[Bug lto/41552] New: Undefined references with -flto, dependent on object file ordering

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

> ./g++ -B. -fPIC -O -flto -c dvector.3.ii slufactor.3.ii
> ./g++ -nostdlib -B. -fPIC -O -shared -o t slufactor.3.o dvector.3.o
> nm t | grep _ZN6soplex7DVectoraSERKNS_6VectorE
> ./g++ -nostdlib -B. -fPIC -O -shared -o t dvector.3.o slufactor.3.o
> nm t | grep _ZN6soplex7DVectoraSERKNS_6VectorE
> ./g++ -nostdlib -B. -fPIC -O -shared -o t dvector.3.o slufactor.3.o -flto
> nm t | grep _ZN6soplex7DVectoraSERKNS_6VectorE
                 U _ZN6soplex7DVectoraSERKNS_6VectorE
> ./g++ -nostdlib -B. -fPIC -O -shared -o t slufactor.3.o dvector.3.o -flto
> nm t | grep _ZN6soplex7DVectoraSERKNS_6VectorE
00000000000004f2 W _ZN6soplex7DVectoraSERKNS_6VectorE

WTF?  1) That function probably is inlined without lto, 2) Obviously the
merged cgraph is dependent on the ordering of object files on the link
command line...

slufactor.3.ii:
---------------
namespace soplex {
    class Vector {
    public:
        Vector& operator=(const Vector& vec);
        int dim() const    { }
    };
    class DVector : public Vector {
    public:
        void reDim(int newdim);
        DVector& operator=(const Vector& vec)    {
            if (vec.dim() != dim())
              reDim(vec.dim());
            Vector::operator=(vec);
        }
    };
    class SLinSolver { };
    class CLUFactor { };
    class SLUFactor : public SLinSolver, private CLUFactor {
        DVector vec;
        void solveRight (Vector& x, const Vector& b);
    };
    void SLUFactor::solveRight (Vector& x, const Vector& b) {
        vec = b;
        vec = b;
    }
}
----------

dvector.3.ii:
------------
namespace soplex {
    typedef double Real;
    class Vector {
        int dimen;
        Real* val;
    public:
        Vector(int p_dimen, Real *p_val)
            : dimen(p_dimen)       , val(p_val)    { }
        int dim() const    {
            return dimen;
        }
    };
    class DVector : public Vector {
        Real* mem;
        void reDim(int newdim);
        explicit DVector(const Vector& old);
        DVector& operator=(const Vector& vec)    {
            if (vec.dim() != dim())
              reDim(vec.dim());
        }
    };
    DVector::DVector(const Vector& old)
        : Vector(0, 0)    , mem( 0 )
      {
        *this = old;
      }
}
----------


-- 
           Summary: Undefined references with -flto, dependent on object
                    file ordering
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41552