1 // FormatString.cpp - Common stuff for handling printf/scanf formats -*- 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 // Shared details for processing format strings of printf and scanf
13 //===----------------------------------------------------------------------===//
15 #include "FormatStringParsing.h"
16 #include "clang/Basic/LangOptions.h"
17 #include "clang/Basic/TargetInfo.h"
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;
28 // Key function to FormatStringHandler.
29 FormatStringHandler::~FormatStringHandler() {}
31 //===----------------------------------------------------------------------===//
32 // Functions for parsing format strings components in both printf and
33 // scanf format strings.
34 //===----------------------------------------------------------------------===//
37 clang::analyze_format_string::ParseAmount(const char *&Beg, const char *E) {
39 UpdateOnReturn <const char*> UpdateBeg(Beg, I);
41 unsigned accumulator = 0;
42 bool hasDigits = false;
44 for ( ; I != E; ++I) {
46 if (c >= '0' && c <= '9') {
48 accumulator = (accumulator * 10) + (c - '0');
53 return OptionalAmount(OptionalAmount::Constant, accumulator, Beg, I - Beg,
59 return OptionalAmount();
63 clang::analyze_format_string::ParseNonPositionAmount(const char *&Beg,
68 return OptionalAmount(OptionalAmount::Arg, argIndex++, Beg, 0, false);
71 return ParseAmount(Beg, E);
75 clang::analyze_format_string::ParsePositionAmount(FormatStringHandler &H,
81 const char *I = Beg + 1;
82 const OptionalAmount &Amt = ParseAmount(I, E);
84 if (Amt.getHowSpecified() == OptionalAmount::NotSpecified) {
85 H.HandleInvalidPosition(Beg, I - Beg, p);
86 return OptionalAmount(false);
90 // No more characters left?
91 H.HandleIncompleteSpecifier(Start, E - Start);
92 return OptionalAmount(false);
95 assert(Amt.getHowSpecified() == OptionalAmount::Constant);
98 // Handle positional arguments
100 // Special case: '*0$', since this is an easy mistake.
101 if (Amt.getConstantAmount() == 0) {
102 H.HandleZeroPosition(Beg, I - Beg + 1);
103 return OptionalAmount(false);
106 const char *Tmp = Beg;
109 return OptionalAmount(OptionalAmount::Arg, Amt.getConstantAmount() - 1,
113 H.HandleInvalidPosition(Beg, I - Beg, p);
114 return OptionalAmount(false);
117 return ParseAmount(Beg, E);
122 clang::analyze_format_string::ParseFieldWidth(FormatStringHandler &H,
125 const char *&Beg, const char *E,
126 unsigned *argIndex) {
127 // FIXME: Support negative field widths.
129 CS.setFieldWidth(ParseNonPositionAmount(Beg, E, *argIndex));
132 const OptionalAmount Amt =
133 ParsePositionAmount(H, Start, Beg, E,
134 analyze_format_string::FieldWidthPos);
138 CS.setFieldWidth(Amt);
144 clang::analyze_format_string::ParseArgPosition(FormatStringHandler &H,
151 const OptionalAmount &Amt = ParseAmount(I, E);
154 // No more characters left?
155 H.HandleIncompleteSpecifier(Start, E - Start);
159 if (Amt.getHowSpecified() == OptionalAmount::Constant && *(I++) == '$') {
160 // Warn that positional arguments are non-standard.
161 H.HandlePosition(Start, I - Start);
163 // Special case: '%0$', since this is an easy mistake.
164 if (Amt.getConstantAmount() == 0) {
165 H.HandleZeroPosition(Start, I - Start);
169 FS.setArgIndex(Amt.getConstantAmount() - 1);
170 FS.setUsesPositionalArg();
171 // Update the caller's pointer if we decided to consume
181 clang::analyze_format_string::ParseLengthModifier(FormatSpecifier &FS,
184 const LangOptions &LO,
186 LengthModifier::Kind lmKind = LengthModifier::None;
187 const char *lmPosition = I;
193 lmKind = (I != E && *I == 'h') ? (++I, LengthModifier::AsChar)
194 : LengthModifier::AsShort;
198 lmKind = (I != E && *I == 'l') ? (++I, LengthModifier::AsLongLong)
199 : LengthModifier::AsLong;
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;
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.
