C++ (Cpp) Sema::IsQualificationConversion Examples

Example #1

File: SemaNamedCast.cpp Project: blickly/llvm-clang-PRETC

/// CastsAwayConstness - Check if the pointer conversion from SrcType to
/// DestType casts away constness as defined in C++ 5.2.11p8ff. This is used by
/// the cast checkers.  Both arguments must denote pointer (possibly to member)
/// types.
bool
CastsAwayConstness(Sema &Self, QualType SrcType, QualType DestType)
{
  // Casting away constness is defined in C++ 5.2.11p8 with reference to
  // C++ 4.4. We piggyback on Sema::IsQualificationConversion for this, since
  // the rules are non-trivial. So first we construct Tcv *...cv* as described
  // in C++ 5.2.11p8.
  assert((SrcType->isPointerType() || SrcType->isMemberPointerType()) &&
         "Source type is not pointer or pointer to member.");
  assert((DestType->isPointerType() || DestType->isMemberPointerType()) &&
         "Destination type is not pointer or pointer to member.");

  QualType UnwrappedSrcType = SrcType, UnwrappedDestType = DestType;
  llvm::SmallVector<unsigned, 8> cv1, cv2;

  // Find the qualifications.
  while (Self.UnwrapSimilarPointerTypes(UnwrappedSrcType, UnwrappedDestType)) {
    cv1.push_back(UnwrappedSrcType.getCVRQualifiers());
    cv2.push_back(UnwrappedDestType.getCVRQualifiers());
  }
  assert(cv1.size() > 0 && "Must have at least one pointer level.");

  // Construct void pointers with those qualifiers (in reverse order of
  // unwrapping, of course).
  QualType SrcConstruct = Self.Context.VoidTy;
  QualType DestConstruct = Self.Context.VoidTy;
  for (llvm::SmallVector<unsigned, 8>::reverse_iterator i1 = cv1.rbegin(),
                                                        i2 = cv2.rbegin();
       i1 != cv1.rend(); ++i1, ++i2)
  {
    SrcConstruct = Self.Context.getPointerType(
      SrcConstruct.getQualifiedType(*i1));
    DestConstruct = Self.Context.getPointerType(
      DestConstruct.getQualifiedType(*i2));
  }

  // Test if they're compatible.
  return SrcConstruct != DestConstruct &&
    !Self.IsQualificationConversion(SrcConstruct, DestConstruct);
}