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() { return flag; }
39 void set() { flag = true; }
40 void clear() { flag = false; }
41 void setPosition(const char *position) {
43 this->position = position;
45 const char *getPosition() const {
49 const char *toString() const { return representation; }
51 // Overloaded operators for bool like qualities
52 explicit operator bool() const { return flag; }
53 OptionalFlag& operator=(const bool &rhs) {
55 return *this; // Return a reference to myself.
58 const char *representation;
63 /// Represents the length modifier in a format string in scanf/printf.
64 class LengthModifier {
72 AsQuad, // 'q' (BSD, deprecated, for 64-bit integer types)
76 AsInt32, // 'I32' (MSVCRT, like __int32)
77 AsInt3264, // 'I' (MSVCRT, like __int3264 from MIDL)
78 AsInt64, // 'I64' (MSVCRT, like __int64)
80 AsAllocate, // for '%as', GNU extension to C90 scanf
81 AsMAllocate, // for '%ms', GNU extension to scanf
82 AsWide, // 'w' (MSVCRT, like l but only for c, C, s, S, or Z
83 AsWideChar = AsLong // for '%ls', only makes sense for printf
87 : Position(nullptr), kind(None) {}
88 LengthModifier(const char *pos, Kind k)
89 : Position(pos), kind(k) {}
91 const char *getStart() const {
95 unsigned getLength() const {
110 Kind getKind() const { return kind; }
111 void setKind(Kind k) { kind = k; }
113 const char *toString() const;
116 const char *Position;
120 class ConversionSpecifier {
123 InvalidSpecifier = 0,
124 // C99 conversion specifiers.
127 DArg, // Apple extension
129 IntArgBeg = dArg, IntArgEnd = iArg,
132 OArg, // Apple extension
134 UArg, // Apple extension
137 UIntArgBeg = oArg, UIntArgEnd = XArg,
147 DoubleArgBeg = fArg, DoubleArgEnd = AArg,
156 // ** Printf-specific **
158 ZArg, // MS extension
160 // Objective-C specific specifiers.
162 ObjCBeg = ObjCObjArg, ObjCEnd = ObjCObjArg,
164 // FreeBSD kernel specific specifiers.
170 // GlibC specific specifiers.
173 PrintfConvBeg = ObjCObjArg, PrintfConvEnd = PrintErrno,
175 // ** Scanf-specific **
177 ScanfConvBeg = ScanListArg, ScanfConvEnd = ScanListArg
180 ConversionSpecifier(bool isPrintf = true)
181 : IsPrintf(isPrintf), Position(nullptr), EndScanList(nullptr),
182 kind(InvalidSpecifier) {}
184 ConversionSpecifier(bool isPrintf, const char *pos, Kind k)
185 : IsPrintf(isPrintf), Position(pos), EndScanList(nullptr), kind(k) {}
187 const char *getStart() const {
191 StringRef getCharacters() const {
192 return StringRef(getStart(), getLength());
195 bool consumesDataArgument() const {
207 Kind getKind() const { return kind; }
208 void setKind(Kind k) { kind = k; }
209 unsigned getLength() const {
210 return EndScanList ? EndScanList - Position : 1;
213 bool isIntArg() const { return (kind >= IntArgBeg && kind <= IntArgEnd) ||
214 kind == FreeBSDrArg || kind == FreeBSDyArg; }
215 bool isUIntArg() const { return kind >= UIntArgBeg && kind <= UIntArgEnd; }
216 bool isAnyIntArg() const { return kind >= IntArgBeg && kind <= UIntArgEnd; }
217 const char *toString() const;
219 bool isPrintfKind() const { return IsPrintf; }
221 Optional<ConversionSpecifier> getStandardSpecifier() const;
225 const char *Position;
226 const char *EndScanList;
232 enum Kind { UnknownTy, InvalidTy, SpecificTy, ObjCPointerTy, CPointerTy,
233 AnyCharTy, CStrTy, WCStrTy, WIntTy };
235 enum MatchKind { NoMatch = 0, Match = 1, NoMatchPedantic };
243 ArgType(Kind k = UnknownTy, const char *n = nullptr)
244 : K(k), Name(n), Ptr(false) {}
245 ArgType(QualType t, const char *n = nullptr)
246 : K(SpecificTy), T(t), Name(n), Ptr(false) {}
247 ArgType(CanQualType t) : K(SpecificTy), T(t), Name(nullptr), Ptr(false) {}
249 static ArgType Invalid() { return ArgType(InvalidTy); }
250 bool isValid() const { return K != InvalidTy; }
252 /// Create an ArgType which corresponds to the type pointer to A.
