Re: [PATCH]tracepoint.c: Add conditionals num to find_matching_tracepoint

Hui Zhu
2011-08-24T09:30:49Z

On Wed, Aug 24, 2011 at 07:24, Stan Shebs <stanshebs@earthlink.net> wrote:
> On 8/14/11 6:40 AM, Hui Zhu wrote:
>>
>> [...]
>> Hi Stan,
>>
>> Thanks for your review.
>>
>> I make a new patch that check the condition according to your mail.
>>
>> Best,
>> Hui
>>
>> 2011-08-14  Hui Zhu<teawater@gmail.com>
>>
>>        * tracepoint.c (cond_string_is_same): New function.
>>        (find_matching_tracepoint): Add condition check
>>        by cond_string_is_same.
>> ---
>>  tracepoint.c |   19 ++++++++++++++++++-
>>  1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> --- a/tracepoint.c
>> +++ b/tracepoint.c
>> @@ -3091,6 +3091,22 @@ free_uploaded_tsvs (struct uploaded_tsv
>>      }
>>  }
>>
>> +static int
>> +cond_string_is_same(char *str1, char *str2)
>
> Don't forget the all-important space! :-)

Sorry for forgot it.

>
>> +{
>> +  if (str1 == NULL || str2 == NULL)
>> +    {
>> +      if (str1 == str2)
>> +       return 1;
>> +      else
>> +       return 0;
>
> This bit is a little simpler as just "return (str1 == str2);"

My code is so ugly. Thanks for help me make it more better. :)

>
>> +    }
>> +  if (strcmp (str1, str2))
>> +    return 0;
>> +
>> +  return 1;
>
> Typically, I would write this as "return (strcmp (str1, str2) == 0);"
>
> It would also be good to add a function header comment that this function is
> heuristic and will miss the cases where the conditional is semantically
> identical but differs in whitespace, such as "x == 0" vs "x==0" - but that's
> generally OK, because it just results in an extra tracepoint that is easily
> deleted.

That is really a issue for us. I add a comment for it. Wish I can
get some time to make it better.

>
> OK to install with these changes, and thanks!

I made a new patch according to your patch and checked it in.

Thanks for your help.

Best,
Hui

>
> Stan
> stan@codesourcery.com
>
>> +}
>> +
>>  /* Look for an existing tracepoint that seems similar enough to the
>>     uploaded one.  Enablement isn't compared, because the user can
>>     toggle that freely, and may have done so in anticipation of the
>> @@ -3111,7 +3127,8 @@ find_matching_tracepoint (struct uploade
>>        if (b->type == utp->type
>>        &&  t->step_count == utp->step
>>        &&  t->pass_count == utp->pass
>> -         /* FIXME also test conditionals and actions.  */
>> +       &&  cond_string_is_same (t->base.cond_string, utp->cond_string)
>> +         /* FIXME also test actions.  */
>>          )
>>        {
>>          /* Scan the locations for an address match.  */
>>
>
>

http://sourceware.org/cgi-bin/cvsweb.cgi/src/gdb/tracepoint.c.diff?cvsroot=src&r1=1.230&r2=1.231

2011-08-24 Hui Zhu <teawater@gmail.com>

* tracepoint.c (cond_string_is_same): New function.
(find_matching_tracepoint): Add condition check
by cond_string_is_same.
===================================================================
RCS file: /cvs/src/src/gdb/tracepoint.c,v
retrieving revision 1.230
retrieving revision 1.231
diff -u -r1.230 -r1.231
--- src/gdb/tracepoint.c 2011/08/04 19:10:13 1.230
+++ src/gdb/tracepoint.c 2011/08/24 09:24:10 1.231
@@ -3091,6 +3091,19 @@
}
}

+/* FIXME this function is heuristic and will miss the cases where the
+ conditional is semantically identical but differs in whitespace,
+ such as "x == 0" vs "x==0". */
+
+static int
+cond_string_is_same (char *str1, char *str2)
+{
+ if (str1 == NULL || str2 == NULL)
+ return (str1 == str2);
+
+ return (strcmp (str1, str2) == 0);
+}
+
/* Look for an existing tracepoint that seems similar enough to the
uploaded one. Enablement isn't compared, because the user can
toggle that freely, and may have done so in anticipation of the
@@ -3111,7 +3124,8 @@
if (b->type == utp->type
&& t->step_count == utp->step
&& t->pass_count == utp->pass
- /* FIXME also test conditionals and actions. */
+ && cond_string_is_same (t->base.cond_string, utp->cond_string)
+ /* FIXME also test actions. */
)
{
/* Scan the locations for an address match. */