reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
  165
  166
  167
  168
  169
  170
  171
  172
  173
  174
  175
  176
  177
  178
  179
  180
  181
  182
  183
  184
  185
  186
  187
  188
  189
  190
  191
  192
  193
  194
  195
  196
  197
  198
  199
  200
  201
  202
  203
  204
  205
  206
  207
  208
  209
  210
  211
  212
  213
  214
  215
  216
  217
  218
  219
  220
  221
  222
  223
  224
  225
  226
  227
  228
  229
  230
  231
  232
  233
  234
  235
  236
  237
  238
  239
  240
  241
  242
  243
  244
  245
  246
  247
  248
  249
  250
  251
  252
  253
  254
  255
  256
  257
  258
  259
  260
  261
  262
  263
  264
  265
  266
  267
  268
  269
  270
  271
  272
  273
  274
  275
  276
  277
  278
  279
  280
  281
  282
  283
  284
  285
  286
  287
  288
  289
  290
  291
  292
  293
  294
  295
  296
  297
  298
  299
  300
  301
  302
  303
  304
  305
  306
  307
  308
  309
  310
  311
  312
  313
  314
  315
  316
  317
  318
  319
  320
  321
  322
  323
  324
  325
  326
  327
  328
  329
  330
  331
  332
  333
  334
  335
  336
  337
  338
  339
  340
  341
  342
  343
  344
  345
  346
  347
  348
  349
  350
  351
  352
  353
  354
  355
  356
  357
  358
  359
  360
  361
  362
  363
  364
  365
  366
  367
  368
  369
  370
  371
  372
  373
  374
  375
  376
  377
  378
  379
  380
  381
  382
  383
  384
  385
  386
  387
  388
  389
  390
  391
  392
  393
  394
  395
  396
  397
  398
  399
  400
  401
  402
  403
  404
  405
  406
  407
  408
  409
  410
  411
  412
  413
  414
  415
  416
  417
  418
  419
  420
  421
  422
  423
  424
  425
  426
  427
  428
  429
  430
  431
  432
  433
  434
  435
  436
  437
  438
  439
  440
  441
  442
  443
  444
  445
  446
  447
  448
  449
  450
  451
  452
  453
  454
  455
  456
  457
  458
  459
  460
  461
  462
  463
  464
  465
  466
  467
  468
  469
  470
  471
  472
  473
  474
  475
  476
  477
  478
  479
  480
  481
  482
  483
  484
  485
  486
  487
  488
  489
  490
  491
  492
  493
  494
  495
  496
  497
  498
  499
  500
  501
  502
  503
  504
  505
  506
  507
  508
  509
  510
  511
  512
  513
  514
  515
  516
  517
  518
  519
  520
  521
  522
  523
  524
  525
  526
  527
  528
  529
  530
  531
  532
  533
  534
  535
  536
  537
  538
  539
  540
  541
  542
  543
  544
  545
  546
  547
  548
  549
  550
  551
  552
  553
  554
  555
  556
  557
  558
  559
  560
  561
  562
  563
  564
  565
  566
  567
  568
  569
  570
  571
  572
  573
  574
  575
  576
  577
  578
  579
  580
  581
  582
  583
  584
  585
  586
  587
  588
  589
  590
  591
  592
  593
  594
  595
  596
  597
  598
  599
  600
  601
  602
  603
  604
  605
  606
  607
  608
  609
  610
  611
  612
  613
  614
  615
  616
  617
  618
  619
  620
  621
  622
  623
  624
  625
  626
  627
  628
  629
  630
  631
  632
  633
  634
  635
  636
  637
  638
  639
  640
  641
  642
  643
  644
  645
  646
  647
  648
  649
  650
  651
  652
  653
  654
  655
  656
  657
  658
  659
  660
  661
  662
  663
  664
  665
  666
  667
  668
  669
  670
  671
  672
  673
  674
  675
  676
  677
  678
  679
  680
  681
  682
  683
  684
  685
  686
  687
  688
  689
  690
  691
  692
  693
  694
  695
  696
  697
  698
  699
  700
  701
  702
  703
  704
  705
  706
  707
  708
  709
  710
  711
  712
  713
  714
  715
  716
  717
  718
  719
  720
  721
  722
  723
  724
  725
  726
  727
  728
  729
  730
  731
  732
  733
  734
  735
  736
  737
  738
  739
  740
  741
  742
  743
  744
  745
  746
  747
  748
  749
  750
  751
  752
  753
  754
  755
  756
  757
  758
  759
  760
  761
  762
  763
  764
  765
  766
  767
  768
  769
  770
  771
  772
  773
//= 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_ANALYSIS_ANALYSES_FORMATSTRING_H
#define LLVM_CLANG_ANALYSIS_ANALYSES_FORMATSTRING_H

#include "clang/AST/CanonicalType.h"

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,
    IntArgBeg = dArg,
    IntArgEnd = iArg,

    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; }

  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 _Bool.
    Match = 1,
    /// 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(0) {}

  OptionalAmount(bool valid = true)
  : start(nullptr),length(0), hs(valid ? NotSpecified : Invalid), amt(0),
  UsesPositionalArg(0), UsesDotPrefix(0) {}

  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;

  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) {
    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