gdb/gdb-6.3-thread-step-2004120...

59 lines
2.0 KiB
Diff

2004-12-07 Jeff Johnston <jjohnstn@redhat.com>
* linux-nat.c (find_singlestep_lwp_callback): New function.
(linux-nat-wait): Before waiting on any pid, check if there
is a stepping lwp and if so, wait on it specifically.
--- gdb-6.3/gdb/linux-nat.c.fix Tue Dec 7 19:39:34 2004
+++ gdb-6.3/gdb/linux-nat.c Tue Dec 7 19:39:46 2004
@@ -1489,9 +1489,21 @@ count_events_callback (struct lwp_info *
return 0;
}
-/* Select the LWP (if any) that is currently being single-stepped. */
+/* Find an LWP (if any) that is currently being single-stepped. */
static int
+find_singlestep_lwp_callback (struct lwp_info *lp, void *data)
+{
+ if (lp->step)
+ return 1;
+ else
+ return 0;
+}
+
+/* Select the LWP with an event (if any) that is currently being
+ single-stepped. */
+
+static int
select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
{
if (lp->step && lp->status != 0)
@@ -1774,7 +1786,25 @@ retry:
least if there are any LWPs at all. */
gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL));
- /* First check if there is a LWP with a wait status pending. */
+ /* Check if there is any LWP that is being single-stepped. We need to
+ wait specifically on such an LWP because the higher-level code is
+ expecting a step operation to find an event on the stepped LWP.
+ It is possible for other events to occur before the step operation
+ gets the expected trap so we don't want to wait on any LWP.
+ This has ramifications when adjustment of the PC is required which can be
+ different after a breakpoint vs a step (e.g. x86). */
+ lp = iterate_over_lwps (find_singlestep_lwp_callback, NULL);
+ if (lp) {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Found step lwp %s.\n",
+ target_pid_to_str (lp->ptid));
+ ptid = lp->ptid;
+ pid = PIDGET (ptid);
+ }
+
+ /* If any pid, check if there is a LWP with a wait status pending. */
+
if (pid == -1)
{
/* Any LWP that's been resumed will do. */