On Tue, 2 Sep 2003, Leopold Toetsch wrote:
> Dan Sugalski <[EMAIL PROTECTED]> wrote:
> > On Tue, 2 Sep 2003, Leopold Toetsch wrote:
>
> >> and no, not that one inside DOD, that one doesn't handle duplicates.
>
> > Yes, yes it *does* handle duplicates. Otherwise it'd get caught in
> > infinite loops every time it came across a circular data structure. That's
> > what the next pointer in the PObj header gets used for, amongst other
> > things.
>
> It does handle duplicates like so:
>
> void pobject_lives(struct Parrot_Interp *interpreter, PObj *obj)
> {
> /* if object is live or on free list return */
> if (PObj_is_live_or_free_TESTALL(obj)) {
> return;
> }
> /* mark it live */
> PObj_live_SET(obj);
>
> So if it was mark()ed already we return. That's not possible for freeze,
> thaw, dump, clone whatever. These must keep track of already visited
> objects via an hash for freeze, dump, clone, and via an ID array for
> thaw.
No, this isn't necessary. What you need to do when freezing an already
frozen PMC is to emit a marker label that refers to the original version
of the PMC, or always emit the marker when a PMC freezes another PMC and
defer actual freezing of the PMC until the master freeze function walks
over the PMC to freeze it.
Dan
