Re: Debugging memory leaks

[Hans Boehm <Hans dot Boehm at hp dot com>]

Unfortunately, you currently have to rebuild libgcj to get this
functionality.  You need to build with --enable-gc-debug.

If you are debugging an application that can be made to leak most of
the memory in its heap, you can usually get the information you want by
setting the GC_BACKTRACES environment variable to a small integer.  This
will print the indicated number of backtraces from random addresses at
each pc.

If you need something more specific, look at gc_backptr.h.  You should be
able to use this directly from a debugger.  But watch out for unintended
reflection:  It's easy for this stuff to accidentally find "pointers" from
your debugging code itself.

Hans

On Fri, 15 Apr 2005, Andrew Haley wrote:

> I've been having a great deal of difficulty tracking down memory leaks
> in libgcj.
>
> What I need is some sort of interface that allows me to enquire who
> points to an object.  The ideal interface would be something like
> points_to (obj) -> obj.  I realize that in practice there is a set of
> objects that point to a particular object, but that doesn't concern
> me: one is all I need.
>
> Is there any interface within the GC that can give me this function?
> If not, how hard would it be to provide?  Can you provide me with some
> guidance?
>
> Ideally, I'd love to have something like Glasgow Haskell Compiler's
> heap profiling, but I'll settle for much less.
>
> Thanks,
> Andrew.
>