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 
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
ParseVectorModifier(FormatStringHandler & H,FormatSpecifier & FS,const char * & I,const char * E,const LangOptions & LO)181 clang::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 
210 bool
ParseLengthModifier(FormatSpecifier & FS,const char * & I,const char * E,const LangOptions & LO,bool IsScanf)211 clang::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 
ParseUTF8InvalidSpecifier(const char * SpecifierBegin,const char * FmtStrEnd,unsigned & Len)296 bool 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 
323 clang::analyze_format_string::ArgType::MatchKind
matchesType(ASTContext & C,QualType argTy) const324 ArgType::matchesType(ASTContext &C, QualType argTy) const {
325   if (Ptr) {
326     // It has to be a pointer.
327     const PointerType *PT = argTy->getAs<PointerType>();
328     if (!PT)
329       return NoMatch;
330 
331     // We cannot write through a const qualified pointer.
332     if (PT->getPointeeType().isConstQualified())
333       return NoMatch;
334 
335     argTy = PT->getPointeeType();
336   }
337 
338   switch (K) {
339     case InvalidTy:
340       llvm_unreachable("ArgType must be valid");
341 
342     case UnknownTy:
343       return Match;
344 
345     case AnyCharTy: {
346       if (const EnumType *ETy = argTy->getAs<EnumType>()) {
347         // If the enum is incomplete we know nothing about the underlying type.
348         // Assume that it's 'int'.
349         if (!ETy->getDecl()->isComplete())
350           return NoMatch;
351         argTy = ETy->getDecl()->getIntegerType();
352       }
353 
354       if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
355         switch (BT->getKind()) {
356           default:
357             break;
358           case BuiltinType::Char_S:
359           case BuiltinType::SChar:
360           case BuiltinType::UChar:
361           case BuiltinType::Char_U:
362           case BuiltinType::Bool:
363             return Match;
364         }
365       return NoMatch;
366     }
367 
368     case SpecificTy: {
369       if (const EnumType *ETy = argTy->getAs<EnumType>()) {
370         // If the enum is incomplete we know nothing about the underlying type.
371         // Assume that it's 'int'.
372         if (!ETy->getDecl()->isComplete())
373           argTy = C.IntTy;
374         else
375           argTy = ETy->getDecl()->getIntegerType();
376       }
377       argTy = C.getCanonicalType(argTy).getUnqualifiedType();
378 
379       if (T == argTy)
380         return Match;
381       // Check for "compatible types".
382       if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
383         switch (BT->getKind()) {
384           default:
385             break;
386           case BuiltinType::Char_S:
387           case BuiltinType::SChar:
388           case BuiltinType::Char_U:
389           case BuiltinType::UChar:
390           case BuiltinType::Bool:
391             if (T == C.UnsignedShortTy || T == C.ShortTy)
392               return NoMatchTypeConfusion;
393             return T == C.UnsignedCharTy || T == C.SignedCharTy ? Match
394                                                                 : NoMatch;
395           case BuiltinType::Short:
396             return T == C.UnsignedShortTy ? Match : NoMatch;
397           case BuiltinType::UShort:
398             return T == C.ShortTy ? Match : NoMatch;
399           case BuiltinType::Int:
400             return T == C.UnsignedIntTy ? Match : NoMatch;
401           case BuiltinType::UInt:
402             return T == C.IntTy ? Match : NoMatch;
403           case BuiltinType::Long:
404             return T == C.UnsignedLongTy ? Match : NoMatch;
405           case BuiltinType::ULong:
406             return T == C.LongTy ? Match : NoMatch;
407           case BuiltinType::LongLong:
408             return T == C.UnsignedLongLongTy ? Match : NoMatch;
409           case BuiltinType::ULongLong:
410             return T == C.LongLongTy ? Match : NoMatch;
411         }
412       return NoMatch;
413     }
414 
415     case CStrTy: {
416       const PointerType *PT = argTy->getAs<PointerType>();
417       if (!PT)
418         return NoMatch;
419       QualType pointeeTy = PT->getPointeeType();
420       if (const BuiltinType *BT = pointeeTy->getAs<BuiltinType>())
421         switch (BT->getKind()) {
422           case BuiltinType::Void:
423           case BuiltinType::Char_U:
424           case BuiltinType::UChar:
425           case BuiltinType::Char_S:
426           case BuiltinType::SChar:
427             return Match;
428           default:
429             break;
430         }
431 
432       return NoMatch;
433     }
434 
435     case WCStrTy: {
436       const PointerType *PT = argTy->getAs<PointerType>();
437       if (!PT)
438         return NoMatch;
439       QualType pointeeTy =
440         C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
441       return pointeeTy == C.getWideCharType() ? Match : NoMatch;
442     }
443 
444     case WIntTy: {
445       QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
446 
447       if (C.getCanonicalType(argTy).getUnqualifiedType() == WInt)
448         return Match;
449 
450       QualType PromoArg = argTy->isPromotableIntegerType()
451                               ? C.getPromotedIntegerType(argTy)
452                               : argTy;
453       PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
454 
455       // If the promoted argument is the corresponding signed type of the
456       // wint_t type, then it should match.
