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'. Do not use the underlying type for a scoped
355        // enumeration.
356        if (!ETy->getDecl()->isComplete())
357          return NoMatch;
358        if (ETy->isUnscopedEnumerationType())
359          argTy = ETy->getDecl()->getIntegerType();
360      }
361
362      if (const auto *BT = argTy->getAs<BuiltinType>()) {
363        // The types are perfectly matched?
364        switch (BT->getKind()) {
365        default:
366          break;
367        case BuiltinType::Char_S:
368        case BuiltinType::SChar:
369        case BuiltinType::UChar:
370        case BuiltinType::Char_U:
371            return Match;
372        case BuiltinType::Bool:
373          if (!Ptr)
374            return Match;
375          break;
376        }
377        // "Partially matched" because of promotions?
378        if (!Ptr) {
379          switch (BT->getKind()) {
380          default:
381            break;
382          case BuiltinType::Int:
383          case BuiltinType::UInt:
384            return MatchPromotion;
385          case BuiltinType::Short:
386          case BuiltinType::UShort:
387          case BuiltinType::WChar_S:
388          case BuiltinType::WChar_U:
389            return NoMatchPromotionTypeConfusion;
390          }
391        }
392      }
393      return NoMatch;
394    }
395
396    case SpecificTy: {
397      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
398        // If the enum is incomplete we know nothing about the underlying type.
399        // Assume that it's 'int'. Do not use the underlying type for a scoped
400        // enumeration as that needs an exact match.
401        if (!ETy->getDecl()->isComplete())
402          argTy = C.IntTy;
403        else if (ETy->isUnscopedEnumerationType())
404          argTy = ETy->getDecl()->getIntegerType();
405      }
406      argTy = C.getCanonicalType(argTy).getUnqualifiedType();
407
408      if (T == argTy)
409        return Match;
410      if (const auto *BT = argTy->getAs<BuiltinType>()) {
411        // Check if the only difference between them is signed vs unsigned
412        // if true, we consider they are compatible.
413        switch (BT->getKind()) {
414          default:
415            break;
416          case BuiltinType::Bool:
417            if (Ptr && (T == C.UnsignedCharTy || T == C.SignedCharTy))
418              return NoMatch;
419            [[fallthrough]];
420          case BuiltinType::Char_S:
421          case BuiltinType::SChar:
422          case BuiltinType::Char_U:
423          case BuiltinType::UChar:
424            if (T == C.UnsignedShortTy || T == C.ShortTy)
425              return NoMatchTypeConfusion;
426            if (T == C.UnsignedCharTy || T == C.SignedCharTy)
427              return Match;
428            break;
429          case BuiltinType::Short:
430            if (T == C.UnsignedShortTy)
431              return Match;
432            break;
433          case BuiltinType::UShort:
434            if (T == C.ShortTy)
435              return Match;
436            break;
437          case BuiltinType::Int:
438            if (T == C.UnsignedIntTy)
439              return Match;
440            break;
441          case BuiltinType::UInt:
442            if (T == C.IntTy)
443              return Match;
444            break;
445          case BuiltinType::Long:
446            if (T == C.UnsignedLongTy)
447              return Match;
448            break;
449          case BuiltinType::ULong:
450            if (T == C.LongTy)
451              return Match;
452            break;
453          case BuiltinType::LongLong:
454            if (T == C.UnsignedLongLongTy)
455              return Match;
456            break;
457          case BuiltinType::ULongLong:
458            if (T == C.LongLongTy)
459              return Match;
460            break;
461          }
462          // "Partially matched" because of promotions?
