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#include <optional>
19
20using clang::analyze_format_string::ArgType;
21using clang::analyze_format_string::FormatStringHandler;
22using clang::analyze_format_string::FormatSpecifier;
23using clang::analyze_format_string::LengthModifier;
24using clang::analyze_format_string::OptionalAmount;
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  // When using the format attribute in C++, you can receive a function or an
326  // array that will necessarily decay to a pointer when passed to the final
327  // format consumer. Apply decay before type comparison.
328  if (argTy->canDecayToPointerType())
329    argTy = C.getDecayedType(argTy);
330
331  if (Ptr) {
332    // It has to be a pointer.
333    const PointerType *PT = argTy->getAs<PointerType>();
334    if (!PT)
335      return NoMatch;
336
337    // We cannot write through a const qualified pointer.
338    if (PT->getPointeeType().isConstQualified())
339      return NoMatch;
340
341    argTy = PT->getPointeeType();
342  }
343
344  switch (K) {
345    case InvalidTy:
346      llvm_unreachable("ArgType must be valid");
347
348    case UnknownTy:
349      return Match;
350
351    case AnyCharTy: {
352      if (const auto *ETy = argTy->getAs<EnumType>()) {
353        // If the enum is incomplete we know nothing about the underlying type.
354        // Assume that it's 'int'.
355        if (!ETy->getDecl()->isComplete())
356          return NoMatch;
357        argTy = ETy->getDecl()->getIntegerType();
358      }
359
360      if (const auto *BT = argTy->getAs<BuiltinType>()) {
361        // The types are perfectly matched?
362        switch (BT->getKind()) {
363        default:
364          break;
365        case BuiltinType::Char_S:
366        case BuiltinType::SChar:
367        case BuiltinType::UChar:
368        case BuiltinType::Char_U:
369        case BuiltinType::Bool:
370          return Match;
371        }
372        // "Partially matched" because of promotions?
373        if (!Ptr) {
374          switch (BT->getKind()) {
375          default:
376            break;
377          case BuiltinType::Int:
378          case BuiltinType::UInt:
379            return MatchPromotion;
380          case BuiltinType::Short:
381          case BuiltinType::UShort:
382          case BuiltinType::WChar_S:
383          case BuiltinType::WChar_U:
384            return NoMatchPromotionTypeConfusion;
385          }
386        }
387      }
388      return NoMatch;
389    }
390
391    case SpecificTy: {
392      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
393        // If the enum is incomplete we know nothing about the underlying type.
394        // Assume that it's 'int'.
395        if (!ETy->getDecl()->isComplete())
396          argTy = C.IntTy;
397        else
398          argTy = ETy->getDecl()->getIntegerType();
399      }
400      argTy = C.getCanonicalType(argTy).getUnqualifiedType();
401
402      if (T == argTy)
403        return Match;
404      if (const auto *BT = argTy->getAs<BuiltinType>()) {
405        // Check if the only difference between them is signed vs unsigned
406        // if true, we consider they are compatible.
407        switch (BT->getKind()) {
408          default:
409            break;
410          case BuiltinType::Char_S:
411          case BuiltinType::SChar:
412          case BuiltinType::Char_U:
413          case BuiltinType::UChar:
414          case BuiltinType::Bool:
415            if (T == C.UnsignedShortTy || T == C.ShortTy)
416              return NoMatchTypeConfusion;
417            if (T == C.UnsignedCharTy || T == C.SignedCharTy)
418              return Match;
419            break;
420          case BuiltinType::Short:
421            if (T == C.UnsignedShortTy)
422              return Match;
423            break;
424          case BuiltinType::UShort:
425            if (T == C.ShortTy)
426              return Match;
427            break;
428          case BuiltinType::Int:
429            if (T == C.UnsignedIntTy)
430              return Match;
431            break;
432          case BuiltinType::UInt:
433            if (T == C.IntTy)
434              return Match;
435            break;
436          case BuiltinType::Long:
437            if (T == C.UnsignedLongTy)
438              return Match;
439            break;
440          case BuiltinType::ULong:
441            if (T == C.LongTy)
442              return Match;
443            break;
444          case BuiltinType::LongLong:
445            if (T == C.UnsignedLongLongTy)
446              return Match;
447            break;
448          case BuiltinType::ULongLong:
449            if (T == C.LongLongTy)
450              return Match;
451            break;
452          }
453          // "Partially matched" because of promotions?
