Re: Reminder: Illegal Package-Private Accesses in libgcj

[Bryce McKinlay <bryce at mckinlay dot net dot nz>]

On Nov 4, 2003, at 12:25 AM, Andrew Haley wrote:

> Bryce McKinlay writes:
> > If there are targets that will never support the unwinder (are
> > there?), then it might make sense to allow platforms to define some
> > platform-specific unwinding functions, but ideally, by far the
> > cleanest and most efficient solution is to get the libgcc DWARF2
> > unwinder working.
>
> Efficient?  I don't think so.  The glibc backtrace() function simply
> walks a linked list, and there's no more efficient way to do it than
> that.  The DWARF unwinder is a couple of orders of magnitude slower.

OK, but how do you get the java.lang.Class object from the IP value 
which backtrace() gives you? backtrace() becomes a lot slower if you 
have to call external programs or use dladdr() + demangling (and the 
demangling approach is fragile and unsafe). The DWARF unwinder gives us 
the method entry point address which is an order of magnitude more 
useful than just the IP ;-)

Regards

Bryce.