Hi Ferruh,
On Tue, Jun 13, 2017 at 04:32:03PM +0100, Ferruh Yigit wrote:
> Hi Adrien, Nelio,
>
> I am getting following build error [1] with clang [2] when debug enabled
> for mlx4 and mlx5.
>
> This started after I update my box, not sure what triggered this.
> Can you please help fixing this?
>
> Thanks,
> ferruh
>
>
> [1]
>
> .../drivers/net/mlx4/mlx4_flow.c:731:3: error: use of GNU statement
> expression extension [-Werror,-Wgnu-statement-expression]
> claim_zero(ibv_destroy_qp(fdq->qp));
> ^
> .../drivers/net/mlx4/mlx4.h:185:25: note: expanded from macro 'claim_zero'
> #define claim_zero(...) assert((__VA_ARGS__) == 0)
> ^
> /usr/include/assert.h:95:6: note: expanded from macro 'assert'
> ({ \
> ^
>
> ....
>
> .../drivers/net/mlx5/mlx5_fdir.c:278:2: error: use of GNU statement
> expression extension [-Werror,-Wgnu-statement-expression]
> assert(((uint8_t *)attr + sizeof(*attr)) == (uint8_t *)spec_offset);
> ^
> /usr/include/assert.h:95:6: note: expanded from macro 'assert'
> ({ \
> ^
>
> [Many of similar ...]
>
>
> [2]
> target: x86_64-native-linuxapp-clang
>
> clang version 4.0.0 (tags/RELEASE_400/final)
Recent Glibc versions now apparently handle assert() through a nonstandard
({ }) construct, which is not pedantic-safe due to a missing __extension__
keyword.
assert.h still provides a standard assert() definition that shouldn't cause
compilation to fail when the following condition is met:
#if !defined __GNUC__ || defined __STRICT_ANSI__
However __GNUC__ is (always?) defined by clang for maximum compatibility
with GCC while __STRICT_ANSI__ is not due to the -std=gnu99 parameter,
assert.h thinks it's OK to use a ({ }) construct but is then caught by
clang's -pedantic parameter.
There are two ways to address this issue while keeping our beloved -pedantic
parameter in debug mode:
1. Replacing -std=gnu99 with -std=c99 (which is even stricter) to bring back
__STRICT_ANSI__.
2. Replacing assert() statements with RTE_ASSERT().
The former should be doable now that DPDK includes have been cleaned up, and
we're thinking about doing the latter at some point.
Since I don't have a recent Glibc handy, can you try replacing -std=gnu99
with -std=c99 in both Makefiles (mlx4 and mlx5), and report how GCC and
clang fare? (GCC at least seems to have no problem with that on my side)
--
Adrien Mazarguil
6WIND
