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

[Hemant Agrawal <hemant.agrawal@oss.nxp.com>]

On 1/18/2021 5:46 PM, Ferruh Yigit wrote:
> On 1/18/2021 12:05 PM, Ferruh Yigit wrote:
>> 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.
>
> Following is fixing the problem [1], but isn't this a generic problem 
> when 64bit version of a library installed but 32bit version of it is 
> missing and 'cmake' exists?
>
> Should all library discovery reduced to the 'pkg-config' only?
>
>
>
> [1]
> diff --git a/app/test/meson.build b/app/test/meson.build
> index 94fd39fecb82..bdbc61947637 100644
> --- a/app/test/meson.build
> +++ b/app/test/meson.build
> @@ -406,7 +406,7 @@ cflags += ['-DALLOW_INTERNAL_API']
>
>  test_dep_objs = []
>  if dpdk_conf.has('RTE_LIB_COMPRESSDEV')
> -       compress_test_dep = dependency('zlib', required: false)
> +       compress_test_dep = dependency('zlib', required: false, 
> method: 'pkg-config')
>         if compress_test_dep.found()
>                 test_dep_objs += compress_test_dep
>                 test_sources += 'test_compressdev.c'
> diff --git a/drivers/compress/zlib/meson.build 
> b/drivers/compress/zlib/meson.build
> index b19a6d2b161f..82cf0dddd649 100644
> --- a/drivers/compress/zlib/meson.build
> +++ b/drivers/compress/zlib/meson.build
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: BSD-3-Clause
>  # Copyright(c) 2018 Cavium Networks
>
> -dep = dependency('zlib', required: false)
> +dep = dependency('zlib', required: false, method: 'pkg-config')
>  if not dep.found()
>         build = false
>         reason = 'missing dependency, "zlib"'
> diff --git a/drivers/net/bnx2x/meson.build 
> b/drivers/net/bnx2x/meson.build
> index 8837ef424760..e260b75926ec 100644
> --- a/drivers/net/bnx2x/meson.build
> +++ b/drivers/net/bnx2x/meson.build
> @@ -7,7 +7,7 @@ if is_windows
>         subdir_done()
>  endif
>
> -dep = dependency('zlib', required: false)
> +dep = dependency('zlib', required: false, method: 'pkg-config')
>  build = dep.found()
>  reason = 'missing dependency, "zlib"'
>  ext_deps += dep



Just tested this patch with my cross compilation env. It works ok.

I will also check now without this patch with aarch64 pkg-config