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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