1// FormatString.cpp - Common stuff for handling printf/scanf formats -*- C++ -*-
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Shared details for processing format strings of printf and scanf
10// (and friends).
11//
12//===----------------------------------------------------------------------===//
13
14#include "FormatStringParsing.h"
15#include "clang/Basic/LangOptions.h"
16#include "clang/Basic/TargetInfo.h"
17#include "llvm/Support/ConvertUTF.h"
18
19using clang::analyze_format_string::ArgType;
20using clang::analyze_format_string::FormatStringHandler;
21using clang::analyze_format_string::FormatSpecifier;
22using clang::analyze_format_string::LengthModifier;
23using clang::analyze_format_string::OptionalAmount;
24using clang::analyze_format_string::PositionContext;
25using clang::analyze_format_string::ConversionSpecifier;
26using namespace clang;
27
28// Key function to FormatStringHandler.
29FormatStringHandler::~FormatStringHandler() {}
30
31//===----------------------------------------------------------------------===//
32// Functions for parsing format strings components in both printf and
33// scanf format strings.
34//===----------------------------------------------------------------------===//
35
36OptionalAmount
37clang::analyze_format_string::ParseAmount(const char *&Beg, const char *E) {
38  const char *I = Beg;
39  UpdateOnReturn <const char*> UpdateBeg(Beg, I);
40
41  unsigned accumulator = 0;
42  bool hasDigits = false;
43
44  for ( ; I != E; ++I) {
45    char c = *I;
46    if (c >= '0' && c <= '9') {
47      hasDigits = true;
48      accumulator = (accumulator * 10) + (c - '0');
49      continue;
50    }
51
52    if (hasDigits)
53      return OptionalAmount(OptionalAmount::Constant, accumulator, Beg, I - Beg,
54          false);
55
56    break;
57  }
58
59  return OptionalAmount();
60}
61
62OptionalAmount
63clang::analyze_format_string::ParseNonPositionAmount(const char *&Beg,
64                                                     const char *E,
65                                                     unsigned &argIndex) {
66  if (*Beg == '*') {
67    ++Beg;
68    return OptionalAmount(OptionalAmount::Arg, argIndex++, Beg, 0, false);
69  }
70
71  return ParseAmount(Beg, E);
72}
73
74OptionalAmount
75clang::analyze_format_string::ParsePositionAmount(FormatStringHandler &H,
76                                                  const char *Start,
77                                                  const char *&Beg,
78                                                  const char *E,
79                                                  PositionContext p) {
80  if (*Beg == '*') {
81    const char *I = Beg + 1;
82    const OptionalAmount &Amt = ParseAmount(I, E);
83
84    if (Amt.getHowSpecified() == OptionalAmount::NotSpecified) {
85      H.HandleInvalidPosition(Beg, I - Beg, p);
86      return OptionalAmount(false);
87    }
88
89    if (I == E) {
90      // No more characters left?
91      H.HandleIncompleteSpecifier(Start, E - Start);
92      return OptionalAmount(false);
93    }
94
95    assert(Amt.getHowSpecified() == OptionalAmount::Constant);
96
97    if (*I == '$') {
98      // Handle positional arguments
99
100      // Special case: '*0$', since this is an easy mistake.
101      if (Amt.getConstantAmount() == 0) {
102        H.HandleZeroPosition(Beg, I - Beg + 1);
103        return OptionalAmount(false);
104      }
105
106      const char *Tmp = Beg;
107      Beg = ++I;
108
109      return OptionalAmount(OptionalAmount::Arg, Amt.getConstantAmount() - 1,
110                            Tmp, 0, true);
111    }
112
113    H.HandleInvalidPosition(Beg, I - Beg, p);
114    return OptionalAmount(false);
115  }
116
117  return ParseAmount(Beg, E);
118}
119
120
121bool
122clang::analyze_format_string::ParseFieldWidth(FormatStringHandler &H,
123                                              FormatSpecifier &CS,
124                                              const char *Start,
125                                              const char *&Beg, const char *E,
126                                              unsigned *argIndex) {
127  // FIXME: Support negative field widths.
