why does exception.cc have "unwinding" code for sjlj?

Fri Feb 1 00:20:00 GMT 2002

I don't get it -- I thought the whole point of SJLJ was that you
couldn't meaningfully "unwind" the stack to get a stack trace. Isn't
that [part of] what makes DWARF2 better than SJLJ?
#ifdef SJLJ_EXCEPTIONS
 // The given "IP" is an index into the call-site table, with two
 // exceptions -- -1 means no-action, and 0 means terminate. But
 // since we're using uleb128 values, we've not got random access
 // to the array.
 if ((int) ip <= 0)
 return _URC_CONTINUE_UNWIND;
 else
 {
 _Unwind_Word cs_lp, cs_action;
 do
 {
 p = read_uleb128 (p, &cs_lp);
....
The main problem I'm running into is that some of the unwind code
requires libstdc++ (specifically, #include <cstdlib>), but libstdc++
has a lot of problems crosscompiling, and I'd rather just not build it
than try to get my (ugly) patches to its configure.in accepted; I'd
probably break more stuff than I would fix, anyways...
Win32 never calls the _Unwind functions anyways; it just throws an
exception out of the signal handler.
Suggestions on how to deal with this?
 - a