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

[Ferruh Yigit]

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.