454          if (!Ptr) {
455            switch (BT->getKind()) {
456            default:
457              break;
458            case BuiltinType::Int:
459            case BuiltinType::UInt:
460              if (T == C.SignedCharTy || T == C.UnsignedCharTy ||
461                  T == C.ShortTy || T == C.UnsignedShortTy || T == C.WCharTy ||
462                  T == C.WideCharTy)
463                return MatchPromotion;
464              break;
465            case BuiltinType::Short:
466            case BuiltinType::UShort:
467              if (T == C.SignedCharTy || T == C.UnsignedCharTy)
468                return NoMatchPromotionTypeConfusion;
469              break;
470            case BuiltinType::WChar_U:
471            case BuiltinType::WChar_S:
472              if (T != C.WCharTy && T != C.WideCharTy)
473                return NoMatchPromotionTypeConfusion;
474            }
475          }
476      }
477      return NoMatch;
478    }
479
480    case CStrTy: {
481      const PointerType *PT = argTy->getAs<PointerType>();
482      if (!PT)
483        return NoMatch;
484      QualType pointeeTy = PT->getPointeeType();
485      if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
486        switch (BT->getKind()) {
487          case BuiltinType::Char_U:
488          case BuiltinType::UChar:
489          case BuiltinType::Char_S:
490          case BuiltinType::SChar:
491            return Match;
492          default:
493            break;
494        }
495
496      return NoMatch;
497    }
498
499    case WCStrTy: {
500      const PointerType *PT = argTy->getAs<PointerType>();
501      if (!PT)
502        return NoMatch;
503      QualType pointeeTy =
504        C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
505      return pointeeTy == C.getWideCharType() ? Match : NoMatch;
506    }
507
508    case WIntTy: {
509      QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
510
511      if (C.getCanonicalType(argTy).getUnqualifiedType() == WInt)
512        return Match;
513
514      QualType PromoArg = C.isPromotableIntegerType(argTy)
515                              ? C.getPromotedIntegerType(argTy)
516                              : argTy;
517      PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
518
519      // If the promoted argument is the corresponding signed type of the
520      // wint_t type, then it should match.
521      if (PromoArg->hasSignedIntegerRepresentation() &&
522          C.getCorrespondingUnsignedType(PromoArg) == WInt)
523        return Match;
524
525      return WInt == PromoArg ? Match : NoMatch;
526    }
527
528    case CPointerTy:
529      if (argTy->isVoidPointerType()) {
530        return Match;
531      } if (argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
532            argTy->isBlockPointerType() || argTy->isNullPtrType()) {
533        return NoMatchPedantic;
534      } else {
535        return NoMatch;
536      }
537
538    case ObjCPointerTy: {
539      if (argTy->getAs<ObjCObjectPointerType>() ||
540          argTy->getAs<BlockPointerType>())
541        return Match;
542
543      // Handle implicit toll-free bridging.
544      if (const PointerType *PT = argTy->getAs<PointerType>()) {
545        // Things such as CFTypeRef are really just opaque pointers
546        // to C structs representing CF types that can often be bridged
547        // to Objective-C objects.  Since the compiler doesn't know which
548        // structs can be toll-free bridged, we just accept them all.
549        QualType pointee = PT->getPointeeType();
550        if (pointee->getAsStructureType() || pointee->isVoidType())
551          return Match;
552      }
553      return NoMatch;
554    }
555  }
556
557  llvm_unreachable("Invalid ArgType Kind!");
558}
559
560ArgType ArgType::makeVectorType(ASTContext &C, unsigned NumElts) const {
561  // Check for valid vector element types.
