> On Mar 9, 2017, at 6:01 PM, Matt Wette <matt.we...@gmail.com> wrote:
>
>
>> On Mar 9, 2017, at 1:33 PM, Andy Wingo <wi...@pobox.com
>> <mailto:wi...@pobox.com>> wrote:
>> On Wed 25 Jan 2017 04:35, Matt Wette <matt.we...@gmail.com
>> <mailto:matt.we...@gmail.com>> writes:
>>> So I am trying to compile using clang. This has detected issues with
>>> atomics-internal.h. I can fix most issues with casts:
>>> static inline uint32_t
>>> scm_atomic_subtract_uint32 (uint32_t *loc, uint32_t arg)
>>> {
>>> - return atomic_fetch_sub (loc, arg);
>>> + return atomic_fetch_sub ((_Atomic uint32_t *)loc, arg);
>>> }
>>>
>>> But problems remain with scm_atomic_set_pointer and scm_atomic_ref_pointer
>>> which use void** and is apparently not defined for use with atomics.
>>>
>>> Apparently gcc does not have a problem with this use but I’m guessing the
>>> C11 standard may have an issue with it.
>>
>> WDYT about this?
>>
>> Andy
>
> Have not tried to chase this down but ...
>
> In file included from async.c:27:
> ../libguile/atomics-internal.h:75:20: error: address argument to atomic
> operation must be a pointer to _Atomic type ('SCM *' (aka 'struct
> scm_unused_struct **') invalid)
> return SCM_PACK (atomic_exchange (loc, val));
> ^ ~~~
> /opt/local/libexec/llvm-3.9/bin/../lib/clang/3.9.1/include/stdatomic.h:137:42:
> note: expanded from macro 'atomic_exchange'
> #define atomic_exchange(object, desired) __c11_atomic_exchange(object,
> desired, __ATOMIC_SEQ_CST)
> ^ ~~~~~~
> ../libguile/tags.h:105:32: note: expanded from macro 'SCM_PACK'
> # define SCM_PACK(x) ((SCM) (x))
> ^
> 1 error generated.
>
With this change it compiles under clang-3.9, though generates warning, and
gets through make check (with required other unrelated patches) OK:
static inline SCM
scm_atomic_swap_scm (SCM *loc, SCM val)
{
volatile atomic_uintptr_t *a_loc = (volatile atomic_uintptr_t *)loc;
return SCM_PACK (atomic_exchange (a_loc, val));
}
