Re: [Valgrind-developers] Porting valgrind to FreeBSD

[Doug R. <df...@nl...>]

On Sat, 2004-01-03 at 13:23, Nicholas Nethercote wrote:
> On Sat, 27 Dec 2003, Doug Rabson wrote:
> 
> > Since I've had a bit of festive spare time available, I thought I would
> > attempt to port valgrind 2.1.0 to FreeBSD-5.x. After a bit of a
> > struggle, two falls and a submission, I have most of it working well
> > enough to pass most of the tests (with the notable exception of the
> > pthread stuff which I haven't even tried to port yet).
> 
> Well done!  A few people have tried this, but it sounds like you've got a
> lot further than anyone else.  Would you be able to write some kind of
> summary describing the changes you had to make?  That would be very useful
> for people to get a grip on what you've done.

I summarised most of the changes in a later message and you can get a
patch against today's cvs at
http://people.freebsd.org/~dfr/valgrind-20040103-dfr.diff.

The most fiddly part was getting syscalls to work. FreeBSD (and probably
all 4.4BSD derived systems) has a quite different syscall ABI with
arguments on the stack and error-returns signalled with the carry flag.
Add to that the fact that some (not all) syscalls return an extra 32bits
in %edx and things get a bit tricky in vg_syscalls.c. Still, it helped
that I've been hacking the FreeBSD kernel for about eight years and
understand it about as well as anyone :-)