1 //= FormatString.h - Analysis of printf/fprintf format strings --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines APIs for analyzing the format strings of printf, fscanf,
13 // The structure of format strings for fprintf are described in C99 7.19.6.1.
15 // The structure of format strings for fscanf are described in C99 7.19.6.2.
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_CLANG_ANALYSIS_ANALYSES_FORMATSTRING_H
20 #define LLVM_CLANG_ANALYSIS_ANALYSES_FORMATSTRING_H
22 #include "clang/AST/CanonicalType.h"
28 //===----------------------------------------------------------------------===//
29 /// Common components of both fprintf and fscanf format strings.
30 namespace analyze_format_string {
32 /// Class representing optional flags with location and representation
36 OptionalFlag(const char *Representation)
37 : representation(Representation), flag(false) {}
38 bool isSet() const { return flag; }
39 void set() { flag = true; }
40 void clear() { flag = false; }
41 void setPosition(const char *position) {
44 this->position = position;
46 const char *getPosition() const {
50 const char *toString() const { return representation; }
52 // Overloaded operators for bool like qualities
53 explicit operator bool() const { return flag; }
54 OptionalFlag& operator=(const bool &rhs) {
56 return *this; // Return a reference to myself.
59 const char *representation;
64 /// Represents the length modifier in a format string in scanf/printf.
65 class LengthModifier {
73 AsQuad, // 'q' (BSD, deprecated, for 64-bit integer types)
77 AsInt32, // 'I32' (MSVCRT, like __int32)
78 AsInt3264, // 'I' (MSVCRT, like __int3264 from MIDL)
79 AsInt64, // 'I64' (MSVCRT, like __int64)
81 AsAllocate, // for '%as', GNU extension to C90 scanf
82 AsMAllocate, // for '%ms', GNU extension to scanf
83 AsWide, // 'w' (MSVCRT, like l but only for c, C, s, S, or Z
84 AsWideChar = AsLong // for '%ls', only makes sense for printf
88 : Position(nullptr), kind(None) {}
89 LengthModifier(const char *pos, Kind k)
90 : Position(pos), kind(k) {}
92 const char *getStart() const {
96 unsigned getLength() const {
111 Kind getKind() const { return kind; }
112 void setKind(Kind k) { kind = k; }
114 const char *toString() const;
117 const char *Position;
121 class ConversionSpecifier {
124 InvalidSpecifier = 0,
125 // C99 conversion specifiers.
128 DArg, // Apple extension
134 OArg, // Apple extension
136 UArg, // Apple extension
160 // Apple extension: P specifies to os_log that the data being pointed to is
161 // to be copied by os_log. The precision indicates the number of bytes to
165 // ** Printf-specific **
167 ZArg, // MS extension
169 // Objective-C specific specifiers.
171 ObjCBeg = ObjCObjArg,
172 ObjCEnd = ObjCObjArg,
174 // FreeBSD kernel specific specifiers.
180 // GlibC specific specifiers.
