C++ QualType::getAsPointerType方法代码示例

/// Tests whether a conversion according to C++ 5.2.9p8 is valid.
TryStaticCastResult
TryStaticPointerDowncast(Sema &Self, QualType SrcType, QualType DestType,
                         const SourceRange &OpRange)
{
  // C++ 5.2.9p8: An rvalue of type "pointer to cv1 B", where B is a class
  //   type, can be converted to an rvalue of type "pointer to cv2 D", where D
  //   is a class derived from B, if a valid standard conversion from "pointer
  //   to D" to "pointer to B" exists, cv2 >= cv1, and B is not a virtual base
  //   class of D.
  // In addition, DR54 clarifies that the base must be accessible in the
  // current context.

  const PointerType *SrcPointer = SrcType->getAsPointerType();
  if (!SrcPointer) {
    return TSC_NotApplicable;
  }

  const PointerType *DestPointer = DestType->getAsPointerType();
  if (!DestPointer) {
    return TSC_NotApplicable;
  }

  return TryStaticDowncast(Self, SrcPointer->getPointeeType(),
                          DestPointer->getPointeeType(),
                          OpRange, SrcType, DestType);
}

/// Helper function to determine whether this is the (deprecated) C++
/// conversion from a string literal to a pointer to non-const char or
/// non-const wchar_t (for narrow and wide string literals,
/// respectively).
bool 
Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
  // Look inside the implicit cast, if it exists.
  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
    From = Cast->getSubExpr();

  // A string literal (2.13.4) that is not a wide string literal can
  // be converted to an rvalue of type "pointer to char"; a wide
  // string literal can be converted to an rvalue of type "pointer
  // to wchar_t" (C++ 4.2p2).
  if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From))
    if (const PointerType *ToPtrType = ToType->getAsPointerType())
      if (const BuiltinType *ToPointeeType 
          = ToPtrType->getPointeeType()->getAsBuiltinType()) {
        // This conversion is considered only when there is an
        // explicit appropriate pointer target type (C++ 4.2p2).
        if (ToPtrType->getPointeeType().getCVRQualifiers() == 0 &&
            ((StrLit->isWide() && ToPointeeType->isWideCharType()) ||
             (!StrLit->isWide() &&
              (ToPointeeType->getKind() == BuiltinType::Char_U ||
               ToPointeeType->getKind() == BuiltinType::Char_S))))
          return true;
      }

  return false;
}

/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
/// @code ::delete ptr; @endcode
/// or
/// @code delete [] ptr; @endcode
Action::OwningExprResult
Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
                     bool ArrayForm, ExprArg Operand)
{
  // C++ 5.3.5p1: "The operand shall have a pointer type, or a class type
  //   having a single conversion function to a pointer type. The result has
  //   type void."
  // DR599 amends "pointer type" to "pointer to object type" in both cases.

  Expr *Ex = (Expr *)Operand.get();
  if (!Ex->isTypeDependent()) {
    QualType Type = Ex->getType();

    if (Type->isRecordType()) {
      // FIXME: Find that one conversion function and amend the type.
    }

    if (!Type->isPointerType())
      return ExprError(Diag(StartLoc, diag::err_delete_operand)
        << Type << Ex->getSourceRange());

    QualType Pointee = Type->getAsPointerType()->getPointeeType();
    if (Pointee->isFunctionType() || Pointee->isVoidType())
      return ExprError(Diag(StartLoc, diag::err_delete_operand)
        << Type << Ex->getSourceRange());
    else if (!Pointee->isDependentType() &&
             RequireCompleteType(StartLoc, Pointee, 
                                 diag::warn_delete_incomplete,
                                 Ex->getSourceRange()))
      return ExprError();

    // FIXME: Look up the correct operator delete overload and pass a pointer
    // along.
    // FIXME: Check access and ambiguity of operator delete and destructor.
  }

  Operand.release();
  return Owned(new (Context) CXXDeleteExpr(Context.VoidTy, UseGlobal, ArrayForm,
                                           0, Ex, StartLoc));
}

QualType Sema::CheckPointerToMemberOperands(
  Expr *&lex, Expr *&rex, SourceLocation Loc, bool isIndirect)
{
  const char *OpSpelling = isIndirect ? "->*" : ".*";
  // C++ 5.5p2
  //   The binary operator .* [p3: ->*] binds its second operand, which shall
  //   be of type "pointer to member of T" (where T is a completely-defined
  //   class type) [...]
  QualType RType = rex->getType();
  const MemberPointerType *MemPtr = RType->getAsMemberPointerType();
  if (!MemPtr) {
    Diag(Loc, diag::err_bad_memptr_rhs)
      << OpSpelling << RType << rex->getSourceRange();
    return QualType();
  } else if (RequireCompleteType(Loc, QualType(MemPtr->getClass(), 0),
                                 diag::err_memptr_rhs_incomplete,
                                 rex->getSourceRange()))
    return QualType();

