Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//= FormatString.h - Analysis of printf/fprintf format strings --*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file defines APIs for analyzing the format strings of printf, fscanf,

// and friends.

//

// The structure of format strings for fprintf are described in C99 7.19.6.1.

//

// The structure of format strings for fscanf are described in C99 7.19.6.2.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_FORMATSTRING_H

#define LLVM_CLANG_AST_FORMATSTRING_H

#include "clang/AST/CanonicalType.h"

#include <optional>

namespace clang {

class TargetInfo;

//===----------------------------------------------------------------------===//

/// Common components of both fprintf and fscanf format strings.

namespace analyze_format_string {

/// Class representing optional flags with location and representation

/// information.

class OptionalFlag {

public:

  OptionalFlag(const char *Representation)

      : representation(Representation), flag(false) {}

  bool isSet() const { return flag; }

  void set() { flag = true; }

  void clear() { flag = false; }

  void setPosition(const char *position) {

    assert(position);

    flag = true;

    this->position = position;

  }

  const char *getPosition() const {

    assert(position);

    return position;

  }

  const char *toString() const { return representation; }

  // Overloaded operators for bool like qualities

  explicit operator bool() const { return flag; }

  OptionalFlag& operator=(const bool &rhs) {

    flag = rhs;

    return *this;  // Return a reference to myself.

  }

private:

  const char *representation;

  const char *position;

  bool flag;

};

/// Represents the length modifier in a format string in scanf/printf.

class LengthModifier {

public:

  enum Kind {

    None,

    AsChar,       // 'hh'

    AsShort,      // 'h'

    AsShortLong,  // 'hl' (OpenCL float/int vector element)

    AsLong,       // 'l'

    AsLongLong,   // 'll'

    AsQuad,       // 'q' (BSD, deprecated, for 64-bit integer types)

    AsIntMax,     // 'j'

    AsSizeT,      // 'z'

    AsPtrDiff,    // 't'

    AsInt32,      // 'I32' (MSVCRT, like __int32)

    AsInt3264,    // 'I'   (MSVCRT, like __int3264 from MIDL)

    AsInt64,      // 'I64' (MSVCRT, like __int64)

    AsLongDouble, // 'L'

    AsAllocate,   // for '%as', GNU extension to C90 scanf

    AsMAllocate,  // for '%ms', GNU extension to scanf

    AsWide,       // 'w' (MSVCRT, like l but only for c, C, s, S, or Z

    AsWideChar = AsLong // for '%ls', only makes sense for printf

  };

  LengthModifier()

    : Position(nullptr), kind(None) {}

  LengthModifier(const char *pos, Kind k)

    : Position(pos), kind(k) {}

  const char *getStart() const {

    return Position;

  }

  unsigned getLength() const {

    switch (kind) {

      default:

        return 1;

      case AsLongLong:

      case AsChar:

        return 2;

      case AsInt32:

      case AsInt64:

        return 3;

      case None:

        return 0;

    }

  }

  Kind getKind() const { return kind; }

  void setKind(Kind k) { kind = k; }

  const char *toString() const;

private:

  const char *Position;

  Kind kind;

};

class ConversionSpecifier {

public:

  enum Kind {

    InvalidSpecifier = 0,

    // C99 conversion specifiers.

    cArg,

    dArg,

    DArg, // Apple extension

    iArg,

    // C23 conversion specifiers.

    bArg,

    BArg,

    IntArgBeg = dArg,

    IntArgEnd = BArg,

    oArg,

    OArg, // Apple extension

    uArg,

    UArg, // Apple extension

    xArg,

    XArg,

    UIntArgBeg = oArg,

    UIntArgEnd = XArg,

    fArg,

    FArg,

    eArg,

    EArg,

    gArg,

    GArg,

    aArg,

    AArg,

    DoubleArgBeg = fArg,

    DoubleArgEnd = AArg,

    sArg,

    pArg,

    nArg,

    PercentArg,

    CArg,

    SArg,

    // Apple extension: P specifies to os_log that the data being pointed to is

    // to be copied by os_log. The precision indicates the number of bytes to

    // copy.

    PArg,

    // ** Printf-specific **

    ZArg, // MS extension

    // Objective-C specific specifiers.