463          if (!Ptr) {
464            switch (BT->getKind()) {
465            default:
466              break;
467            case BuiltinType::Bool:
468              if (T == C.IntTy || T == C.UnsignedIntTy)
469                return MatchPromotion;
470              break;
471            case BuiltinType::Int:
472            case BuiltinType::UInt:
473              if (T == C.SignedCharTy || T == C.UnsignedCharTy ||
474                  T == C.ShortTy || T == C.UnsignedShortTy || T == C.WCharTy ||
475                  T == C.WideCharTy)
476                return MatchPromotion;
477              break;
478            case BuiltinType::Char_U:
479              if (T == C.UnsignedIntTy)
480                return MatchPromotion;
481              if (T == C.UnsignedShortTy)
482                return NoMatchPromotionTypeConfusion;
483              break;
484            case BuiltinType::Char_S:
485              if (T == C.IntTy)
486                return MatchPromotion;
487              if (T == C.ShortTy)
488                return NoMatchPromotionTypeConfusion;
489              break;
490            case BuiltinType::Half:
491            case BuiltinType::Float:
492              if (T == C.DoubleTy)
493                return MatchPromotion;
494              break;
495            case BuiltinType::Short:
496            case BuiltinType::UShort:
497              if (T == C.SignedCharTy || T == C.UnsignedCharTy)
498                return NoMatchPromotionTypeConfusion;
499              break;
500            case BuiltinType::WChar_U:
501            case BuiltinType::WChar_S:
502              if (T != C.WCharTy && T != C.WideCharTy)
503                return NoMatchPromotionTypeConfusion;
504            }
505          }
506      }
507      return NoMatch;
508    }
509
510    case CStrTy: {
511      const PointerType *PT = argTy->getAs<PointerType>();
512      if (!PT)
513        return NoMatch;
514      QualType pointeeTy = PT->getPointeeType();
515      if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
516        switch (BT->getKind()) {
517          case BuiltinType::Char_U:
518          case BuiltinType::UChar:
519          case BuiltinType::Char_S:
520          case BuiltinType::SChar:
521            return Match;
522          default:
523            break;
524        }
525
526      return NoMatch;
527    }
528
529    case WCStrTy: {
530      const PointerType *PT = argTy->getAs<PointerType>();
531      if (!PT)
532        return NoMatch;
533      QualType pointeeTy =
534        C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
535      return pointeeTy == C.getWideCharType() ? Match : NoMatch;
536    }
537
538    case WIntTy: {
539      QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
540
541      if (C.getCanonicalType(argTy).getUnqualifiedType() == WInt)
542        return Match;
543
544      QualType PromoArg = C.isPromotableIntegerType(argTy)
545                              ? C.getPromotedIntegerType(argTy)
546                              : argTy;
547      PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
548
549      // If the promoted argument is the corresponding signed type of the
550      // wint_t type, then it should match.
551      if (PromoArg->hasSignedIntegerRepresentation() &&
552          C.getCorrespondingUnsignedType(PromoArg) == WInt)
553        return Match;
554
555      return WInt == PromoArg ? Match : NoMatch;
556    }
557
558    case CPointerTy:
559      if (argTy->isVoidPointerType()) {
560        return Match;
561      } if (argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
562            argTy->isBlockPointerType() || argTy->isNullPtrType()) {
563        return NoMatchPedantic;
564      } else {
565        return NoMatch;
566      }
567
568    case ObjCPointerTy: {
569      if (argTy->getAs<ObjCObjectPointerType>() ||
570          argTy->getAs<BlockPointerType>())
571        return Match;
572
573      // Handle implicit toll-free bridging.
574      if (const PointerType *PT = argTy->getAs<PointerType>()) {
575        // Things such as CFTypeRef are really just opaque pointers
576        // to C structs representing CF types that can often be bridged
577        // to Objective-C objects.  Since the compiler doesn't know which
578        // structs can be toll-free bridged, we just accept them all.
579        QualType pointee = PT->getPointeeType();
580        if (pointee->getAsStructureType() || pointee->isVoidType())
581          return Match;
582      }
583      return NoMatch;
584    }
585  }
586
587  llvm_unreachable("Invalid ArgType Kind!");
588}
589
590ArgType ArgType::makeVectorType(ASTContext &C, unsigned NumElts) const {
591  // Check for valid vector element types.
