1 // FormatString.cpp - Common stuff for handling printf/scanf formats -*- C++ -*-
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Shared details for processing format strings of printf and scanf
11 // (and friends).
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "FormatStringParsing.h"
16 #include "clang/Basic/LangOptions.h"
17 #include "clang/Basic/TargetInfo.h"
18 
19 using clang::analyze_format_string::ArgType;
20 using clang::analyze_format_string::FormatStringHandler;
21 using clang::analyze_format_string::FormatSpecifier;
22 using clang::analyze_format_string::LengthModifier;
23 using clang::analyze_format_string::OptionalAmount;
24 using clang::analyze_format_string::PositionContext;
25 using clang::analyze_format_string::ConversionSpecifier;
26 using namespace clang;
27 
28 // Key function to FormatStringHandler.
~FormatStringHandler()29 FormatStringHandler::~FormatStringHandler() {}
30 
31 //===----------------------------------------------------------------------===//
32 // Functions for parsing format strings components in both printf and
33 // scanf format strings.
34 //===----------------------------------------------------------------------===//
35 
36 OptionalAmount
ParseAmount(const char * & Beg,const char * E)37 clang::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 
62 OptionalAmount
ParseNonPositionAmount(const char * & Beg,const char * E,unsigned & argIndex)63 clang::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 
74 OptionalAmount
ParsePositionAmount(FormatStringHandler & H,const char * Start,const char * & Beg,const char * E,PositionContext p)75 clang::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 
121 bool
ParseFieldWidth(FormatStringHandler & H,FormatSpecifier & CS,const char * Start,const char * & Beg,const char * E,unsigned * argIndex)122 clang::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 
143 bool
ParseArgPosition(FormatStringHandler & H,FormatSpecifier & FS,const char * Start,const char * & Beg,const char * E)144 clang::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 
180 bool
ParseLengthModifier(FormatSpecifier & FS,const char * & I,const char * E,const LangOptions & LO,bool IsScanf)181 clang::analyze_format_string::ParseLengthModifier(FormatSpecifier &FS,
182                                                   const char *&I,
183                                                   const char *E,
184                                                   const LangOptions &LO,
185                                                   bool IsScanf) {
186   LengthModifier::Kind lmKind = LengthModifier::None;
187   const char *lmPosition = I;
188   switch (*I) {
189     default:
190       return false;
191     case 'h':
192       ++I;
193       lmKind = (I != E && *I == 'h') ? (++I, LengthModifier::AsChar)
194                                      : LengthModifier::AsShort;
195       break;
196     case 'l':
197       ++I;
198       lmKind = (I != E && *I == 'l') ? (++I, LengthModifier::AsLongLong)
199                                      : LengthModifier::AsLong;
200       break;
201     case 'j': lmKind = LengthModifier::AsIntMax;     ++I; break;
202     case 'z': lmKind = LengthModifier::AsSizeT;      ++I; break;
203     case 't': lmKind = LengthModifier::AsPtrDiff;    ++I; break;
204     case 'L': lmKind = LengthModifier::AsLongDouble; ++I; break;
205     case 'q': lmKind = LengthModifier::AsQuad;       ++I; break;
206     case 'a':
207       if (IsScanf && !LO.C99 && !LO.CPlusPlus11) {
208         // For scanf in C90, look at the next character to see if this should
209         // be parsed as the GNU extension 'a' length modifier. If not, this
210         // will be parsed as a conversion specifier.
211         ++I;
212         if (I != E && (*I == 's' || *I == 'S' || *I == '[')) {
213           lmKind = LengthModifier::AsAllocate;
214           break;
215         }
216         --I;
217       }
218       return false;
219     case 'm':
220       if (IsScanf) {
221         lmKind = LengthModifier::AsMAllocate;
222         ++I;
223         break;
224       }
225       return false;
226     // printf: AsInt64, AsInt32, AsInt3264
227     // scanf:  AsInt64
228     case 'I':
229       if (I + 1 != E && I + 2 != E) {
230         if (I[1] == '6' && I[2] == '4') {
231           I += 3;
232           lmKind = LengthModifier::AsInt64;
233           break;
234         }
235         if (IsScanf)
236           return false;
237 
238         if (I[1] == '3' && I[2] == '2') {
239           I += 3;
240           lmKind = LengthModifier::AsInt32;
241           break;
242         }
243       }
244       ++I;
245       lmKind = LengthModifier::AsInt3264;
246       break;
247     case 'w':
248       lmKind = LengthModifier::AsWide; ++I; break;
249   }
250   LengthModifier lm(lmPosition, lmKind);
251   FS.setLengthModifier(lm);
252   return true;
253 }
254 
255 //===----------------------------------------------------------------------===//
256 // Methods on ArgType.