212 if (I != E && (*I == 's' || *I == 'S' || *I == '[')) {
213 lmKind = LengthModifier::AsAllocate;
221 lmKind = LengthModifier::AsMAllocate;
226 // printf: AsInt64, AsInt32, AsInt3264
229 if (I + 1 != E && I + 2 != E) {
230 if (I[1] == '6' && I[2] == '4') {
232 lmKind = LengthModifier::AsInt64;
238 if (I[1] == '3' && I[2] == '2') {
240 lmKind = LengthModifier::AsInt32;
245 lmKind = LengthModifier::AsInt3264;
248 lmKind = LengthModifier::AsWide; ++I; break;
250 LengthModifier lm(lmPosition, lmKind);
251 FS.setLengthModifier(lm);
255 //===----------------------------------------------------------------------===//
256 // Methods on ArgType.
257 //===----------------------------------------------------------------------===//
259 bool ArgType::matchesType(ASTContext &C, QualType argTy) const {
261 // It has to be a pointer.
262 const PointerType *PT = argTy->getAs<PointerType>();
266 // We cannot write through a const qualified pointer.
267 if (PT->getPointeeType().isConstQualified())
270 argTy = PT->getPointeeType();
275 llvm_unreachable("ArgType must be valid");
281 if (const EnumType *ETy = argTy->getAs<EnumType>())
282 argTy = ETy->getDecl()->getIntegerType();
284 if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
285 switch (BT->getKind()) {
288 case BuiltinType::Char_S:
289 case BuiltinType::SChar:
290 case BuiltinType::UChar:
291 case BuiltinType::Char_U:
298 if (const EnumType *ETy = argTy->getAs<EnumType>())
299 argTy = ETy->getDecl()->getIntegerType();
300 argTy = C.getCanonicalType(argTy).getUnqualifiedType();
304 // Check for "compatible types".
305 if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
306 switch (BT->getKind()) {
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:
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;
335 const PointerType *PT = argTy->getAs<PointerType>();
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:
355 const PointerType *PT = argTy->getAs<PointerType>();
359 C.getCanonicalType(PT->getPointeeType()).getUnqualifiedType();
360 return pointeeTy == C.getWideCharType();
366 argTy->isPromotableIntegerType()
367 ? C.getPromotedIntegerType(argTy) : argTy;
369 QualType WInt = C.getCanonicalType(C.getWIntType()).getUnqualifiedType();
370 PromoArg = C.getCanonicalType(PromoArg).getUnqualifiedType();
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)
378 return WInt == PromoArg;
382 return argTy->isPointerType() || argTy->isObjCObjectPointerType() ||
383 argTy->isBlockPointerType() || argTy->isNullPtrType();
385 case ObjCPointerTy: {
386 if (argTy->getAs<ObjCObjectPointerType>() ||
387 argTy->getAs<BlockPointerType>())
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())
404 llvm_unreachable("Invalid ArgType Kind!");
407 QualType ArgType::getRepresentativeType(ASTContext &C) const {
411 llvm_unreachable("No representative type for Invalid ArgType");
413 llvm_unreachable("No representative type for Unknown ArgType");
421 Res = C.getPointerType(C.CharTy);
424 Res = C.getPointerType(C.getWideCharType());
427 Res = C.ObjCBuiltinIdTy;
433 Res = C.getWIntType();
439 Res = C.getPointerType(Res);
443 std::string ArgType::getRepresentativeTypeName(ASTContext &C) const {
444 std::string S = getRepresentativeType(C).getAsString();
448 // Use a specific name for this type, e.g. "size_t".
451 // If ArgType is actually a pointer to T, append an asterisk.