592  if (T.isNull())
593    return ArgType::Invalid();
594
595  QualType Vec = C.getExtVectorType(T, NumElts);
596  return ArgType(Vec, Name);
597}
598
599QualType ArgType::getRepresentativeType(ASTContext &C) const {
600  QualType Res;
601  switch (K) {
602    case InvalidTy:
603      llvm_unreachable("No representative type for Invalid ArgType");
604    case UnknownTy:
605      llvm_unreachable("No representative type for Unknown ArgType");
606    case AnyCharTy:
607      Res = C.CharTy;
608      break;
609    case SpecificTy:
610      Res = T;
611      break;
612    case CStrTy:
613      Res = C.getPointerType(C.CharTy);
614      break;
615    case WCStrTy:
616      Res = C.getPointerType(C.getWideCharType());
617      break;
618    case ObjCPointerTy:
619      Res = C.ObjCBuiltinIdTy;
620      break;
621    case CPointerTy:
622      Res = C.VoidPtrTy;
623      break;
624    case WIntTy: {
625      Res = C.getWIntType();
626      break;
627    }
628  }
629
630  if (Ptr)
631    Res = C.getPointerType(Res);
632  return Res;
633}
634
635std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
636  std::string S = getRepresentativeType(C).getAsString(C.getPrintingPolicy());
637
638  std::string Alias;
639  if (Name) {
640    // Use a specific name for this type, e.g. "size_t".
641    Alias = Name;
642    if (Ptr) {
643      // If ArgType is actually a pointer to T, append an asterisk.
644      Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
645    }
646    // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
647    if (S == Alias)
648      Alias.clear();
649  }
650
651  if (!Alias.empty())
652    return std::string("'") + Alias + "' (aka '" + S + "')";
653  return std::string("'") + S + "'";
654}
655
656
657//===----------------------------------------------------------------------===//
658// Methods on OptionalAmount.
659//===----------------------------------------------------------------------===//
660
661ArgType
662analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
663  return Ctx.IntTy;
664}
665
666//===----------------------------------------------------------------------===//
667// Methods on LengthModifier.
668//===----------------------------------------------------------------------===//
669
670const char *
671analyze_format_string::LengthModifier::toString() const {
672  switch (kind) {
673  case AsChar:
674    return "hh";
675  case AsShort:
676    return "h";
677  case AsShortLong:
678    return "hl";
679  case AsLong: // or AsWideChar
680    return "l";
681  case AsLongLong:
682    return "ll";
683  case AsQuad:
684    return "q";
685  case AsIntMax:
686    return "j";
687  case AsSizeT:
688    return "z";
689  case AsPtrDiff:
690    return "t";
691  case AsInt32:
692    return "I32";
693  case AsInt3264:
694    return "I";
695  case AsInt64:
696    return "I64";
697  case AsLongDouble:
698    return "L";
699  case AsAllocate:
700    return "a";
701  case AsMAllocate:
702    return "m";
703  case AsWide:
704    return "w";
705  case None:
706    return "";
707  }
708  return nullptr;
709}
710
711//===----------------------------------------------------------------------===//
712// Methods on ConversionSpecifier.
713//===----------------------------------------------------------------------===//
714
715const char *ConversionSpecifier::toString() const {
716  switch (kind) {
717  case bArg: return "b";
718  case BArg: return "B";
719  case dArg: return "d";
720  case DArg: return "D";
721  case iArg: return "i";
722  case oArg: return "o";
723  case OArg: return "O";
724  case uArg: return "u";
725  case UArg: return "U";
726  case xArg: return "x";
727  case XArg: return "X";
728  case fArg: return "f";
729  case FArg: return "F";
730  case eArg: return "e";
731  case EArg: return "E";
732  case gArg: return "g";
733  case GArg: return "G";
734  case aArg: return "a";
735  case AArg: return "A";
736  case cArg: return "c";
737  case sArg: return "s";
738  case pArg: return "p";
739  case PArg:
740    return "P";
741  case nArg: return "n";
742  case PercentArg:  return "%";
743  case ScanListArg: return "[";
744  case InvalidSpecifier: return nullptr;
745
746  // POSIX unicode extensions.
747  case CArg: return "C";
748  case SArg: return "S";
749
750  // Objective-C specific specifiers.
751  case ObjCObjArg: return "@";
752
753  // FreeBSD kernel specific specifiers.
754  case FreeBSDbArg: return "b";
755  case FreeBSDDArg: return "D";
756  case FreeBSDrArg: return "r";
757  case FreeBSDyArg: return "y";
758
759  // GlibC specific specifiers.
760  case PrintErrno: return "m";
761
762  // MS specific specifiers.
