool TargetInfo::resolveSymbolicName(const char *&Name,
                                     ArrayRef<ConstraintInfo> OutputConstraints,
                                     unsigned &Index) const {
  assert(*Name == '[' && "Symbolic name did not start with '['");
  Name++;
  const char *Start = Name;
  while (*Name && *Name != ']')
    Name++;

  if (!*Name) {
    // Missing ']'
    return false;
  }

  std::string SymbolicName(Start, Name - Start);

  for (Index = 0; Index != OutputConstraints.size(); ++Index)
    if (SymbolicName == OutputConstraints[Index].getName())
      return true;

  return false;
}

bool TargetInfo::validateInputConstraint(
                              MutableArrayRef<ConstraintInfo> OutputConstraints,
                              ConstraintInfo &Info) const {
  const char *Name = Info.ConstraintStr.c_str();

  if (!*Name)
    return false;

  while (*Name) {
    switch (*Name) {
    default:
      // Check if we have a matching constraint
      if (*Name >= '0' && *Name <= '9') {
        const char *DigitStart = Name;
        while (Name[1] >= '0' && Name[1] <= '9')
          Name++;
        const char *DigitEnd = Name;
        unsigned i;
        if (StringRef(DigitStart, DigitEnd - DigitStart + 1)
                .getAsInteger(10, i))
          return false;

        // Check if matching constraint is out of bounds.
        if (i >= OutputConstraints.size()) return false;

        // A number must refer to an output only operand.
        if (OutputConstraints[i].isReadWrite())
          return false;

        // If the constraint is already tied, it must be tied to the
        // same operand referenced to by the number.
        if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
          return false;

        // The constraint should have the same info as the respective
        // output constraint.
        Info.setTiedOperand(i, OutputConstraints[i]);
      } else if (!validateAsmConstraint(Name, Info)) {
        // FIXME: This error return is in place temporarily so we can
        // add more constraints as we hit it.  Eventually, an unknown
        // constraint should just be treated as 'g'.
        return false;
      }
      break;
    case '[': {
      unsigned Index = 0;
      if (!resolveSymbolicName(Name, OutputConstraints, Index))
        return false;

      // If the constraint is already tied, it must be tied to the
      // same operand referenced to by the number.
      if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
        return false;

      // A number must refer to an output only operand.
      if (OutputConstraints[Index].isReadWrite())
        return false;

      Info.setTiedOperand(Index, OutputConstraints[Index]);
      break;
    }
    case '%': // commutative
      // FIXME: Fail if % is used with the last operand.
      break;
    case 'i': // immediate integer.
      break;
    case 'n': // immediate integer with a known value.
      Info.setRequiresImmediate();
      break;
    case 'I':  // Various constant constraints with target-specific meanings.
    case 'J':
    case 'K':
    case 'L':
    case 'M':
    case 'N':
    case 'O':
    case 'P':
      if (!validateAsmConstraint(Name, Info))
        return false;
      break;
    case 'r': // general register.
      Info.setAllowsRegister();
      break;
    case 'm': // memory operand.
    case 'o': // offsettable memory operand.
    case 'V': // non-offsettable memory operand.
    case '<': // autodecrement memory operand.
    case '>': // autoincrement memory operand.
      Info.setAllowsMemory();
      break;
    case 'g': // general register, memory operand or immediate integer.
    case 'X': // any operand.
      Info.setAllowsRegister();
      Info.setAllowsMemory();
      break;
    case 'E': // immediate floating point.
    case 'F': // immediate floating point.
    case 'p': // address operand.
      break;
    case ',': // multiple alternative constraint.  Ignore comma.
      break;
    case '#': // Ignore as constraint.
      while (Name[1] && Name[1] != ',')
        Name++;
      break;
    case '?': // Disparage slightly code.
    case '!': // Disparage severely.
    case '*': // Ignore for choosing register preferences.
      break;  // Pass them.
    }

    Name++;
  }

  return true;
}

void TargetInfo::CheckFixedPointBits() const {
  // Check that the number of fractional and integral bits (and maybe sign) can
  // fit into the bits given for a fixed point type.
  assert(ShortAccumScale + getShortAccumIBits() + 1 <= ShortAccumWidth);
  assert(AccumScale + getAccumIBits() + 1 <= AccumWidth);
  assert(LongAccumScale + getLongAccumIBits() + 1 <= LongAccumWidth);
  assert(getUnsignedShortAccumScale() + getUnsignedShortAccumIBits() <=
         ShortAccumWidth);
  assert(getUnsignedAccumScale() + getUnsignedAccumIBits() <= AccumWidth);
  assert(getUnsignedLongAccumScale() + getUnsignedLongAccumIBits() <=
         LongAccumWidth);

  assert(getShortFractScale() + 1 <= ShortFractWidth);
  assert(getFractScale() + 1 <= FractWidth);
  assert(getLongFractScale() + 1 <= LongFractWidth);
  assert(getUnsignedShortFractScale() <= ShortFractWidth);
  assert(getUnsignedFractScale() <= FractWidth);
  assert(getUnsignedLongFractScale() <= LongFractWidth);

  // Each unsigned fract type has either the same number of fractional bits
  // as, or one more fractional bit than, its corresponding signed fract type.
  assert(getShortFractScale() == getUnsignedShortFractScale() ||
         getShortFractScale() == getUnsignedShortFractScale() - 1);
  assert(getFractScale() == getUnsignedFractScale() ||
         getFractScale() == getUnsignedFractScale() - 1);
  assert(getLongFractScale() == getUnsignedLongFractScale() ||
         getLongFractScale() == getUnsignedLongFractScale() - 1);

  // When arranged in order of increasing rank (see 6.3.1.3a), the number of
  // fractional bits is nondecreasing for each of the following sets of
  // fixed-point types:
  // - signed fract types
  // - unsigned fract types
  // - signed accum types
  // - unsigned accum types.
  assert(getLongFractScale() >= getFractScale() &&
         getFractScale() >= getShortFractScale());
  assert(getUnsignedLongFractScale() >= getUnsignedFractScale() &&
         getUnsignedFractScale() >= getUnsignedShortFractScale());
  assert(LongAccumScale >= AccumScale && AccumScale >= ShortAccumScale);
  assert(getUnsignedLongAccumScale() >= getUnsignedAccumScale() &&
         getUnsignedAccumScale() >= getUnsignedShortAccumScale());

  // When arranged in order of increasing rank (see 6.3.1.3a), the number of
  // integral bits is nondecreasing for each of the following sets of
  // fixed-point types:
  // - signed accum types
  // - unsigned accum types
  assert(getLongAccumIBits() >= getAccumIBits() &&
         getAccumIBits() >= getShortAccumIBits());
  assert(getUnsignedLongAccumIBits() >= getUnsignedAccumIBits() &&
         getUnsignedAccumIBits() >= getUnsignedShortAccumIBits());

  // Each signed accum type has at least as many integral bits as its
  // corresponding unsigned accum type.
  assert(getShortAccumIBits() >= getUnsignedShortAccumIBits());
  assert(getAccumIBits() >= getUnsignedAccumIBits());
  assert(getLongAccumIBits() >= getUnsignedLongAccumIBits());
}