452 Alias += (Alias[Alias.size()-1] == '*') ? "*" : " *";
454 // If Alias is the same as the underlying type, e.g. wchar_t, then drop it.
460 return std::string("'") + Alias + "' (aka '" + S + "')";
461 return std::string("'") + S + "'";
465 //===----------------------------------------------------------------------===//
466 // Methods on OptionalAmount.
467 //===----------------------------------------------------------------------===//
470 analyze_format_string::OptionalAmount::getArgType(ASTContext &Ctx) const {
474 //===----------------------------------------------------------------------===//
475 // Methods on LengthModifier.
476 //===----------------------------------------------------------------------===//
479 analyze_format_string::LengthModifier::toString() const {
485 case AsLong: // or AsWideChar
517 //===----------------------------------------------------------------------===//
518 // Methods on ConversionSpecifier.
519 //===----------------------------------------------------------------------===//
521 const char *ConversionSpecifier::toString() const {
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;
548 // POSIX unicode extensions.
549 case CArg: return "C";
550 case SArg: return "S";
552 // Objective-C specific specifiers.
553 case ObjCObjArg: return "@";
555 // FreeBSD kernel specific specifiers.
556 case FreeBSDbArg: return "b";
557 case FreeBSDDArg: return "D";
558 case FreeBSDrArg: return "r";
559 case FreeBSDyArg: return "y";
561 // GlibC specific specifiers.
562 case PrintErrno: return "m";
564 // MS specific specifiers.
565 case ZArg: return "Z";
570 Optional<ConversionSpecifier>
571 ConversionSpecifier::getStandardSpecifier() const {
572 ConversionSpecifier::Kind NewKind;
588 ConversionSpecifier FixedCS(*this);
589 FixedCS.setKind(NewKind);
593 //===----------------------------------------------------------------------===//
594 // Methods on OptionalAmount.
595 //===----------------------------------------------------------------------===//
597 void OptionalAmount::toString(raw_ostream &os) const {
605 if (usesPositionalArg())
606 os << "*" << getPositionalArgIndex() << "$";
618 bool FormatSpecifier::hasValidLengthModifier(const TargetInfo &Target) const {
619 switch (LM.getKind()) {
620 case LengthModifier::None:
623 // Handle most integer flags
624 case LengthModifier::AsShort:
625 if (Target.getTriple().isOSMSVCRT()) {
626 switch (CS.getKind()) {
627 case ConversionSpecifier::cArg:
628 case ConversionSpecifier::CArg:
629 case ConversionSpecifier::sArg:
630 case ConversionSpecifier::SArg:
631 case ConversionSpecifier::ZArg:
638 case LengthModifier::AsChar:
639 case LengthModifier::AsLongLong:
640 case LengthModifier::AsQuad:
641 case LengthModifier::AsIntMax:
642 case LengthModifier::AsSizeT:
643 case LengthModifier::AsPtrDiff:
644 switch (CS.getKind()) {
645 case ConversionSpecifier::dArg:
646 case ConversionSpecifier::DArg:
647 case ConversionSpecifier::iArg:
648 case ConversionSpecifier::oArg:
649 case ConversionSpecifier::OArg:
650 case ConversionSpecifier::uArg:
651 case ConversionSpecifier::UArg:
652 case ConversionSpecifier::xArg:
653 case ConversionSpecifier::XArg:
654 case ConversionSpecifier::nArg:
656 case ConversionSpecifier::FreeBSDrArg:
657 case ConversionSpecifier::FreeBSDyArg:
658 return Target.getTriple().isOSFreeBSD();