763  case ZArg: return "Z";
764  }
765  return nullptr;
766}
767
768std::optional<ConversionSpecifier>
769ConversionSpecifier::getStandardSpecifier() const {
770  ConversionSpecifier::Kind NewKind;
771
772  switch (getKind()) {
773  default:
774    return std::nullopt;
775  case DArg:
776    NewKind = dArg;
777    break;
778  case UArg:
779    NewKind = uArg;
780    break;
781  case OArg:
782    NewKind = oArg;
783    break;
784  }
785
786  ConversionSpecifier FixedCS(*this);
787  FixedCS.setKind(NewKind);
788  return FixedCS;
789}
790
791//===----------------------------------------------------------------------===//
792// Methods on OptionalAmount.
793//===----------------------------------------------------------------------===//
794
795void OptionalAmount::toString(raw_ostream &os) const {
796  switch (hs) {
797  case Invalid:
798  case NotSpecified:
799    return;
800  case Arg:
801    if (UsesDotPrefix)
802        os << ".";
803    if (usesPositionalArg())
804      os << "*" << getPositionalArgIndex() << "$";
805    else
806      os << "*";
807    break;
808  case Constant:
809    if (UsesDotPrefix)
810        os << ".";
811    os << amt;
812    break;
813  }
814}
815
816bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target,
817                                             const LangOptions &LO) const {
818  switch (LM.getKind()) {
819    case LengthModifier::None:
820      return true;
821
822    // Handle most integer flags
823    case LengthModifier::AsShort:
824      // Length modifier only applies to FP vectors.
825      if (LO.OpenCL && CS.isDoubleArg())
826        return !VectorNumElts.isInvalid();
827
828      if (Target.getTriple().isOSMSVCRT()) {
829        switch (CS.getKind()) {
830          case ConversionSpecifier::cArg:
831          case ConversionSpecifier::CArg:
832          case ConversionSpecifier::sArg:
833          case ConversionSpecifier::SArg:
834          case ConversionSpecifier::ZArg:
835            return true;
836          default:
837            break;
838        }
839      }
840      [[fallthrough]];
841    case LengthModifier::AsChar:
842    case LengthModifier::AsLongLong:
843    case LengthModifier::AsQuad:
844    case LengthModifier::AsIntMax:
845    case LengthModifier::AsSizeT:
846    case LengthModifier::AsPtrDiff:
847      switch (CS.getKind()) {
848        case ConversionSpecifier::bArg:
849        case ConversionSpecifier::BArg:
850        case ConversionSpecifier::dArg:
851        case ConversionSpecifier::DArg:
852        case ConversionSpecifier::iArg:
853        case ConversionSpecifier::oArg:
854        case ConversionSpecifier::OArg:
855        case ConversionSpecifier::uArg:
856        case ConversionSpecifier::UArg:
857        case ConversionSpecifier::xArg:
858        case ConversionSpecifier::XArg:
859        case ConversionSpecifier::nArg:
860          return true;
861        case ConversionSpecifier::FreeBSDrArg:
862        case ConversionSpecifier::FreeBSDyArg:
863          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS();
864        default:
865          return false;
866      }
867
868    case LengthModifier::AsShortLong:
869      return LO.OpenCL && !VectorNumElts.isInvalid();
870
871    // Handle 'l' flag
872    case LengthModifier::AsLong: // or AsWideChar
873      if (CS.isDoubleArg()) {
874        // Invalid for OpenCL FP scalars.
