[dpdk-dev] mlx debug build error with clang

[dpdk-dev] mlx debug build error with clang

[Ferruh Yigit]

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)

Re: [dpdk-dev] mlx debug build error with clang

[Adrien Mazarguil]

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

Re: [dpdk-dev] mlx debug build error with clang

[Ferruh Yigit]

On 6/16/2017 1:19 PM, Adrien Mazarguil wrote:
> 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)

Sure, I will try -std=c99

> 

Re: [dpdk-dev] mlx debug build error with clang

[Ferruh Yigit]

On 6/16/2017 1:58 PM, Ferruh Yigit wrote:
> On 6/16/2017 1:19 PM, Adrien Mazarguil wrote:
>> 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)
> 
> Sure, I will try -std=c99

This fixes the build error.

> 
>>
> 

Re: [dpdk-dev] mlx debug build error with clang

[Ferruh Yigit]

On 6/16/2017 3:49 PM, Ferruh Yigit wrote:
> On 6/16/2017 1:58 PM, Ferruh Yigit wrote:
>> On 6/16/2017 1:19 PM, Adrien Mazarguil wrote:
>>> 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)
>>
>> Sure, I will try -std=c99
> 
> This fixes the build error.

Hi Adrien,

Are you planning to send a patch for this?

Thanks,
ferruh

> 
>>
>>>
>>
>