128  if (argIndex) {
129    CS.setFieldWidth(ParseNonPositionAmount(Beg, E, *argIndex));
130  }
131  else {
132    const OptionalAmount Amt =
133      ParsePositionAmount(H, Start, Beg, E,
134                          analyze_format_string::FieldWidthPos);
135
136    if (Amt.isInvalid())
137      return true;
138    CS.setFieldWidth(Amt);
139  }
140  return false;
141}
142
143bool
144clang::analyze_format_string::ParseArgPosition(FormatStringHandler &H,
145                                               FormatSpecifier &FS,
146                                               const char *Start,
147                                               const char *&Beg,
148                                               const char *E) {
149  const char *I = Beg;
150
151  const OptionalAmount &Amt = ParseAmount(I, E);
152
153  if (I == E) {
154    // No more characters left?
155    H.HandleIncompleteSpecifier(Start, E - Start);
156    return true;
157  }
158
159  if (Amt.getHowSpecified() == OptionalAmount::Constant && *(I++) == '$') {
160    // Warn that positional arguments are non-standard.
161    H.HandlePosition(Start, I - Start);
162
163    // Special case: '%0$', since this is an easy mistake.
164    if (Amt.getConstantAmount() == 0) {
165      H.HandleZeroPosition(Start, I - Start);
166      return true;
167    }
168
169    FS.setArgIndex(Amt.getConstantAmount() - 1);
170    FS.setUsesPositionalArg();
171    // Update the caller's pointer if we decided to consume
172    // these characters.
173    Beg = I;
174    return false;
175  }
176
177  return false;
178}
179
180bool
181clang::analyze_format_string::ParseVectorModifier(FormatStringHandler &H,
182                                                  FormatSpecifier &FS,
183                                                  const char *&I,
184                                                  const char *E,
185                                                  const LangOptions &LO) {
186  if (!LO.OpenCL)
187    return false;
188
189  const char *Start = I;
190  if (*I == 'v') {
191    ++I;
192
193    if (I == E) {
194      H.HandleIncompleteSpecifier(Start, E - Start);
195      return true;
196    }
197
198    OptionalAmount NumElts = ParseAmount(I, E);
199    if (NumElts.getHowSpecified() != OptionalAmount::Constant) {
200      H.HandleIncompleteSpecifier(Start, E - Start);
201      return true;
202    }
203
204    FS.setVectorNumElts(NumElts);
205  }
206
207  return false;
208}
209
210bool
211clang::analyze_format_string::ParseLengthModifier(FormatSpecifier &FS,
212                                                  const char *&I,
213                                                  const char *E,
214                                                  const LangOptions &LO,
215                                                  bool IsScanf) {
216  LengthModifier::Kind lmKind = LengthModifier::None;
217  const char *lmPosition = I;
218  switch (*I) {
219    default:
220      return false;
221    case 'h':
222      ++I;
223      if (I != E && *I == 'h') {
224        ++I;
225        lmKind = LengthModifier::AsChar;
226      } else if (I != E && *I == 'l' && LO.OpenCL) {
227        ++I;
228        lmKind = LengthModifier::AsShortLong;
229      } else {
230        lmKind = LengthModifier::AsShort;
231      }
232      break;
233    case 'l':
234      ++I;
235      if (I != E && *I == 'l') {
236        ++I;
237        lmKind = LengthModifier::AsLongLong;
238      } else {
239        lmKind = LengthModifier::AsLong;
240      }
241      break;
242    case 'j': lmKind = LengthModifier::AsIntMax;     ++I; break;
243    case 'z': lmKind = LengthModifier::AsSizeT;      ++I; break;
244    case 't': lmKind = LengthModifier::AsPtrDiff;    ++I; break;
245    case 'L': lmKind = LengthModifier::AsLongDouble; ++I; break;
246    case 'q': lmKind = LengthModifier::AsQuad;       ++I; break;
247    case 'a':
248      if (IsScanf && !LO.C99 && !LO.CPlusPlus11) {
249        // For scanf in C90, look at the next character to see if this should
250        // be parsed as the GNU extension 'a' length modifier. If not, this
251        // will be parsed as a conversion specifier.