875        if (LO.OpenCL && VectorNumElts.isInvalid())
876          return false;
877        return true;
878      }
879
880      switch (CS.getKind()) {
881        case ConversionSpecifier::bArg:
882        case ConversionSpecifier::BArg:
883        case ConversionSpecifier::dArg:
884        case ConversionSpecifier::DArg:
885        case ConversionSpecifier::iArg:
886        case ConversionSpecifier::oArg:
887        case ConversionSpecifier::OArg:
888        case ConversionSpecifier::uArg:
889        case ConversionSpecifier::UArg:
890        case ConversionSpecifier::xArg:
891        case ConversionSpecifier::XArg:
892        case ConversionSpecifier::nArg:
893        case ConversionSpecifier::cArg:
894        case ConversionSpecifier::sArg:
895        case ConversionSpecifier::ScanListArg:
896        case ConversionSpecifier::ZArg:
897          return true;
898        case ConversionSpecifier::FreeBSDrArg:
899        case ConversionSpecifier::FreeBSDyArg:
900          return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS();
901        default:
902          return false;
903      }
904
905    case LengthModifier::AsLongDouble:
906      switch (CS.getKind()) {
907        case ConversionSpecifier::aArg:
908        case ConversionSpecifier::AArg:
909        case ConversionSpecifier::fArg:
910        case ConversionSpecifier::FArg:
911        case ConversionSpecifier::eArg:
912        case ConversionSpecifier::EArg:
913        case ConversionSpecifier::gArg:
914        case ConversionSpecifier::GArg:
915          return true;
916        // GNU libc extension.
917        case ConversionSpecifier::dArg:
918        case ConversionSpecifier::iArg:
919        case ConversionSpecifier::oArg:
920        case ConversionSpecifier::uArg:
921        case ConversionSpecifier::xArg:
922        case ConversionSpecifier::XArg:
923          return !Target.getTriple().isOSDarwin() &&
924                 !Target.getTriple().isOSWindows();
925        default:
926          return false;
927      }
928
929    case LengthModifier::AsAllocate:
930      switch (CS.getKind()) {
931        case ConversionSpecifier::sArg:
932        case ConversionSpecifier::SArg:
933        case ConversionSpecifier::ScanListArg:
934          return true;
935        default:
936          return false;
937      }
938
939    case LengthModifier::AsMAllocate:
940      switch (CS.getKind()) {
941        case ConversionSpecifier::cArg:
942        case ConversionSpecifier::CArg:
943        case ConversionSpecifier::sArg:
944        case ConversionSpecifier::SArg:
945        case ConversionSpecifier::ScanListArg:
946          return true;
947        default:
948          return false;
949      }
950    case LengthModifier::AsInt32:
951    case LengthModifier::AsInt3264:
952    case LengthModifier::AsInt64:
953      switch (CS.getKind()) {
954        case ConversionSpecifier::dArg:
955        case ConversionSpecifier::iArg:
956        case ConversionSpecifier::oArg:
957        case ConversionSpecifier::uArg:
958        case ConversionSpecifier::xArg:
959        case ConversionSpecifier::XArg:
960          return Target.getTriple().isOSMSVCRT();
961        default:
962          return false;
963      }
964    case LengthModifier::AsWide:
965      switch (CS.getKind()) {
966        case ConversionSpecifier::cArg:
967        case ConversionSpecifier::CArg:
968        case ConversionSpecifier::sArg:
969        case ConversionSpecifier::SArg:
970        case ConversionSpecifier::ZArg:
971          return Target.getTriple().isOSMSVCRT();
972        default:
973          return false;
974      }
975  }
976  llvm_unreachable("Invalid LengthModifier Kind!");
977}
978
979bool FormatSpecifier::hasStandardLengthModifier() const {
980  switch (LM.getKind()) {
981    case LengthModifier::None:
982    case LengthModifier::AsChar:
983    case LengthModifier::AsShort:
984    case LengthModifier::AsLong:
985    case LengthModifier::AsLongLong:
986    case LengthModifier::AsIntMax:
987    case LengthModifier::AsSizeT:
988    case LengthModifier::AsPtrDiff:
989    case LengthModifier::AsLongDouble:
990      return true;
991    case LengthModifier::AsAllocate:
992    case LengthModifier::AsMAllocate:
993    case LengthModifier::AsQuad:
994    case LengthModifier::AsInt32:
995    case LengthModifier::AsInt3264:
996    case LengthModifier::AsInt64:
997    case LengthModifier::AsWide:
998    case LengthModifier::AsShortLong: // ???
