Acked-by: Eitan Eliahu <[email protected]> -----Original Message----- From: dev [mailto:[email protected]] On Behalf Of Gurucharan Shetty Sent: Monday, September 15, 2014 10:36 AM To: [email protected] Cc: Gurucharan Shetty Subject: [ovs-dev] [PATCH 4/4] ovs-atomic-msvc: Disable a compiler warning.
MSVC does not support c11 style atomics for the C compiler. Windows has different InterLocked* functions for different data sizes. ovs-atomic-msvc.h maps the api in ovs-atomic.h (which is similar to c11 atomics) to the available atomic functions in Windows. In some cases, this causes compiler warnings about mismatched data sizes because the generated code has 'if else' conditions on different data sizes and proper casting is not possible. In current OVS code base, we get one compiler warning through ovs-rcu.h which says "‘void *’ differs in levels of indirection from LONGLONG." This comes from the following in ovs-atomic-msvc.h for atomic_read64(): *(DST) = InterlockedOr64((int64_t volatile *) (SRC), 0); when *DST is a void pointer (because InterLockedOr64 returns LONGLONG). But this code path is only every hit for 64 bit data. So it should be safe to disable the warning. (Any real bugs in api calls would hopefully be caught while compiling on Linux using gcc/clang). Signed-off-by: Gurucharan Shetty <[email protected]> --- lib/ovs-atomic-msvc.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/ovs-atomic-msvc.h b/lib/ovs-atomic-msvc.h index 11f5ad2..e8e4891 100644 --- a/lib/ovs-atomic-msvc.h +++ b/lib/ovs-atomic-msvc.h @@ -154,7 +154,10 @@ atomic_signal_fence(memory_order order) if (((size_t) (SRC) & (sizeof *(SRC) - 1)) == 0) { \ *(DST) = *(SRC); \ } else { \ + __pragma (warning(push)) \ + __pragma (warning(disable:4047)) \ *(DST) = InterlockedOr64((int64_t volatile *) (SRC), 0); \ + __pragma (warning(pop)) \ } #define atomic_read(SRC, DST) \ -- 1.7.9.5 _______________________________________________ dev mailing list [email protected] https://urldefense.proofpoint.com/v1/url?u=http://openvswitch.org/mailman/listinfo/dev&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=yTvML8OxA42Jb6ViHe7fUXbvPVOYDPVq87w43doxtlY%3D%0A&m=LTLCGxbBwtVWHd4CpE1c%2BEexQO67%2BiyF%2Ba6R8acUumQ%3D%0A&s=f089dc9d797922130e5981e9e3fd16613d8b6b18de173ec63b37c96c7ab04595 _______________________________________________ dev mailing list [email protected] http://openvswitch.org/mailman/listinfo/dev