252        ++I;
253        if (I != E && (*I == 's' || *I == 'S' || *I == '[')) {
254          lmKind = LengthModifier::AsAllocate;
255          break;
256        }
257        --I;
258      }
259      return false;
260    case 'm':
261      if (IsScanf) {
262        lmKind = LengthModifier::AsMAllocate;
263        ++I;
264        break;
265      }
266      return false;
267    // printf: AsInt64, AsInt32, AsInt3264
268    // scanf:  AsInt64
269    case 'I':
270      if (I + 1 != E && I + 2 != E) {
271        if (I[1] == '6' && I[2] == '4') {
272          I += 3;
273          lmKind = LengthModifier::AsInt64;
274          break;
275        }
276        if (IsScanf)
277          return false;
278
279        if (I[1] == '3' && I[2] == '2') {
280          I += 3;
281          lmKind = LengthModifier::AsInt32;
282          break;
283        }
284      }
285      ++I;
286      lmKind = LengthModifier::AsInt3264;
287      break;
288    case 'w':
289      lmKind = LengthModifier::AsWide; ++I; break;
290  }
291  LengthModifier lm(lmPosition, lmKind);
292  FS.setLengthModifier(lm);
293  return true;
294}
295
296bool clang::analyze_format_string::ParseUTF8InvalidSpecifier(
297    const char *SpecifierBegin, const char *FmtStrEnd, unsigned &Len) {
298  if (SpecifierBegin + 1 >= FmtStrEnd)
299    return false;
300
301  const llvm::UTF8 *SB =
302      reinterpret_cast<const llvm::UTF8 *>(SpecifierBegin + 1);
303  const llvm::UTF8 *SE = reinterpret_cast<const llvm::UTF8 *>(FmtStrEnd);
304  const char FirstByte = *SB;
305
306  // If the invalid specifier is a multibyte UTF-8 string, return the
307  // total length accordingly so that the conversion specifier can be
308  // properly updated to reflect a complete UTF-8 specifier.
309  unsigned NumBytes = llvm::getNumBytesForUTF8(FirstByte);
310  if (NumBytes == 1)
311    return false;
312  if (SB + NumBytes > SE)
313    return false;
314
315  Len = NumBytes + 1;
316  return true;
317}
318
319//===----------------------------------------------------------------------===//
320// Methods on ArgType.
321//===----------------------------------------------------------------------===//
322
323clang::analyze_format_string::ArgType::MatchKind
324ArgType::matchesType(ASTContext &C, QualType argTy) const {
325  if (Ptr) {
326    // It has to be a pointer.
327    const PointerType *PT = argTy->getAs<PointerType>();
328    if (!PT)
329      return NoMatch;
330
331    // We cannot write through a const qualified pointer.
332    if (PT->getPointeeType().isConstQualified())
333      return NoMatch;
334
335    argTy = PT->getPointeeType();
336  }
337
338  switch (K) {
339    case InvalidTy:
340      llvm_unreachable("ArgType must be valid");
341
342    case UnknownTy:
343      return Match;
344
345    case AnyCharTy: {
346      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
347        // If the enum is incomplete we know nothing about the underlying type.
348        // Assume that it's 'int'.
349        if (!ETy->getDecl()->isComplete())
350          return NoMatch;
351        argTy = ETy->getDecl()->getIntegerType();
352      }
353
354      if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
355        switch (BT->getKind()) {
356          default:
357            break;
358          case BuiltinType::Char_S:
359          case BuiltinType::SChar:
360          case BuiltinType::UChar:
361          case BuiltinType::Char_U:
362          case BuiltinType::Bool:
363            return Match;
364        }
365      return NoMatch;
366    }
367
368    case SpecificTy: {
369      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
370        // If the enum is incomplete we know nothing about the underlying type.
371        // Assume that it's 'int'.
372        if (!ETy->getDecl()->isComplete())
373          argTy = C.IntTy;
374        else
375          argTy = ETy->getDecl()->getIntegerType();
376      }
377      argTy = C.getCanonicalType(argTy).getUnqualifiedType();
378
379      if (T == argTy)
380        return Match;
381      // Check for "compatible types".
