Re: [RFA] Displaced stepping just enable in non-stop mode

teawater
2008-10-14T07:36:45Z

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Fix a little bug in "displaced_step_non_step_doc.txt".

On Fri, Oct 10, 2008 at 11:37, teawater <teawater@gmail.com> wrote:
> Hi Pedro,
>
> Thanks for your example, I make a new patch for infrun.c and other for manual.
>
> 2008-10-10 Hui Zhu <teawater@gmail.com>
>
> Displaced stepping can be set to
> auto (enable in non-stop mode), on, off.
>
> * infrun.c (can_use_displaced_stepping): Change type to const
> char pointer.
> (can_use_displaced_stepping_auto): New string.
> (can_use_displaced_stepping_on): New string.
> (can_use_displaced_stepping_off): New string.
> (can_use_displaced_stepping_enum): New array.
> (show_can_use_displaced_stepping): In auto mode, also show the
> current effect of the option.
> (use_displaced_stepping): Return non-zero if displaced stepping
> is auto, and can be used with GDBARCH, and in non-stop mode.
> Return non-zero if displaced stepping is on, and can be used
> with GDBARCH.
> (_initialize_infrun): "can-use-displaced-stepping" function
> change to add_setshow_enum_cmd.
>
> 2008-10-10 Hui Zhu <teawater@gmail.com>
>
> * gdb.texinfo (can-use-displaced-stepping) Describe the auto mode
> setting, and make it the default.
>
>
> Thanks,
> Hui
>
> On Thu, Oct 9, 2008 at 22:49, Pedro Alves <pedro@codesourcery.com> wrote:
>> Hi,
>>
>> Thanks for doing this.
>>
>> On Wednesday 08 October 2008 07:10:43, teawater wrote:
>>
>>> -int can_use_displaced_stepping = 1;
>>> +const char can_use_displaced_stepping_auto[] = "auto";
>>> +const char can_use_displaced_stepping_on[] = "on";
>>> +const char can_use_displaced_stepping_off[] = "off";
>>> +const char *can_use_displaced_stepping_enum[] =
>>> +{
>>> + can_use_displaced_stepping_auto,
>>> + can_use_displaced_stepping_on,
>>> + can_use_displaced_stepping_off,
>>> + NULL,
>>> +};
>>> +const char *can_use_displaced_stepping = can_use_displaced_stepping_auto;
>>
>> Could you make these static while you're at it, please? It was just missed
>> in the old boolean setting.
>>
>>> static void
>>> show_can_use_displaced_stepping (struct ui_file *file, int from_tty,
>>> struct cmd_list_element *c,
>>> @@ -567,12 +579,16 @@ Debugger's willingness to use displaced
>>> "breakpoints is %s.\n"), value);
>>
>> Could you update this function to show what effect the auto setting
>> is currently having? See breakpoint.c:show_always_inserted_mode for
>> an example.
>>
>>> }
>>>
>>> -/* Return non-zero if displaced stepping is enabled, and can be used
>>> +/* Return non-zero if displaced stepping is auto, and can be used
>>> + with GDBARCH, and in non-stop mode.
>>> + Return non-zero if displaced stepping is on, and can be used
>>> with GDBARCH. */
>>> static int
>>> use_displaced_stepping (struct gdbarch *gdbarch)
>>> {
>>> - return (can_use_displaced_stepping
>>> + return (((can_use_displaced_stepping == can_use_displaced_stepping_auto
>>> + && non_stop)
>>> + || can_use_displaced_stepping == can_use_displaced_stepping_on)
>>> && gdbarch_displaced_step_copy_insn_p (gdbarch));
>>> }
>>>
>>> @@ -4857,11 +4873,14 @@ function is skipped and the step command
>>> show_step_stop_if_no_debug,
>>> &setlist, &showlist);
>>>
>>> - add_setshow_boolean_cmd ("can-use-displaced-stepping", class_maintenance,
>>> + add_setshow_enum_cmd ("can-use-displaced-stepping", class_maintenance,
>>> + can_use_displaced_stepping_enum,
>>> &can_use_displaced_stepping, _("\
>>> Set debugger's willingness to use displaced stepping."), _("\
>>> Show debugger's willingness to use displaced stepping."), _("\
>>> -If zero, gdb will not use displaced stepping to step over\n\
>>> +If auto, gdb will auto use displaced stepping if it need (in non-stop mode).\n\
>>> +If on, gdb will use displaced stepping if such is supported by the target.\n\
>>> +If off, gdb will not use displaced stepping to step over\n\
>>> breakpoints, even if such is supported by the target."),
>>
>> This also needs to be updated in the manual. I'd suggest borrowing the text
>> from breakpoint.c's "always-inserted" command description to make it a
>> bit more descriptive, and mention which mode is the default. Should mostly
>> be a matter of copy-paste, I think.
>>
>> --
>> Pedro Alves
>>
>

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--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2008-10-10 Hui Zhu <teawater@gmail.com>
+
+ * gdb.texinfo (can-use-displaced-stepping) Describe the auto mode
+ setting, and make it the default.
+
2008-10-06 Doug Evans <dje@google.com>

* gdb.texinfo (set debug dwarf2-die): Document it.
--- a/gdb.texinfo
+++ b/gdb.texinfo
@@ -23935,16 +23935,25 @@ Shared library events.

@kindex maint set can-use-displaced-stepping
@kindex maint show can-use-displaced-stepping
-@cindex displaced stepping support
-@cindex out-of-line single-stepping
-@item maint set can-use-displaced-stepping
-@itemx maint show can-use-displaced-stepping
-Control whether or not @value{GDBN} will do @dfn{displaced stepping}
-if the target supports it. The default is on. Displaced stepping is
-a way to single-step over breakpoints without removing them from the
-inferior, by executing an out-of-line copy of the instruction that was
-originally at the breakpoint location. It is also known as
-out-of-line single-stepping.
+@table @code
+@item maint set can-use-displaced-stepping on
+If the target supports it. Gdb behaves are single-step over
+breakpoints without removing them from the inferior, by executing
+an out-of-line copy of the instruction that was originally at the
+breakpoint location. It is also known as out-of-line single-stepping.
+
+@item maint set can-use-displaced-stepping off
+Gdb behaves are single-step over breakpoints with removing them from
+the inferior.
+
+@cindex non-stop mode, and @samp{maint set can-use-displaced-stepping}
+@item maint set can-use-displaced-stepping auto
+This is the default mode. If @value{GDBN} is controlling the inferior
+in non-stop mode (@pxref{Non-Stop Mode}), gdb behaves as if
+@code{can-use-displaced-stepping} mode is on. If @value{GDBN} is
+controlling the inferior in all-stop mode, @value{GDBN} behaves as if
+@code{can-use-displaced-stepping} mode is off.
+@end table

@kindex maint check-symtabs
@item maint check-symtabs