Re: I'm new and wanting to help!

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Joel" == Joel Dice <dicej@mailsnare.net> writes:

>> * The holy grail would be to allow a copying GC somehow.
>> We think this is very, very hard.

Joel> This is a topic near to my heart, since I'm implementing a Lisp
Joel> interpreter using a copying GC.

I probably shouldn't have mentioned this one :-)

Joel> Would it be possible to use debug information to determine the stack
Joel> layout, similar to how DWARF is used for unwinding?

Yes.  Actually there is a paper from 10 years ago or so where the
authors did just this, in GCC, for Modula-3 as I recall.  As I
remember the paper, it was a lot of work.  And, the patches were never
integrated.

I'm not a GC expert, so I don't know how well this would really
compare to what we've got now.  And, maybe a mostly-copying GC would
serve just as well.

Joel> Also, how might java.util.IdentityHashMap or the hash-synchronization
Joel> option be implemented when using a copying GC, given that object
Joel> addresses may change at any time?

I'm not sure how other VMs do this.  I know earlier ones kept the
"system" hash code in the object header, but I'm not sure whether this
is current practice.

Tom