More directly, I don't think we should warn here unless there is a really
compelling argument. I just see this as producing way too much noise. I can
only see warning about these cases if it was put under a different warning
flag, and that warning wasn't on by default.
On Jul 14, 2011, at 10:28 AM, Ted Kremenek wrote:
> Hi Kaelyn,
>
> I was reviewing this patch (which I think is a great step), and I had a
> high-level comment about the following test case:
>
> +void swallow (const char *x) { (void)x; }
> +void test_pointer_arithmetic() {
> + const char hello[] = "Hello world!"; // expected-note 2 {{declared here}}
> + const char *helloptr = hello;
> +
> + swallow("Hello world!" + 6); // no-warning
> + swallow("Hello world!" - 6); // expected-warning {{refers before the
> beginning of the array}}
> + swallow("Hello world!" + 14); // expected-warning {{refers past the end of
> the array}}
>
> Do we really want this to be a warning? There are plenty of examples where
> an out-of-bounds pointer is computed for legit reasons. As long as that
> address is not dereferenced, there isn't necessarily a problem. I'm fearful
> this may generate a fair amount of noise on codebases that do elaborate
> tricks with pointer offsets. Indeed this very example doesn't actually
> exhibit a "bug".
>
> Ted
>
> On Jul 11, 2011, at 4:25 PM, Kaelyn Uhrain wrote:
>
>> Here's the updated patch that includes the changes Nick suggested and
>> rebased against the current TOT.
>>
>> On Mon, Jul 11, 2011 at 3:30 PM, Ted Kremenek <[email protected]> wrote:
>> Hi Kaelyn,
>>
>> This looks great. Nick already made some great comments on the code. If you
>> could address the last couple review comments I think this is ready to push
>> back to mainline.
>>
>> Cheers,
>> Ted
>>
>> On Jul 8, 2011, at 5:03 PM, Kaelyn Uhrain wrote:
>>
>>> The attached patch enhances the existing array bounds checking to include
>>> support for bounds checking on pointer arithmetic when possible (e.g. "Foo"
>>> + 5 or somearray - 7 when the size of somearray is known). It also fixes
>>> the bounds checking to work with unary operators like & and *; without this
>>> patch, for "char foo[4]", foo[15] would trigger the warning but &foo[15]
>>> wouldn't.
>>>
>>> You can also view and comment on the changes at:
>>> http://codereview.appspot.com/4675068
>>>
>>> Cheers,
>>> Kaelyn
>>> _______________________________________________
>>> cfe-commits mailing list
>>> [email protected]
>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>
>>
>> <array-bounds-enhancement.diff>
>
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