382      if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
383        switch (BT->getKind()) {
384          default:
385            break;
386          case BuiltinType::Char_S:
387          case BuiltinType::SChar:
388          case BuiltinType::Char_U:
389          case BuiltinType::UChar:
390          case BuiltinType::Bool:
391            if (T == C.UnsignedShortTy || T == C.ShortTy)
392              return NoMatchTypeConfusion;
393            return T == C.UnsignedCharTy || T == C.SignedCharTy ? Match
394                                                                : NoMatch;
395          case BuiltinType::Short:
396            return T == C.UnsignedShortTy ? Match : NoMatch;
397          case BuiltinType::UShort:
398            return T == C.ShortTy ? Match : NoMatch;
399          case BuiltinType::Int:
400            return T == C.UnsignedIntTy ? Match : NoMatch;
401          case BuiltinType::UInt:
402            return T == C.IntTy ? Match : NoMatch;
403          case BuiltinType::Long:
404            return T == C.UnsignedLongTy ? Match : NoMatch;
405          case BuiltinType::ULong:
406            return T == C.LongTy ? Match : NoMatch;
407          case BuiltinType::LongLong:
408            return T == C.UnsignedLongLongTy ? Match : NoMatch;
409          case BuiltinType::ULongLong:
410            return T == C.LongLongTy ? Match : NoMatch;
411        }
412      return NoMatch;
413    }
414
415    case CStrTy: {
416      const PointerType *PT = argTy->getAs<PointerType>();
417      if (!PT)
418        return NoMatch;
419      QualType pointeeTy = PT->getPointeeType();
420      if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
421        switch (BT->getKind()) {
422          case BuiltinType::Char_U:
423          case BuiltinType::UChar:
424          case BuiltinType::Char_S:
425          case BuiltinType::SChar:
426            return Match;
427          default:
428            break;
429        }
430
431      return NoMatch;
432    }
433
434    case WCStrTy: {
435      const PointerType *PT = argTy->getAs<PointerType>();
436      if (!PT)
437        return NoMatch;
438      QualType pointeeTy =
439        C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
440      return pointeeTy == C.getWideCharType() ? Match : NoMatch;
441    }
442
443    case WIntTy: {
444      QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
445
446      if (C.getCanonicalType(argTy).getUnqualifiedType() == WInt)
447        return Match;
448
449      QualType PromoArg = argTy->isPromotableIntegerType()
450                              ? C.getPromotedIntegerType(argTy)
451                              : argTy;
452      PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
453
454      // If the promoted argument is the corresponding signed type of the
455      // wint_t type, then it should match.
456      if (PromoArg->hasSignedIntegerRepresentation() &&
457          C.getCorrespondingUnsignedType(PromoArg) == WInt)
458        return Match;
459
460      return WInt == PromoArg ? Match : NoMatch;
461    }
462
463    case CPointerTy:
464      if (argTy->isVoidPointerType()) {
465        return Match;
466      } if (argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
467            argTy->isBlockPointerType() || argTy->isNullPtrType()) {
468        return NoMatchPedantic;
469      } else {
470        return NoMatch;
471      }
472
473    case ObjCPointerTy: {
474      if (argTy->getAs<ObjCObjectPointerType>() ||
475          argTy->getAs<BlockPointerType>())
476        return Match;
477
478      // Handle implicit toll-free bridging.
479      if (const PointerType *PT = argTy->getAs<PointerType>()) {
480        // Things such as CFTypeRef are really just opaque pointers
481        // to C structs representing CF types that can often be bridged
482        // to Objective-C objects.  Since the compiler doesn't know which
483        // structs can be toll-free bridged, we just accept them all.
484        QualType pointee = PT->getPointeeType();
485        if (pointee->getAsStructureType() || pointee->isVoidType())
486          return Match;
487      }
488      return NoMatch;
489    }
490  }
491
492  llvm_unreachable("Invalid ArgType Kind!");
493}
494
495ArgType ArgType::makeVectorType(ASTContext &C, unsigned NumElts) const {
496  // Check for valid vector element types.
