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Re: java aliasing rules
- From: Jeff Sturm <jsturm at one-point dot com>
- To: Andrew Haley <aph at cambridge dot redhat dot com>
- Cc: Bryce McKinlay <bryce at waitaki dot otago dot ac dot nz>, tromey at redhat dot com, Dan Nicolaescu <dann at godzilla dot ics dot uci dot edu>, java at gcc dot gnu dot org, gcc at gcc dot gnu dot org
- Date: Thu, 4 Apr 2002 16:10:14 -0500 (EST)
- Subject: Re: java aliasing rules
On Thu, 4 Apr 2002, Andrew Haley wrote:
> > > Right, its not optimal scheduling, but there's no way to avoid that and
> > > still have the correct behaviour for NullPointers. And as you suggest, a
> > > modern processor may be speculativly executing the following loads, so
> > > it probibly doesn't matter too much.
>
> If it doesn't annul such speculation on SEGV I don't think it's
> correct Java semantics.
I've been told that EV6 does, don't know about others. (CPUs are complex
beasts nowadays, that's for sure.)
> > It might be useful to turn this "correctness" off with a compiler option,
> > as we do with -fno-bounds-check. I habitually check for null in my code,
> > and don't do anything useful with a NullPointerException besides aborting.
> > I suspect that's true of a great deal of Java code.
>
> I know what you mean, but turning this off is a pretty major departure
> from the Java language spec.
Perhaps. There are days I wonder if Java is the language I need. What
I'd really like is Java that easily binds to C++ code... um, never
mind ;)
Jeff