Re: Fix backtrace for interpreted code

[Andrew Haley <aph at redhat dot com>]

Ranjit Mathew writes:
 > Andrew Haley wrote:
 > > 
 > > There's no truly portable way to do something like this, but with a
 > > little help from the unwinder library we can do it.  This won't work
 > > without the unwinder, but as far as I'm aware
 > > _Unwind_FindEnclosingFunction should work on all targets.
 > > 
 > > Is this true even of mingw and Cygwin?  Anyone who knows, please let
 > > me know.
 > 
 > _Unwind_FindEnclosingFunction in unwind-sjlj.c always
 > returns NULL, so I would assume that it would not work
 > as expected on MinGW and Cygwin if GCC for these targets
 > is built to use SJLJ EH instead of DWARF-2 EH.

I see.  So, if you use SJLJ EH on these targets, it disables the
unwinder library as well?

The unwinder library is so important that systems without it will be
left behind.  It really is about time that the mingw mainatainers
fixed the unwinder so that it works through SEH frames.

In any case, I don't think this patch will break such systems, as
they're already broken.

Andrew.