253 static ArgType PtrTo(const ArgType& A) {
254 assert(A.K >= InvalidTy && "ArgType cannot be pointer to invalid/unknown");
260 MatchKind matchesType(ASTContext &C, QualType argTy) const;
262 QualType getRepresentativeType(ASTContext &C) const;
264 std::string getRepresentativeTypeName(ASTContext &C) const;
267 class OptionalAmount {
269 enum HowSpecified { NotSpecified, Constant, Arg, Invalid };
271 OptionalAmount(HowSpecified howSpecified,
273 const char *amountStart,
274 unsigned amountLength,
275 bool usesPositionalArg)
276 : start(amountStart), length(amountLength), hs(howSpecified), amt(amount),
277 UsesPositionalArg(usesPositionalArg), UsesDotPrefix(0) {}
279 OptionalAmount(bool valid = true)
280 : start(nullptr),length(0), hs(valid ? NotSpecified : Invalid), amt(0),
281 UsesPositionalArg(0), UsesDotPrefix(0) {}
283 bool isInvalid() const {
284 return hs == Invalid;
287 HowSpecified getHowSpecified() const { return hs; }
288 void setHowSpecified(HowSpecified h) { hs = h; }
290 bool hasDataArgument() const { return hs == Arg; }
292 unsigned getArgIndex() const {
293 assert(hasDataArgument());
297 unsigned getConstantAmount() const {
298 assert(hs == Constant);
302 const char *getStart() const {
303 // We include the . character if it is given.
304 return start - UsesDotPrefix;
307 unsigned getConstantLength() const {
308 assert(hs == Constant);
309 return length + UsesDotPrefix;
312 ArgType getArgType(ASTContext &Ctx) const;
314 void toString(raw_ostream &os) const;
316 bool usesPositionalArg() const { return (bool) UsesPositionalArg; }
317 unsigned getPositionalArgIndex() const {
318 assert(hasDataArgument());
322 bool usesDotPrefix() const { return UsesDotPrefix; }
323 void setUsesDotPrefix() { UsesDotPrefix = true; }
330 bool UsesPositionalArg : 1;
335 class FormatSpecifier {
338 OptionalAmount FieldWidth;
339 ConversionSpecifier CS;
340 /// Positional arguments, an IEEE extension:
341 /// IEEE Std 1003.1, 2004 Edition
342 /// http://www.opengroup.org/onlinepubs/009695399/functions/printf.html
343 bool UsesPositionalArg;
346 FormatSpecifier(bool isPrintf)
347 : CS(isPrintf), UsesPositionalArg(false), argIndex(0) {}
349 void setLengthModifier(LengthModifier lm) {
353 void setUsesPositionalArg() { UsesPositionalArg = true; }
355 void setArgIndex(unsigned i) {
359 unsigned getArgIndex() const {
363 unsigned getPositionalArgIndex() const {
367 const LengthModifier &getLengthModifier() const {
371 const OptionalAmount &getFieldWidth() const {
375 void setFieldWidth(const OptionalAmount &Amt) {
379 bool usesPositionalArg() const { return UsesPositionalArg; }
381 bool hasValidLengthModifier(const TargetInfo &Target) const;
383 bool hasStandardLengthModifier() const;
385 Optional<LengthModifier> getCorrectedLengthModifier() const;
387 bool hasStandardConversionSpecifier(const LangOptions &LangOpt) const;
389 bool hasStandardLengthConversionCombination() const;
391 /// For a TypedefType QT, if it is a named integer type such as size_t,
392 /// assign the appropriate value to LM and return true.
393 static bool namedTypeToLengthModifier(QualType QT, LengthModifier &LM);
396 } // end analyze_format_string namespace
398 //===----------------------------------------------------------------------===//
399 /// Pieces specific to fprintf format strings.
