PATCH: Fix restarting breakpoint (Re: gdb 5.2 removes the conditional breakpoints)

H . J . Lu
2002-04-18T00:33:52Z

On Wed, Apr 17, 2002 at 04:57:56PM -0700, H . J . Lu wrote:
> On Wed, Apr 10, 2002 at 10:52:51AM +0300, Michael Veksler wrote:
> > /References/: <20020322095020.A12445@lucon.org
> > <http://sources.redhat.com/ml/gdb/2002-03/msg00196.html> >
> > <3C9B76F5.6050809@cygnus.com
> > <http://sources.redhat.com/ml/gdb/2002-03/msg00198.html> >
> >
> >
> > On Fri, Mar 22, 2002 at 01:24:53PM -0500, Andrew Cagney wrote:
> > > > When I do
> > > >
> > > > (gdb) b 100
> > > > (gdb) cond 1 i == 3
> > > > (gdb) r
> > > > (gdb) r
> > > >
> > > > gdb 5.2 will remove the conditional breakpoints on Linux/x86 after I
> > > > restart the debug session. Am I the only one who sees it?
> > >
> > > It would be very helpful if you could illustrate this problem by
> > > submitting a real testcase. That way people can run it and check
> > > before/after effects on various platforms and GDB releases.
> > >
> >
> > Here are the instructions for reproducing this annoying problem:
> >
> > // Debugged source:
> > typedef int operation(int val);
> >
> > int f(operation * op, int value)
> > {
> > return op(value);
> > }
> >
> > int nop(int val)
> > {
> > return val;
> > }
> >
> > int main()
> > {
> > return f(nop, 5);
> > }
> > // End source
> >
> > Compile it on Linux using gcc 3.0.4 or redhat's 2.96 (did not test it
> > on other versions).
> > (gdb) b main
> > (gdb) r
> > Breakpoint 1, main () at t.c:15
> > 15 return f(nop, 5);
> > (gdb) s
> > f (op=0x8048448 <nop>, value=5) at t.c:5
> > 5 return op(value);
> > (gdb) b
> > Breakpoint 2 at 0x8048432: file t.c, line 5.
>
> Thanks for the testcase. Basically, we deleted all break points set
> with "break" when we restart. It is a very bad regression from gdb
> 4.17. Here is a patch. May I check it into gdb 5.2?
>
> Thanks.
>
>
> H.J.
> ----
> 2002-04-17 H.J. Lu (hjl@gnu.org)
>
> * breakpoint.c (create_thread_event_breakpoint): Use xasprintf.
> (create_breakpoints): Make sure the addr_string field is not
> NULL.
>

Here is an update. It just uses

xasprintf (&b->addr_string, "*0x%s", paddr (b->address));

H.J.
---
2002-04-17 H.J. Lu (hjl@gnu.org)

* breakpoint.c (create_thread_event_breakpoint): Use xasprintf.
(create_breakpoints): Make sure the addr_string field is not
NULL.

--- gdb/breakpoint.c.break Wed Mar 6 22:30:42 2002
+++ gdb/breakpoint.c Wed Apr 17 17:29:58 2002
@@ -3859,14 +3859,12 @@ struct breakpoint *
create_thread_event_breakpoint (CORE_ADDR address)
{
struct breakpoint *b;
- char addr_string[80]; /* Surely an addr can't be longer than that. */

b = create_internal_breakpoint (address, bp_thread_event);

b->enable_state = bp_enabled;
/* addr_string has to be used or breakpoint_re_set will delete me. */
- sprintf (addr_string, "*0x%s", paddr (b->address));
- b->addr_string = xstrdup (addr_string);
+ xasprintf (&b->addr_string, "*0x%s", paddr (b->address));

return b;
}
@@ -4422,7 +4420,12 @@ create_breakpoints (struct symtabs_and_l
b->number = breakpoint_count;
b->cond = cond[i];
b->thread = thread;
- b->addr_string = addr_string[i];
+ if (addr_string[i])
+ b->addr_string = addr_string[i];
+ else
+ /* addr_string has to be used or breakpoint_re_set will delete
+ me. */
+ xasprintf (&b->addr_string, "*0x%s", paddr (b->address));
b->cond_string = cond_string[i];
b->ignore_count = ignore_count;
b->enable_state = bp_enabled;