183 PrintfConvBeg = ObjCObjArg,
184 PrintfConvEnd = PrintErrno,
186 // ** Scanf-specific **
188 ScanfConvBeg = ScanListArg,
189 ScanfConvEnd = ScanListArg
192 ConversionSpecifier(bool isPrintf = true)
193 : IsPrintf(isPrintf), Position(nullptr), EndScanList(nullptr),
194 kind(InvalidSpecifier) {}
196 ConversionSpecifier(bool isPrintf, const char *pos, Kind k)
197 : IsPrintf(isPrintf), Position(pos), EndScanList(nullptr), kind(k) {}
199 const char *getStart() const {
203 StringRef getCharacters() const {
204 return StringRef(getStart(), getLength());
207 bool consumesDataArgument() const {
214 case InvalidSpecifier:
221 Kind getKind() const { return kind; }
222 void setKind(Kind k) { kind = k; }
223 unsigned getLength() const {
224 return EndScanList ? EndScanList - Position : 1;
226 void setEndScanList(const char *pos) { EndScanList = pos; }
228 bool isIntArg() const { return (kind >= IntArgBeg && kind <= IntArgEnd) ||
229 kind == FreeBSDrArg || kind == FreeBSDyArg; }
230 bool isUIntArg() const { return kind >= UIntArgBeg && kind <= UIntArgEnd; }
231 bool isAnyIntArg() const { return kind >= IntArgBeg && kind <= UIntArgEnd; }
232 bool isDoubleArg() const {
233 return kind >= DoubleArgBeg && kind <= DoubleArgEnd;
236 const char *toString() const;
238 bool isPrintfKind() const { return IsPrintf; }
240 Optional<ConversionSpecifier> getStandardSpecifier() const;
244 const char *Position;
245 const char *EndScanList;
251 enum Kind { UnknownTy, InvalidTy, SpecificTy, ObjCPointerTy, CPointerTy,
252 AnyCharTy, CStrTy, WCStrTy, WIntTy };
254 enum MatchKind { NoMatch = 0, Match = 1, NoMatchPedantic };
259 const char *Name = nullptr;
262 /// The TypeKind identifies certain well-known types like size_t and
264 enum class TypeKind { DontCare, SizeT, PtrdiffT };
265 TypeKind TK = TypeKind::DontCare;
268 ArgType(Kind K = UnknownTy, const char *N = nullptr) : K(K), Name(N) {}
269 ArgType(QualType T, const char *N = nullptr) : K(SpecificTy), T(T), Name(N) {}
270 ArgType(CanQualType T) : K(SpecificTy), T(T) {}
272 static ArgType Invalid() { return ArgType(InvalidTy); }
273 bool isValid() const { return K != InvalidTy; }
275 bool isSizeT() const { return TK == TypeKind::SizeT; }
277 bool isPtrdiffT() const { return TK == TypeKind::PtrdiffT; }
279 /// Create an ArgType which corresponds to the type pointer to A.
280 static ArgType PtrTo(const ArgType& A) {
281 assert(A.K >= InvalidTy && "ArgType cannot be pointer to invalid/unknown");
287 /// Create an ArgType which corresponds to the size_t/ssize_t type.
288 static ArgType makeSizeT(const ArgType &A) {
290 Res.TK = TypeKind::SizeT;
294 /// Create an ArgType which corresponds to the ptrdiff_t/unsigned ptrdiff_t
296 static ArgType makePtrdiffT(const ArgType &A) {
298 Res.TK = TypeKind::PtrdiffT;
302 MatchKind matchesType(ASTContext &C, QualType argTy) const;
304 QualType getRepresentativeType(ASTContext &C) const;
306 std::string getRepresentativeTypeName(ASTContext &C) const;
309 class OptionalAmount {
311 enum HowSpecified { NotSpecified, Constant, Arg, Invalid };
313 OptionalAmount(HowSpecified howSpecified,
315 const char *amountStart,
316 unsigned amountLength,
317 bool usesPositionalArg)
318 : start(amountStart), length(amountLength), hs(howSpecified), amt(amount),
319 UsesPositionalArg(usesPositionalArg), UsesDotPrefix(0) {}
321 OptionalAmount(bool valid = true)
322 : start(nullptr),length(0), hs(valid ? NotSpecified : Invalid), amt(0),
323 UsesPositionalArg(0), UsesDotPrefix(0) {}
325 bool isInvalid() const {
326 return hs == Invalid;
329 HowSpecified getHowSpecified() const { return hs; }
330 void setHowSpecified(HowSpecified h) { hs = h; }
332 bool hasDataArgument() const { return hs == Arg; }
334 unsigned getArgIndex() const {
335 assert(hasDataArgument());
339 unsigned getConstantAmount() const {
340 assert(hs == Constant);
344 const char *getStart() const {
345 // We include the . character if it is given.
