[compiler-rt] r248346 - [builtins] Fixing broken bot building on linux with -Werror

[Aaron Ballman via llvm-commits]

On Tue, Sep 22, 2015 at 8:01 PM, Chris Bieneman <beanz at apple.com> wrote:
>
>
>> On Sep 22, 2015, at 4:38 PM, Aaron Ballman <aaron at aaronballman.com> wrote:
>>
>> On Tue, Sep 22, 2015 at 7:35 PM, Chris Bieneman via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>>> Author: cbieneman
>>> Date: Tue Sep 22 18:35:24 2015
>>> New Revision: 248346
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=248346&view=rev
>>> Log:
>>> [builtins] Fixing broken bot building on linux with -Werror
>>>
>>> Returning a void expression is bad.
>>
>> Why is returning a void expression bad? Also, why do these require
>> return statements at all?
>
> Returning a void expression is a warning on -Wpedantic (lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/20392).

Good to know, thanks!

> The return itself isn't needed, but is common C convention.

This is the first I've heard that this is a C convention (but I'm not
claiming that it isn't). It doesn't appear to be one we adhere to with
any consistency -- I did a quick scan of other builtins (see
atomic_signal_fence.c and atomic_thread_fence.c) and they elide the
return. Since it's not needed anyway, I think it'd be good to remove.

~Aaron

>
> -Chris
>>
>> ~Aaron
>>
>>>
>>> Modified:
>>>    compiler-rt/trunk/lib/builtins/atomic_flag_clear.c
>>>    compiler-rt/trunk/lib/builtins/atomic_flag_clear_explicit.c
>>>
>>> Modified: compiler-rt/trunk/lib/builtins/atomic_flag_clear.c
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/builtins/atomic_flag_clear.c?rev=248346&r1=248345&r2=248346&view=diff
>>> ==============================================================================
>>> --- compiler-rt/trunk/lib/builtins/atomic_flag_clear.c (original)
>>> +++ compiler-rt/trunk/lib/builtins/atomic_flag_clear.c Tue Sep 22 18:35:24 2015
>>> @@ -21,7 +21,8 @@
>>> #include <stdatomic.h>
>>> #undef atomic_flag_clear
>>> void atomic_flag_clear(volatile atomic_flag *object) {
>>> -  return __c11_atomic_store(&(object)->_Value, 0, __ATOMIC_SEQ_CST);
>>> +  __c11_atomic_store(&(object)->_Value, 0, __ATOMIC_SEQ_CST);
>>> +  return;
>>> }
>>>
>>> #endif
>>>
>>> Modified: compiler-rt/trunk/lib/builtins/atomic_flag_clear_explicit.c
>>> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/builtins/atomic_flag_clear_explicit.c?rev=248346&r1=248345&r2=248346&view=diff
>>> ==============================================================================
>>> --- compiler-rt/trunk/lib/builtins/atomic_flag_clear_explicit.c (original)
>>> +++ compiler-rt/trunk/lib/builtins/atomic_flag_clear_explicit.c Tue Sep 22 18:35:24 2015
>>> @@ -22,7 +22,8 @@
>>> #undef atomic_flag_clear_explicit
>>> void atomic_flag_clear_explicit(volatile atomic_flag *object,
>>>                                 memory_order order) {
>>> -  return __c11_atomic_store(&(object)->_Value, 0, order);
>>> +  __c11_atomic_store(&(object)->_Value, 0, order);
>>> +  return;
>>> }
>>>
>>> #endif
>>>
>>>
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