This is the mail archive of the
mailing list for the GDB project.
gdb_assert when resetting breakpoints
- From: Roland Schwingel <roland dot schwingel at onevision dot de>
- To: gdb <gdb at sourceware dot org>
- Date: Tue, 10 Mar 2009 15:02:40 +0100
- Subject: gdb_assert when resetting breakpoints
When using current gdb cvs head sources I encounter a gdb_assert() in
breakpoint.c line 7451.
This is in function breakpoint_re_set_one().
Let me tell you what I am doing to get it (reproduceably). I am not a
guru to gdb's internals so
please forgive me if I conclude something wrong.
I am having a mixed C and Objective C application. I am running on
windows using GNUstep
for my ObjC Foundation classes. GNUstep-base is a shared library loaded
Due to the nature of this bug I assume that this will also appear on
other platforms like linux
(according to my analysis). So it is not windows specific.
I start gdb and set a breakpoint to main() using "b main". Then I run my
app using "r".
A few seconds later I get the assert in breakpoint.c:7451
When I debug into it sals.nelts == 2. The assert happens when the
library was loaded.
What has happenend: In breakpoint.c line 7417 you find:
sals = decode_line_1 (&s, 1, (struct symtab *) NULL, 0, (char ***)
s points to "main" at that moment as found in the breakpoint structure
supplied to breakpoint_re_set_one().
sals (returned from decode_line_1) contains 2 entries.
Sals entry 0 points to the ObjectiveC METHOD main of the foundation base
(written in ObjC notation -[NSThread main]). This is a real ObjC
baseclass not something
from my own code. It has also nothing to do with an application's
entrypoint. It also perfectly
legal in ObjectiveC to name methods like C functions. They do not collide.
Sals entry 1 points to the function "main()" of my application. This is
the entry which I think is
the correct one to use here.
Obviously decode_line_1 returns every symbol matching a certain string
its language. As far as I understand gdb at the moment this appears to
So what is the correct behaviour here to fix this problem? I assume that
there might be more
areas of symbol duplicates that can occur not only main() vs -[NSThread
Maybe the assert should be replaced by a loop over the sals entries
matching the infos from the
breakpoint structure passed to breakpoint_re_set_one() and the
individual symtab entry of one
sals entry by filename(?) matching?
Thanks in advance for your help,