346 return start - UsesDotPrefix;
349 unsigned getConstantLength() const {
350 assert(hs == Constant);
351 return length + UsesDotPrefix;
354 ArgType getArgType(ASTContext &Ctx) const;
356 void toString(raw_ostream &os) const;
358 bool usesPositionalArg() const { return (bool) UsesPositionalArg; }
359 unsigned getPositionalArgIndex() const {
360 assert(hasDataArgument());
364 bool usesDotPrefix() const { return UsesDotPrefix; }
365 void setUsesDotPrefix() { UsesDotPrefix = true; }
372 bool UsesPositionalArg : 1;
377 class FormatSpecifier {
380 OptionalAmount FieldWidth;
381 ConversionSpecifier CS;
382 /// Positional arguments, an IEEE extension:
383 /// IEEE Std 1003.1, 2004 Edition
384 /// http://www.opengroup.org/onlinepubs/009695399/functions/printf.html
385 bool UsesPositionalArg;
388 FormatSpecifier(bool isPrintf)
389 : CS(isPrintf), UsesPositionalArg(false), argIndex(0) {}
391 void setLengthModifier(LengthModifier lm) {
395 void setUsesPositionalArg() { UsesPositionalArg = true; }
397 void setArgIndex(unsigned i) {
401 unsigned getArgIndex() const {
405 unsigned getPositionalArgIndex() const {
409 const LengthModifier &getLengthModifier() const {
413 const OptionalAmount &getFieldWidth() const {
417 void setFieldWidth(const OptionalAmount &Amt) {
421 bool usesPositionalArg() const { return UsesPositionalArg; }
423 bool hasValidLengthModifier(const TargetInfo &Target) const;
425 bool hasStandardLengthModifier() const;
427 Optional<LengthModifier> getCorrectedLengthModifier() const;
429 bool hasStandardConversionSpecifier(const LangOptions &LangOpt) const;
431 bool hasStandardLengthConversionCombination() const;
433 /// For a TypedefType QT, if it is a named integer type such as size_t,
434 /// assign the appropriate value to LM and return true.
435 static bool namedTypeToLengthModifier(QualType QT, LengthModifier &LM);
438 } // end analyze_format_string namespace
440 //===----------------------------------------------------------------------===//
441 /// Pieces specific to fprintf format strings.
443 namespace analyze_printf {
445 class PrintfConversionSpecifier :
446 public analyze_format_string::ConversionSpecifier {
448 PrintfConversionSpecifier()
449 : ConversionSpecifier(true, nullptr, InvalidSpecifier) {}
451 PrintfConversionSpecifier(const char *pos, Kind k)
452 : ConversionSpecifier(true, pos, k) {}
454 bool isObjCArg() const { return kind >= ObjCBeg && kind <= ObjCEnd; }
455 bool isDoubleArg() const { return kind >= DoubleArgBeg &&
456 kind <= DoubleArgEnd; }
458 static bool classof(const analyze_format_string::ConversionSpecifier *CS) {
459 return CS->isPrintfKind();
463 using analyze_format_string::ArgType;
464 using analyze_format_string::LengthModifier;
465 using analyze_format_string::OptionalAmount;
466 using analyze_format_string::OptionalFlag;
468 class PrintfSpecifier : public analyze_format_string::FormatSpecifier {
469 OptionalFlag HasThousandsGrouping; // ''', POSIX extension.
470 OptionalFlag IsLeftJustified; // '-'
471 OptionalFlag HasPlusPrefix; // '+'
472 OptionalFlag HasSpacePrefix; // ' '
473 OptionalFlag HasAlternativeForm; // '#'
474 OptionalFlag HasLeadingZeroes; // '0'
475 OptionalFlag HasObjCTechnicalTerm; // '[tt]'
476 OptionalFlag IsPrivate; // '{private}'
477 OptionalFlag IsPublic; // '{public}'
478 OptionalAmount Precision;
481 : FormatSpecifier(/* isPrintf = */ true), HasThousandsGrouping("'"),
482 IsLeftJustified("-"), HasPlusPrefix("+"), HasSpacePrefix(" "),
483 HasAlternativeForm("#"), HasLeadingZeroes("0"),
484 HasObjCTechnicalTerm("tt"), IsPrivate("private"), IsPublic("public") {}
486 static PrintfSpecifier Parse(const char *beg, const char *end);
488 // Methods for incrementally constructing the PrintfSpecifier.