401 namespace analyze_printf {
403 class PrintfConversionSpecifier :
404 public analyze_format_string::ConversionSpecifier {
406 PrintfConversionSpecifier()
407 : ConversionSpecifier(true, nullptr, InvalidSpecifier) {}
409 PrintfConversionSpecifier(const char *pos, Kind k)
410 : ConversionSpecifier(true, pos, k) {}
412 bool isObjCArg() const { return kind >= ObjCBeg && kind <= ObjCEnd; }
413 bool isDoubleArg() const { return kind >= DoubleArgBeg &&
414 kind <= DoubleArgEnd; }
415 unsigned getLength() const {
416 // Conversion specifiers currently only are represented by
417 // single characters, but we be flexible.
421 static bool classof(const analyze_format_string::ConversionSpecifier *CS) {
422 return CS->isPrintfKind();
426 using analyze_format_string::ArgType;
427 using analyze_format_string::LengthModifier;
428 using analyze_format_string::OptionalAmount;
429 using analyze_format_string::OptionalFlag;
431 class PrintfSpecifier : public analyze_format_string::FormatSpecifier {
432 OptionalFlag HasThousandsGrouping; // ''', POSIX extension.
433 OptionalFlag IsLeftJustified; // '-'
434 OptionalFlag HasPlusPrefix; // '+'
435 OptionalFlag HasSpacePrefix; // ' '
436 OptionalFlag HasAlternativeForm; // '#'
437 OptionalFlag HasLeadingZeroes; // '0'
438 OptionalAmount Precision;
441 FormatSpecifier(/* isPrintf = */ true),
442 HasThousandsGrouping("'"), IsLeftJustified("-"), HasPlusPrefix("+"),
443 HasSpacePrefix(" "), HasAlternativeForm("#"), HasLeadingZeroes("0") {}
445 static PrintfSpecifier Parse(const char *beg, const char *end);
447 // Methods for incrementally constructing the PrintfSpecifier.
448 void setConversionSpecifier(const PrintfConversionSpecifier &cs) {
451 void setHasThousandsGrouping(const char *position) {
452 HasThousandsGrouping = true;
453 HasThousandsGrouping.setPosition(position);
455 void setIsLeftJustified(const char *position) {
456 IsLeftJustified = true;
457 IsLeftJustified.setPosition(position);
459 void setHasPlusPrefix(const char *position) {
460 HasPlusPrefix = true;
461 HasPlusPrefix.setPosition(position);
463 void setHasSpacePrefix(const char *position) {
464 HasSpacePrefix = true;
465 HasSpacePrefix.setPosition(position);
467 void setHasAlternativeForm(const char *position) {
468 HasAlternativeForm = true;
469 HasAlternativeForm.setPosition(position);
471 void setHasLeadingZeros(const char *position) {
472 HasLeadingZeroes = true;
473 HasLeadingZeroes.setPosition(position);
475 void setUsesPositionalArg() { UsesPositionalArg = true; }
477 // Methods for querying the format specifier.
479 const PrintfConversionSpecifier &getConversionSpecifier() const {
480 return cast<PrintfConversionSpecifier>(CS);
483 void setPrecision(const OptionalAmount &Amt) {
485 Precision.setUsesDotPrefix();
488 const OptionalAmount &getPrecision() const {
492 bool consumesDataArgument() const {
493 return getConversionSpecifier().consumesDataArgument();
496 /// \brief Returns the builtin type that a data argument
497 /// paired with this format specifier should have. This method
498 /// will return null if the format specifier does not have
499 /// a matching data argument or the matching argument matches
500 /// more than one type.
501 ArgType getArgType(ASTContext &Ctx, bool IsObjCLiteral) const;
503 const OptionalFlag &hasThousandsGrouping() const {
504 return HasThousandsGrouping;
506 const OptionalFlag &isLeftJustified() const { return IsLeftJustified; }
507 const OptionalFlag &hasPlusPrefix() const { return HasPlusPrefix; }
508 const OptionalFlag &hasAlternativeForm() const { return HasAlternativeForm; }
509 const OptionalFlag &hasLeadingZeros() const { return HasLeadingZeroes; }
510 const OptionalFlag &hasSpacePrefix() const { return HasSpacePrefix; }
511 bool usesPositionalArg() const { return UsesPositionalArg; }
513 /// Changes the specifier and length according to a QualType, retaining any
514 /// flags or options. Returns true on success, or false when a conversion
515 /// was not successful.
