Re: [Caml-list] native-code stack backtraces (was: Ocaml compiler features)

[Xavier Leroy <Xavier.Leroy@inria.fr>]

Among the 150 messages that accumulated while I was at the POPL
conference, I notice that the topic of native-code exception
backtraces is making its come-back:

> Well, seeing that the very useful native exception backtrace patch has
been
> sitting idle (acknowledged) for more than a year, I think that's not
> working it out too well :\

Like elephants, I'm slow, but never forget :-)  You'll be pleased to
learn that I've been working recently on exception backtraces for
ocamlopt.  The code (nearly finished) currently sits in the
"opt_backtrace" branch of the repository and should be part of
release 3.10.

It implements an exception backtrace mechanism similar to that already
available in bytecode, but different from Markus Mottl's call backtrace.
The two kinds of backtraces are incomparable in general, but while
Markus's solution is quite low overhead already, mine has even lower
overhead, especially in terms of code size.

Native-code backtraces will be available initially for the following
back-ends: i386, amd64 and powerpc, both for Unix-like OS and for
Windows.  Ports to other back-ends will be considered if there is
sufficient demand.

- Xavier Leroy