457       if (PromoArg->hasSignedIntegerRepresentation() &&
458           C.getCorrespondingUnsignedType(PromoArg) == WInt)
459         return Match;
460 
461       return WInt == PromoArg ? Match : NoMatch;
462     }
463 
464     case CPointerTy:
465       if (argTy->isVoidPointerType()) {
466         return Match;
467       } if (argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
468             argTy->isBlockPointerType() || argTy->isNullPtrType()) {
469         return NoMatchPedantic;
470       } else {
471         return NoMatch;
472       }
473 
474     case ObjCPointerTy: {
475       if (argTy->getAs<ObjCObjectPointerType>() ||
476           argTy->getAs<BlockPointerType>())
477         return Match;
478 
479       // Handle implicit toll-free bridging.
480       if (const PointerType *PT = argTy->getAs<PointerType>()) {
481         // Things such as CFTypeRef are really just opaque pointers
482         // to C structs representing CF types that can often be bridged
483         // to Objective-C objects.  Since the compiler doesn't know which
484         // structs can be toll-free bridged, we just accept them all.
485         QualType pointee = PT->getPointeeType();
486         if (pointee->getAsStructureType() || pointee->isVoidType())
487           return Match;
488       }
489       return NoMatch;
490     }
491   }
492 
493   llvm_unreachable("Invalid ArgType Kind!");
494 }
495 
makeVectorType(ASTContext & C,unsigned NumElts) const496 ArgType ArgType::makeVectorType(ASTContext &C, unsigned NumElts) const {
497   // Check for valid vector element types.
498   if (T.isNull())
499     return ArgType::Invalid();
500 
501   QualType Vec = C.getExtVectorType(T, NumElts);
502   return ArgType(Vec, Name);
503 }
504 
getRepresentativeType(ASTContext & C) const505 QualType ArgType::getRepresentativeType(ASTContext &C) const {
506   QualType Res;
507   switch (K) {
508     case InvalidTy:
509       llvm_unreachable("No representative type for Invalid ArgType");
510     case UnknownTy:
511       llvm_unreachable("No representative type for Unknown ArgType");
512     case AnyCharTy:
513       Res = C.CharTy;
514       break;
515     case SpecificTy:
516       Res = T;
517       break;
518     case CStrTy:
519       Res = C.getPointerType(C.CharTy);
520       break;
521     case WCStrTy:
522       Res = C.getPointerType(C.getWideCharType());
523       break;
524     case ObjCPointerTy:
525       Res = C.ObjCBuiltinIdTy;
526       break;
527     case CPointerTy:
528       Res = C.VoidPtrTy;
529       break;
530     case WIntTy: {
531       Res = C.getWIntType();
532       break;
533     }
534   }
535 
536   if (Ptr)
537     Res = C.getPointerType(Res);
538   return Res;
539 }
540 
getRepresentativeTypeName(ASTContext & C) const541 std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
542   std::string S = getRepresentativeType(C).getAsString();
543 
544   std::string Alias;
545   if (Name) {
546     // Use a specific name for this type, e.g. "size_t".