497  if (T.isNull())
498    return ArgType::Invalid();
499
500  QualType Vec = C.getExtVectorType(T, NumElts);
501  return ArgType(Vec, Name);
502}
503
504QualType ArgType::getRepresentativeType(ASTContext &C) const {
505  QualType Res;
506  switch (K) {
507    case InvalidTy:
508      llvm_unreachable("No representative type for Invalid ArgType");
509    case UnknownTy:
510      llvm_unreachable("No representative type for Unknown ArgType");
511    case AnyCharTy:
512      Res = C.CharTy;
513      break;
514    case SpecificTy:
515      Res = T;
516      break;
517    case CStrTy:
518      Res = C.getPointerType(C.CharTy);
519      break;
520    case WCStrTy:
521      Res = C.getPointerType(C.getWideCharType());
522      break;
523    case ObjCPointerTy:
524      Res = C.ObjCBuiltinIdTy;
525      break;
526    case CPointerTy:
527      Res = C.VoidPtrTy;
528      break;
529    case WIntTy: {
530      Res = C.getWIntType();
531      break;
532    }
533  }
534
535  if (Ptr)
536    Res = C.getPointerType(Res);
537  return Res;
538}
539
540std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
541  std::string S = getRepresentativeType(C).getAsString(C.getPrintingPolicy());
542
543  std::string Alias;
544  if (Name) {
545    // Use a specific name for this type, e.g. "size_t".
546    Alias = Name;
547    if (Ptr) {
548      // If ArgType is actually a pointer to T, append an asterisk.
549      Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
550    }
551    // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
552    if (S == Alias)
553      Alias.clear();
554  }
555
556  if (!Alias.empty())
557    return std::string("'") + Alias + "' (aka '" + S + "')";
558  return std::string("'") + S + "'";
559}
560
561
562//===----------------------------------------------------------------------===//
563// Methods on OptionalAmount.
564//===----------------------------------------------------------------------===//
565
566ArgType
567analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
568  return Ctx.IntTy;
569}
570
571//===----------------------------------------------------------------------===//
572// Methods on LengthModifier.
573//===----------------------------------------------------------------------===//
574
575const char *
576analyze_format_string::LengthModifier::toString() const {
577  switch (kind) {
578  case AsChar:
579    return "hh";
580  case AsShort:
581    return "h";
582  case AsShortLong:
583    return "hl";
584  case AsLong: // or AsWideChar
585    return "l";
586  case AsLongLong:
587    return "ll";
588  case AsQuad:
589    return "q";
590  case AsIntMax:
591    return "j";
592  case AsSizeT:
593    return "z";
594  case AsPtrDiff:
595    return "t";
596  case AsInt32:
597    return "I32";
598  case AsInt3264:
599    return "I";
600  case AsInt64:
601    return "I64";
602  case AsLongDouble:
603    return "L";
604  case AsAllocate:
605    return "a";
606  case AsMAllocate:
607    return "m";
608  case AsWide:
609    return "w";
610  case None:
611    return "";
612  }
613  return nullptr;
614}
615
616//===----------------------------------------------------------------------===//
617// Methods on ConversionSpecifier.
618//===----------------------------------------------------------------------===//
619
620const char *ConversionSpecifier::toString() const {
621  switch (kind) {
622  case dArg: return "d";
623  case DArg: return "D";
624  case iArg: return "i";
625  case oArg: return "o";
626  case OArg: return "O";
627  case uArg: return "u";
628  case UArg: return "U";
629  case xArg: return "x";
630  case XArg: return "X";
631  case fArg: return "f";
632  case FArg: return "F";
633  case eArg: return "e";
634  case EArg: return "E";
635  case gArg: return "g";
636  case GArg: return "G";
637  case aArg: return "a";
638  case AArg: return "A";
639  case cArg: return "c";
640  case sArg: return "s";
641  case pArg: return "p";
642  case PArg:
643    return "P";
644  case nArg: return "n";
645  case PercentArg:  return "%";
646  case ScanListArg: return "[";
647  case InvalidSpecifier: return nullptr;
648
649  // POSIX unicode extensions.
650  case CArg: return "C";
651  case SArg: return "S";
652
653  // Objective-C specific specifiers.
654  case ObjCObjArg: return "@";
655
656  // FreeBSD kernel specific specifiers.