664 case LengthModifier::AsLong: // or AsWideChar
665 switch (CS.getKind()) {
666 case ConversionSpecifier::dArg:
667 case ConversionSpecifier::DArg:
668 case ConversionSpecifier::iArg:
669 case ConversionSpecifier::oArg:
670 case ConversionSpecifier::OArg:
671 case ConversionSpecifier::uArg:
672 case ConversionSpecifier::UArg:
673 case ConversionSpecifier::xArg:
674 case ConversionSpecifier::XArg:
675 case ConversionSpecifier::aArg:
676 case ConversionSpecifier::AArg:
677 case ConversionSpecifier::fArg:
678 case ConversionSpecifier::FArg:
679 case ConversionSpecifier::eArg:
680 case ConversionSpecifier::EArg:
681 case ConversionSpecifier::gArg:
682 case ConversionSpecifier::GArg:
683 case ConversionSpecifier::nArg:
684 case ConversionSpecifier::cArg:
685 case ConversionSpecifier::sArg:
686 case ConversionSpecifier::ScanListArg:
687 case ConversionSpecifier::ZArg:
689 case ConversionSpecifier::FreeBSDrArg:
690 case ConversionSpecifier::FreeBSDyArg:
691 return Target.getTriple().isOSFreeBSD();
696 case LengthModifier::AsLongDouble:
697 switch (CS.getKind()) {
698 case ConversionSpecifier::aArg:
699 case ConversionSpecifier::AArg:
700 case ConversionSpecifier::fArg:
701 case ConversionSpecifier::FArg:
702 case ConversionSpecifier::eArg:
703 case ConversionSpecifier::EArg:
704 case ConversionSpecifier::gArg:
705 case ConversionSpecifier::GArg:
707 // GNU libc extension.
708 case ConversionSpecifier::dArg:
709 case ConversionSpecifier::iArg:
710 case ConversionSpecifier::oArg:
711 case ConversionSpecifier::uArg:
712 case ConversionSpecifier::xArg:
713 case ConversionSpecifier::XArg:
714 return !Target.getTriple().isOSDarwin() &&
715 !Target.getTriple().isOSWindows();
720 case LengthModifier::AsAllocate:
721 switch (CS.getKind()) {
722 case ConversionSpecifier::sArg:
723 case ConversionSpecifier::SArg:
724 case ConversionSpecifier::ScanListArg:
730 case LengthModifier::AsMAllocate:
731 switch (CS.getKind()) {
732 case ConversionSpecifier::cArg:
733 case ConversionSpecifier::CArg:
734 case ConversionSpecifier::sArg:
735 case ConversionSpecifier::SArg:
736 case ConversionSpecifier::ScanListArg:
741 case LengthModifier::AsInt32:
742 case LengthModifier::AsInt3264:
743 case LengthModifier::AsInt64:
744 switch (CS.getKind()) {
745 case ConversionSpecifier::dArg:
746 case ConversionSpecifier::iArg:
747 case ConversionSpecifier::oArg:
748 case ConversionSpecifier::uArg:
749 case ConversionSpecifier::xArg:
750 case ConversionSpecifier::XArg:
751 return Target.getTriple().isOSMSVCRT();
755 case LengthModifier::AsWide:
756 switch (CS.getKind()) {
757 case ConversionSpecifier::cArg:
758 case ConversionSpecifier::CArg:
759 case ConversionSpecifier::sArg:
760 case ConversionSpecifier::SArg:
761 case ConversionSpecifier::ZArg:
762 return Target.getTriple().isOSMSVCRT();
767 llvm_unreachable("Invalid LengthModifier Kind!");
770 bool FormatSpecifier::hasStandardLengthModifier() const {
771 switch (LM.getKind()) {
772 case LengthModifier::None:
773 case LengthModifier::AsChar:
774 case LengthModifier::AsShort:
775 case LengthModifier::AsLong:
776 case LengthModifier::AsLongLong:
777 case LengthModifier::AsIntMax:
778 case LengthModifier::AsSizeT:
779 case LengthModifier::AsPtrDiff:
780 case LengthModifier::AsLongDouble:
782 case LengthModifier::AsAllocate:
783 case LengthModifier::AsMAllocate:
784 case LengthModifier::AsQuad:
785 case LengthModifier::AsInt32:
786 case LengthModifier::AsInt3264:
787 case LengthModifier::AsInt64:
788 case LengthModifier::AsWide:
791 llvm_unreachable("Invalid LengthModifier Kind!");
794 bool FormatSpecifier::hasStandardConversionSpecifier(const LangOptions &LangOpt) const {
795 switch (CS.getKind()) {
796 case ConversionSpecifier::cArg:
797 case ConversionSpecifier::dArg:
798 case ConversionSpecifier::iArg:
799 case ConversionSpecifier::oArg:
800 case ConversionSpecifier::uArg:
801 case ConversionSpecifier::xArg:
802 case ConversionSpecifier::XArg:
803 case ConversionSpecifier::fArg:
804 case ConversionSpecifier::FArg:
805 case ConversionSpecifier::eArg:
806 case ConversionSpecifier::EArg:
807 case ConversionSpecifier::gArg:
808 case ConversionSpecifier::GArg:
809 case ConversionSpecifier::aArg:
810 case ConversionSpecifier::AArg:
811 case ConversionSpecifier::sArg:
812 case ConversionSpecifier::pArg:
813 case ConversionSpecifier::nArg:
814 case ConversionSpecifier::ObjCObjArg:
815 case ConversionSpecifier::ScanListArg:
816 case ConversionSpecifier::PercentArg:
818 case ConversionSpecifier::CArg:
819 case ConversionSpecifier::SArg:
820 return LangOpt.ObjC1 || LangOpt.ObjC2;
821 case ConversionSpecifier::InvalidSpecifier:
822 case ConversionSpecifier::FreeBSDbArg:
823 case ConversionSpecifier::FreeBSDDArg:
824 case ConversionSpecifier::FreeBSDrArg:
825 case ConversionSpecifier::FreeBSDyArg:
826 case ConversionSpecifier::PrintErrno:
827 case ConversionSpecifier::DArg:
828 case ConversionSpecifier::OArg:
829 case ConversionSpecifier::UArg:
830 case ConversionSpecifier::ZArg:
833 llvm_unreachable("Invalid ConversionSpecifier Kind!");
836 bool FormatSpecifier::hasStandardLengthConversionCombination() const {
837 if (LM.getKind() == LengthModifier::AsLongDouble) {
838 switch(CS.getKind()) {
839 case ConversionSpecifier::dArg:
840 case ConversionSpecifier::iArg:
841 case ConversionSpecifier::oArg:
842 case ConversionSpecifier::uArg:
843 case ConversionSpecifier::xArg:
844 case ConversionSpecifier::XArg:
853 Optional<LengthModifier> FormatSpecifier::getCorrectedLengthModifier() const {
854 if (CS.isAnyIntArg() || CS.getKind() == ConversionSpecifier::nArg) {
855 if (LM.getKind() == LengthModifier::AsLongDouble ||
856 LM.getKind() == LengthModifier::AsQuad) {
857 LengthModifier FixedLM(LM);
858 FixedLM.setKind(LengthModifier::AsLongLong);
866 bool FormatSpecifier::namedTypeToLengthModifier(QualType QT,
867 LengthModifier &LM) {
868 assert(isa<TypedefType>(QT) && "Expected a TypedefType");
869 const TypedefNameDecl *Typedef = cast<TypedefType>(QT)->getDecl();
872 const IdentifierInfo *Identifier = Typedef->getIdentifier();
873 if (Identifier->getName() == "size_t") {
874 LM.setKind(LengthModifier::AsSizeT);
876 } else if (Identifier->getName() == "ssize_t") {
877 // Not C99, but common in Unix.
878 LM.setKind(LengthModifier::AsSizeT);
880 } else if (Identifier->getName() == "intmax_t") {
881 LM.setKind(LengthModifier::AsIntMax);
883 } else if (Identifier->getName() == "uintmax_t") {
884 LM.setKind(LengthModifier::AsIntMax);
886 } else if (Identifier->getName() == "ptrdiff_t") {
887 LM.setKind(LengthModifier::AsPtrDiff);
891 QualType T = Typedef->getUnderlyingType();
892 if (!isa<TypedefType>(T))
895 Typedef = cast<TypedefType>(T)->getDecl();