r199663 - Making some minor improvements to r199626.

[Aaron Ballman]

On Fri, Jul 11, 2014 at 10:48 AM, Hal Finkel <hfinkel at anl.gov> wrote:
> ----- Original Message -----
>> From: "Aaron Ballman" <aaron at aaronballman.com>
>> To: cfe-commits at cs.uiuc.edu
>> Sent: Monday, January 20, 2014 8:19:44 AM
>> Subject: r199663 - Making some minor improvements to r199626.
>>
>> Author: aaronballman
>> Date: Mon Jan 20 08:19:44 2014
>> New Revision: 199663
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=199663&view=rev
>> Log:
>> Making some minor improvements to r199626.
>>
>> Modified:
>>     cfe/trunk/include/clang/Basic/Attr.td
>>     cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>>     cfe/trunk/test/Sema/nonnull.c
>>
>
> [snip]
>
>> Modified: cfe/trunk/test/Sema/nonnull.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/nonnull.c?rev=199663&r1=199662&r2=199663&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/Sema/nonnull.c (original)
>> +++ cfe/trunk/test/Sema/nonnull.c Mon Jan 20 08:19:44 2014
>> @@ -32,10 +32,10 @@ void test_baz() {
>>    baz3(0); // no-warning
>>  }
>>
>> -void test_void_returns_nonnull() __attribute__((returns_nonnull));
>> // expected-warning {{'returns_nonnull' attribute only applies to
>> return values that are pointers}}
>> -int test_int_returns_nonnull() __attribute__((returns_nonnull)); //
>> expected-warning {{'returns_nonnull' attribute only applies to
>> return values that are pointers}}
>> -void *test_ptr_returns_nonnull() __attribute__((returns_nonnull));
>> // no-warning
>> +void test_void_returns_nonnull(void)
>> __attribute__((returns_nonnull)); // expected-warning
>> {{'returns_nonnull' attribute only applies to return values that are
>> pointers}}
>> +int test_int_returns_nonnull(void) __attribute__((returns_nonnull));
>> // expected-warning {{'returns_nonnull' attribute only applies to
>> return values that are pointers}}
>> +void *test_ptr_returns_nonnull(void)
>> __attribute__((returns_nonnull)); // no-warning
>>
>>  int i __attribute__((nonnull)); // expected-warning {{'nonnull'
>>  attribute only applies to functions, methods, and parameters}}
>>  int j __attribute__((returns_nonnull)); // expected-warning
>>  {{'returns_nonnull' attribute only applies to functions and
>>  methods}}
>> -
>> +void *test_no_fn_proto() __attribute__((returns_nonnull));  //
>> expected-warning {{'returns_nonnull' attribute only applies to
>> functions and methods}}
>
> This last check seems wrong to me. There is now a difference between this:
>
> void *test_ptr_returns_nonnull(void) __attribute__((returns_nonnull));
>
> which we handle and this:
>
> void *test_ptr_returns_nonnull() __attribute__((returns_nonnull));
>
> for which we ignore the attribute. However:
>
>  - Most people don't put void in the parameter lists, and

This is a C test file, where () is different than (void). The former
has no prototype and is almost equivalent to it being written (...),
while the latter has a prototype accepting no arguments. In C++ mode,
there is no distinction.

>  - gcc 4.9.0 does not distinguish between the two forms w.r.t. the application of this attribute.
>
> Can you please fix this?

Ted was the original author of this functionality
(http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140113/097562.html),
this commit was a tidying of his original code but had no functional
changes. Are you asking to have C code with no function prototype
honor this attribute? If so, Ted, does that seem reasonable to you?

~Aaron