562  if (T.isNull())
563    return ArgType::Invalid();
564
565  QualType Vec = C.getExtVectorType(T, NumElts);
566  return ArgType(Vec, Name);
567}
568
569QualType ArgType::getRepresentativeType(ASTContext &C) const {
570  QualType Res;
571  switch (K) {
572    case InvalidTy:
573      llvm_unreachable("No representative type for Invalid ArgType");
574    case UnknownTy:
575      llvm_unreachable("No representative type for Unknown ArgType");
576    case AnyCharTy:
577      Res = C.CharTy;
578      break;
579    case SpecificTy:
580      Res = T;
581      break;
582    case CStrTy:
583      Res = C.getPointerType(C.CharTy);
584      break;
585    case WCStrTy:
586      Res = C.getPointerType(C.getWideCharType());
587      break;
588    case ObjCPointerTy:
589      Res = C.ObjCBuiltinIdTy;
590      break;
591    case CPointerTy:
592      Res = C.VoidPtrTy;
593      break;
594    case WIntTy: {
595      Res = C.getWIntType();
596      break;
597    }
598  }
599
600  if (Ptr)
601    Res = C.getPointerType(Res);
602  return Res;
603}
604
605std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
606  std::string S = getRepresentativeType(C).getAsString(C.getPrintingPolicy());
607
608  std::string Alias;
609  if (Name) {
610    // Use a specific name for this type, e.g. "size_t".
611    Alias = Name;
612    if (Ptr) {
613      // If ArgType is actually a pointer to T, append an asterisk.
614      Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
615    }
616    // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
617    if (S == Alias)
618      Alias.clear();
619  }
620
621  if (!Alias.empty())
622    return std::string("'") + Alias + "' (aka '" + S + "')";
623  return std::string("'") + S + "'";
624}
625
626
627//===----------------------------------------------------------------------===//
628// Methods on OptionalAmount.
629//===----------------------------------------------------------------------===//
630
631ArgType
632analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
633  return Ctx.IntTy;
634}
635
636//===----------------------------------------------------------------------===//
637// Methods on LengthModifier.
638//===----------------------------------------------------------------------===//
639
640const char *
641analyze_format_string::LengthModifier::toString() const {
642  switch (kind) {
643  case AsChar:
644    return "hh";
645  case AsShort:
646    return "h";
647  case AsShortLong:
648    return "hl";
649  case AsLong: // or AsWideChar
650    return "l";
651  case AsLongLong:
652    return "ll";
653  case AsQuad:
654    return "q";
655  case AsIntMax:
656    return "j";
657  case AsSizeT:
658    return "z";
659  case AsPtrDiff:
660    return "t";
661  case AsInt32:
662    return "I32";
663  case AsInt3264:
664    return "I";
665  case AsInt64:
666    return "I64";
667  case AsLongDouble:
668    return "L";
669  case AsAllocate:
670    return "a";
671  case AsMAllocate:
672    return "m";
673  case AsWide:
674    return "w";
675  case None:
676    return "";
677  }
678  return nullptr;
679}
680
681//===----------------------------------------------------------------------===//
682// Methods on ConversionSpecifier.
683//===----------------------------------------------------------------------===//
684
685const char *ConversionSpecifier::toString() const {
686  switch (kind) {
687  case bArg: return "b";
688  case BArg: return "B";
689  case dArg: return "d";
690  case DArg: return "D";
691  case iArg: return "i";
692  case oArg: return "o";
693  case OArg: return "O";
694  case uArg: return "u";
695  case UArg: return "U";
696  case xArg: return "x";
697  case XArg: return "X";
698  case fArg: return "f";
699  case FArg: return "F";
700  case eArg: return "e";
701  case EArg: return "E";
702  case gArg: return "g";
703  case GArg: return "G";
704  case aArg: return "a";
705  case AArg: return "A";
706  case cArg: return "c";
707  case sArg: return "s";
708  case pArg: return "p";
709  case PArg:
710    return "P";
711  case nArg: return "n";
712  case PercentArg:  return "%";
713  case ScanListArg: return "[";
714  case InvalidSpecifier: return nullptr;
715
716  // POSIX unicode extensions.
717  case CArg: return "C";
718  case SArg: return "S";
719
720  // Objective-C specific specifiers.
721  case ObjCObjArg: return "@";
722
723  // FreeBSD kernel specific specifiers.
724  case FreeBSDbArg: return "b";
725  case FreeBSDDArg: return "D";
726  case FreeBSDrArg: return "r";
727  case FreeBSDyArg: return "y";
728
729  // GlibC specific specifiers.
730  case PrintErrno: return "m";
731
732  // MS specific specifiers.
