gcc emit wrong symbols in multiple inheritance case

[Bo Yang]

Hi Dear Gcc developers,

    When I am trying to build Mozilla with gcc-mingw, I came across
the linkage error of undefined symbols in multiple inheritance case.
And I have made a simple test case to reproduce the problem. But the
test case is still very complex, I think. So, I came down to find the
what are the real problems. And now, I think I have, so I just
describe what I found here:

For a class hierarchy :

class SuperSuperBase {
public:
        SuperSuperBase();
        ~SuperSuperBase();

        virtual void __attribute__((__stdcall__)) funcSSB() = 0;
};

class SuperBase : public SuperSuperBase {
public:
        SuperBase();
        ~SuperBase();

        virtual void __attribute__((__stdcall__)) funcSB() = 0;
};

class Base : public SuperBase {
public:
        Base();
        ~Base();

        virtual void __attribute__((__stdcall__)) funcB() = 0;
};

class ChildA: public Base {
public:
        ChildA();
        ~ChildA();

        virtual void __attribute__((__stdcall__)) funcCA() = 0;
};

class ChildB: public SuperBase {
public:
        ChildB();
        ~ChildB();

        virtual void __attribute__((__stdcall__)) funcCB() = 0;
};

class DLL Child :       public  ChildA,
                 public  ChildB {
public:
        Child();
        ~Child();

        virtual void __attribute__((__stdcall__)) funcSSB();
        virtual void __attribute__((__stdcall__)) funcSB();
        virtual void __attribute__((__stdcall__)) funcB();
        virtual void __attribute__((__stdcall__)) funcCB();
        virtual void __attribute__((__stdcall__)) funcCA();
};

I make the Child in a DLL and then I import it from the DLL to build a
test application. But I failed with the undefined symbols of
"funcSSB,funcSB,funcCB".
And the errors occurs when I build with gcc 4.3.0 but not with gcc
3.4.2. So, I use i686-mingw32-nm to dump the object file which
contains the definition of the Child class. And for the three
undefined functions, the two compiler output different symbols,
Gcc 3.4.2:
         U __ZTVN10__cxxabiv117__class_type_infoE
         U __ZTVN10__cxxabiv120__si_class_type_infoE
         U __ZTVN10__cxxabiv121__vmi_class_type_infoE
00000000 T [EMAIL PROTECTED]
00000000 T [EMAIL PROTECTED]
00000000 T [EMAIL PROTECTED]

Gcc 4.3.0:
         U __ZTVN10__cxxabiv117__class_type_infoE
         U __ZTVN10__cxxabiv120__si_class_type_infoE
         U __ZTVN10__cxxabiv121__vmi_class_type_infoE
00000306 T __ZThn4_N5Child6funcCBEv
         U [EMAIL PROTECTED]
000002d7 T __ZThn4_N5Child6funcSBEv
         U [EMAIL PROTECTED]
000002c8 T __ZThn4_N5Child7funcSSBEv
         U [EMAIL PROTECTED]

I think the difference here is the key point of the linkage error.
Could anybody help to give some more insight here? Any advice will be
appreciated very much!

Regards!
Bo