On Thu, Apr 30, 2015 at 12:42 PM, Jordan Rose <[email protected]> wrote:
> Rather than contort GNU attributes into an expression context, I'd rather
> just encourage the parameter forrm of __attribute__((nonnull)) that we added
> a while back:
This makes sense to me. Thank you for the friendly reminder!
~Aaron
>
> ^(int *p1 __attribute__((nonnull))) {}(0);
>
> ...although admittedly that doesn't warn either at the moment.
>
> (There's also still a hole with this syntax, which Richard pointed out a long
> time ago:
>
>> This still seems to be GCC-incompatible. Per the GCC documentation,
>> "__attribute__((nonnull))" on a pointer-to-function parameter means that all
>> of *that* function's parameters can't be null. For instance:
>>
>> void f(int (*p)(int *a, int *b) __attribute__((nonnull))) {
>> if (p)
>> p(0, 0); // #1
>> }
>> void g() { f(0); } // #2
>>
>> GCC warns on line #1, Clang warns on line #2.
>
> ...and then we never got around to doing anything about.)
>
> There's also Apple's nullability specifiers: ^(int * __nonnull p1) {}(0), but
> those haven't been integrated yet, even though it seemed like most people
> were happy with the proposal. (Doug's been quite busy over here.) These
> aren't quite the same, though, because they don't affect codegen.
>
> Jordan
>
>
>> On Apr 29, 2015, at 11:59 , Aaron Ballman <[email protected]> wrote:
>>
>> PR23416 points out that we currently diagnose nonnull properly on a
>> block declaration, but not on a block expression. Specifically:
>>
>> void(^bp)(int *) __attribute__((nonnull(1)));
>> void f() {
>> bp(0); // Diagnose this already
>> ^(int *p1) __attribute__((nonnull(1))) {}(0); // Not diagnosing this
>> }
>>
>> It seems reasonable and relatively straight-forward to support the
>> BlockExpr case as well. The attached patch is a stab at implementing
>> support for this, but since my ObjC-fu is weak (at best), I am
>> wondering if I'm missing something.
>>
>> Thanks!
>>
>> ~Aaron
>> <NonnullBlockExpr.patch>
>
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