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Re: GC changes
- To: dewar at gnat dot com
- Subject: Re: GC changes
- From: Jamie Lokier <egcs at tantalophile dot demon dot co dot uk>
- Date: Mon, 15 Jan 2001 19:42:04 +0100
- Cc: bernds at redhat dot com, amylaar at cambridge dot redhat dot com, gcc at gcc dot gnu dot org, geoffk at geoffk dot org, mrs at windriver dot com, tej at melbpc dot org dot au
- References: <20010115183002.470E134D84@nile.gnat.com>
dewar@gnat.com wrote:
> <<Actually there is another approach. You could generate unwind stubs
> similar to exception handling, with a table indexed by program counter
> to the stubs. For most program addresses the stub would be empty, but
> for certain places where only an offset address is present, the stub
> would generate the non-offset address.
>
> This has the advantage that no optimisation is penalised. It's quite
> complex to implement though.
> >>
>
> Well it's a step along the route to type accurate GC, and really if you
> even contemplate going this far, you may as well go all the way.
Sometimes you don't have accurate types. E.g. you may still want a
Boehm-style conservative GC to emulate malloc() for C programs, and the
type information in those C programs is not accurate enough for typed GC.
However I agree it would be very nice to do full type accurate GC.
_Much_ more stub code & tables though.
-- Jamie