257 //===----------------------------------------------------------------------===//
258 
matchesType(ASTContext & C,QualType argTy) const259 bool ArgType::matchesType(ASTContext &C, QualType argTy) const {
260   if (Ptr) {
261     // It has to be a pointer.
262     const PointerType *PT = argTy->getAs<PointerType>();
263     if (!PT)
264       return false;
265 
266     // We cannot write through a const qualified pointer.
267     if (PT->getPointeeType().isConstQualified())
268       return false;
269 
270     argTy = PT->getPointeeType();
271   }
272 
273   switch (K) {
274     case InvalidTy:
275       llvm_unreachable("ArgType must be valid");
276 
277     case UnknownTy:
278       return true;
279 
280     case AnyCharTy: {
281       if (const EnumType *ETy = argTy->getAs<EnumType>())
282         argTy = ETy->getDecl()->getIntegerType();
283 
284       if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
285         switch (BT->getKind()) {
286           default:
287             break;
288           case BuiltinType::Char_S:
289           case BuiltinType::SChar:
290           case BuiltinType::UChar:
291           case BuiltinType::Char_U:
292             return true;
293         }
294       return false;
295     }
296 
297     case SpecificTy: {
298       if (const EnumType *ETy = argTy->getAs<EnumType>())
299         argTy = ETy->getDecl()->getIntegerType();
300       argTy = C.getCanonicalType(argTy).getUnqualifiedType();
301 
302       if (T == argTy)
303         return true;
304       // Check for "compatible types".
305       if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
306         switch (BT->getKind()) {
307           default:
308             break;
309           case BuiltinType::Char_S:
310           case BuiltinType::SChar:
311           case BuiltinType::Char_U:
312           case BuiltinType::UChar:
313             return T == C.UnsignedCharTy || T == C.SignedCharTy;
314           case BuiltinType::Short:
315             return T == C.UnsignedShortTy;
316           case BuiltinType::UShort:
317             return T == C.ShortTy;
318           case BuiltinType::Int:
319             return T == C.UnsignedIntTy;
320           case BuiltinType::UInt:
321             return T == C.IntTy;
322           case BuiltinType::Long:
323             return T == C.UnsignedLongTy;
324           case BuiltinType::ULong:
325             return T == C.LongTy;
326           case BuiltinType::LongLong:
327             return T == C.UnsignedLongLongTy;
328           case BuiltinType::ULongLong:
329             return T == C.LongLongTy;
330         }
331       return false;
332     }
333 
334     case CStrTy: {
335       const PointerType *PT = argTy->getAs<PointerType>();
336       if (!PT)
337         return false;
338       QualType pointeeTy = PT->getPointeeType();
339       if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
340         switch (BT->getKind()) {
341           case BuiltinType::Void:
342           case BuiltinType::Char_U:
343           case BuiltinType::UChar:
344           case BuiltinType::Char_S:
345           case BuiltinType::SChar:
346             return true;
347           default:
348             break;
349         }
350 
351       return false;
352     }
353 
354     case WCStrTy: {
355       const PointerType *PT = argTy->getAs<PointerType>();
356       if (!PT)
357         return false;
358       QualType pointeeTy =
359         C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
360       return pointeeTy == C.getWideCharType();
361     }
362 
363     case WIntTy: {
364 
365       QualType PromoArg =
366         argTy->isPromotableIntegerType()
367           ? C.getPromotedIntegerType(argTy) : argTy;
368 
369       QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
370       PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
371 
372       // If the promoted argument is the corresponding signed type of the
373       // wint_t type, then it should match.
