[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
gdb-ui bogosity with conditional breakpoints
From: |
Nick Roberts |
Subject: |
gdb-ui bogosity with conditional breakpoints |
Date: |
Fri, 7 Apr 2006 10:50:13 +1200 |
> I'm running a program invoked with Emacs gdb-ui with a conditional
> breakpoint. Normally gdb will appear to just run silently until it hits
> the breakpoint and the condition evaluates to true (it's somewhat
> slower than normal because of gdb's involvement, but in many cases,
> quite usable).
>
> However, using gdb-ui, it appears to be notifying Emacs _every time_ it
> hits the breakpoint, even when the condition is not true! As a result
> it's running, but the "run status" in the mode-line keeps flickering
> between "[running]" and "[stopped]", and the "current location" icon in
> the fring is flashing (at the breakpoint position).
You don't say what your condition was, but my crystal ball (which can't see
as clearly as Stefan's) says that it calls a function e.g
int mysquare (int x)
{
return x*x;
}
(gdb) break 81 if mysquare (i) == 49
and that something like
(gdb) break 81 if i == 7
doesn't have the same problem.
> This _drastically_ slows down execution, far more than the normal speed
> penalty for using a conditional breakpoint. It also insists on popping
> up the source window every time it hits the breakpoint (even though it
> doesn't actually stop), which obviously messes up the user's window
> arrangement (continually!).
It might be a bit quicker if you use GDB 6.4 as this version doesn't spew
out so many annotations for level 3.
> Is there anyway to disable this behavior? If so, I think it should be
> the default -- the icon and mode-line flashing is not particularly
> useful, and the annoyance level is fairly high.
If my diagnosis is correct then I think the answer is no, without delving into
GDB to stop the erroneous starting and stopped annotations from being
generated. I don't plan to do that because a) annotations are being
deprecated and b) while setting a condition on a breakpoint with a function is
perfectly reasonable, it's probably not done that often.
If my diagnosis is wrong, please post a complete testcase and/or the value of
gdb-debug-ring (after setting gdb-enable-debug to t at the start of the
session). Keep the number of iterations small but if there is still a
lot of data please send it off list.
--
Nick http://www.inet.net.nz/~nickrob