[PATCH v3 03/19] btrace: improve stepping debugging

Markus Metzger
2015-09-17T14:10:03Z

* record-btrace.c (btrace_thread_flag_to_str)
(record_btrace_cancel_resume): New.
(record_btrace_step_thread): Call btrace_thread_flag_to_str.
(record_btrace_resume): Print execution direction.
(record_btrace_resume_thread): Call btrace_thread_flag_to_str.
(record_btrace_wait): Call record_btrace_cancel_resume.
---
gdb/record-btrace.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 53 insertions(+), 4 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index a9ed4b7..7ee681c 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1659,6 +1659,32 @@ record_btrace_to_get_tailcall_unwinder (struct target_ops *self)
return &record_btrace_tailcall_frame_unwind;
}

+/* Return a human-readable string for FLAG. */
+
+static const char *
+btrace_thread_flag_to_str (enum btrace_thread_flag flag)
+{
+ switch (flag)
+ {
+ case BTHR_STEP:
+ return "step";
+
+ case BTHR_RSTEP:
+ return "reverse-step";
+
+ case BTHR_CONT:
+ return "cont";
+
+ case BTHR_RCONT:
+ return "reverse-cont";
+
+ case BTHR_STOP:
+ return "stop";
+ }
+
+ return "<invalid>";
+}
+
/* Indicate that TP should be resumed according to FLAG. */

static void
@@ -1667,7 +1693,8 @@ record_btrace_resume_thread (struct thread_info *tp,
{
struct btrace_thread_info *btinfo;

- DEBUG ("resuming %d (%s): %u", tp->num, target_pid_to_str (tp->ptid), flag);
+ DEBUG ("resuming thread %d (%s): %x (%s)", tp->num,
+ target_pid_to_str (tp->ptid), flag, btrace_thread_flag_to_str (flag));

btinfo = &tp->btrace;

@@ -1820,7 +1847,9 @@ record_btrace_resume (struct target_ops *ops, ptid_t ptid, int step,
struct thread_info *tp, *other;
enum btrace_thread_flag flag;

- DEBUG ("resume %s: %s", target_pid_to_str (ptid), step ? "step" : "cont");
+ DEBUG ("resume %s: %s%s", target_pid_to_str (ptid),
+ execution_direction == EXEC_REVERSE ? "reverse-" : "",
+ step ? "step" : "cont");

/* Store the execution direction of the last resume. */
record_btrace_resume_exec_dir = execution_direction;
@@ -1865,6 +1894,24 @@ record_btrace_resume (struct target_ops *ops, ptid_t ptid, int step,
}
}

+/* Cancel resuming TP. */
+
+static void
+record_btrace_cancel_resume (struct thread_info *tp)
+{
+ enum btrace_thread_flag flags;
+
+ flags = tp->btrace.flags & (BTHR_MOVE | BTHR_STOP);
+ if (flags == 0)
+ return;
+
+ DEBUG ("cancel resume thread %d (%s): %x (%s)", tp->num,
+ target_pid_to_str (tp->ptid), flags,
+ btrace_thread_flag_to_str (flags));
+
+ tp->btrace.flags &= ~(BTHR_MOVE | BTHR_STOP);
+}
+
/* Find a thread to move. */

static struct thread_info *
@@ -1955,7 +2002,9 @@ record_btrace_step_thread (struct thread_info *tp)
flags = btinfo->flags & (BTHR_MOVE | BTHR_STOP);
btinfo->flags &= ~(BTHR_MOVE | BTHR_STOP);

- DEBUG ("stepping %d (%s): %u", tp->num, target_pid_to_str (tp->ptid), flags);
+ DEBUG ("stepping thread %d (%s): %x (%s)", tp->num,
+ target_pid_to_str (tp->ptid), flags,
+ btrace_thread_flag_to_str (flags));

/* We can't step without an execution history. */
if ((flags & BTHR_MOVE) != 0 && btrace_is_empty (tp))
@@ -2126,7 +2175,7 @@ record_btrace_wait (struct target_ops *ops, ptid_t ptid,
/* Stop all other threads. */
if (!target_is_non_stop_p ())
ALL_NON_EXITED_THREADS (other)
- other->btrace.flags &= ~(BTHR_MOVE | BTHR_STOP);
+ record_btrace_cancel_resume (other);

/* Start record histories anew from the current position. */
record_btrace_clear_histories (&tp->btrace);
--
1.8.3.1