516 bool fixType(QualType QT, const LangOptions &LangOpt, ASTContext &Ctx,
519 void toString(raw_ostream &os) const;
521 // Validation methods - to check if any element results in undefined behavior
522 bool hasValidPlusPrefix() const;
523 bool hasValidAlternativeForm() const;
524 bool hasValidLeadingZeros() const;
525 bool hasValidSpacePrefix() const;
526 bool hasValidLeftJustified() const;
527 bool hasValidThousandsGroupingPrefix() const;
529 bool hasValidPrecision() const;
530 bool hasValidFieldWidth() const;
532 } // end analyze_printf namespace
534 //===----------------------------------------------------------------------===//
535 /// Pieces specific to fscanf format strings.
537 namespace analyze_scanf {
539 class ScanfConversionSpecifier :
540 public analyze_format_string::ConversionSpecifier {
542 ScanfConversionSpecifier()
543 : ConversionSpecifier(false, nullptr, InvalidSpecifier) {}
545 ScanfConversionSpecifier(const char *pos, Kind k)
546 : ConversionSpecifier(false, pos, k) {}
548 void setEndScanList(const char *pos) { EndScanList = pos; }
550 static bool classof(const analyze_format_string::ConversionSpecifier *CS) {
551 return !CS->isPrintfKind();
555 using analyze_format_string::ArgType;
556 using analyze_format_string::LengthModifier;
557 using analyze_format_string::OptionalAmount;
558 using analyze_format_string::OptionalFlag;
560 class ScanfSpecifier : public analyze_format_string::FormatSpecifier {
561 OptionalFlag SuppressAssignment; // '*'
564 FormatSpecifier(/* isPrintf = */ false),
565 SuppressAssignment("*") {}
567 void setSuppressAssignment(const char *position) {
568 SuppressAssignment = true;
569 SuppressAssignment.setPosition(position);
572 const OptionalFlag &getSuppressAssignment() const {
573 return SuppressAssignment;
576 void setConversionSpecifier(const ScanfConversionSpecifier &cs) {
580 const ScanfConversionSpecifier &getConversionSpecifier() const {
581 return cast<ScanfConversionSpecifier>(CS);
584 bool consumesDataArgument() const {
585 return CS.consumesDataArgument() && !SuppressAssignment;
588 ArgType getArgType(ASTContext &Ctx) const;
590 bool fixType(QualType QT, QualType RawQT, const LangOptions &LangOpt,
593 void toString(raw_ostream &os) const;
595 static ScanfSpecifier Parse(const char *beg, const char *end);
598 } // end analyze_scanf namespace
600 //===----------------------------------------------------------------------===//
601 // Parsing and processing of format strings (both fprintf and fscanf).
603 namespace analyze_format_string {
605 enum PositionContext { FieldWidthPos = 0, PrecisionPos = 1 };
607 class FormatStringHandler {
609 FormatStringHandler() {}
610 virtual ~FormatStringHandler();
612 virtual void HandleNullChar(const char *nullCharacter) {}
614 virtual void HandlePosition(const char *startPos, unsigned posLen) {}
616 virtual void HandleInvalidPosition(const char *startPos, unsigned posLen,
617 PositionContext p) {}
619 virtual void HandleZeroPosition(const char *startPos, unsigned posLen) {}
621 virtual void HandleIncompleteSpecifier(const char *startSpecifier,
622 unsigned specifierLen) {}
624 // Printf-specific handlers.
626 virtual bool HandleInvalidPrintfConversionSpecifier(
627 const analyze_printf::PrintfSpecifier &FS,
628 const char *startSpecifier,
629 unsigned specifierLen) {
633 virtual bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
634 const char *startSpecifier,
635 unsigned specifierLen) {
639 // Scanf-specific handlers.
641 virtual bool HandleInvalidScanfConversionSpecifier(
642 const analyze_scanf::ScanfSpecifier &FS,
643 const char *startSpecifier,
644 unsigned specifierLen) {
648 virtual bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
649 const char *startSpecifier,
650 unsigned specifierLen) {
654 virtual void HandleIncompleteScanList(const char *start, const char *end) {}
657 bool ParsePrintfString(FormatStringHandler &H,
658 const char *beg, const char *end, const LangOptions &LO,
659 const TargetInfo &Target, bool isFreeBSDKPrintf);
661 bool ParseFormatStringHasSArg(const char *beg, const char *end,
662 const LangOptions &LO, const TargetInfo &Target);
664 bool ParseScanfString(FormatStringHandler &H,
665 const char *beg, const char *end, const LangOptions &LO,
666 const TargetInfo &Target);
668 } // end analyze_format_string namespace
669 } // end clang namespace