547     Alias = Name;
548     if (Ptr) {
549       // If ArgType is actually a pointer to T, append an asterisk.
550       Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
551     }
552     // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
553     if (S == Alias)
554       Alias.clear();
555   }
556 
557   if (!Alias.empty())
558     return std::string("'") + Alias + "' (aka '" + S + "')";
559   return std::string("'") + S + "'";
560 }
561 
562 
563 //===----------------------------------------------------------------------===//
564 // Methods on OptionalAmount.
565 //===----------------------------------------------------------------------===//
566 
567 ArgType
getArgType(ASTContext & Ctx) const568 analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
569   return Ctx.IntTy;
570 }
571 
572 //===----------------------------------------------------------------------===//
573 // Methods on LengthModifier.
574 //===----------------------------------------------------------------------===//
575 
576 const char *
toString() const577 analyze_format_string::LengthModifier::toString() const {
578   switch (kind) {
579   case AsChar:
580     return "hh";
581   case AsShort:
582     return "h";
583   case AsShortLong:
584     return "hl";
585   case AsLong: // or AsWideChar
586     return "l";
587   case AsLongLong:
588     return "ll";
589   case AsQuad:
590     return "q";
591   case AsIntMax:
592     return "j";
593   case AsSizeT:
594     return "z";
595   case AsPtrDiff:
596     return "t";
597   case AsInt32:
598     return "I32";
599   case AsInt3264:
600     return "I";
601   case AsInt64:
602     return "I64";
603   case AsLongDouble:
604     return "L";
605   case AsAllocate:
606     return "a";
607   case AsMAllocate:
608     return "m";
609   case AsWide:
610     return "w";
611   case None:
612     return "";
613   }
614   return nullptr;
615 }
616 
617 //===----------------------------------------------------------------------===//
618 // Methods on ConversionSpecifier.
619 //===----------------------------------------------------------------------===//
620 
toString() const621 const char *ConversionSpecifier::toString() const {
622   switch (kind) {
623   case dArg: return "d";
624   case DArg: return "D";
625   case iArg: return "i";
626   case oArg: return "o";
627   case OArg: return "O";
628   case uArg: return "u";
629   case UArg: return "U";
630   case xArg: return "x";
631   case XArg: return "X";
632   case fArg: return "f";
633   case FArg: return "F";
634   case eArg: return "e";
635   case EArg: return "E";
636   case gArg: return "g";
637   case GArg: return "G";
638   case aArg: return "a";
639   case AArg: return "A";
640   case cArg: return "c";
641   case sArg: return "s";
642   case pArg: return "p";
643   case PArg:
644     return "P";
645   case nArg: return "n";
646   case PercentArg:  return "%";
647   case ScanListArg: return "[";
648   case InvalidSpecifier: return nullptr;
649 
650   // POSIX unicode extensions.
651   case CArg: return "C";
652   case SArg: return "S";
653 
654   // Objective-C specific specifiers.
655   case ObjCObjArg: return "@";
656 
657   // FreeBSD kernel specific specifiers.
658   case FreeBSDbArg: return "b";
659   case FreeBSDDArg: return "D";
660   case FreeBSDrArg: return "r";
661   case FreeBSDyArg: return "y";
662 
663   // GlibC specific specifiers.
664   case PrintErrno: return "m";
665 
666   // MS specific specifiers.
667   case ZArg: return "Z";
668   }
669   return nullptr;
670 }
671 
672 Optional<ConversionSpecifier>
getStandardSpecifier() const673 ConversionSpecifier::getStandardSpecifier() const {
674   ConversionSpecifier::Kind NewKind;
675 
676   switch (getKind()) {
677   default:
678     return None;
679   case DArg:
680     NewKind = dArg;
681     break;
682   case UArg:
683     NewKind = uArg;
684     break;
685   case OArg:
686     NewKind = oArg;
687     break;
688   }
689 
690   ConversionSpecifier FixedCS(*this);
691   FixedCS.setKind(NewKind);
692   return FixedCS;
693 }
694 
695 //===----------------------------------------------------------------------===//
696 // Methods on OptionalAmount.