    ObjCObjArg, // '@'

    ObjCBeg = ObjCObjArg,

    ObjCEnd = ObjCObjArg,

    // FreeBSD kernel specific specifiers.

    FreeBSDbArg,

    FreeBSDDArg,

    FreeBSDrArg,

    FreeBSDyArg,

    // GlibC specific specifiers.

    PrintErrno, // 'm'

    PrintfConvBeg = ObjCObjArg,

    PrintfConvEnd = PrintErrno,

    // ** Scanf-specific **

    ScanListArg, // '['

    ScanfConvBeg = ScanListArg,

    ScanfConvEnd = ScanListArg

  };

  ConversionSpecifier(bool isPrintf = true)

    : IsPrintf(isPrintf), Position(nullptr), EndScanList(nullptr),

      kind(InvalidSpecifier) {}

  ConversionSpecifier(bool isPrintf, const char *pos, Kind k)

    : IsPrintf(isPrintf), Position(pos), EndScanList(nullptr), kind(k) {}

  const char *getStart() const {

    return Position;

  }

  StringRef getCharacters() const {

    return StringRef(getStart(), getLength());

  }

  bool consumesDataArgument() const {

    switch (kind) {

      case PrintErrno:

        assert(IsPrintf);

        return false;

      case PercentArg:

        return false;

      case InvalidSpecifier:

        return false;

      default:

        return true;

    }

  }

  Kind getKind() const { return kind; }

  void setKind(Kind k) { kind = k; }

  unsigned getLength() const {

    return EndScanList ? EndScanList - Position : 1;

  }

  void setEndScanList(const char *pos) { EndScanList = pos; }

  bool isIntArg() const { return (kind >= IntArgBeg && kind <= IntArgEnd) ||

    kind == FreeBSDrArg || kind == FreeBSDyArg; }

  bool isUIntArg() const { return kind >= UIntArgBeg && kind <= UIntArgEnd; }

  bool isAnyIntArg() const { return kind >= IntArgBeg && kind <= UIntArgEnd; }

  bool isDoubleArg() const {

    return kind >= DoubleArgBeg && kind <= DoubleArgEnd;

  }

  const char *toString() const;

  bool isPrintfKind() const { return IsPrintf; }

  std::optional<ConversionSpecifier> getStandardSpecifier() const;

protected:

  bool IsPrintf;

  const char *Position;

  const char *EndScanList;

  Kind kind;

};

class ArgType {

public:

  enum Kind { UnknownTy, InvalidTy, SpecificTy, ObjCPointerTy, CPointerTy,

              AnyCharTy, CStrTy, WCStrTy, WIntTy };

  /// How well a given conversion specifier matches its argument.

  enum MatchKind {

    /// The conversion specifier and the argument types are incompatible. For

    /// instance, "%d" and float.

    NoMatch = 0,

    /// The conversion specifier and the argument type are compatible. For

    /// instance, "%d" and int.

    Match = 1,

    /// The conversion specifier and the argument type are compatible because of

    /// default argument promotions. For instance, "%hhd" and int.

    MatchPromotion,

    /// The conversion specifier and the argument type are compatible but still

    /// seems likely to be an error. For instanace, "%hhd" and short.

    NoMatchPromotionTypeConfusion,

    /// The conversion specifier and the argument type are disallowed by the C

    /// standard, but are in practice harmless. For instance, "%p" and int*.

    NoMatchPedantic,

    /// The conversion specifier and the argument type are compatible, but still

    /// seems likely to be an error. For instance, "%hd" and _Bool.