489 void setConversionSpecifier(const PrintfConversionSpecifier &cs) {
492 void setHasThousandsGrouping(const char *position) {
493 HasThousandsGrouping.setPosition(position);
495 void setIsLeftJustified(const char *position) {
496 IsLeftJustified.setPosition(position);
498 void setHasPlusPrefix(const char *position) {
499 HasPlusPrefix.setPosition(position);
501 void setHasSpacePrefix(const char *position) {
502 HasSpacePrefix.setPosition(position);
504 void setHasAlternativeForm(const char *position) {
505 HasAlternativeForm.setPosition(position);
507 void setHasLeadingZeros(const char *position) {
508 HasLeadingZeroes.setPosition(position);
510 void setHasObjCTechnicalTerm(const char *position) {
511 HasObjCTechnicalTerm.setPosition(position);
513 void setIsPrivate(const char *position) { IsPrivate.setPosition(position); }
514 void setIsPublic(const char *position) { IsPublic.setPosition(position); }
515 void setUsesPositionalArg() { UsesPositionalArg = true; }
517 // Methods for querying the format specifier.
519 const PrintfConversionSpecifier &getConversionSpecifier() const {
520 return cast<PrintfConversionSpecifier>(CS);
523 void setPrecision(const OptionalAmount &Amt) {
525 Precision.setUsesDotPrefix();
528 const OptionalAmount &getPrecision() const {
532 bool consumesDataArgument() const {
533 return getConversionSpecifier().consumesDataArgument();
536 /// Returns the builtin type that a data argument
537 /// paired with this format specifier should have. This method
538 /// will return null if the format specifier does not have
539 /// a matching data argument or the matching argument matches
540 /// more than one type.
541 ArgType getArgType(ASTContext &Ctx, bool IsObjCLiteral) const;
543 const OptionalFlag &hasThousandsGrouping() const {
544 return HasThousandsGrouping;
546 const OptionalFlag &isLeftJustified() const { return IsLeftJustified; }
547 const OptionalFlag &hasPlusPrefix() const { return HasPlusPrefix; }
548 const OptionalFlag &hasAlternativeForm() const { return HasAlternativeForm; }
549 const OptionalFlag &hasLeadingZeros() const { return HasLeadingZeroes; }
550 const OptionalFlag &hasSpacePrefix() const { return HasSpacePrefix; }
551 const OptionalFlag &hasObjCTechnicalTerm() const { return HasObjCTechnicalTerm; }
552 const OptionalFlag &isPrivate() const { return IsPrivate; }
553 const OptionalFlag &isPublic() const { return IsPublic; }
554 bool usesPositionalArg() const { return UsesPositionalArg; }
556 /// Changes the specifier and length according to a QualType, retaining any
557 /// flags or options. Returns true on success, or false when a conversion
558 /// was not successful.
559 bool fixType(QualType QT, const LangOptions &LangOpt, ASTContext &Ctx,
562 void toString(raw_ostream &os) const;
564 // Validation methods - to check if any element results in undefined behavior
565 bool hasValidPlusPrefix() const;
566 bool hasValidAlternativeForm() const;
567 bool hasValidLeadingZeros() const;
568 bool hasValidSpacePrefix() const;
569 bool hasValidLeftJustified() const;
570 bool hasValidThousandsGroupingPrefix() const;
572 bool hasValidPrecision() const;
573 bool hasValidFieldWidth() const;
575 } // end analyze_printf namespace
577 //===----------------------------------------------------------------------===//
578 /// Pieces specific to fscanf format strings.
