[Bug c++/66666] ARM compiled code segmentation fault on multiple inheritance

[antonio.poggiali at datalogic dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66666

--- Comment #3 from Antonio Poggiali <antonio.poggiali at datalogic dot com> ---
I've understand a little better the problem.
The compiler passes to std::list copy constructor a different address respect
to the destination variable. 
This causes size() call to fail (endless loop or segmentation fault).

Here you can find a simpler test-bench:

#include <iostream>

using namespace std;

class TestReference
{
        public:

        // This is a pointer to me
        const TestReference * _me;

        TestReference() {
                _me = this;
        }

        TestReference(const TestReference &obj)
        {
                _me = this;
        }
};

class SmartObject
{
        public:

        SmartObject(){}

        // removing this destructor makes it work
        virtual ~SmartObject(){}
};

class IMyInterface
{
        public:

        IMyInterface(){}

        // removing this destructor have no effect (fails anyway)
        virtual ~IMyInterface(){}

        virtual TestReference getTestReference() = 0;
};

// inheriting SmartObject virtually makes it work (but it is not feasible on
the overall application architecture)
class MyObject : public virtual IMyInterface, public SmartObject
{
        public:

        MyObject() : IMyInterface(), SmartObject() {}

        virtual TestReference getTestReference() {
                return testReference;
        }

        virtual ~MyObject(){
        }

        TestReference testReference;
};

int main()
{
        IMyInterface *ip = new MyObject();

        TestReference TestReference_local;
        std::cout << "object address " << &TestReference_local << std::endl;
        std::cout << "object address in constructor " <<
TestReference_local._me << std::endl;
        if (&TestReference_local != TestReference_local._me)
                std::cout << "warning! addresses are different!" << std::endl;

        TestReference TestReference_clone = ip->getTestReference();
        std::cout << "object address " << &TestReference_clone << std::endl;
        std::cout << "object address in copy constructor " <<
TestReference_clone._me << std::endl;
        if (&TestReference_clone != TestReference_clone._me)
                std::cout << "warning! addresses are different!" << std::endl;

        delete ip;
        return 0;
}

Basically I expect the object address in the copy constructor (this) to be the
same of the object in the calling code, but when the program fails it is not
so!