999      return false;
1000  }
1001  llvm_unreachable("Invalid LengthModifier Kind!");
1002}
1003
1004bool FormatSpecifier::hasStandardConversionSpecifier(
1005    const LangOptions &LangOpt) const {
1006  switch (CS.getKind()) {
1007    case ConversionSpecifier::bArg:
1008    case ConversionSpecifier::BArg:
1009    case ConversionSpecifier::cArg:
1010    case ConversionSpecifier::dArg:
1011    case ConversionSpecifier::iArg:
1012    case ConversionSpecifier::oArg:
1013    case ConversionSpecifier::uArg:
1014    case ConversionSpecifier::xArg:
1015    case ConversionSpecifier::XArg:
1016    case ConversionSpecifier::fArg:
1017    case ConversionSpecifier::FArg:
1018    case ConversionSpecifier::eArg:
1019    case ConversionSpecifier::EArg:
1020    case ConversionSpecifier::gArg:
1021    case ConversionSpecifier::GArg:
1022    case ConversionSpecifier::aArg:
1023    case ConversionSpecifier::AArg:
1024    case ConversionSpecifier::sArg:
1025    case ConversionSpecifier::pArg:
1026    case ConversionSpecifier::nArg:
1027    case ConversionSpecifier::ObjCObjArg:
1028    case ConversionSpecifier::ScanListArg:
1029    case ConversionSpecifier::PercentArg:
1030    case ConversionSpecifier::PArg:
1031      return true;
1032    case ConversionSpecifier::CArg:
1033    case ConversionSpecifier::SArg:
1034      return LangOpt.ObjC;
1035    case ConversionSpecifier::InvalidSpecifier:
1036    case ConversionSpecifier::FreeBSDbArg:
1037    case ConversionSpecifier::FreeBSDDArg:
1038    case ConversionSpecifier::FreeBSDrArg:
1039    case ConversionSpecifier::FreeBSDyArg:
1040    case ConversionSpecifier::PrintErrno:
1041    case ConversionSpecifier::DArg:
1042    case ConversionSpecifier::OArg:
1043    case ConversionSpecifier::UArg:
1044    case ConversionSpecifier::ZArg:
1045      return false;
1046  }
1047  llvm_unreachable("Invalid ConversionSpecifier Kind!");
1048}
1049
1050bool FormatSpecifier::hasStandardLengthConversionCombination() const {
1051  if (LM.getKind() == LengthModifier::AsLongDouble) {
1052    switch(CS.getKind()) {
1053        case ConversionSpecifier::dArg:
1054        case ConversionSpecifier::iArg:
1055        case ConversionSpecifier::oArg:
1056        case ConversionSpecifier::uArg:
1057        case ConversionSpecifier::xArg:
1058        case ConversionSpecifier::XArg:
1059          return false;
1060        default:
1061          return true;
1062    }
1063  }
1064  return true;
1065}
1066
1067std::optional<LengthModifier>
1068FormatSpecifier::getCorrectedLengthModifier() const {
1069  if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
1070    if (LM.getKind() == LengthModifier::AsLongDouble ||
1071        LM.getKind() == LengthModifier::AsQuad) {
1072      LengthModifier FixedLM(LM);
1073      FixedLM.setKind(LengthModifier::AsLongLong);
1074      return FixedLM;
1075    }
1076  }
1077
1078  return std::nullopt;
1079}
1080
1081bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
1082                                                LengthModifier &LM) {
1083  for (/**/; const auto *TT = QT->getAs<TypedefType>();
1084       QT = TT->getDecl()->getUnderlyingType()) {
1085    const TypedefNameDecl *Typedef = TT->getDecl();
1086    const IdentifierInfo *Identifier = Typedef->getIdentifier();
1087    if (Identifier->getName() == "size_t") {
1088      LM.setKind(LengthModifier::AsSizeT);
1089      return true;
1090    } else if (Identifier->getName() == "ssize_t") {
1091      // Not C99, but common in Unix.
1092      LM.setKind(LengthModifier::AsSizeT);
1093      return true;
1094    } else if (Identifier->getName() == "intmax_t") {
1095      LM.setKind(LengthModifier::AsIntMax);
1096      return true;
1097    } else if (Identifier->getName() == "uintmax_t") {
1098      LM.setKind(LengthModifier::AsIntMax);
1099      return true;
1100    } else if (Identifier->getName() == "ptrdiff_t") {
1101      LM.setKind(LengthModifier::AsPtrDiff);
1102      return true;
1103    }
1104  }
1105  return false;
1106}
1107