733  case ZArg: return "Z";
734  }
735  return nullptr;
736}
737
738std::optional<ConversionSpecifier>
739ConversionSpecifier::getStandardSpecifier() const {
740  ConversionSpecifier::Kind NewKind;
741
742  switch (getKind()) {
743  default:
744    return std::nullopt;
745  case DArg:
746    NewKind = dArg;
747    break;
748  case UArg:
749    NewKind = uArg;
750    break;
751  case OArg:
752    NewKind = oArg;
753    break;
754  }
755
756  ConversionSpecifier FixedCS(*this);
757  FixedCS.setKind(NewKind);
758  return FixedCS;
759}
760
761//===----------------------------------------------------------------------===//
762// Methods on OptionalAmount.
763//===----------------------------------------------------------------------===//
764
765void OptionalAmount::toString(raw_ostream &os) const {
766  switch (hs) {
767  case Invalid:
768  case NotSpecified:
769    return;
770  case Arg:
771    if (UsesDotPrefix)
772        os << ".";
773    if (usesPositionalArg())
774      os << "*" << getPositionalArgIndex() << "$";
775    else
776      os << "*";
777    break;
778  case Constant:
779    if (UsesDotPrefix)
780        os << ".";
781    os << amt;
782    break;
783  }
784}
785
786bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target,
787                                             const LangOptions &LO) const {
788  switch (LM.getKind()) {
789    case LengthModifier::None:
790      return true;
791
792    // Handle most integer flags
793    case LengthModifier::AsShort:
794      // Length modifier only applies to FP vectors.
795      if (LO.OpenCL && CS.isDoubleArg())
796        return !VectorNumElts.isInvalid();
797
798      if (Target.getTriple().isOSMSVCRT()) {
799        switch (CS.getKind()) {
800          case ConversionSpecifier::cArg:
801          case ConversionSpecifier::CArg:
802          case ConversionSpecifier::sArg:
803          case ConversionSpecifier::SArg:
804          case ConversionSpecifier::ZArg:
805            return true;
806          default:
807            break;
808        }
809      }
810      [[fallthrough]];
811    case LengthModifier::AsChar:
812    case LengthModifier::AsLongLong:
813    case LengthModifier::AsQuad:
814    case LengthModifier::AsIntMax:
815    case LengthModifier::AsSizeT:
816    case LengthModifier::AsPtrDiff:
817      switch (CS.getKind()) {
818        case ConversionSpecifier::bArg:
819        case ConversionSpecifier::BArg:
820        case ConversionSpecifier::dArg:
821        case ConversionSpecifier::DArg:
822        case ConversionSpecifier::iArg:
823        case ConversionSpecifier::oArg:
824        case ConversionSpecifier::OArg:
825        case ConversionSpecifier::uArg:
826        case ConversionSpecifier::UArg:
827        case ConversionSpecifier::xArg:
828        case ConversionSpecifier::XArg:
829        case ConversionSpecifier::nArg:
830          return true;
831        case ConversionSpecifier::FreeBSDbArg:
832          return Target.getTriple().isOSFreeBSD() ||
833                 Target.getTriple().isPS4() ||
834                 Target.getTriple().isOSOpenBSD();
835        case ConversionSpecifier::FreeBSDrArg:
836        case ConversionSpecifier::FreeBSDyArg:
837          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS();
838        default:
839          return false;
840      }
841
842    case LengthModifier::AsShortLong:
843      return LO.OpenCL && !VectorNumElts.isInvalid();
844
845    // Handle 'l' flag
846    case LengthModifier::AsLong: // or AsWideChar
847      if (CS.isDoubleArg()) {
848        // Invalid for OpenCL FP scalars.
