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Use reinsert_breakpoint for vCont;s

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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 and reports it back to
GDB.

gdb/gdbserver:

2016-07-21  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_lwp_throw): Don't assert the thread has reinsert
	breakpoints or not.
	(proceed_one_lwp): If resume request is resume_step, install
	reinsert breakpoints and call maybe_hw_step.
This commit is contained in:
Yao Qi 2016-07-21 12:12:18 +01:00
parent 0e9a339ec8
commit 8901d1936e
2 changed files with 83 additions and 8 deletions
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11
gdb/gdbserver/ChangeLog
View File

@ -1,3 +1,14 @@
2016-07-21 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_lwp_throw): Don't assert the thread has reinsert
breakpoints or not.
(proceed_one_lwp): If resume request is resume_step, install
reinsert breakpoints and call maybe_hw_step.
2016-07-21 Yao Qi <yao.qi@linaro.org>
* linux-low.c (proceed_one_lwp): Declare.

80
gdb/gdbserver/linux-low.c
View File

@ -2641,7 +2641,10 @@ 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",
@ -3700,6 +3703,66 @@ linux_wait_1 (ptid_t ptid,
/* Alright, we're going to report a stop. */
/* Remove reinsert breakpoints. */
if (can_software_single_step ())
{
/* Remove reinsert breakpoints or not. It it is true, stop all
lwps, so that other threads won't hit the breakpoint in the
staled memory. */
int remove_reinsert_breakpoints_p = 0;
if (non_stop)
{
remove_reinsert_breakpoints_p
= has_reinsert_breakpoints (current_thread);
}
else
{
/* In all-stop, a stop reply cancels all previous resume
requests. Delete all reinsert breakpoints. */
struct inferior_list_entry *inf, *tmp;
ALL_INFERIORS (&all_threads, inf, tmp)
{
struct thread_info *thread = (struct thread_info *) inf;
if (has_reinsert_breakpoints (thread))
{
remove_reinsert_breakpoints_p = 1;
break;
}
}
}
if (remove_reinsert_breakpoints_p)
{
/* If we remove reinsert breakpoints from memory, stop all lwps,
so that other threads won't hit the breakpoint in the staled
memory. */
stop_all_lwps (0, event_child);
if (non_stop)
{
gdb_assert (has_reinsert_breakpoints (current_thread));
delete_reinsert_breakpoints (current_thread);
}
else
{
struct inferior_list_entry *inf, *tmp;
ALL_INFERIORS (&all_threads, inf, tmp)
{
struct thread_info *thread = (struct thread_info *) inf;
if (has_reinsert_breakpoints (thread))
delete_reinsert_breakpoints (thread);
}
}
unstop_all_lwps (0, event_child);
}
}
if (!stabilizing_threads)
{
/* In all-stop, stop all threads. */
@ -4353,12 +4416,6 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
step = maybe_hw_step (thread);
}
else
{
/* If the thread isn't doing step-over, there shouldn't be any
reinsert breakpoints. */
gdb_assert (!has_reinsert_breakpoints (thread));
}
if (fast_tp_collecting == 1)
{
@ -5166,7 +5223,14 @@ 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;
/* If resume_step is requested by GDB, install reinsert
breakpoints when the thread is about to be actually resumed if
the reinsert breakpoints weren't removed. */
if (can_software_single_step () && !has_reinsert_breakpoints (thread))
install_software_single_step_breakpoints (lwp);
step = maybe_hw_step (thread);
}
else if (lwp->bp_reinsert != 0)
{