Re: [PATCH 4/7] range stepping: gdb

[Yao Qi <yao@codesourcery.com>]

On 04/11/2013 10:43 AM, Yao Qi wrote:
>   - Use phex_nz instead of hexnumstr to get the address.
.....

> +
> +	  p += xsnprintf (p, endp - p, ";r%s,%s",
> +			  phex_nz (tp->control.step_range_start,
> +				   addr_size),
> +			  phex_nz (tp->control.step_range_end,
> +				   addr_size));

It is incorrect to copy address to buffer via phex_nz here and
somewhere else in remote.c.  We should use remote_address_masked first
to mask the CORE_ADDR and then call hexnumstr to copy address to
buffer.  Here is an updated one.

This patch teaches GDB to send 'vCont;r' packet when appropriate.
GDB has to check whether the target understand '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.

In V2, there are several changes:

 - Call remote_address_masked first before call hexnumstr to get the
address.
 - Define an internalvar range_stepping_counter and increment it each
time GDB does range-stepping.

-- 
Yao (齐尧)

gdb:

2013-04-10  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 and
	increment internalvar range_stepping_counter.
---
 gdb/remote.c |   49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 48 insertions(+), 1 deletions(-)

diff --git a/gdb/remote.c b/gdb/remote.c
index f6a3f4c..4158a09 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -256,6 +256,8 @@ 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
@@ -4649,6 +4651,7 @@ 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++;
@@ -4662,6 +4665,8 @@ 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, ';');
 	}
@@ -4694,7 +4699,49 @@ 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))
+	{
+	  struct internalvar *range_stepping_counter
+	    = lookup_internalvar ("range_stepping_counter");
+	  LONGEST result = 0;
+	  CORE_ADDR addr;
+
+	  p += xsnprintf (p, endp - p, ";r");
+
+	  addr = tp->control.step_range_start;
+	  p += hexnumstr (p, (ULONGEST) remote_address_masked (addr));
+	  p += xsnprintf (p, endp - p, ",");
+	  addr = tp->control.step_range_end;
+	  p += hexnumstr (p, (ULONGEST) remote_address_masked (addr));
+
+	  get_internalvar_integer (range_stepping_counter, &result);
+	  set_internalvar_integer (range_stepping_counter,
+				   result + 1);
+
+	}
+      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