    NoMatchTypeConfusion,

  };

private:

  const Kind K;

  QualType T;

  const char *Name = nullptr;

  bool Ptr = false;

  /// The TypeKind identifies certain well-known types like size_t and

  /// ptrdiff_t.

  enum class TypeKind { DontCare, SizeT, PtrdiffT };

  TypeKind TK = TypeKind::DontCare;

public:

  ArgType(Kind K = UnknownTy, const char *N = nullptr) : K(K), Name(N) {}

  ArgType(QualType T, const char *N = nullptr) : K(SpecificTy), T(T), Name(N) {}

  ArgType(CanQualType T) : K(SpecificTy), T(T) {}

  static ArgType Invalid() { return ArgType(InvalidTy); }

  bool isValid() const { return K != InvalidTy; }

  bool isSizeT() const { return TK == TypeKind::SizeT; }

  bool isPtrdiffT() const { return TK == TypeKind::PtrdiffT; }

  /// Create an ArgType which corresponds to the type pointer to A.

  static ArgType PtrTo(const ArgType& A) {

    assert(A.K >= InvalidTy && "ArgType cannot be pointer to invalid/unknown");

    ArgType Res = A;

    Res.Ptr = true;

    return Res;

  }

  /// Create an ArgType which corresponds to the size_t/ssize_t type.

  static ArgType makeSizeT(const ArgType &A) {

    ArgType Res = A;

    Res.TK = TypeKind::SizeT;

    return Res;

  }

  /// Create an ArgType which corresponds to the ptrdiff_t/unsigned ptrdiff_t

  /// type.

  static ArgType makePtrdiffT(const ArgType &A) {

    ArgType Res = A;

    Res.TK = TypeKind::PtrdiffT;

    return Res;

  }

  MatchKind matchesType(ASTContext &C, QualType argTy) const;

  QualType getRepresentativeType(ASTContext &C) const;

  ArgType makeVectorType(ASTContext &C, unsigned NumElts) const;

  std::string getRepresentativeTypeName(ASTContext &C) const;

};

class OptionalAmount {

public:

  enum HowSpecified { NotSpecified, Constant, Arg, Invalid };

  OptionalAmount(HowSpecified howSpecified,

                 unsigned amount,

                 const char *amountStart,

                 unsigned amountLength,

                 bool usesPositionalArg)

  : start(amountStart), length(amountLength), hs(howSpecified), amt(amount),

  UsesPositionalArg(usesPositionalArg), UsesDotPrefix(false) {}

  OptionalAmount(bool valid = true)

  : start(nullptr),length(0), hs(valid ? NotSpecified : Invalid), amt(0),

  UsesPositionalArg(false), UsesDotPrefix(false) {}

  explicit OptionalAmount(unsigned Amount)

    : start(nullptr), length(0), hs(Constant), amt(Amount),

    UsesPositionalArg(false), UsesDotPrefix(false) {}

  bool isInvalid() const {

    return hs == Invalid;

  }

  HowSpecified getHowSpecified() const { return hs; }

  void setHowSpecified(HowSpecified h) { hs = h; }

  bool hasDataArgument() const { return hs == Arg; }

  unsigned getArgIndex() const {

    assert(hasDataArgument());

    return amt;

  }

  unsigned getConstantAmount() const {

    assert(hs == Constant);

    return amt;

  }

  const char *getStart() const {

      // We include the . character if it is given.

    return start - UsesDotPrefix;

  }

  unsigned getConstantLength() const {

    assert(hs == Constant);

    return length + UsesDotPrefix;

  }

  ArgType getArgType(ASTContext &Ctx) const;

  void toString(raw_ostream &os) const;

  bool usesPositionalArg() const { return (bool) UsesPositionalArg; }

  unsigned getPositionalArgIndex() const {

    assert(hasDataArgument());

    return amt + 1;

  }

  bool usesDotPrefix() const { return UsesDotPrefix; }

  void setUsesDotPrefix() { UsesDotPrefix = true; }

private:

  const char *start;

  unsigned length;

  HowSpecified hs;

  unsigned amt;

  bool UsesPositionalArg : 1;

  bool UsesDotPrefix;

};

class FormatSpecifier {

protected:

  LengthModifier LM;

  OptionalAmount FieldWidth;

  ConversionSpecifier CS;

  OptionalAmount VectorNumElts;

  /// Positional arguments, an IEEE extension:

  ///  IEEE Std 1003.1, 2004 Edition

  ///  http://www.opengroup.org/onlinepubs/009695399/functions/printf.html

  bool UsesPositionalArg;

  unsigned argIndex;

public:

  FormatSpecifier(bool isPrintf)

    : CS(isPrintf), VectorNumElts(false),

      UsesPositionalArg(false), argIndex(0) {}

  void setLengthModifier(LengthModifier lm) {

    LM = lm;