580 namespace analyze_scanf {
582 class ScanfConversionSpecifier :
583 public analyze_format_string::ConversionSpecifier {
585 ScanfConversionSpecifier()
586 : ConversionSpecifier(false, nullptr, InvalidSpecifier) {}
588 ScanfConversionSpecifier(const char *pos, Kind k)
589 : ConversionSpecifier(false, pos, k) {}
591 static bool classof(const analyze_format_string::ConversionSpecifier *CS) {
592 return !CS->isPrintfKind();
596 using analyze_format_string::ArgType;
597 using analyze_format_string::LengthModifier;
598 using analyze_format_string::OptionalAmount;
599 using analyze_format_string::OptionalFlag;
601 class ScanfSpecifier : public analyze_format_string::FormatSpecifier {
602 OptionalFlag SuppressAssignment; // '*'
605 FormatSpecifier(/* isPrintf = */ false),
606 SuppressAssignment("*") {}
608 void setSuppressAssignment(const char *position) {
609 SuppressAssignment.setPosition(position);
612 const OptionalFlag &getSuppressAssignment() const {
613 return SuppressAssignment;
616 void setConversionSpecifier(const ScanfConversionSpecifier &cs) {
620 const ScanfConversionSpecifier &getConversionSpecifier() const {
621 return cast<ScanfConversionSpecifier>(CS);
624 bool consumesDataArgument() const {
625 return CS.consumesDataArgument() && !SuppressAssignment;
628 ArgType getArgType(ASTContext &Ctx) const;
630 bool fixType(QualType QT, QualType RawQT, const LangOptions &LangOpt,
633 void toString(raw_ostream &os) const;
635 static ScanfSpecifier Parse(const char *beg, const char *end);
638 } // end analyze_scanf namespace
640 //===----------------------------------------------------------------------===//
641 // Parsing and processing of format strings (both fprintf and fscanf).
643 namespace analyze_format_string {
645 enum PositionContext { FieldWidthPos = 0, PrecisionPos = 1 };
647 class FormatStringHandler {
649 FormatStringHandler() {}
650 virtual ~FormatStringHandler();
652 virtual void HandleNullChar(const char *nullCharacter) {}
654 virtual void HandlePosition(const char *startPos, unsigned posLen) {}
656 virtual void HandleInvalidPosition(const char *startPos, unsigned posLen,
657 PositionContext p) {}
659 virtual void HandleZeroPosition(const char *startPos, unsigned posLen) {}
661 virtual void HandleIncompleteSpecifier(const char *startSpecifier,
662 unsigned specifierLen) {}
664 virtual void HandleEmptyObjCModifierFlag(const char *startFlags,
665 unsigned flagsLen) {}
667 virtual void HandleInvalidObjCModifierFlag(const char *startFlag,
670 virtual void HandleObjCFlagsWithNonObjCConversion(const char *flagsStart,
671 const char *flagsEnd,
672 const char *conversionPosition) {}
673 // Printf-specific handlers.
675 virtual bool HandleInvalidPrintfConversionSpecifier(
676 const analyze_printf::PrintfSpecifier &FS,
677 const char *startSpecifier,
678 unsigned specifierLen) {
682 virtual bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
683 const char *startSpecifier,
684 unsigned specifierLen) {
688 // Scanf-specific handlers.
690 virtual bool HandleInvalidScanfConversionSpecifier(
691 const analyze_scanf::ScanfSpecifier &FS,
692 const char *startSpecifier,
693 unsigned specifierLen) {
697 virtual bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
698 const char *startSpecifier,
699 unsigned specifierLen) {
703 virtual void HandleIncompleteScanList(const char *start, const char *end) {}
706 bool ParsePrintfString(FormatStringHandler &H,
707 const char *beg, const char *end, const LangOptions &LO,
708 const TargetInfo &Target, bool isFreeBSDKPrintf);
710 bool ParseFormatStringHasSArg(const char *beg, const char *end,
711 const LangOptions &LO, const TargetInfo &Target);
713 bool ParseScanfString(FormatStringHandler &H,
714 const char *beg, const char *end, const LangOptions &LO,
715 const TargetInfo &Target);
717 } // end analyze_format_string namespace
718 } // end clang namespace