C++ ASTContext::getBuiltinVaListType方法代码示例

/// DecodeTypeFromStr - This decodes one type descriptor from Str, advancing the
/// pointer over the consumed characters.  This returns the resultant type.
static QualType DecodeTypeFromStr(const char *&Str, ASTContext &Context, 
                                  Builtin::Context::GetBuiltinTypeError &Error,
                                  bool AllowTypeModifiers = true) {
  // Modifiers.
  int HowLong = 0;
  bool Signed = false, Unsigned = false;
  
  // Read the modifiers first.
  bool Done = false;
  while (!Done) {
    switch (*Str++) {
    default: Done = true; --Str; break; 
    case 'S':
      assert(!Unsigned && "Can't use both 'S' and 'U' modifiers!");
      assert(!Signed && "Can't use 'S' modifier multiple times!");
      Signed = true;
      break;
    case 'U':
      assert(!Signed && "Can't use both 'S' and 'U' modifiers!");
      assert(!Unsigned && "Can't use 'S' modifier multiple times!");
      Unsigned = true;
      break;
    case 'L':
      assert(HowLong <= 2 && "Can't have LLLL modifier");
      ++HowLong;
      break;
    }
  }

  QualType Type;
  
  // Read the base type.
  switch (*Str++) {
  default: assert(0 && "Unknown builtin type letter!");
  case 'v':
    assert(HowLong == 0 && !Signed && !Unsigned &&
           "Bad modifiers used with 'v'!");
    Type = Context.VoidTy;
    break;
  case 'f':
    assert(HowLong == 0 && !Signed && !Unsigned &&
           "Bad modifiers used with 'f'!");
    Type = Context.FloatTy;
    break;
  case 'd':
    assert(HowLong < 2 && !Signed && !Unsigned &&
           "Bad modifiers used with 'd'!");
    if (HowLong)
      Type = Context.LongDoubleTy;
    else
      Type = Context.DoubleTy;
    break;
  case 's':
    assert(HowLong == 0 && "Bad modifiers used with 's'!");
    if (Unsigned)
      Type = Context.UnsignedShortTy;
    else
      Type = Context.ShortTy;
    break;
  case 'i':
    if (HowLong == 3)
      Type = Unsigned ? Context.UnsignedInt128Ty : Context.Int128Ty;
    else if (HowLong == 2)
      Type = Unsigned ? Context.UnsignedLongLongTy : Context.LongLongTy;
    else if (HowLong == 1)
      Type = Unsigned ? Context.UnsignedLongTy : Context.LongTy;
    else
      Type = Unsigned ? Context.UnsignedIntTy : Context.IntTy;
    break;
  case 'c':
    assert(HowLong == 0 && "Bad modifiers used with 'c'!");
    if (Signed)
      Type = Context.SignedCharTy;
    else if (Unsigned)
      Type = Context.UnsignedCharTy;
    else
      Type = Context.CharTy;
    break;
  case 'b': // boolean
    assert(HowLong == 0 && !Signed && !Unsigned && "Bad modifiers for 'b'!");
    Type = Context.BoolTy;
    break;
  case 'z':  // size_t.
    assert(HowLong == 0 && !Signed && !Unsigned && "Bad modifiers for 'z'!");
    Type = Context.getSizeType();
    break;
  case 'F':
    Type = Context.getCFConstantStringType();
    break;
  case 'a':
    Type = Context.getBuiltinVaListType();
    assert(!Type.isNull() && "builtin va list type not initialized!");
    break;
  case 'A':
    // This is a "reference" to a va_list; however, what exactly
    // this means depends on how va_list is defined. There are two
    // different kinds of va_list: ones passed by value, and ones
    // passed by reference.  An example of a by-value va_list is
//.........这里部分代码省略.........

// Returns a desugared version of the QualType, and marks ShouldAKA as true
// whenever we remove significant sugar from the type.
static QualType Desugar(ASTContext &Context, QualType QT, bool &ShouldAKA) {
  QualifierCollector QC;

  while (true) {
    const Type *Ty = QC.strip(QT);

    // Don't aka just because we saw an elaborated type...
    if (const ElaboratedType *ET = dyn_cast<ElaboratedType>(Ty)) {
      QT = ET->desugar();
      continue;
    }
    // ... or a paren type ...
    if (const ParenType *PT = dyn_cast<ParenType>(Ty)) {
      QT = PT->desugar();
      continue;
    }
    // ...or a substituted template type parameter ...
    if (const SubstTemplateTypeParmType *ST =
          dyn_cast<SubstTemplateTypeParmType>(Ty)) {
      QT = ST->desugar();
      continue;
    }
    // ...or an attributed type...
    if (const AttributedType *AT = dyn_cast<AttributedType>(Ty)) {
      QT = AT->desugar();
      continue;
    }
    // ... or an auto type.
    if (const AutoType *AT = dyn_cast<AutoType>(Ty)) {
      if (!AT->isSugared())
        break;
      QT = AT->desugar();
      continue;
    }

    // Don't desugar template specializations. 
    if (isa<TemplateSpecializationType>(Ty))
      break;

    // Don't desugar magic Objective-C types.
    if (QualType(Ty,0) == Context.getObjCIdType() ||
        QualType(Ty,0) == Context.getObjCClassType() ||
        QualType(Ty,0) == Context.getObjCSelType() ||
        QualType(Ty,0) == Context.getObjCProtoType())
      break;

    // Don't desugar va_list.
    if (QualType(Ty,0) == Context.getBuiltinVaListType())
      break;