657  case FreeBSDbArg: return "b";
658  case FreeBSDDArg: return "D";
659  case FreeBSDrArg: return "r";
660  case FreeBSDyArg: return "y";
661
662  // GlibC specific specifiers.
663  case PrintErrno: return "m";
664
665  // MS specific specifiers.
666  case ZArg: return "Z";
667  }
668  return nullptr;
669}
670
671Optional<ConversionSpecifier>
672ConversionSpecifier::getStandardSpecifier() const {
673  ConversionSpecifier::Kind NewKind;
674
675  switch (getKind()) {
676  default:
677    return None;
678  case DArg:
679    NewKind = dArg;
680    break;
681  case UArg:
682    NewKind = uArg;
683    break;
684  case OArg:
685    NewKind = oArg;
686    break;
687  }
688
689  ConversionSpecifier FixedCS(*this);
690  FixedCS.setKind(NewKind);
691  return FixedCS;
692}
693
694//===----------------------------------------------------------------------===//
695// Methods on OptionalAmount.
696//===----------------------------------------------------------------------===//
697
698void OptionalAmount::toString(raw_ostream &os) const {
699  switch (hs) {
700  case Invalid:
701  case NotSpecified:
702    return;
703  case Arg:
704    if (UsesDotPrefix)
705        os << ".";
706    if (usesPositionalArg())
707      os << "*" << getPositionalArgIndex() << "$";
708    else
709      os << "*";
710    break;
711  case Constant:
712    if (UsesDotPrefix)
713        os << ".";
714    os << amt;
715    break;
716  }
717}
718
719bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target,
720                                             const LangOptions &LO) const {
721  switch (LM.getKind()) {
722    case LengthModifier::None:
723      return true;
724
725    // Handle most integer flags
726    case LengthModifier::AsShort:
727      // Length modifier only applies to FP vectors.
728      if (LO.OpenCL && CS.isDoubleArg())
729        return !VectorNumElts.isInvalid();
730
731      if (Target.getTriple().isOSMSVCRT()) {
732        switch (CS.getKind()) {
733          case ConversionSpecifier::cArg:
734          case ConversionSpecifier::CArg:
735          case ConversionSpecifier::sArg:
736          case ConversionSpecifier::SArg:
737          case ConversionSpecifier::ZArg:
738            return true;
739          default:
740            break;
741        }
742      }
743      LLVM_FALLTHROUGH;
744    case LengthModifier::AsChar:
745    case LengthModifier::AsLongLong:
746    case LengthModifier::AsQuad:
747    case LengthModifier::AsIntMax:
748    case LengthModifier::AsSizeT:
749    case LengthModifier::AsPtrDiff:
750      switch (CS.getKind()) {
751        case ConversionSpecifier::dArg:
752        case ConversionSpecifier::DArg:
753        case ConversionSpecifier::iArg:
754        case ConversionSpecifier::oArg:
755        case ConversionSpecifier::OArg:
756        case ConversionSpecifier::uArg:
757        case ConversionSpecifier::UArg:
758        case ConversionSpecifier::xArg:
759        case ConversionSpecifier::XArg:
760        case ConversionSpecifier::nArg:
761          return true;
762        case ConversionSpecifier::FreeBSDrArg:
763        case ConversionSpecifier::FreeBSDyArg:
764          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS4();
765        default:
766          return false;
767      }
768
769    case LengthModifier::AsShortLong:
770      return LO.OpenCL && !VectorNumElts.isInvalid();
771
772    // Handle 'l' flag
773    case LengthModifier::AsLong: // or AsWideChar
774      if (CS.isDoubleArg()) {
775        // Invalid for OpenCL FP scalars.
