[PATCH 4/7] range stepping: gdb

[Yao Qi <yao@codesourcery.com>]

This patch teaches GDB to send 'vCont;r' packet when appropriate.
GDB has to check whether the target understands 'r' action of 'vCont'
packet.  We also make use of fields 'step_range_start' and
'step_range_end' of 'struct thread_control_state' to compose the range
of the stepping.

gdb:

2013-03-11  Yao Qi  <yao@codesourcery.com>

	* remote.c (struct support_v_cont) <r>: New field.
	(remote_vcont_probe): Handle 'r' action of 'vCont' packet.
	(append_resumption): Send 'vCont;r' for range stepping.
---
 gdb/remote.c |   36 +++++++++++++++++++++++++++++++++++-
 1 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/gdb/remote.c b/gdb/remote.c
index ae0ae7e..84e09b0 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -253,6 +253,8 @@ struct support_v_cont
 {
   /* True if the stub reports support for vCont;t.  */
   int t;
+  /* True if the stub reports support for vCont;r.  */
+  int r;
 };
 
 /* Description of the remote protocol state for the currently
@@ -4644,6 +4646,7 @@ remote_vcont_probe (struct remote_state *rs)
       support_c = 0;
       support_C = 0;
       rs->support_vCont.t = 0;
+      rs->support_vCont.r = 0;
       while (p && *p == ';')
 	{
 	  p++;
@@ -4657,6 +4660,8 @@ remote_vcont_probe (struct remote_state *rs)
 	    support_C = 1;
 	  else if (*p == 't' && (*(p + 1) == ';' || *(p + 1) == 0))
 	    rs->support_vCont.t = 1;
+	  else if (*p == 'r' && (*(p + 1) == ';' || *(p + 1) == 0))
+	    rs->support_vCont.r = 1;
 
 	  p = strchr (p, ';');
 	}
@@ -4689,7 +4694,36 @@ append_resumption (char *p, char *endp,
   if (step && siggnal != GDB_SIGNAL_0)
     p += xsnprintf (p, endp - p, ";S%02x", siggnal);
   else if (step)
-    p += xsnprintf (p, endp - p, ";s");
+    {
+      struct thread_info *tp = NULL;
+      CORE_ADDR pc;
+
+      gdb_assert (!ptid_equal (ptid, minus_one_ptid));
+
+      if (ptid_is_pid (ptid))
+	tp = find_thread_ptid (inferior_ptid);
+      else
+	tp = find_thread_ptid (ptid);
+      gdb_assert (tp != NULL);
+
+      pc = regcache_read_pc (get_thread_regcache (ptid));
+      if (rs->support_vCont.r /* Target supports step range.  */
+	  /* Can't do range stepping for all threads of a process
+	     'pPID.-1'.  */
+	  && !(remote_multi_process_p (rs) && ptid_is_pid (ptid))
+	  /* Not step over a breakpoint.  */
+	  && !tp->control.trap_expected
+	  /* We have a range to single step.  */
+	  && THREAD_WITHIN_SINGLE_STEP_RANGE (tp, pc))
+	{
+	  p += xsnprintf (p, endp - p, ";r");
+	  p += hexnumstr (p, tp->control.step_range_start);
+	  p += xsnprintf (p, endp - p, ",");
+	  p += hexnumstr (p, tp->control.step_range_end);
+	}
+      else
+	p += xsnprintf (p, endp - p, ";s");
+    }
   else if (siggnal != GDB_SIGNAL_0)
     p += xsnprintf (p, endp - p, ";C%02x", siggnal);
   else
-- 
1.7.7.6