697 //===----------------------------------------------------------------------===//
698 
toString(raw_ostream & os) const699 void OptionalAmount::toString(raw_ostream &os) const {
700   switch (hs) {
701   case Invalid:
702   case NotSpecified:
703     return;
704   case Arg:
705     if (UsesDotPrefix)
706         os << ".";
707     if (usesPositionalArg())
708       os << "*" << getPositionalArgIndex() << "$";
709     else
710       os << "*";
711     break;
712   case Constant:
713     if (UsesDotPrefix)
714         os << ".";
715     os << amt;
716     break;
717   }
718 }
719 
hasValidLengthModifier(const TargetInfo & Target,const LangOptions & LO) const720 bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target,
721                                              const LangOptions &LO) const {
722   switch (LM.getKind()) {
723     case LengthModifier::None:
724       return true;
725 
726     // Handle most integer flags
727     case LengthModifier::AsShort:
728       // Length modifier only applies to FP vectors.
729       if (LO.OpenCL && CS.isDoubleArg())
730         return !VectorNumElts.isInvalid();
731 
732       if (Target.getTriple().isOSMSVCRT()) {
733         switch (CS.getKind()) {
734           case ConversionSpecifier::cArg:
735           case ConversionSpecifier::CArg:
736           case ConversionSpecifier::sArg:
737           case ConversionSpecifier::SArg:
738           case ConversionSpecifier::ZArg:
739             return true;
740           default:
741             break;
742         }
743       }
744       LLVM_FALLTHROUGH;
745     case LengthModifier::AsChar:
746     case LengthModifier::AsLongLong:
747     case LengthModifier::AsQuad:
748     case LengthModifier::AsIntMax:
749     case LengthModifier::AsSizeT:
750     case LengthModifier::AsPtrDiff:
751       switch (CS.getKind()) {
752         case ConversionSpecifier::dArg:
753         case ConversionSpecifier::DArg:
754         case ConversionSpecifier::iArg:
755         case ConversionSpecifier::oArg:
756         case ConversionSpecifier::OArg:
757         case ConversionSpecifier::uArg:
758         case ConversionSpecifier::UArg:
759         case ConversionSpecifier::xArg:
760         case ConversionSpecifier::XArg:
761         case ConversionSpecifier::nArg:
762           return true;
763         case ConversionSpecifier::FreeBSDrArg:
764         case ConversionSpecifier::FreeBSDyArg:
765           return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS4();
766         default:
767           return false;
768       }
769 
770     case LengthModifier::AsShortLong:
771       return LO.OpenCL && !VectorNumElts.isInvalid();
772 
773     // Handle 'l' flag
774     case LengthModifier::AsLong: // or AsWideChar
775       if (CS.isDoubleArg()) {
776         // Invalid for OpenCL FP scalars.
777         if (LO.OpenCL && VectorNumElts.isInvalid())
778           return false;
779         return true;
780       }
781 
782       switch (CS.getKind()) {
783         case ConversionSpecifier::dArg:
784         case ConversionSpecifier::DArg:
785         case ConversionSpecifier::iArg:
786         case ConversionSpecifier::oArg:
787         case ConversionSpecifier::OArg:
788         case ConversionSpecifier::uArg:
789         case ConversionSpecifier::UArg:
790         case ConversionSpecifier::xArg:
791         case ConversionSpecifier::XArg:
792         case ConversionSpecifier::nArg:
793         case ConversionSpecifier::cArg:
794         case ConversionSpecifier::sArg:
795         case ConversionSpecifier::ScanListArg:
796         case ConversionSpecifier::ZArg:
797           return true;
798         case ConversionSpecifier::FreeBSDrArg:
799         case ConversionSpecifier::FreeBSDyArg:
800           return Target.getTriple().isOSFreeBSD() || Target.getTriple().isPS4();
801         default:
802           return false;
803       }
804 
805     case LengthModifier::AsLongDouble:
806       switch (CS.getKind()) {
807         case ConversionSpecifier::aArg:
808         case ConversionSpecifier::AArg:
809         case ConversionSpecifier::fArg:
810         case ConversionSpecifier::FArg:
811         case ConversionSpecifier::eArg:
812         case ConversionSpecifier::EArg:
813         case ConversionSpecifier::gArg:
814         case ConversionSpecifier::GArg:
815           return true;
816         // GNU libc extension.