849        if (LO.OpenCL && VectorNumElts.isInvalid())
850          return false;
851        return true;
852      }
853
854      switch (CS.getKind()) {
855        case ConversionSpecifier::dArg:
856        case ConversionSpecifier::DArg:
857        case ConversionSpecifier::iArg:
858        case ConversionSpecifier::oArg:
859        case ConversionSpecifier::OArg:
860        case ConversionSpecifier::uArg:
861        case ConversionSpecifier::UArg:
862        case ConversionSpecifier::xArg:
863        case ConversionSpecifier::XArg:
864        case ConversionSpecifier::nArg:
865        case ConversionSpecifier::cArg:
866        case ConversionSpecifier::sArg:
867        case ConversionSpecifier::ScanListArg:
868        case ConversionSpecifier::ZArg:
869          return true;
870        case ConversionSpecifier::FreeBSDbArg:
871          return Target.getTriple().isOSFreeBSD() ||
872                 Target.getTriple().isPS4() ||
873                 Target.getTriple().isOSOpenBSD();
874        case ConversionSpecifier::FreeBSDrArg:
875        case ConversionSpecifier::FreeBSDyArg:
876          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS();
877        default:
878          return false;
879      }
880
881    case LengthModifier::AsLongDouble:
882      switch (CS.getKind()) {
883        case ConversionSpecifier::aArg:
884        case ConversionSpecifier::AArg:
885        case ConversionSpecifier::fArg:
886        case ConversionSpecifier::FArg:
887        case ConversionSpecifier::eArg:
888        case ConversionSpecifier::EArg:
889        case ConversionSpecifier::gArg:
890        case ConversionSpecifier::GArg:
891          return true;
892        // GNU libc extension.
893        case ConversionSpecifier::dArg:
894        case ConversionSpecifier::iArg:
895        case ConversionSpecifier::oArg:
896        case ConversionSpecifier::uArg:
897        case ConversionSpecifier::xArg:
898        case ConversionSpecifier::XArg:
899          return !Target.getTriple().isOSDarwin() &&
900                 !Target.getTriple().isOSWindows();
901        default:
902          return false;
903      }
904
905    case LengthModifier::AsAllocate:
906      switch (CS.getKind()) {
907        case ConversionSpecifier::sArg:
908        case ConversionSpecifier::SArg:
909        case ConversionSpecifier::ScanListArg:
910          return true;
911        default:
912          return false;
913      }
914
915    case LengthModifier::AsMAllocate:
916      switch (CS.getKind()) {
917        case ConversionSpecifier::cArg:
918        case ConversionSpecifier::CArg:
919        case ConversionSpecifier::sArg:
920        case ConversionSpecifier::SArg:
921        case ConversionSpecifier::ScanListArg:
922          return true;
923        default:
924          return false;
925      }
926    case LengthModifier::AsInt32:
927    case LengthModifier::AsInt3264:
928    case LengthModifier::AsInt64:
929      switch (CS.getKind()) {
930        case ConversionSpecifier::dArg:
931        case ConversionSpecifier::iArg:
932        case ConversionSpecifier::oArg:
933        case ConversionSpecifier::uArg:
934        case ConversionSpecifier::xArg:
935        case ConversionSpecifier::XArg:
936          return Target.getTriple().isOSMSVCRT();
937        default:
938          return false;
939      }
940    case LengthModifier::AsWide:
941      switch (CS.getKind()) {
942        case ConversionSpecifier::cArg:
943        case ConversionSpecifier::CArg:
944        case ConversionSpecifier::sArg:
945        case ConversionSpecifier::SArg:
946        case ConversionSpecifier::ZArg:
947          return Target.getTriple().isOSMSVCRT();
948        default:
949          return false;
950      }
951  }
952  llvm_unreachable("Invalid LengthModifier Kind!");
953}
954
955bool FormatSpecifier::hasStandardLengthModifier() const {
956  switch (LM.getKind()) {
957    case LengthModifier::None:
958    case LengthModifier::AsChar:
959    case LengthModifier::AsShort:
960    case LengthModifier::AsLong:
961    case LengthModifier::AsLongLong:
962    case LengthModifier::AsIntMax:
963    case LengthModifier::AsSizeT:
964    case LengthModifier::AsPtrDiff:
965    case LengthModifier::AsLongDouble:
966      return true;
967    case LengthModifier::AsAllocate:
968    case LengthModifier::AsMAllocate:
969    case LengthModifier::AsQuad:
970    case LengthModifier::AsInt32:
971    case LengthModifier::AsInt3264:
972    case LengthModifier::AsInt64:
973    case LengthModifier::AsWide:
974    case LengthModifier::AsShortLong: // ???
