Re: does this dynamic_cast<> bug know?

[Bowie Owens <bowie owens csiro au>]

Hi Alexander,

Nice work on the bug report. I was able to reproduce the problem with 
your sample code. It looks like the problem might be easy to fix. 
Deleting public virtual T from the X base list was sufficient to get the 
sample working. I don't think IDLStruct needs to directly inherit from 
IDLType. Please try commenting out the public virtual IDLType in the 
IDLStruct base class list:

class IDLStruct: public IDLCompound, /*public virtual IDLType,*/ public 
IDLCompoundSeqElem

Can you confirm that this allows the idl compiler to function properly 
or at least better.


Alexander Nedotsukov wrote:

> Hi,
>
> I think this may be considered as serious bug in C++ idl compiller
> backend when it built with gcc 2.95.x. Look at the file
> orbitcpp/idl-compiller/types.cc. It contains following pice of code
> (actually there is may be much more places like that).
>
> IDLType *
> IDLTypeParser::parseTypeSpec(IDLScope &scope,IDL_tree typespec) {
> ...
>        case IDLN_IDENT:
>            {
>                IDLElement *item =
> scope.lookup(idlGetQualIdentifier(typespec));
>                if (!item) throw
> IDLExUnknownIdentifier(typespec,idlGetQualIdentifier(typespec));
>                if (!item->isType()) throw
> IDLExTypeIdentifierExpected(typespec,IDL_IDENT(typespec).str);
>                type = dynamic_cast<IDLType *>(item);
>                break;
>            }
>
> I believe gcc 2.95.x dynamic_cast<> implementation is buggy and if
> scope.lookup() return IDLStruct* then dynamic_cast<> two lines bellow
> will result in NULL pointer and .idl compilation will be aborted with
> the "not yet implemented: idln_ident". Code compilled with gcc 3.2 works
> just fine. Here is a small sample that reproduce classes hierarchy
> involved in case.
>
> class T {};
> class TI { public: virtual void m() {} };
> class CS : public virtual T, public virtual TI {};
> class E : public virtual TI {};
> class S : public E {};
> class C : public S {};
> class X : public C, public virtual T, public CS {};
>
> int
> main()
> {
>  E* e = new X;
>  T* t = dynamic_cast<T*>(e);
>  delete e;
>  return 0;
> }
>
> All the best,
> Alexander.
>
>
>
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--
Bowie Owens

CSIRO Mathematical & Information Sciences
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