374       if (PromoArg->hasSignedIntegerRepresentation() &&
375           C.getCorrespondingUnsignedType(PromoArg) == WInt)
376         return true;
377 
378       return WInt == PromoArg;
379     }
380 
381     case CPointerTy:
382       return argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
383              argTy->isBlockPointerType() || argTy->isNullPtrType();
384 
385     case ObjCPointerTy: {
386       if (argTy->getAs<ObjCObjectPointerType>() ||
387           argTy->getAs<BlockPointerType>())
388         return true;
389 
390       // Handle implicit toll-free bridging.
391       if (const PointerType *PT = argTy->getAs<PointerType>()) {
392         // Things such as CFTypeRef are really just opaque pointers
393         // to C structs representing CF types that can often be bridged
394         // to Objective-C objects.  Since the compiler doesn't know which
395         // structs can be toll-free bridged, we just accept them all.
396         QualType pointee = PT->getPointeeType();
397         if (pointee->getAsStructureType() || pointee->isVoidType())
398           return true;
399       }
400       return false;
401     }
402   }
403 
404   llvm_unreachable("Invalid ArgType Kind!");
405 }
406 
getRepresentativeType(ASTContext & C) const407 QualType ArgType::getRepresentativeType(ASTContext &C) const {
408   QualType Res;
409   switch (K) {
410     case InvalidTy:
411       llvm_unreachable("No representative type for Invalid ArgType");
412     case UnknownTy:
413       llvm_unreachable("No representative type for Unknown ArgType");
414     case AnyCharTy:
415       Res = C.CharTy;
416       break;
417     case SpecificTy:
418       Res = T;
419       break;
420     case CStrTy:
421       Res = C.getPointerType(C.CharTy);
422       break;
423     case WCStrTy:
424       Res = C.getPointerType(C.getWideCharType());
425       break;
426     case ObjCPointerTy:
427       Res = C.ObjCBuiltinIdTy;
428       break;
429     case CPointerTy:
430       Res = C.VoidPtrTy;
431       break;
432     case WIntTy: {
433       Res = C.getWIntType();
434       break;
435     }
436   }
437 
438   if (Ptr)
439     Res = C.getPointerType(Res);
440   return Res;
441 }
442 
getRepresentativeTypeName(ASTContext & C) const443 std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
444   std::string S = getRepresentativeType(C).getAsString();
445 
446   std::string Alias;
447   if (Name) {
448     // Use a specific name for this type, e.g. "size_t".
449     Alias = Name;
450     if (Ptr) {
451       // If ArgType is actually a pointer to T, append an asterisk.
452       Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
453     }
454     // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
455     if (S == Alias)
456       Alias.clear();
457   }
458 
459   if (!Alias.empty())
460     return std::string("'") + Alias + "' (aka '" + S + "')";
461   return std::string("'") + S + "'";
462 }
463 
464 
465 //===----------------------------------------------------------------------===//
466 // Methods on OptionalAmount.
467 //===----------------------------------------------------------------------===//
468 
469 ArgType
getArgType(ASTContext & Ctx) const470 analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
471   return Ctx.IntTy;
472 }
473 
474 //===----------------------------------------------------------------------===//
475 // Methods on LengthModifier.
476 //===----------------------------------------------------------------------===//
477 
478 const char *
toString() const479 analyze_format_string::LengthModifier::toString() const {
480   switch (kind) {
481   case AsChar:
482     return "hh";
483   case AsShort:
484     return "h";
485   case AsLong: // or AsWideChar
486     return "l";
487   case AsLongLong:
488     return "ll";
489   case AsQuad:
490     return "q";
491   case AsIntMax:
492     return "j";
493   case AsSizeT:
494     return "z";
495   case AsPtrDiff:
496     return "t";
497   case AsInt32:
498     return "I32";
499   case AsInt3264:
500     return "I";
501   case AsInt64:
502     return "I64";
503   case AsLongDouble:
504     return "L";
505   case AsAllocate:
506     return "a";
507   case AsMAllocate:
508     return "m";
509   case AsWide:
510     return "w";
511   case None:
512     return "";
513   }
514   return nullptr;
515 }
516 
517 //===----------------------------------------------------------------------===//
518 // Methods on ConversionSpecifier.
