Calling C++ destructor directly in resourceHash.hpp

[Ioi Lam]

On 6/12/17 12:16 AM, Thomas Stüfe wrote:
>
>
> On Mon, Jun 12, 2017 at 7:20 AM, John Rose <john.r.rose at oracle.com 
> <mailto:john.r.rose at oracle.com>> wrote:
>
>     On Jun 11, 2017, at 9:19 PM, Ioi Lam <ioi.lam at oracle.com
>     <mailto:ioi.lam at oracle.com>> wrote:
>     >
>     > I am looking at these two functions in "utilities/resourceHash.hpp":
>
>     You are worried about the V destructor running,
>     where the V struct is a member of Node (Node::_value).
>     In the normal case, running the destructor of Node
>     transparently runs the destructors of the K and V
>     members of Node.
>
>     The place where dropped destructors can happen
>     in this sort of pattern is when you overwrite a variable,
>     which is point (a) in your example.  Your V::operator=
>     is responsible for retiring any resources used by the
>     previous value of Node::_value which are not going to
>     be used by the new value.
>
>     Eventually, when "delete node" happens, whatever
>     resources were in use in Node::_value will be freed.
>
>     So I don't think you have to do anything with point (b).
>     Your problem, if you have one, is operator=.  Those are
>     hard to get right.
>
>     — John
>
>
> Also, all usages of ResourceHashTable I can see have either primitive 
> data types as value type or they do their own cleanup (e.g. Handle in 
> jvmci). Do you see any concrete usage where a real object needing 
> destruction is placed in a ResourceHashTable?
>
I am adding a new ResourceHashTable that needs destruction of the stored 
object. And I found out that my destructor is not called.

Thanks
- Ioi

> ..Thomas
>