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Re: GC changes
- To: Jamie Lokier <egcs at tantalophile dot demon dot co dot uk>
- Subject: Re: GC changes
- From: Fergus Henderson <fjh at cs dot mu dot oz dot au>
- Date: Tue, 16 Jan 2001 01:13:48 +1100
- Cc: Mike Stump <mrs at windriver dot com>, amylaar at cambridge dot redhat dot com, gcc at gcc dot gnu dot org, geoffk at geoffk dot org, tej at melbpc dot org dot au
- References: <200101150255.SAA03643@kankakee.wrs.com> <20010115100442.A18014@pcep-jamie.cern.ch>
On 15-Jan-2001, Jamie Lokier <email@example.com> wrote:
> Mike Stump wrote:
> > > That is not safe. You can't predict what kind of address arithmetic
> > > the compiler will make. For example, strength reduction could cause
> > > a pointer to be pointing into the middle of an array, or worse,
> > > somewhere beyond it (incorporating some constant adjustments).
> > We already need a switch to disable GC unfriendly optimizations.
> Or two -- some GCs can handle interior pointers but some cannot.
And some GCs can handle some interior pointers but not others.
E.g. the Boehm GC can be configured to handle
- no interior pointers
- interior pointers with an offset up to N
- all interior pointers but not the one-past-the-end pointers
- all interior pointers plus one-past-the-end pointers
Fergus Henderson <firstname.lastname@example.org> | "I have always known that the pursuit
| of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.