  }

  void setUsesPositionalArg() { UsesPositionalArg = true; }

  void setArgIndex(unsigned i) {

    argIndex = i;

  }

  unsigned getArgIndex() const {

    return argIndex;

  }

  unsigned getPositionalArgIndex() const {

    return argIndex + 1;

  }

  const LengthModifier &getLengthModifier() const {

    return LM;

  }

  const OptionalAmount &getFieldWidth() const {

    return FieldWidth;

  }

  void setVectorNumElts(const OptionalAmount &Amt) {

    VectorNumElts = Amt;

  }

  const OptionalAmount &getVectorNumElts() const {

    return VectorNumElts;

  }

  void setFieldWidth(const OptionalAmount &Amt) {

    FieldWidth = Amt;

  }

  bool usesPositionalArg() const { return UsesPositionalArg; }

  bool hasValidLengthModifier(const TargetInfo &Target,

                              const LangOptions &LO) const;

  bool hasStandardLengthModifier() const;

  std::optional<LengthModifier> getCorrectedLengthModifier() const;

  bool hasStandardConversionSpecifier(const LangOptions &LangOpt) const;

  bool hasStandardLengthConversionCombination() const;

  /// For a TypedefType QT, if it is a named integer type such as size_t,

  /// assign the appropriate value to LM and return true.

  static bool namedTypeToLengthModifier(QualType QT, LengthModifier &LM);

};

} // end analyze_format_string namespace

//===----------------------------------------------------------------------===//

/// Pieces specific to fprintf format strings.

namespace analyze_printf {

class PrintfConversionSpecifier :

  public analyze_format_string::ConversionSpecifier  {

public:

  PrintfConversionSpecifier()

    : ConversionSpecifier(true, nullptr, InvalidSpecifier) {}

  PrintfConversionSpecifier(const char *pos, Kind k)

    : ConversionSpecifier(true, pos, k) {}

  bool isObjCArg() const { return kind >= ObjCBeg && kind <= ObjCEnd; }

  bool isDoubleArg() const { return kind >= DoubleArgBeg &&

                                    kind <= DoubleArgEnd; }

  static bool classof(const analyze_format_string::ConversionSpecifier *CS) {

    return CS->isPrintfKind();

  }

};

using analyze_format_string::ArgType;

using analyze_format_string::LengthModifier;

using analyze_format_string::OptionalAmount;

using analyze_format_string::OptionalFlag;

class PrintfSpecifier : public analyze_format_string::FormatSpecifier {

  OptionalFlag HasThousandsGrouping; // ''', POSIX extension.

  OptionalFlag IsLeftJustified; // '-'

  OptionalFlag HasPlusPrefix; // '+'

  OptionalFlag HasSpacePrefix; // ' '

  OptionalFlag HasAlternativeForm; // '#'

  OptionalFlag HasLeadingZeroes; // '0'

  OptionalFlag HasObjCTechnicalTerm; // '[tt]'

  OptionalFlag IsPrivate;            // '{private}'

  OptionalFlag IsPublic;             // '{public}'

  OptionalFlag IsSensitive;          // '{sensitive}'

  OptionalAmount Precision;

  StringRef MaskType;

  ArgType getScalarArgType(ASTContext &Ctx, bool IsObjCLiteral) const;

public:

  PrintfSpecifier()

      : FormatSpecifier(/* isPrintf = */ true), HasThousandsGrouping("'"),

        IsLeftJustified("-"), HasPlusPrefix("+"), HasSpacePrefix(" "),

        HasAlternativeForm("#"), HasLeadingZeroes("0"),

        HasObjCTechnicalTerm("tt"), IsPrivate("private"), IsPublic("public"),

        IsSensitive("sensitive") {}

  static PrintfSpecifier Parse(const char *beg, const char *end);

    // Methods for incrementally constructing the PrintfSpecifier.

  void setConversionSpecifier(const PrintfConversionSpecifier &cs) {

    CS = cs;

  }

  void setHasThousandsGrouping(const char *position) {

    HasThousandsGrouping.setPosition(position);

  }

  void setIsLeftJustified(const char *position) {

    IsLeftJustified.setPosition(position);