776        if (LO.OpenCL && VectorNumElts.isInvalid())
777          return false;
778        return true;
779      }
780
781      switch (CS.getKind()) {
782        case ConversionSpecifier::dArg:
783        case ConversionSpecifier::DArg:
784        case ConversionSpecifier::iArg:
785        case ConversionSpecifier::oArg:
786        case ConversionSpecifier::OArg:
787        case ConversionSpecifier::uArg:
788        case ConversionSpecifier::UArg:
789        case ConversionSpecifier::xArg:
790        case ConversionSpecifier::XArg:
791        case ConversionSpecifier::nArg:
792        case ConversionSpecifier::cArg:
793        case ConversionSpecifier::sArg:
794        case ConversionSpecifier::ScanListArg:
795        case ConversionSpecifier::ZArg:
796          return true;
797        case ConversionSpecifier::FreeBSDrArg:
798        case ConversionSpecifier::FreeBSDyArg:
799          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS4();
800        default:
801          return false;
802      }
803
804    case LengthModifier::AsLongDouble:
805      switch (CS.getKind()) {
806        case ConversionSpecifier::aArg:
807        case ConversionSpecifier::AArg:
808        case ConversionSpecifier::fArg:
809        case ConversionSpecifier::FArg:
810        case ConversionSpecifier::eArg:
811        case ConversionSpecifier::EArg:
812        case ConversionSpecifier::gArg:
813        case ConversionSpecifier::GArg:
814          return true;
815        // GNU libc extension.
816        case ConversionSpecifier::dArg:
817        case ConversionSpecifier::iArg:
818        case ConversionSpecifier::oArg:
819        case ConversionSpecifier::uArg:
820        case ConversionSpecifier::xArg:
821        case ConversionSpecifier::XArg:
822          return !Target.getTriple().isOSDarwin() &&
823                 !Target.getTriple().isOSWindows();
824        default:
825          return false;
826      }
827
828    case LengthModifier::AsAllocate:
829      switch (CS.getKind()) {
830        case ConversionSpecifier::sArg:
831        case ConversionSpecifier::SArg:
832        case ConversionSpecifier::ScanListArg:
833          return true;
834        default:
835          return false;
836      }
837
838    case LengthModifier::AsMAllocate:
839      switch (CS.getKind()) {
840        case ConversionSpecifier::cArg:
841        case ConversionSpecifier::CArg:
842        case ConversionSpecifier::sArg:
843        case ConversionSpecifier::SArg:
844        case ConversionSpecifier::ScanListArg:
845          return true;
846        default:
847          return false;
848      }
849    case LengthModifier::AsInt32:
850    case LengthModifier::AsInt3264:
851    case LengthModifier::AsInt64:
852      switch (CS.getKind()) {
853        case ConversionSpecifier::dArg:
854        case ConversionSpecifier::iArg:
855        case ConversionSpecifier::oArg:
856        case ConversionSpecifier::uArg:
857        case ConversionSpecifier::xArg:
858        case ConversionSpecifier::XArg:
859          return Target.getTriple().isOSMSVCRT();
860        default:
861          return false;
862      }
863    case LengthModifier::AsWide:
864      switch (CS.getKind()) {
865        case ConversionSpecifier::cArg:
866        case ConversionSpecifier::CArg:
867        case ConversionSpecifier::sArg:
868        case ConversionSpecifier::SArg:
869        case ConversionSpecifier::ZArg:
870          return Target.getTriple().isOSMSVCRT();
871        default:
872          return false;
873      }
874  }
875  llvm_unreachable("Invalid LengthModifier Kind!");
876}
877
878bool FormatSpecifier::hasStandardLengthModifier() const {
879  switch (LM.getKind()) {
880    case LengthModifier::None:
881    case LengthModifier::AsChar:
882    case LengthModifier::AsShort:
883    case LengthModifier::AsLong:
884    case LengthModifier::AsLongLong:
885    case LengthModifier::AsIntMax:
886    case LengthModifier::AsSizeT:
887    case LengthModifier::AsPtrDiff:
888    case LengthModifier::AsLongDouble:
889      return true;
890    case LengthModifier::AsAllocate:
891    case LengthModifier::AsMAllocate:
892    case LengthModifier::AsQuad:
893    case LengthModifier::AsInt32:
894    case LengthModifier::AsInt3264:
895    case LengthModifier::AsInt64:
896    case LengthModifier::AsWide:
897    case LengthModifier::AsShortLong: // ???
