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[PATCH 5/7] range stepping: New command 'maint set range stepping'
- From: Yao Qi <yao at codesourcery dot com>
- To: <gdb-patches at sourceware dot org>
- Date: Thu, 11 Apr 2013 10:43:40 +0800
- Subject: [PATCH 5/7] range stepping: New command 'maint set range stepping'
- References: <1363006291-13334-1-git-send-email-yao at codesourcery dot com> <1365648222-12540-1-git-send-email-yao at codesourcery dot com>
On 03/18/2013 11:45 AM, Eli Zaretskii wrote:
>> Don't have any special reasons to do this. The range stepping should be
>> >always on if target supports, and it can be turned off for some
>> >"maintenance purpose", so I set this command as a maintenance
>> >command.
> What would be the possible reasons to turn this feature off?
>
> Once we have the reasons, we could try thinking whether or not they
> are limited to GDB maintenance.
Range-stepping is useful to speed up some operations, so users don't
have to turn it off. The reason turning it off could be that the
remote stub has a bug in supporting range stepping, so we have to
disable it in GDB side.
I considered to name the command to "set remote range-stepping", but
range-stepping is not specific to remote target, and it can be
implemented on native target as well. So "set remote range-stepping"
is not a good choice. I also considered "set range-stepping", but
unable to find a reasonable place for documentation on it. In V2, I
don't update the command name.
gdb:
2013-04-11 Yao Qi <yao@codesourcery.com>
* remote.c (use_range_stepping): New.
(remote_vcont_probe): Set 'use_range_stepping' if the remote
target supports range stepping.
(append_resumption): Use 'vCont;r' packet if 'use_range_stepping'
is true.
(maint_show_range_stepping): New.
(maint_set_range_stepping): New.
(_initialize_remote): Call add_setshow_boolean_cmd to register
commands 'maint set range-stepping' and
'maint show range-stepping'.
gdb/doc:
2013-04-11 Yao Qi <yao@codesourcery.com>
* gdb.texinfo (Maintenance Commands): Document commands
'maint set range-stepping' and 'maint show range-stepping' and
convenience variable '$range_stepping_counter'.
---
gdb/doc/gdb.texinfo | 10 ++++++++
gdb/remote.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 73 insertions(+), 1 deletions(-)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index bf7e25e..9292b94 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -35620,6 +35620,16 @@ data in a @file{gmon.out} file, be sure to move it to a safe location.
Configuring with @samp{--enable-profiling} arranges for @value{GDBN} to be
compiled with the @samp{-pg} compiler option.
+@kindex maint set range-stepping
+@kindex maint show range-stepping
+@cindex range-stepping
+@item maint set range-stepping
+@itemx maint show range-stepping
+@vindex $range_stepping_counter
+Control whether to do stepping in an address range. The debugger convenience
+variable @samp{$range_stepping_counter} contains the number of range stepping
+@value{GDBN} has performed.
+
@kindex maint set show-debug-regs
@kindex maint show show-debug-regs
@cindex hardware debug registers
diff --git a/gdb/remote.c b/gdb/remote.c
index a063698..7022275 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -260,6 +260,10 @@ struct support_v_cont
int r;
};
+/* A flag on GDB is willing to use range-stepping or not. */
+
+static int use_range_stepping = 0;
+
/* Description of the remote protocol state for the currently
connected target. This is per-target state, and independent of the
selected architecture. */
@@ -4652,6 +4656,7 @@ remote_vcont_probe (struct remote_state *rs)
support_C = 0;
rs->support_vCont.t = 0;
rs->support_vCont.r = 0;
+ use_range_stepping = 0;
while (p && *p == ';')
{
p++;
@@ -4666,7 +4671,10 @@ remote_vcont_probe (struct remote_state *rs)
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;
+ {
+ rs->support_vCont.r = 1;
+ use_range_stepping = 1;
+ }
p = strchr (p, ';');
}
@@ -4713,6 +4721,8 @@ append_resumption (char *p, char *endp,
pc = regcache_read_pc (get_thread_regcache (ptid));
if (rs->support_vCont.r /* Target supports step range. */
+ /* GDB is willing to do range stepping. */
+ && use_range_stepping
/* Can't do range stepping for all threads of a process
'pPID.-1'. */
&& !(remote_multi_process_p (rs) && ptid_is_pid (ptid))
@@ -11697,6 +11707,45 @@ remote_upload_trace_state_variables (struct uploaded_tsv **utsvp)
return 0;
}
+static void
+maint_show_range_stepping (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c,
+ const char *value)
+{
+ fprintf_filtered (file,
+ _("Debugger's willingness to do range-stepping "
+ "is %s.\n"), value);
+}
+
+static void
+maint_set_range_stepping (char *ignore_args, int from_tty,
+ struct cmd_list_element *c)
+{
+ /* Check range stepping is supported when turns it on. */
+ if (use_range_stepping)
+ {
+ if (remote_desc != NULL)
+ {
+ struct remote_state *rs = get_remote_state ();
+
+ if (remote_protocol_packets[PACKET_vCont].support == PACKET_SUPPORT_UNKNOWN)
+ remote_vcont_probe (rs);
+
+ if (remote_protocol_packets[PACKET_vCont].support == PACKET_DISABLE
+ || !rs->support_vCont.r)
+ {
+ use_range_stepping = 0;
+ error (_("Range stepping is not supported"));
+ }
+ }
+ else
+ {
+ use_range_stepping = 0;
+ error (_("Range stepping is not supported"));
+ }
+ }
+}
+
void
_initialize_remote (void)
{
@@ -12094,6 +12143,19 @@ Set the remote pathname for \"run\""), _("\
Show the remote pathname for \"run\""), NULL, NULL, NULL,
&remote_set_cmdlist, &remote_show_cmdlist);
+ add_setshow_boolean_cmd ("range-stepping", class_maintenance,
+ &use_range_stepping, _("\
+Enable or disable range-stepping."), _("\
+Show whether range-stepping is enabled."), _("\
+If On, GDB will tell the target to do stepping a range of address.\n\
+This will speed up stepping a line of source file.\n\
+If off, GDB will not use it, even if such is supported by the \n\
+target"),
+ maint_set_range_stepping,
+ maint_show_range_stepping,
+ &maintenance_set_cmdlist,
+ &maintenance_show_cmdlist);
+
/* Eventually initialize fileio. See fileio.c */
initialize_remote_fileio (remote_set_cmdlist, remote_show_cmdlist);
--
1.7.7.6