[RFC] Backtrace limit

David Lecomber
2004-08-25T19:49:57Z

I've just filed a bug (1790) and done some investigation into the
backtrace limit variable.

Essentially the limiting doesn't work: set it to 10, and it always
claims to be true. The culprit is that the type of frame->level is
int, and the type of backtrace_limit is uint.

This wouldn't be a problem except that there is always a frame with
level -1 (it seems to be the 0 level-frame when printed out).

So, the non-elegant fix is:

RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.190
diff -c -p -r1.190 frame.c
*** frame.c 2 Aug 2004 03:36:24 -0000 1.190
--- frame.c 25 Aug 2004 19:48:30 -0000
*************** get_prev_frame (struct frame_info *this_
*** 1179,1185 ****
return NULL;
}

! if (this_frame->level > backtrace_limit)
{
error ("Backtrace limit of %d exceeded", backtrace_limit);
}
--- 1179,1186 ----
return NULL;
}

! if (this_frame->level != -1 &&
! (unsigned int) this_frame->level > backtrace_limit)
{
error ("Backtrace limit of %d exceeded", backtrace_limit);

But I'm open to suggestions involving making backtrace_limit a signed
int.

Any comments?

Cheers
David