  }

  void setHasPlusPrefix(const char *position) {

    HasPlusPrefix.setPosition(position);

  }

  void setHasSpacePrefix(const char *position) {

    HasSpacePrefix.setPosition(position);

  }

  void setHasAlternativeForm(const char *position) {

    HasAlternativeForm.setPosition(position);

  }

  void setHasLeadingZeros(const char *position) {

    HasLeadingZeroes.setPosition(position);

  }

  void setHasObjCTechnicalTerm(const char *position) {

    HasObjCTechnicalTerm.setPosition(position);

  }

  void setIsPrivate(const char *position) { IsPrivate.setPosition(position); }

  void setIsPublic(const char *position) { IsPublic.setPosition(position); }

  void setIsSensitive(const char *position) {

    IsSensitive.setPosition(position);

  }

  void setUsesPositionalArg() { UsesPositionalArg = true; }

    // Methods for querying the format specifier.

  const PrintfConversionSpecifier &getConversionSpecifier() const {

    return cast<PrintfConversionSpecifier>(CS);

  }

  void setPrecision(const OptionalAmount &Amt) {

    Precision = Amt;

    Precision.setUsesDotPrefix();

  }

  const OptionalAmount &getPrecision() const {

    return Precision;

  }

  bool consumesDataArgument() const {

    return getConversionSpecifier().consumesDataArgument();

  }

  /// Returns the builtin type that a data argument

  /// paired with this format specifier should have.  This method

  /// will return null if the format specifier does not have

  /// a matching data argument or the matching argument matches

  /// more than one type.

  ArgType getArgType(ASTContext &Ctx, bool IsObjCLiteral) const;

  const OptionalFlag &hasThousandsGrouping() const {

      return HasThousandsGrouping;

  }

  const OptionalFlag &isLeftJustified() const { return IsLeftJustified; }

  const OptionalFlag &hasPlusPrefix() const { return HasPlusPrefix; }

  const OptionalFlag &hasAlternativeForm() const { return HasAlternativeForm; }

  const OptionalFlag &hasLeadingZeros() const { return HasLeadingZeroes; }

  const OptionalFlag &hasSpacePrefix() const { return HasSpacePrefix; }

  const OptionalFlag &hasObjCTechnicalTerm() const { return HasObjCTechnicalTerm; }

  const OptionalFlag &isPrivate() const { return IsPrivate; }

  const OptionalFlag &isPublic() const { return IsPublic; }

  const OptionalFlag &isSensitive() const { return IsSensitive; }

  bool usesPositionalArg() const { return UsesPositionalArg; }

  StringRef getMaskType() const { return MaskType; }

  void setMaskType(StringRef S) { MaskType = S; }

  /// Changes the specifier and length according to a QualType, retaining any

  /// flags or options. Returns true on success, or false when a conversion

  /// was not successful.

  bool fixType(QualType QT, const LangOptions &LangOpt, ASTContext &Ctx,

               bool IsObjCLiteral);

  void toString(raw_ostream &os) const;

  // Validation methods - to check if any element results in undefined behavior

  bool hasValidPlusPrefix() const;

  bool hasValidAlternativeForm() const;

  bool hasValidLeadingZeros() const;

  bool hasValidSpacePrefix() const;

  bool hasValidLeftJustified() const;

  bool hasValidThousandsGroupingPrefix() const;

  bool hasValidPrecision() const;

  bool hasValidFieldWidth() const;

};

}  // end analyze_printf namespace

//===----------------------------------------------------------------------===//

/// Pieces specific to fscanf format strings.

namespace analyze_scanf {

class ScanfConversionSpecifier :

    public analyze_format_string::ConversionSpecifier  {

public:

  ScanfConversionSpecifier()

    : ConversionSpecifier(false, nullptr, InvalidSpecifier) {}

  ScanfConversionSpecifier(const char *pos, Kind k)

    : ConversionSpecifier(false, pos, k) {}

  static bool classof(const analyze_format_string::ConversionSpecifier *CS) {

    return !CS->isPrintfKind();

