Garbage collection

Simon Marlow marlowsd at
Mon Nov 24 10:17:40 UTC 2014

On 18/11/2014 18:03, Mathieu Boespflug wrote:
> On 18 November 2014 16:59, Simon Peyton Jones <simonpj at> wrote:
>> Isn't it this simple: the Static Pointer Table must be a source of roots for the garbage collector.  Of course!  An item in the SPT may be looked up at any time.
> As Facundo says, the existence of the SPT would solve everything. But
> we haven't quite figured out how to create a simple SPT yet, so were
> wondering whether there is an existing generic mechanism to register
> new GC roots.

Yes - the generic mechanism is StablePtrs, so you're on the right lines. 
  Even when you have an SPT you'll probably need to make a StablePtr to 
it (though I haven't been following the discussion so just ignore me if 
I'm wrong here).


> I guess there is no better solution but to just create an SPT, even if
> we don't yet have TypeRep's to put in it.
> With an SPT, and under the assumption of everyone sharing the same
> binary in the distributed system, there will be no need to hold on to
> *all* CAF's - just the ones that are known to have a StaticPointer
> created for them at compile time.
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