[m-dev.] LCO

[Erwan Jahier]

Fergus Henderson wrote:
> 
> On 18-Sep-1998, Erwan Jahier <Erwan.Jahier at irisa.fr> wrote:
> > Zoltan Somogyi wrote:
> >
> > > > 2) Is LCO switch off when tracing is on ?
> > >
> > > Effectively, yes. The code of the exit event will prevent any kind of last
> > > call optimization.
> >
> > hmm... shouldn't we have a --trace-exit option in order to still be able
> > to trace programs that makes strong use of LCO ?
> 
> Is this a real need, or an imagined need?
> How common are such programs?

Well in fact, that is not the reason why I am asking that. 
The reason is that if we could have a tracer "ligth" enough to allow
user to always compile their program with trace information on, it would
be great !

I've done benchmarks on a program that solve the hanoi tower problem
with 19 disks, and it happends that the program with tracing on runs
around 15% slower which is already not too bad (I shall do more
benchmarks).

so if we could have a tracing level that preserve LCO, it would be nice
in that respect.

Moreover, we may be able to reconstruct dynamicly that information (I
mean, the exit ports) at the opium level. It could be very expensive (we
may need to look into the source files), but it would be done only on
demand.

-- 
R1.