[dpdk-dev] meson: wrong dependency in cross compilation on ARM

[Ferruh Yigit]

On 1/18/2021 11:58 AM, Ferruh Yigit wrote:
> On 1/18/2021 10:51 AM, Bruce Richardson wrote:
>> On Fri, Jan 15, 2021 at 06:40:56PM +0000, Ferruh Yigit wrote:
>>> On 12/21/2020 2:04 PM, Bruce Richardson wrote:
>>>> On Mon, Dec 21, 2020 at 12:19:17PM +0000, Hemant Agrawal wrote:
>>>>> Hi,
>>>>>                   I am trying to cross compile DPDK for arm64 on a ubuntu 
>>>>> machine, which has a zlib pre-installed for native env.
>>>>>
>>>>> I am encountering following build error in net_bnx2x as it has dependency 
>>>>> on zlib.  It is trying to link with x86 arch based zlib.
>>>>>
>>>>> Cross compiling zlib and setting the PKG_CONFIG_PATH solve the issue. But, 
>>>>> Is their an easy way to disable these dependencies?
>>>>>
>>>> Can you try with setting PKG_CONFIG_LIBDIR rather than PKG_CONFIG_PATH?
>>>> PKG_CONFIG_PATH simply extends the search locations, which means that
>>>> host-paths will still be searched, while PKG_CONFIG_LIBDIR replaces the
>>>> default path, eliminating the host-based search paths.
>>>>
>>>
>>> The 'PKG_CONFIG_LIBDIR' seems not taken into account by meson, Akhil
>>> reported a 32bit build error when zlib is missing, I can reproduce the same.
>>>
>>> I have only 64bit version of the library:
>>>
>>> $ pkg-config --path zlib
>>> /usr/lib64/pkgconfig/zlib.pc
>>>
>>> $ PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig/ pkg-config --path zlib
>>> <no output>
>>> $ echo $?
>>> 1
>>>
>>> When I run the meson as following:
>>> "PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig/ meson --werror -Dc_args=-m32
>>> -Dc_link_args=-m32 -Dexamples=all build32"
>>>
>>> It still detects the zlib:
>>> Run-time dependency zlib found: YES 1.2.11
>>>
>>
>> I've just tried this on my system and it works as expected: the 32-bit lib
>> is not found and a build succeeds. Omitting the PKG_CONFIG_LIBDIR and it is
>> found, but linking fails due to "file in wrong format" errors, again as
>> expected.
>>
>> In your case, I suspect it might be meson falling back to cmake in the
>> detection logic. If you have cmake installed on your system, can you
>> perhaps temporarily remove it, and retry the 32-bit build? If that is the
>> cause, we can modify the dependency call to add "method: 'pkg-config'" to
>> it, to force pkg-config searches only.
>>
> 
> Yes I have cmake, I will try without it.
> 
> Meanwhile I have Fedora, and it seems it is using different version of the 
> pkg-config (pkgconf), not sure if this can be a problem.
> 

I confirm removing the 'cmake' solved the issue, now I am getting:
"Run-time dependency zlib found: NO (tried pkgconfig and cmake)"

And zlib dependent modules not enabled, so build runs successfully.