    // Otherwise, do a single-step desugar.
    QualType Underlying;
    bool IsSugar = false;
    switch (Ty->getTypeClass()) {
#define ABSTRACT_TYPE(Class, Base)
#define TYPE(Class, Base) \
case Type::Class: { \
const Class##Type *CTy = cast<Class##Type>(Ty); \
if (CTy->isSugared()) { \
IsSugar = true; \
Underlying = CTy->desugar(); \
} \
break; \
}
#include "clang/AST/TypeNodes.def"
    }

    // If it wasn't sugared, we're done.
    if (!IsSugar)
      break;

    // If the desugared type is a vector type, we don't want to expand
    // it, it will turn into an attribute mess. People want their "vec4".
    if (isa<VectorType>(Underlying))
      break;

    // Don't desugar through the primary typedef of an anonymous type.
    if (const TagType *UTT = Underlying->getAs<TagType>())
      if (const TypedefType *QTT = dyn_cast<TypedefType>(QT))
        if (UTT->getDecl()->getTypedefForAnonDecl() == QTT->getDecl())
          break;

    // Record that we actually looked through an opaque type here.
    ShouldAKA = true;
    QT = Underlying;
  }

  // If we have a pointer-like type, desugar the pointee as well.
  // FIXME: Handle other pointer-like types.
  if (const PointerType *Ty = QT->getAs<PointerType>()) {
    QT = Context.getPointerType(Desugar(Context, Ty->getPointeeType(),
                                        ShouldAKA));
  } else if (const LValueReferenceType *Ty = QT->getAs<LValueReferenceType>()) {
    QT = Context.getLValueReferenceType(Desugar(Context, Ty->getPointeeType(),
                                                ShouldAKA));
  } else if (const RValueReferenceType *Ty = QT->getAs<RValueReferenceType>()) {
    QT = Context.getRValueReferenceType(Desugar(Context, Ty->getPointeeType(),
                                                ShouldAKA));
//.........这里部分代码省略.........

/// Determines whether we should have an a.k.a. clause when
/// pretty-printing a type.  There are three main criteria:
///
/// 1) Some types provide very minimal sugar that doesn't impede the
///    user's understanding --- for example, elaborated type
///    specifiers.  If this is all the sugar we see, we don't want an
///    a.k.a. clause.
/// 2) Some types are technically sugared but are much more familiar
///    when seen in their sugared form --- for example, va_list,
///    vector types, and the magic Objective C types.  We don't
///    want to desugar these, even if we do produce an a.k.a. clause.
/// 3) Some types may have already been desugared previously in this diagnostic.
///    if this is the case, doing another "aka" would just be clutter.
///
static bool ShouldAKA(ASTContext &Context, QualType QT,
                      const Diagnostic::ArgumentValue *PrevArgs,
                      unsigned NumPrevArgs,
                      QualType &DesugaredQT) {
  QualType InputTy = QT;
  
  bool AKA = false;
  QualifierCollector Qc;
  
  while (true) {
    const Type *Ty = Qc.strip(QT);
    
    // Don't aka just because we saw an elaborated type...
    if (isa<ElaboratedType>(Ty)) {
      QT = cast<ElaboratedType>(Ty)->desugar();
      continue;
    }
    
    // ...or a qualified name type...
    if (isa<QualifiedNameType>(Ty)) {
      QT = cast<QualifiedNameType>(Ty)->desugar();
      continue;
    }

    // ...or an injected class name...
    if (isa<InjectedClassNameType>(Ty)) {
      QT = cast<InjectedClassNameType>(Ty)->desugar();
      continue;
    }
    
    // ...or a substituted template type parameter.
    if (isa<SubstTemplateTypeParmType>(Ty)) {
      QT = cast<SubstTemplateTypeParmType>(Ty)->desugar();
      continue;
    }
    
    // Don't desugar template specializations. 
    if (isa<TemplateSpecializationType>(Ty))
      break;
    
    // Don't desugar magic Objective-C types.
    if (QualType(Ty,0) == Context.getObjCIdType() ||
        QualType(Ty,0) == Context.getObjCClassType() ||
        QualType(Ty,0) == Context.getObjCSelType() ||
        QualType(Ty,0) == Context.getObjCProtoType())
      break;
    
    // Don't desugar va_list.
    if (QualType(Ty,0) == Context.getBuiltinVaListType())
      break;
    
    // Otherwise, do a single-step desugar.
    QualType Underlying;
    bool IsSugar = false;
    switch (Ty->getTypeClass()) {
#define ABSTRACT_TYPE(Class, Base)
#define TYPE(Class, Base) \
case Type::Class: { \
const Class##Type *CTy = cast<Class##Type>(Ty); \
if (CTy->isSugared()) { \
IsSugar = true; \
Underlying = CTy->desugar(); \
} \
break; \
}
#include "clang/AST/TypeNodes.def"
    }
    
    // If it wasn't sugared, we're done.
    if (!IsSugar)
      break;
    
    // If the desugared type is a vector type, we don't want to expand
    // it, it will turn into an attribute mess. People want their "vec4".
    if (isa<VectorType>(Underlying))
      break;
    
    // Don't desugar through the primary typedef of an anonymous type.
    if (isa<TagType>(Underlying) && isa<TypedefType>(QT))
      if (cast<TagType>(Underlying)->getDecl()->getTypedefForAnonDecl() ==
          cast<TypedefType>(QT)->getDecl())
        break;
    
    // Otherwise, we're tearing through something opaque; note that
    // we'll eventually need an a.k.a. clause and keep going.
    AKA = true;
//.........这里部分代码省略.........