Re: How to identify the type of the object being created using the new operator?

[Swati Rathi <swatirathi at cse dot iitb dot ac dot in>]

On Monday 06 October 2014 02:28 PM, Marc Glisse wrote:
> On Mon, 6 Oct 2014, Swati Rathi wrote:
>
> > Statement : A *a = new B;
> >
> > gets translated in GIMPLE as
> > 1. void * D.2805;
> > 2. struct A * a;
> > 3. D.2805 = operator new (20);
> > 4. a = D.2805;
> >
> > A is the base class and B is the derived class.
> > In statement 3, new operator is creating an object of derived class B.
> > By analyzing the RHS of the assignment statement 3, how can we 
> > identify the type (in this case B) of the object being created?
>
> I strongly doubt you can. It is calling B's constructor that will turn 
> this memory region into a B, operator new is the same as malloc, it 
> only returns raw memory.
>
> (If A and B don't have the same size, the argument 20 can be a hint)
Argument 20 is the size of class B.
This was obtained only if we knew that object B is created here.
Is this information not stored anywhere else?