519 //===----------------------------------------------------------------------===//
520 
toString() const521 const char *ConversionSpecifier::toString() const {
522   switch (kind) {
523   case dArg: return "d";
524   case DArg: return "D";
525   case iArg: return "i";
526   case oArg: return "o";
527   case OArg: return "O";
528   case uArg: return "u";
529   case UArg: return "U";
530   case xArg: return "x";
531   case XArg: return "X";
532   case fArg: return "f";
533   case FArg: return "F";
534   case eArg: return "e";
535   case EArg: return "E";
536   case gArg: return "g";
537   case GArg: return "G";
538   case aArg: return "a";
539   case AArg: return "A";
540   case cArg: return "c";
541   case sArg: return "s";
542   case pArg: return "p";
543   case nArg: return "n";
544   case PercentArg:  return "%";
545   case ScanListArg: return "[";
546   case InvalidSpecifier: return nullptr;
547 
548   // POSIX unicode extensions.
549   case CArg: return "C";
550   case SArg: return "S";
551 
552   // Objective-C specific specifiers.
553   case ObjCObjArg: return "@";
554 
555   // GlibC specific specifiers.
556   case PrintErrno: return "m";
557 
558   // MS specific specifiers.
559   case ZArg: return "Z";
560   }
561   return nullptr;
562 }
563 
564 Optional<ConversionSpecifier>
getStandardSpecifier() const565 ConversionSpecifier::getStandardSpecifier() const {
566   ConversionSpecifier::Kind NewKind;
567 
568   switch (getKind()) {
569   default:
570     return None;
571   case DArg:
572     NewKind = dArg;
573     break;
574   case UArg:
575     NewKind = uArg;
576     break;
577   case OArg:
578     NewKind = oArg;
579     break;
580   }
581 
582   ConversionSpecifier FixedCS(*this);
583   FixedCS.setKind(NewKind);
584   return FixedCS;
585 }
586 
587 //===----------------------------------------------------------------------===//
588 // Methods on OptionalAmount.
589 //===----------------------------------------------------------------------===//
590 
toString(raw_ostream & os) const591 void OptionalAmount::toString(raw_ostream &os) const {
592   switch (hs) {
593   case Invalid:
594   case NotSpecified:
595     return;
596   case Arg:
597     if (UsesDotPrefix)
598         os << ".";
599     if (usesPositionalArg())
600       os << "*" << getPositionalArgIndex() << "$";
601     else
602       os << "*";
603     break;
604   case Constant:
605     if (UsesDotPrefix)
606         os << ".";
607     os << amt;
608     break;
609   }
610 }
611 
hasValidLengthModifier(const TargetInfo & Target) const612 bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target) const {
613   switch (LM.getKind()) {
614     case LengthModifier::None:
615       return true;
616 
617     // Handle most integer flags
618     case LengthModifier::AsShort:
619       if (Target.getTriple().isOSMSVCRT()) {
620         switch (CS.getKind()) {
621           case ConversionSpecifier::cArg:
622           case ConversionSpecifier::CArg:
623           case ConversionSpecifier::sArg:
624           case ConversionSpecifier::SArg:
625           case ConversionSpecifier::ZArg:
626             return true;
627           default:
628             break;
629         }
630       }
631       // Fall through.
632     case LengthModifier::AsChar:
633     case LengthModifier::AsLongLong:
634     case LengthModifier::AsQuad:
635     case LengthModifier::AsIntMax:
636     case LengthModifier::AsSizeT:
637     case LengthModifier::AsPtrDiff:
638       switch (CS.getKind()) {
639         case ConversionSpecifier::dArg:
640         case ConversionSpecifier::DArg:
641         case ConversionSpecifier::iArg:
642         case ConversionSpecifier::oArg:
643         case ConversionSpecifier::OArg:
644         case ConversionSpecifier::uArg:
645         case ConversionSpecifier::UArg:
646         case ConversionSpecifier::xArg:
647         case ConversionSpecifier::XArg:
648         case ConversionSpecifier::nArg:
649           return true;
650         default:
651           return false;
652       }
653 
654     // Handle 'l' flag
655     case LengthModifier::AsLong: // or AsWideChar
656       switch (CS.getKind()) {
657         case ConversionSpecifier::dArg:
658         case ConversionSpecifier::DArg:
659         case ConversionSpecifier::iArg:
660         case ConversionSpecifier::oArg:
661         case ConversionSpecifier::OArg:
662         case ConversionSpecifier::uArg:
663         case ConversionSpecifier::UArg:
664         case ConversionSpecifier::xArg:
665         case ConversionSpecifier::XArg:
666         case ConversionSpecifier::aArg:
667         case ConversionSpecifier::AArg:
668         case ConversionSpecifier::fArg:
669         case ConversionSpecifier::FArg:
670         case ConversionSpecifier::eArg:
671         case ConversionSpecifier::EArg:
672         case ConversionSpecifier::gArg:
673         case ConversionSpecifier::GArg:
674         case ConversionSpecifier::nArg:
675         case ConversionSpecifier::cArg:
676         case ConversionSpecifier::sArg:
677         case ConversionSpecifier::ScanListArg:
678         case ConversionSpecifier::ZArg:
679           return true;
680         default:
681           return false;
682       }
683 
684     case LengthModifier::AsLongDouble:
685       switch (CS.getKind()) {
686         case ConversionSpecifier::aArg:
687         case ConversionSpecifier::AArg:
688         case ConversionSpecifier::fArg:
689         case ConversionSpecifier::FArg:
690         case ConversionSpecifier::eArg:
691         case ConversionSpecifier::EArg:
692         case ConversionSpecifier::gArg:
693         case ConversionSpecifier::GArg:
694           return true;
695         // GNU libc extension.
