The hack to convert ExtVector to CXType_Vector

ExtVector_hack.cpp

namespace clng {
// All the types below are POD and bitwise compatible with corresponding clang classes

struct PointerIntPair {
	intptr_t Value = 0;
};

struct QualType {
	PointerIntPair Value; // llvm::PointerIntPair<llvm::PointerUnion<const Type *, const ExtQuals *>, Qualifiers::FastWidth> Value;
};

struct Type;
struct ExtQualsTypeCommonBase {
	Type * BaseType;
	QualType CanonicalType;
};

struct TypeBitfields {
	/// TypeClass bitfield - Enum that specifies what subclass this belongs to.
	unsigned TC : 8;
	unsigned : 24;
 };

struct Type : public ExtQualsTypeCommonBase {
    TypeBitfields TypeBits;

	uint8_t getTypeClass() const { return TypeBits.TC; }
	void setTypeClass(uint8_t tc) { TypeBits.TC = tc; }
};

} // namesoace clng

bool tryCast2Vector(CXType type) {
	type = clang_getCanonicalType(type); // always safe
	auto *base = reinterpret_cast<clng::Type *>( reinterpret_cast<intptr_t>(type.data[0]) & ~0xf );

	if (base && base->getTypeClass() == 15) {
		// This is ExtVectorType; pretend to be VectorType instead
		base->setTypeClass(13);
		return true;
	}
	return false;
}

//  Usage:
//  val type = clang_getCursorType(cursor)
//  if (type.kind == CXType_Vector || tryCast2Vector(type))  {
//	    do_whatever_as_it_would_be_CXType_Vector(type)
//  }