817         case ConversionSpecifier::dArg:
818         case ConversionSpecifier::iArg:
819         case ConversionSpecifier::oArg:
820         case ConversionSpecifier::uArg:
821         case ConversionSpecifier::xArg:
822         case ConversionSpecifier::XArg:
823           return !Target.getTriple().isOSDarwin() &&
824                  !Target.getTriple().isOSWindows();
825         default:
826           return false;
827       }
828 
829     case LengthModifier::AsAllocate:
830       switch (CS.getKind()) {
831         case ConversionSpecifier::sArg:
832         case ConversionSpecifier::SArg:
833         case ConversionSpecifier::ScanListArg:
834           return true;
835         default:
836           return false;
837       }
838 
839     case LengthModifier::AsMAllocate:
840       switch (CS.getKind()) {
841         case ConversionSpecifier::cArg:
842         case ConversionSpecifier::CArg:
843         case ConversionSpecifier::sArg:
844         case ConversionSpecifier::SArg:
845         case ConversionSpecifier::ScanListArg:
846           return true;
847         default:
848           return false;
849       }
850     case LengthModifier::AsInt32:
851     case LengthModifier::AsInt3264:
852     case LengthModifier::AsInt64:
853       switch (CS.getKind()) {
854         case ConversionSpecifier::dArg:
855         case ConversionSpecifier::iArg:
856         case ConversionSpecifier::oArg:
857         case ConversionSpecifier::uArg:
858         case ConversionSpecifier::xArg:
859         case ConversionSpecifier::XArg:
860           return Target.getTriple().isOSMSVCRT();
861         default:
862           return false;
863       }
864     case LengthModifier::AsWide:
865       switch (CS.getKind()) {
866         case ConversionSpecifier::cArg:
867         case ConversionSpecifier::CArg:
868         case ConversionSpecifier::sArg:
869         case ConversionSpecifier::SArg:
870         case ConversionSpecifier::ZArg:
871           return Target.getTriple().isOSMSVCRT();
872         default:
873           return false;
874       }
875   }
876   llvm_unreachable("Invalid LengthModifier Kind!");
877 }
878 
hasStandardLengthModifier() const879 bool FormatSpecifier::hasStandardLengthModifier() const {
880   switch (LM.getKind()) {
881     case LengthModifier::None:
882     case LengthModifier::AsChar:
883     case LengthModifier::AsShort:
884     case LengthModifier::AsLong:
885     case LengthModifier::AsLongLong:
886     case LengthModifier::AsIntMax:
887     case LengthModifier::AsSizeT:
888     case LengthModifier::AsPtrDiff:
889     case LengthModifier::AsLongDouble:
890       return true;
891     case LengthModifier::AsAllocate:
892     case LengthModifier::AsMAllocate:
893     case LengthModifier::AsQuad:
894     case LengthModifier::AsInt32:
895     case LengthModifier::AsInt3264:
896     case LengthModifier::AsInt64:
897     case LengthModifier::AsWide:
898     case LengthModifier::AsShortLong: // ???
