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

//.........这里部分代码省略.........
  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
    // x86, where va_list is a char*. An example of by-ref va_list
    // is x86-64, where va_list is a __va_list_tag[1]. For x86,
    // we want this argument to be a char*&; for x86-64, we want
    // it to be a __va_list_tag*.
    Type = Context.getBuiltinVaListType();
    assert(!Type.isNull() && "builtin va list type not initialized!");
    if (Type->isArrayType()) {
      Type = Context.getArrayDecayedType(Type);
    } else {
      Type = Context.getLValueReferenceType(Type);
    }
    break;
  case 'V': {
    char *End;
    
    unsigned NumElements = strtoul(Str, &End, 10);
    assert(End != Str && "Missing vector size");
    
    Str = End;
    
    QualType ElementType = DecodeTypeFromStr(Str, Context, Error, false);
    Type = Context.getVectorType(ElementType, NumElements);
    break;
  }
  case 'P': {
    IdentifierInfo *II = &Context.Idents.get("FILE");
    DeclContext::lookup_result Lookup 
      = Context.getTranslationUnitDecl()->lookup(Context, II);
    if (Lookup.first != Lookup.second && isa<TypeDecl>(*Lookup.first)) {
      Type = Context.getTypeDeclType(cast<TypeDecl>(*Lookup.first));
      break;
    }
    else {
      Error = Builtin::Context::GE_Missing_FILE;
      return QualType();
    }
  }
  }
  
  if (!AllowTypeModifiers)
    return Type;
  
  Done = false;
  while (!Done) {
    switch (*Str++) {
      default: Done = true; --Str; break;
      case '*':
        Type = Context.getPointerType(Type);
        break;
      case '&':
        Type = Context.getLValueReferenceType(Type);
        break;
      // FIXME: There's no way to have a built-in with an rvalue ref arg.
      case 'C':
        Type = Type.getQualifiedType(QualType::Const);
        break;
    }
  }
  
  return Type;
}

// 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.........

/// \brief Return the fully qualified type, including fully-qualified
/// versions of any template parameters.
QualType getFullyQualifiedType(QualType QT, const ASTContext &Ctx) {
  // In case of myType* we need to strip the pointer first, fully
  // qualify and attach the pointer once again.
  if (isa<PointerType>(QT.getTypePtr())) {
    // Get the qualifiers.
    Qualifiers Quals = QT.getQualifiers();
    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx);
    QT = Ctx.getPointerType(QT);
    // Add back the qualifiers.
    QT = Ctx.getQualifiedType(QT, Quals);
    return QT;
  }

  // In case of myType& we need to strip the reference first, fully
  // qualify and attach the reference once again.
  if (isa<ReferenceType>(QT.getTypePtr())) {
    // Get the qualifiers.
    bool IsLValueRefTy = isa<LValueReferenceType>(QT.getTypePtr());
    Qualifiers Quals = QT.getQualifiers();
    QT = getFullyQualifiedType(QT->getPointeeType(), Ctx);
    // Add the r- or l-value reference type back to the fully
    // qualified one.
    if (IsLValueRefTy)
      QT = Ctx.getLValueReferenceType(QT);
    else
      QT = Ctx.getRValueReferenceType(QT);
    // Add back the qualifiers.
    QT = Ctx.getQualifiedType(QT, Quals);
    return QT;
  }

  // Remove the part of the type related to the type being a template
  // parameter (we won't report it as part of the 'type name' and it
  // is actually make the code below to be more complex (to handle
  // those)
  while (isa<SubstTemplateTypeParmType>(QT.getTypePtr())) {
    // Get the qualifiers.
    Qualifiers Quals = QT.getQualifiers();

    QT = dyn_cast<SubstTemplateTypeParmType>(QT.getTypePtr())->desugar();

    // Add back the qualifiers.
    QT = Ctx.getQualifiedType(QT, Quals);
  }

  NestedNameSpecifier *Prefix = nullptr;
  Qualifiers PrefixQualifiers;
  ElaboratedTypeKeyword Keyword = ETK_None;
  if (const auto *ETypeInput = dyn_cast<ElaboratedType>(QT.getTypePtr())) {
    QT = ETypeInput->getNamedType();
    Keyword = ETypeInput->getKeyword();
  }
  // Create a nested name specifier if needed (i.e. if the decl context
  // is not the global scope.
  Prefix = createNestedNameSpecifierForScopeOf(Ctx, QT.getTypePtr(),
                                               true /*FullyQualified*/);

  // move the qualifiers on the outer type (avoid 'std::const string'!)
  if (Prefix) {
    PrefixQualifiers = QT.getLocalQualifiers();
    QT = QualType(QT.getTypePtr(), 0);
  }

  // In case of template specializations iterate over the arguments and
  // fully qualify them as well.
  if (isa<const TemplateSpecializationType>(QT.getTypePtr()) ||
      isa<const RecordType>(QT.getTypePtr())) {
    // We are asked to fully qualify and we have a Record Type (which
    // may pont to a template specialization) or Template
    // Specialization Type. We need to fully qualify their arguments.

    Qualifiers Quals = QT.getLocalQualifiers();
    const Type *TypePtr = getFullyQualifiedTemplateType(Ctx, QT.getTypePtr());
    QT = Ctx.getQualifiedType(TypePtr, Quals);
  }
  if (Prefix || Keyword != ETK_None) {
    QT = Ctx.getElaboratedType(Keyword, Prefix, QT);
    QT = Ctx.getQualifiedType(QT, PrefixQualifiers);
  }
  return QT;
}