898      return false;
899  }
900  llvm_unreachable("Invalid LengthModifier Kind!");
901}
902
903bool FormatSpecifier::hasStandardConversionSpecifier(
904    const LangOptions &LangOpt) const {
905  switch (CS.getKind()) {
906    case ConversionSpecifier::cArg:
907    case ConversionSpecifier::dArg:
908    case ConversionSpecifier::iArg:
909    case ConversionSpecifier::oArg:
910    case ConversionSpecifier::uArg:
911    case ConversionSpecifier::xArg:
912    case ConversionSpecifier::XArg:
913    case ConversionSpecifier::fArg:
914    case ConversionSpecifier::FArg:
915    case ConversionSpecifier::eArg:
916    case ConversionSpecifier::EArg:
917    case ConversionSpecifier::gArg:
918    case ConversionSpecifier::GArg:
919    case ConversionSpecifier::aArg:
920    case ConversionSpecifier::AArg:
921    case ConversionSpecifier::sArg:
922    case ConversionSpecifier::pArg:
923    case ConversionSpecifier::nArg:
924    case ConversionSpecifier::ObjCObjArg:
925    case ConversionSpecifier::ScanListArg:
926    case ConversionSpecifier::PercentArg:
927    case ConversionSpecifier::PArg:
928      return true;
929    case ConversionSpecifier::CArg:
930    case ConversionSpecifier::SArg:
931      return LangOpt.ObjC;
932    case ConversionSpecifier::InvalidSpecifier:
933    case ConversionSpecifier::FreeBSDbArg:
934    case ConversionSpecifier::FreeBSDDArg:
935    case ConversionSpecifier::FreeBSDrArg:
936    case ConversionSpecifier::FreeBSDyArg:
937    case ConversionSpecifier::PrintErrno:
938    case ConversionSpecifier::DArg:
939    case ConversionSpecifier::OArg:
940    case ConversionSpecifier::UArg:
941    case ConversionSpecifier::ZArg:
942      return false;
943  }
944  llvm_unreachable("Invalid ConversionSpecifier Kind!");
945}
946
947bool FormatSpecifier::hasStandardLengthConversionCombination() const {
948  if (LM.getKind() == LengthModifier::AsLongDouble) {
949    switch(CS.getKind()) {
950        case ConversionSpecifier::dArg:
951        case ConversionSpecifier::iArg:
952        case ConversionSpecifier::oArg:
953        case ConversionSpecifier::uArg:
954        case ConversionSpecifier::xArg:
955        case ConversionSpecifier::XArg:
956          return false;
957        default:
958          return true;
959    }
960  }
961  return true;
962}
963
964Optional<LengthModifier> FormatSpecifier::getCorrectedLengthModifier() const {
965  if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
966    if (LM.getKind() == LengthModifier::AsLongDouble ||
967        LM.getKind() == LengthModifier::AsQuad) {
968      LengthModifier FixedLM(LM);
969      FixedLM.setKind(LengthModifier::AsLongLong);
970      return FixedLM;
971    }
972  }
973
974  return None;
975}
976
977bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
978                                                LengthModifier &LM) {
979  assert(isa<TypedefType>(QT) && "Expected a TypedefType");
980  const TypedefNameDecl *Typedef = cast<TypedefType>(QT)->getDecl();
981
982  for (;;) {
983    const IdentifierInfo *Identifier = Typedef->getIdentifier();
984    if (Identifier->getName() == "size_t") {
985      LM.setKind(LengthModifier::AsSizeT);
986      return true;
987    } else if (Identifier->getName() == "ssize_t") {
988      // Not C99, but common in Unix.
989      LM.setKind(LengthModifier::AsSizeT);
990      return true;
991    } else if (Identifier->getName() == "intmax_t") {
992      LM.setKind(LengthModifier::AsIntMax);
993      return true;
994    } else if (Identifier->getName() == "uintmax_t") {
995      LM.setKind(LengthModifier::AsIntMax);
996      return true;
997    } else if (Identifier->getName() == "ptrdiff_t") {
998      LM.setKind(LengthModifier::AsPtrDiff);
999      return true;
1000    }
1001
1002    QualType T = Typedef->getUnderlyingType();
1003    if (!isa<TypedefType>(T))
1004      break;
1005
1006    Typedef = cast<TypedefType>(T)->getDecl();
1007  }
1008  return false;
1009}
1010