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Re: [RFC] When debugging infrun, print stop_pc in all possible cases.
- From: Pedro Alves <pedro at codesourcery dot com>
- To: gdb-patches at sourceware dot org
- Cc: Doug Evans <dje at google dot com>
- Date: Sat, 14 Mar 2009 12:43:42 +0000
- Subject: Re: [RFC] When debugging infrun, print stop_pc in all possible cases.
- References: <20090226180105.138461C78A7@localhost> <e394668d0903131006g688f0f5dp953d0ec4a3ebab15@mail.gmail.com>
On Friday 13 March 2009 17:06:13, Doug Evans wrote:
> On Thu, Feb 26, 2009 at 11:01 AM, Doug Evans <dje@google.com> wrote:
> > Hi.
> >
> > I've been debugging a few issues and it's been really helpful to know
> > stop_pc in cases that aren't printed today.
> > This patch moves the debug printing of stop_pc up.
> >
> > I'm not submitting it RFA because I'm not entirely happy with it.
> > Printing stop_pc has been helpful, I'd like to improve what's there today,
> > but it's not clear to me that this patch reasonably handles the cases
> > when one can't read pc before the big switch() on ecs->ws.kind.
Hmm,:
- not ignoring TARGET_WAITKIND_IGNORE.
- accessing the target before the set_executing call. It may end
up being a problem in the future.
- With displaced stepping, we lost the printing of the stop_pc
*after* the fixup.
- I'm not sure we want to move the watchpoint debug bits
as well.
> Any comments on this approach?
> Would you do it differently?
> [E.g. One could add code to print the pc to all the appropriate cases
> in the switch(), but that seems clumsy.]
Dunno, perhaps, come up with a "set_stop_pc (CORE_ADDR)" function, do
the debug printing there, and replace all the appropriate accesses
to that global by a call to the new function?
This is probably one of the cases where I'd hack the debug
output, fix the issue, and then remove the hack and forget
about it. :-)
> >
> > Comments?
> >
> > 2009-02-26 Doug Evans <dje@google.com>
> >
> > * infrun.c (handle_inferior_event): Move the debug printing of stop_pc,
> > and possible watchpoint address, to an earlier point so we print it
> > in all cases (where it's possible).
> >
> > Index: infrun.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/infrun.c,v
> > retrieving revision 1.360
> > diff -u -p -r1.360 infrun.c
> > --- infrun.c 25 Feb 2009 02:14:22 -0000 1.360
> > +++ infrun.c 26 Feb 2009 17:52:28 -0000
> > @@ -2178,6 +2178,46 @@ handle_inferior_event (struct execution_
> > /* Dependent on the current PC value modified by adjust_pc_after_break. */
> > reinit_frame_cache ();
> >
> > + if (debug_infrun)
> > + {
> > + /* It's helpful to know the stop pc in all cases when we stop
> > + (even if we're eventually going to resume).
> > + To keep things simple we print it here before the big switch on
> > + ecs->ws.kind. If we leave printing of stop_pc until later,
> > + we will miss the cases where we "return;" early.
> > + There are a few cases where we can't read pc though. */
> > +
> > + switch (ecs->ws.kind)
> > + {
> > + case TARGET_WAITKIND_EXITED:
> > + case TARGET_WAITKIND_SIGNALLED:
> > + break;
> > +
> > + default:
> > + {
> > + CORE_ADDR debug_stop_pc =
> > + regcache_read_pc (get_thread_regcache (ecs->ptid));
> > +
> > + fprintf_unfiltered (gdb_stdlog, "infrun: stop_pc = 0x%s\n",
> > + paddr_nz (debug_stop_pc));
> > +
> > + if (STOPPED_BY_WATCHPOINT (&ecs->ws))
> > + {
> > + CORE_ADDR addr;
> > +
> > + if (target_stopped_data_address (¤t_target, &addr))
> > + fprintf_unfiltered (gdb_stdlog,
> > + "infrun: stopped by watchpoint, data address = 0x%s\n",
> > + paddr_nz (addr));
> > + else
> > + fprintf_unfiltered (gdb_stdlog,
> > + "infrun: stopped by watchpoint, no data address available\n");
> > + }
> > + break;
> > + }
> > + }
> > + }
> > +
> > if (ecs->ws.kind != TARGET_WAITKIND_IGNORE)
> > {
> > breakpoint_retire_moribund ();
> > @@ -2507,25 +2547,6 @@ targets should add new threads to the th
> >
> > stop_pc = regcache_read_pc (get_thread_regcache (ecs->ptid));
> >
> > - if (debug_infrun)
> > - {
> > - fprintf_unfiltered (gdb_stdlog, "infrun: stop_pc = 0x%s\n",
> > - paddr_nz (stop_pc));
> > - if (STOPPED_BY_WATCHPOINT (&ecs->ws))
> > - {
> > - CORE_ADDR addr;
> > - fprintf_unfiltered (gdb_stdlog, "infrun: stopped by watchpoint\n");
> > -
> > - if (target_stopped_data_address (¤t_target, &addr))
> > - fprintf_unfiltered (gdb_stdlog,
> > - "infrun: stopped data address = 0x%s\n",
> > - paddr_nz (addr));
> > - else
> > - fprintf_unfiltered (gdb_stdlog,
> > - "infrun: (no data address available)\n");
> > - }
> > - }
> > -
> > if (stepping_past_singlestep_breakpoint)
> > {
> > gdb_assert (singlestep_breakpoints_inserted_p);
> >
>
--
Pedro Alves