899       return false;
900   }
901   llvm_unreachable("Invalid LengthModifier Kind!");
902 }
903 
hasStandardConversionSpecifier(const LangOptions & LangOpt) const904 bool FormatSpecifier::hasStandardConversionSpecifier(
905     const LangOptions &LangOpt) const {
906   switch (CS.getKind()) {
907     case ConversionSpecifier::cArg:
908     case ConversionSpecifier::dArg:
909     case ConversionSpecifier::iArg:
910     case ConversionSpecifier::oArg:
911     case ConversionSpecifier::uArg:
912     case ConversionSpecifier::xArg:
913     case ConversionSpecifier::XArg:
914     case ConversionSpecifier::fArg:
915     case ConversionSpecifier::FArg:
916     case ConversionSpecifier::eArg:
917     case ConversionSpecifier::EArg:
918     case ConversionSpecifier::gArg:
919     case ConversionSpecifier::GArg:
920     case ConversionSpecifier::aArg:
921     case ConversionSpecifier::AArg:
922     case ConversionSpecifier::sArg:
923     case ConversionSpecifier::pArg:
924     case ConversionSpecifier::nArg:
925     case ConversionSpecifier::ObjCObjArg:
926     case ConversionSpecifier::ScanListArg:
927     case ConversionSpecifier::PercentArg:
928     case ConversionSpecifier::PArg:
929       return true;
930     case ConversionSpecifier::CArg:
931     case ConversionSpecifier::SArg:
932       return LangOpt.ObjC;
933     case ConversionSpecifier::InvalidSpecifier:
934     case ConversionSpecifier::FreeBSDbArg:
935     case ConversionSpecifier::FreeBSDDArg:
936     case ConversionSpecifier::FreeBSDrArg:
937     case ConversionSpecifier::FreeBSDyArg:
938     case ConversionSpecifier::PrintErrno:
939     case ConversionSpecifier::DArg:
940     case ConversionSpecifier::OArg:
941     case ConversionSpecifier::UArg:
942     case ConversionSpecifier::ZArg:
943       return false;
944   }
945   llvm_unreachable("Invalid ConversionSpecifier Kind!");
946 }
947 
hasStandardLengthConversionCombination() const948 bool FormatSpecifier::hasStandardLengthConversionCombination() const {
949   if (LM.getKind() == LengthModifier::AsLongDouble) {
950     switch(CS.getKind()) {
951         case ConversionSpecifier::dArg:
952         case ConversionSpecifier::iArg:
953         case ConversionSpecifier::oArg:
954         case ConversionSpecifier::uArg:
955         case ConversionSpecifier::xArg:
956         case ConversionSpecifier::XArg:
957           return false;
958         default:
959           return true;
960     }
961   }
962   return true;
963 }
964 
getCorrectedLengthModifier() const965 Optional<LengthModifier> FormatSpecifier::getCorrectedLengthModifier() const {
966   if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
967     if (LM.getKind() == LengthModifier::AsLongDouble ||
968         LM.getKind() == LengthModifier::AsQuad) {
969       LengthModifier FixedLM(LM);
970       FixedLM.setKind(LengthModifier::AsLongLong);
971       return FixedLM;
972     }
973   }
974 
975   return None;
976 }
977 
namedTypeToLengthModifier(QualType QT,LengthModifier & LM)978 bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
979                                                 LengthModifier &LM) {
980   assert(isa<TypedefType>(QT) && "Expected a TypedefType");
981   const TypedefNameDecl *Typedef = cast<TypedefType>(QT)->getDecl();
982 
983   for (;;) {
984     const IdentifierInfo *Identifier = Typedef->getIdentifier();
985     if (Identifier->getName() == "size_t") {
986       LM.setKind(LengthModifier::AsSizeT);
987       return true;
988     } else if (Identifier->getName() == "ssize_t") {
989       // Not C99, but common in Unix.
990       LM.setKind(LengthModifier::AsSizeT);
991       return true;
992     } else if (Identifier->getName() == "intmax_t") {
993       LM.setKind(LengthModifier::AsIntMax);
994       return true;
995     } else if (Identifier->getName() == "uintmax_t") {
996       LM.setKind(LengthModifier::AsIntMax);
997       return true;
998     } else if (Identifier->getName() == "ptrdiff_t") {
999       LM.setKind(LengthModifier::AsPtrDiff);
1000       return true;
1001     }
1002 
1003     QualType T = Typedef->getUnderlyingType();
1004     if (!isa<TypedefType>(T))
1005       break;
1006 
1007     Typedef = cast<TypedefType>(T)->getDecl();
1008   }
1009   return false;
1010 }
1011