975      return false;
976  }
977  llvm_unreachable("Invalid LengthModifier Kind!");
978}
979
980bool FormatSpecifier::hasStandardConversionSpecifier(
981    const LangOptions &LangOpt) const {
982  switch (CS.getKind()) {
983    case ConversionSpecifier::bArg:
984    case ConversionSpecifier::BArg:
985    case ConversionSpecifier::cArg:
986    case ConversionSpecifier::dArg:
987    case ConversionSpecifier::iArg:
988    case ConversionSpecifier::oArg:
989    case ConversionSpecifier::uArg:
990    case ConversionSpecifier::xArg:
991    case ConversionSpecifier::XArg:
992    case ConversionSpecifier::fArg:
993    case ConversionSpecifier::FArg:
994    case ConversionSpecifier::eArg:
995    case ConversionSpecifier::EArg:
996    case ConversionSpecifier::gArg:
997    case ConversionSpecifier::GArg:
998    case ConversionSpecifier::aArg:
999    case ConversionSpecifier::AArg:
1000    case ConversionSpecifier::sArg:
1001    case ConversionSpecifier::pArg:
1002    case ConversionSpecifier::nArg:
1003    case ConversionSpecifier::ObjCObjArg:
1004    case ConversionSpecifier::ScanListArg:
1005    case ConversionSpecifier::PercentArg:
1006    case ConversionSpecifier::PArg:
1007      return true;
1008    case ConversionSpecifier::CArg:
1009    case ConversionSpecifier::SArg:
1010      return LangOpt.ObjC;
1011    case ConversionSpecifier::InvalidSpecifier:
1012    case ConversionSpecifier::FreeBSDbArg:
1013    case ConversionSpecifier::FreeBSDDArg:
1014    case ConversionSpecifier::FreeBSDrArg:
1015    case ConversionSpecifier::FreeBSDyArg:
1016    case ConversionSpecifier::PrintErrno:
1017    case ConversionSpecifier::DArg:
1018    case ConversionSpecifier::OArg:
1019    case ConversionSpecifier::UArg:
1020    case ConversionSpecifier::ZArg:
1021      return false;
1022  }
1023  llvm_unreachable("Invalid ConversionSpecifier Kind!");
1024}
1025
1026bool FormatSpecifier::hasStandardLengthConversionCombination() const {
1027  if (LM.getKind() == LengthModifier::AsLongDouble) {
1028    switch(CS.getKind()) {
1029        case ConversionSpecifier::dArg:
1030        case ConversionSpecifier::iArg:
1031        case ConversionSpecifier::oArg:
1032        case ConversionSpecifier::uArg:
1033        case ConversionSpecifier::xArg:
1034        case ConversionSpecifier::XArg:
1035        case ConversionSpecifier::FreeBSDbArg:
1036          return false;
1037        default:
1038          return true;
1039    }
1040  }
1041  return true;
1042}
1043
1044std::optional<LengthModifier>
1045FormatSpecifier::getCorrectedLengthModifier() const {
1046  if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
1047    if (LM.getKind() == LengthModifier::AsLongDouble ||
1048        LM.getKind() == LengthModifier::AsQuad) {
1049      LengthModifier FixedLM(LM);
1050      FixedLM.setKind(LengthModifier::AsLongLong);
1051      return FixedLM;
1052    }
1053  }
1054
1055  return std::nullopt;
1056}
1057
1058bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
1059                                                LengthModifier &LM) {
1060  for (/**/; const auto *TT = QT->getAs<TypedefType>();
1061       QT = TT->getDecl()->getUnderlyingType()) {
1062    const TypedefNameDecl *Typedef = TT->getDecl();
1063    const IdentifierInfo *Identifier = Typedef->getIdentifier();
1064    if (Identifier->getName() == "size_t") {
1065      LM.setKind(LengthModifier::AsSizeT);
1066      return true;
1067    } else if (Identifier->getName() == "ssize_t") {
1068      // Not C99, but common in Unix.
1069      LM.setKind(LengthModifier::AsSizeT);
1070      return true;
1071    } else if (Identifier->getName() == "intmax_t") {
1072      LM.setKind(LengthModifier::AsIntMax);
1073      return true;
1074    } else if (Identifier->getName() == "uintmax_t") {
1075      LM.setKind(LengthModifier::AsIntMax);
1076      return true;
1077    } else if (Identifier->getName() == "ptrdiff_t") {
1078      LM.setKind(LengthModifier::AsPtrDiff);
1079      return true;
1080    }
1081  }
1082  return false;
1083}
1084