Re: possible regression in gdb 7.4 with -break-insert +0

[Keith Seitz <keiths at redhat dot com>]

On 03/21/2012 08:01 AM, Martin wrote:
> I believe I found a regression in gdb 7.4. (Tested on Win 32bit Vista)
>
> using "gdb -i mi", the command "-break-insert +0" should insert a
> breakpoint at the an offset of 0 lines from current.
> - With previous versions of gdb, if the command was issued before
> -exec-run, then a breakpoint was inserted at the first line of code.
> - With 7.4-2, it is inserted, but when running gives the error:
> &"Error in re-setting breakpoint 1: No line 0 in file \"Test.pas\".\n"

I can reproduce this with CVS HEAD today. I believe this is fallout from 
the ambiguous linespec patch, but I did not investigate it, because I've 
just submitted a monstrous patch to rewrite most of this area (linespecs).

I mention this because on my archer-keiths-linespec-rewrite branch 
(which is CVS HEAD + my linespec rewrite patch), this appears to work:

$ ./gdb -q gdb
Reading symbols from /home/keiths/work/archer/linespec/linux/gdb/gdb...done.
(top-gdb) b +0
Breakpoint 1 at 0x455153: file ../../archer/gdb/gdb.c, line 25.
(top-gdb) r -nx -q
Starting program: /home/keiths/work/archer/linespec/linux/gdb/gdb
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Breakpoint 1, main (argc=1, argv=0x7fffffffe0a8) at 
../../archer/gdb/gdb.c:29
29	  memset (&args, 0, sizeof args);

Compare to CVS HEAD:

$ ./gdb -nx -q gdb
Reading symbols from 
/home/keiths/sources/gdb/git/virgin/linux/gdb/gdb...done.
(top-gdb) b +0
Breakpoint 1 at 0x487343: file ../../gdb/gdb/gdb.c, line 20.
(top-gdb) r -nx -q
Starting program: /home/keiths/sources/gdb/git/virgin/linux/gdb/gdb -nx -q
Error in re-setting breakpoint 1: No line 0 in file "../../gdb/gdb/gdb.c".
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

So when my patch is approved (might take many days yet), this should be 
working again. I'm afraid that doesn't help you much now, though...

Keith