  }

};

using analyze_format_string::ArgType;

using analyze_format_string::LengthModifier;

using analyze_format_string::OptionalAmount;

using analyze_format_string::OptionalFlag;

class ScanfSpecifier : public analyze_format_string::FormatSpecifier {

  OptionalFlag SuppressAssignment; // '*'

public:

  ScanfSpecifier() :

    FormatSpecifier(/* isPrintf = */ false),

    SuppressAssignment("*") {}

  void setSuppressAssignment(const char *position) {

    SuppressAssignment.setPosition(position);

  }

  const OptionalFlag &getSuppressAssignment() const {

    return SuppressAssignment;

  }

  void setConversionSpecifier(const ScanfConversionSpecifier &cs) {

    CS = cs;

  }

  const ScanfConversionSpecifier &getConversionSpecifier() const {

    return cast<ScanfConversionSpecifier>(CS);

  }

  bool consumesDataArgument() const {

    return CS.consumesDataArgument() && !SuppressAssignment;

  }

  ArgType getArgType(ASTContext &Ctx) const;

  bool fixType(QualType QT, QualType RawQT, const LangOptions &LangOpt,

               ASTContext &Ctx);

  void toString(raw_ostream &os) const;

  static ScanfSpecifier Parse(const char *beg, const char *end);

};

} // end analyze_scanf namespace

//===----------------------------------------------------------------------===//

// Parsing and processing of format strings (both fprintf and fscanf).

namespace analyze_format_string {

enum PositionContext { FieldWidthPos = 0, PrecisionPos = 1 };

class FormatStringHandler {

public:

  FormatStringHandler() {}

  virtual ~FormatStringHandler();

  virtual void HandleNullChar(const char *nullCharacter) {}

  virtual void HandlePosition(const char *startPos, unsigned posLen) {}

  virtual void HandleInvalidPosition(const char *startPos, unsigned posLen,

                                     PositionContext p) {}

  virtual void HandleZeroPosition(const char *startPos, unsigned posLen) {}

  virtual void HandleIncompleteSpecifier(const char *startSpecifier,

                                         unsigned specifierLen) {}

  virtual void HandleEmptyObjCModifierFlag(const char *startFlags,

                                           unsigned flagsLen) {}

  virtual void HandleInvalidObjCModifierFlag(const char *startFlag,

                                             unsigned flagLen) {}

  virtual void HandleObjCFlagsWithNonObjCConversion(const char *flagsStart,

                                            const char *flagsEnd,

                                            const char *conversionPosition) {}

  // Printf-specific handlers.

  virtual bool HandleInvalidPrintfConversionSpecifier(

                                      const analyze_printf::PrintfSpecifier &FS,

                                      const char *startSpecifier,

                                      unsigned specifierLen) {

    return true;

  }

  virtual bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,

                                     const char *startSpecifier,

                                     unsigned specifierLen,

                                     const TargetInfo &Target) {

    return true;

  }

  /// Handle mask types whose sizes are not between one and eight bytes.

  virtual void handleInvalidMaskType(StringRef MaskType) {}

    // Scanf-specific handlers.

  virtual bool HandleInvalidScanfConversionSpecifier(

                                        const analyze_scanf::ScanfSpecifier &FS,

                                        const char *startSpecifier,

                                        unsigned specifierLen) {

    return true;

  }

  virtual bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,

                                    const char *startSpecifier,

                                    unsigned specifierLen) {

    return true;

  }

  virtual void HandleIncompleteScanList(const char *start, const char *end) {}

};

bool ParsePrintfString(FormatStringHandler &H,

                       const char *beg, const char *end, const LangOptions &LO,

                       const TargetInfo &Target, bool isFreeBSDKPrintf);

bool ParseFormatStringHasSArg(const char *beg, const char *end,

                              const LangOptions &LO, const TargetInfo &Target);

bool ParseScanfString(FormatStringHandler &H,

                      const char *beg, const char *end, const LangOptions &LO,

                      const TargetInfo &Target);

/// Return true if the given string has at least one formatting specifier.

bool parseFormatStringHasFormattingSpecifiers(const char *Begin,

                                              const char *End,

                                              const LangOptions &LO,

                                              const TargetInfo &Target);

} // end analyze_format_string namespace

} // end clang namespace

#endif