Re: PR80613

[Jeff Law <law@redhat.com>]

On 05/04/2017 11:52 AM, Martin Sebor wrote:
> On 05/04/2017 10:00 AM, Prathamesh Kulkarni wrote:
>> Hi,
>> As mentioned in PR, the issue is that cddce1 marks the call to
>> __builtin_strdup as necessary:
>> marking necessary through .MEM_6 stmt p_7 = __builtin_strdup (&d);
>>
>> and since p_7 doesn't get added to worklist in propagate_necessity()
>> because it's used only within free(), it's treated as "dead"
>> and wrongly gets released.
>> The patch fixes that by adding strdup/strndup in corresponding condition
>> in eliminate_unnecessary_stmts().
>>
>> Another issue, was that my previous patch failed to remove multiple
>> calls to strdup:
>> char *f(char **tt)
>> {
>>   char *t = *tt;
>>   char *p;
>>
>>   p = __builtin_strdup (t);
>>   p = __builtin_strdup (t);
>>   return p;
> 
> Since this is clearly a bug in the program -- the first result
> leaks -- would it make sense to issue a warning before removing
> the duplicate call?  (It would be nice to issue a warning not
> just for strdup but also for other memory allocation functions,
> so perhaps that should be a separate enhancement request.)
Seems like it should be a separate enhancement request.

jeff