  QualType Class(MemPtr->getClass(), 0);

  // C++ 5.5p2
  //   [...] to its first operand, which shall be of class T or of a class of
  //   which T is an unambiguous and accessible base class. [p3: a pointer to
  //   such a class]
  QualType LType = lex->getType();
  if (isIndirect) {
    if (const PointerType *Ptr = LType->getAsPointerType())
      LType = Ptr->getPointeeType().getNonReferenceType();
    else {
      Diag(Loc, diag::err_bad_memptr_lhs)
        << OpSpelling << 1 << LType << lex->getSourceRange();
      return QualType();
    }
  }

  if (Context.getCanonicalType(Class).getUnqualifiedType() !=
      Context.getCanonicalType(LType).getUnqualifiedType()) {
    BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false,
                    /*DetectVirtual=*/false);
    // FIXME: Would it be useful to print full ambiguity paths,
    // or is that overkill?
    if (!IsDerivedFrom(LType, Class, Paths) ||
        Paths.isAmbiguous(Context.getCanonicalType(Class))) {
      Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
        << (int)isIndirect << lex->getType() << lex->getSourceRange();
      return QualType();
    }
  }

  // C++ 5.5p2
  //   The result is an object or a function of the type specified by the
  //   second operand.
  // The cv qualifiers are the union of those in the pointer and the left side,
  // in accordance with 5.5p5 and 5.2.5.
  // FIXME: This returns a dereferenced member function pointer as a normal
  // function type. However, the only operation valid on such functions is
  // calling them. There's also a GCC extension to get a function pointer to
  // the thing, which is another complication, because this type - unlike the
  // type that is the result of this expression - takes the class as the first
  // argument.
  // We probably need a "MemberFunctionClosureType" or something like that.
  QualType Result = MemPtr->getPointeeType();
  if (LType.isConstQualified())
    Result.addConst();
  if (LType.isVolatileQualified())
    Result.addVolatile();
  return Result;
}

/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
/// checked downcasts in class hierarchies.
void
CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
                 const SourceRange &OpRange,
                 const SourceRange &DestRange)
{
  QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
  DestType = Self.Context.getCanonicalType(DestType);

  // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
  //   or "pointer to cv void".

  QualType DestPointee;
  const PointerType *DestPointer = DestType->getAsPointerType();
  const ReferenceType *DestReference = DestType->getAsReferenceType();
  if (DestPointer) {
    DestPointee = DestPointer->getPointeeType();
  } else if (DestReference) {
    DestPointee = DestReference->getPointeeType();
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
      << OrigDestType << DestRange;
    return;
  }

  const RecordType *DestRecord = DestPointee->getAsRecordType();
  if (DestPointee->isVoidType()) {
    assert(DestPointer && "Reference to void is not possible");
  } else if (DestRecord) {
    if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, 
                                    diag::err_bad_dynamic_cast_incomplete,
                                    DestRange))
      return;
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
      << DestPointee.getUnqualifiedType() << DestRange;
    return;
  }

  // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
  //   complete class type, [...]. If T is an lvalue reference type, v shall be
  //   an lvalue of a complete class type, [...]. If T is an rvalue reference
  //   type, v shall be an expression having a complete effective class type,
  //   [...]

  QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
  QualType SrcPointee;
  if (DestPointer) {
    if (const PointerType *SrcPointer = SrcType->getAsPointerType()) {
      SrcPointee = SrcPointer->getPointeeType();
    } else {
      Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
        << OrigSrcType << SrcExpr->getSourceRange();
      return;
    }
  } else if (DestReference->isLValueReferenceType()) {
    if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
      Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
        << "dynamic_cast" << OrigDestType << OpRange;
    }
    SrcPointee = SrcType;
  } else {
    SrcPointee = SrcType;
  }

  const RecordType *SrcRecord = SrcPointee->getAsRecordType();
  if (SrcRecord) {
    if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
                                    diag::err_bad_dynamic_cast_incomplete,
                                    SrcExpr->getSourceRange()))
      return;
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
      << SrcPointee.getUnqualifiedType() << SrcExpr->getSourceRange();
    return;
  }

  assert((DestPointer || DestReference) &&
    "Bad destination non-ptr/ref slipped through.");
  assert((DestRecord || DestPointee->isVoidType()) &&
    "Bad destination pointee slipped through.");
  assert(SrcRecord && "Bad source pointee slipped through.");

  // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
  if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
    Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
      << "dynamic_cast" << OrigDestType << OrigSrcType << OpRange;
    return;
  }

  // C++ 5.2.7p3: If the type of v is the same as the required result type,
  //   [except for cv].
  if (DestRecord == SrcRecord) {
    return;
  }

  // C++ 5.2.7p5
  // Upcasts are resolved statically.
//.........这里部分代码省略.........