[cfe-commits] [PATCH] review request - strcmp checker

[Ted Kremenek]

Yeah, I think it's fine to commit as is, and refine in further patches.

Thanks Lenny!

On Apr 11, 2011, at 12:25 PM, Lenny Maiorani wrote:

> On 04/08/2011 05:37 PM, Ted Kremenek wrote:
>> Hi Lenny,
>> 
>> I understand the intent is to model comparing raw string literals, but I think the use of getCStringLiteral() discards too much information.  For example, I don't think the following will be handled correctly:
>> 
>>   const char *s1 = "foobar";
>>   const char *s2 = "bar";
>>   return strcmp(&s1[3], s2);
>> 
>> In order to model strcmp() properly, you will also need to take into account the offset within the string literal.
>> 
>> Also, could you add a FIXME indicating that this logic only handles comparing string literals (albeit, it handles flow analysis)?  Conceptually, we could enhance this to also handle non-literals as well in a variety of ways.
> Nice catch Ted!
> 
> In fact, I think the entire CString checker needs this. I just tested strlen and that didn't work in this case either:
>    void strlen_with_offset(const char *x) {
>      if (strlen(x) != 5)
>        return;
>      if (strlen(&x[2]) != 3)
>        (void)*(char*)0; // no-warning
>    }
> 
> Is this patch ok to be committed in lieu of this change? The next task I will take on will be fixing the modeling of all the functions in the CString checker to accommodate for this oversight. It will probably be a small change, but pervasive throughout the checker.
> 
> 
> -Lenny
>