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[PATCH 11/12] Use reinsert_breakpoint for vCont;s
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Thu, 2 Jun 2016 10:30:45 +0100
- Subject: [PATCH 11/12] Use reinsert_breakpoint for vCont;s
- Authentication-results: sourceware.org; auth=none
- References: <1464859846-15619-1-git-send-email-yao dot qi at linaro dot org>
V2: fix spaces in changelog entry,
use maybe_hw_step,
cancel step-over if signal arrives (!maybe_internal_trap),
This patch is to teach GDBserver using software single step to handle
vCont;s. Simply speaking, if the thread's resume request is resume_step,
install reinsert breakpoint at the next pcs when GDBserver is about to
resume threads. These reinsert breakpoints of a thread are removed,
when GDBserver gets an event from that thread. Note that GDBserver may
or may not report this event back to GDB.
gdb/gdbserver:
2016-05-20 Yao Qi <yao.qi@linaro.org>
* linux-low.c (resume_stopped_resumed_lwps): If resume request
is resume_step, call maybe_hw_step.
(linux_wait_1): Stop all threads, remove reinsert breakpoints,
and unstop them.
(linux_resume_one_thread): If resume request is resume_step,
call maybe_hw_step.
(linux_resume): Install reinsert breakpoints if the thread is
requested to resume_step.
(proceed_one_lwp): If resume request is resume_step, call
maybe_hw_step.
(proceed_all_lwps): Install reinsert breakpoints if the thread is
requested to resume_step.
---
gdb/gdbserver/linux-low.c | 99 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 94 insertions(+), 5 deletions(-)
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 6f32911..4e79ec1 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -2579,7 +2579,10 @@ resume_stopped_resumed_lwps (struct inferior_list_entry *entry)
&& !lp->status_pending_p
&& thread->last_status.kind == TARGET_WAITKIND_IGNORE)
{
- int step = thread->last_resume_kind == resume_step;
+ int step = 0;
+
+ if (thread->last_resume_kind == resume_step)
+ step = maybe_hw_step (thread);
if (debug_threads)
debug_printf ("RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
@@ -3530,6 +3533,23 @@ linux_wait_1 (ptid_t ptid,
return ignore_event (ourstatus);
}
+ /* Remove reinsert breakpoints ... */
+ if (can_software_single_step ()
+ && has_reinsert_breakpoints (current_thread)
+ /*... if GDB requests this thread doing resume_step or ...*/
+ && (current_thread->last_resume_kind == resume_step
+ /* GDBserver has already started the step-over for vCont;s,
+ but it gets some other signal, like SIGSTOP sent by
+ GDBserver for vCont;t or other signal program received. */
+ || !maybe_internal_trap))
+ {
+ stop_all_lwps (1, event_child);
+
+ delete_reinsert_breakpoints (current_ptid);
+
+ unstop_all_lwps (1, event_child);
+ }
+
/* Note that all addresses are always "out of the step range" when
there's no range to begin with. */
in_step_range = lwp_in_step_range (event_child);
@@ -4293,7 +4313,7 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
step = maybe_hw_step (thread);
}
- else
+ else if (lwp->resume != NULL && lwp->resume->kind != resume_step)
{
/* If the thread isn't doing step-over, there shouldn't be any
reinsert breakpoints. */
@@ -4853,7 +4873,6 @@ linux_resume_one_thread (struct inferior_list_entry *entry, void *arg)
{
struct thread_info *thread = (struct thread_info *) entry;
struct lwp_info *lwp = get_thread_lwp (thread);
- int step;
int leave_all_stopped = * (int *) arg;
int leave_pending;
@@ -4922,10 +4941,14 @@ linux_resume_one_thread (struct inferior_list_entry *entry, void *arg)
if (!leave_pending)
{
+ int step = 0;
+
if (debug_threads)
debug_printf ("resuming LWP %ld\n", lwpid_of (thread));
- step = (lwp->resume->kind == resume_step);
+ if (lwp->resume->kind == resume_step)
+ step = maybe_hw_step (thread);
+
linux_resume_one_lwp (lwp, step, lwp->resume->sig, NULL);
}
else
@@ -4966,6 +4989,7 @@ linux_resume (struct thread_resume *resume_info, size_t n)
struct thread_info *need_step_over = NULL;
int any_pending;
int leave_all_stopped;
+ int resume_step_is_handled = 0;
if (debug_threads)
{
@@ -5009,12 +5033,52 @@ linux_resume (struct thread_resume *resume_info, size_t n)
debug_printf ("Resuming, no pending status or step over needed\n");
}
+ /* Before we resume the threads, if resume_step is requested by GDB,
+ stop all threads and install reinsert breakpoints. */
+ if (!leave_all_stopped && can_software_single_step ())
+ {
+ struct inferior_list_entry *inf, *tmp;
+
+ if (debug_threads)
+ debug_printf ("Handle resume_step.\n");
+
+ ALL_INFERIORS (&all_threads, inf, tmp)
+ {
+ struct thread_info *thread = (struct thread_info *) inf;
+ struct lwp_info *lwp = get_thread_lwp (thread);
+
+ if (lwp->resume != NULL && lwp->resume->kind == resume_step)
+ {
+ if (!resume_step_is_handled)
+ {
+ stop_all_lwps (0, NULL);
+
+ if (debug_threads)
+ debug_printf ("Done stopping all threads.\n");
+
+ resume_step_is_handled = 1;
+ }
+
+ install_software_single_step_breakpoints (lwp);
+
+ if (debug_threads)
+ debug_printf ("Insert breakpoint for resume_step LWP %ld\n",
+ lwpid_of (thread));
+ }
+ }
+
+ if (debug_threads)
+ debug_printf ("Handle resume_step. Done\n");
+ }
+
/* Even if we're leaving threads stopped, queue all signals we'd
otherwise deliver. */
find_inferior (&all_threads, linux_resume_one_thread, &leave_all_stopped);
if (need_step_over)
start_step_over (get_thread_lwp (need_step_over));
+ else if (resume_step_is_handled)
+ unstop_all_lwps (0, NULL);
if (debug_threads)
{
@@ -5110,7 +5174,8 @@ proceed_one_lwp (struct inferior_list_entry *entry, void *except)
if (debug_threads)
debug_printf (" stepping LWP %ld, client wants it stepping\n",
lwpid_of (thread));
- step = 1;
+
+ step = maybe_hw_step (thread);
}
else if (lwp->bp_reinsert != 0)
{
@@ -5176,6 +5241,30 @@ proceed_all_lwps (void)
if (debug_threads)
debug_printf ("Proceeding, no step-over needed\n");
+ /* Re-install the reinsert breakpoints on software single step target
+ if the client wants it step. */
+ if (can_software_single_step ())
+ {
+ struct inferior_list_entry *inf, *tmp;
+
+ ALL_INFERIORS (&all_threads, inf, tmp)
+ {
+ struct thread_info *thread = (struct thread_info *) inf;
+
+ if (thread->last_resume_kind == resume_step)
+ {
+ struct lwp_info *lwp = get_thread_lwp (thread);
+
+ if (!has_reinsert_breakpoints (thread))
+ install_software_single_step_breakpoints (lwp);
+
+ if (debug_threads)
+ debug_printf ("Insert breakpoint for resume_step LWP %ld\n",
+ lwpid_of (thread));
+ }
+ }
+ }
+
find_inferior (&all_threads, proceed_one_lwp, NULL);
}
--
1.9.1