696         case ConversionSpecifier::dArg:
697         case ConversionSpecifier::iArg:
698         case ConversionSpecifier::oArg:
699         case ConversionSpecifier::uArg:
700         case ConversionSpecifier::xArg:
701         case ConversionSpecifier::XArg:
702           return !Target.getTriple().isOSDarwin() &&
703                  !Target.getTriple().isOSWindows();
704         default:
705           return false;
706       }
707 
708     case LengthModifier::AsAllocate:
709       switch (CS.getKind()) {
710         case ConversionSpecifier::sArg:
711         case ConversionSpecifier::SArg:
712         case ConversionSpecifier::ScanListArg:
713           return true;
714         default:
715           return false;
716       }
717 
718     case LengthModifier::AsMAllocate:
719       switch (CS.getKind()) {
720         case ConversionSpecifier::cArg:
721         case ConversionSpecifier::CArg:
722         case ConversionSpecifier::sArg:
723         case ConversionSpecifier::SArg:
724         case ConversionSpecifier::ScanListArg:
725           return true;
726         default:
727           return false;
728       }
729     case LengthModifier::AsInt32:
730     case LengthModifier::AsInt3264:
731     case LengthModifier::AsInt64:
732       switch (CS.getKind()) {
733         case ConversionSpecifier::dArg:
734         case ConversionSpecifier::iArg:
735         case ConversionSpecifier::oArg:
736         case ConversionSpecifier::uArg:
737         case ConversionSpecifier::xArg:
738         case ConversionSpecifier::XArg:
739           return Target.getTriple().isOSMSVCRT();
740         default:
741           return false;
742       }
743     case LengthModifier::AsWide:
744       switch (CS.getKind()) {
745         case ConversionSpecifier::cArg:
746         case ConversionSpecifier::CArg:
747         case ConversionSpecifier::sArg:
748         case ConversionSpecifier::SArg:
749         case ConversionSpecifier::ZArg:
750           return Target.getTriple().isOSMSVCRT();
751         default:
752           return false;
753       }
754   }
755   llvm_unreachable("Invalid LengthModifier Kind!");
756 }
757 
hasStandardLengthModifier() const758 bool FormatSpecifier::hasStandardLengthModifier() const {
759   switch (LM.getKind()) {
760     case LengthModifier::None:
761     case LengthModifier::AsChar:
762     case LengthModifier::AsShort:
763     case LengthModifier::AsLong:
764     case LengthModifier::AsLongLong:
765     case LengthModifier::AsIntMax:
766     case LengthModifier::AsSizeT:
767     case LengthModifier::AsPtrDiff:
768     case LengthModifier::AsLongDouble:
769       return true;
770     case LengthModifier::AsAllocate:
771     case LengthModifier::AsMAllocate:
772     case LengthModifier::AsQuad:
773     case LengthModifier::AsInt32:
774     case LengthModifier::AsInt3264:
775     case LengthModifier::AsInt64:
776     case LengthModifier::AsWide:
777       return false;
778   }
779   llvm_unreachable("Invalid LengthModifier Kind!");
780 }
781 
hasStandardConversionSpecifier(const LangOptions & LangOpt) const782 bool FormatSpecifier::hasStandardConversionSpecifier(const LangOptions &LangOpt) const {
783   switch (CS.getKind()) {
784     case ConversionSpecifier::cArg:
785     case ConversionSpecifier::dArg:
786     case ConversionSpecifier::iArg:
787     case ConversionSpecifier::oArg:
788     case ConversionSpecifier::uArg:
789     case ConversionSpecifier::xArg:
790     case ConversionSpecifier::XArg:
791     case ConversionSpecifier::fArg:
792     case ConversionSpecifier::FArg:
793     case ConversionSpecifier::eArg:
794     case ConversionSpecifier::EArg:
795     case ConversionSpecifier::gArg:
796     case ConversionSpecifier::GArg:
797     case ConversionSpecifier::aArg:
798     case ConversionSpecifier::AArg:
799     case ConversionSpecifier::sArg:
800     case ConversionSpecifier::pArg:
801     case ConversionSpecifier::nArg:
802     case ConversionSpecifier::ObjCObjArg:
803     case ConversionSpecifier::ScanListArg:
804     case ConversionSpecifier::PercentArg:
805       return true;
806     case ConversionSpecifier::CArg:
807     case ConversionSpecifier::SArg:
808       return LangOpt.ObjC1 || LangOpt.ObjC2;
809     case ConversionSpecifier::InvalidSpecifier:
810     case ConversionSpecifier::PrintErrno:
811     case ConversionSpecifier::DArg:
812     case ConversionSpecifier::OArg:
813     case ConversionSpecifier::UArg:
814     case ConversionSpecifier::ZArg:
815       return false;
816   }
817   llvm_unreachable("Invalid ConversionSpecifier Kind!");
818 }
819 
hasStandardLengthConversionCombination() const820 bool FormatSpecifier::hasStandardLengthConversionCombination() const {
821   if (LM.getKind() == LengthModifier::AsLongDouble) {
822     switch(CS.getKind()) {
823         case ConversionSpecifier::dArg:
824         case ConversionSpecifier::iArg:
825         case ConversionSpecifier::oArg:
826         case ConversionSpecifier::uArg:
827         case ConversionSpecifier::xArg:
828         case ConversionSpecifier::XArg:
829           return false;
830         default:
831           return true;
832     }
833   }
834   return true;
835 }
836 
getCorrectedLengthModifier() const837 Optional<LengthModifier> FormatSpecifier::getCorrectedLengthModifier() const {
838   if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
839     if (LM.getKind() == LengthModifier::AsLongDouble ||
840         LM.getKind() == LengthModifier::AsQuad) {
841       LengthModifier FixedLM(LM);
842       FixedLM.setKind(LengthModifier::AsLongLong);
843       return FixedLM;
844     }
845   }
846 
847   return None;
848 }
849 
namedTypeToLengthModifier(QualType QT,LengthModifier & LM)850 bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
851                                                 LengthModifier &LM) {
852   assert(isa<TypedefType>(QT) && "Expected a TypedefType");
853   const TypedefNameDecl *Typedef = cast<TypedefType>(QT)->getDecl();
854 
855   for (;;) {
856     const IdentifierInfo *Identifier = Typedef->getIdentifier();
857     if (Identifier->getName() == "size_t") {
858       LM.setKind(LengthModifier::AsSizeT);
859       return true;
860     } else if (Identifier->getName() == "ssize_t") {
861       // Not C99, but common in Unix.
862       LM.setKind(LengthModifier::AsSizeT);
863       return true;
864     } else if (Identifier->getName() == "intmax_t") {
865       LM.setKind(LengthModifier::AsIntMax);
866       return true;
867     } else if (Identifier->getName() == "uintmax_t") {
868       LM.setKind(LengthModifier::AsIntMax);
869       return true;
870     } else if (Identifier->getName() == "ptrdiff_t") {
871       LM.setKind(LengthModifier::AsPtrDiff);
872       return true;
873     }
874 
875     QualType T = Typedef->getUnderlyingType();
876     if (!isa<TypedefType>(T))
877       break;
878 
879     Typedef = cast<TypedefType>(T)->getDecl();
880   }
881   return false;
882 }
883