[OE-core] non-standard library locations and rpath

[Khem Raj]

On Mon, Dec 5, 2016 at 2:54 AM, Jack Mitchell <ml at embed.me.uk> wrote:
>
>
> On 05/12/16 10:44, Jack Mitchell wrote:
>>
>> On 02/12/16 07:08, Khem Raj wrote:
>>>
>>> On Thu, Dec 1, 2016 at 8:18 AM, Jack Mitchell <ml at embed.me.uk> wrote:
>>>>
>>>> I'm having some troubles with shared library, shared library
>>>> dependencies
>>>> and rpaths. I have libfoo, which depends on libbar when I try to link
>>>> libfoo
>>>> with my app, it requires libbar to be found. libbar is in a non-standard
>>>> location, /usr/local/bar when I compiled libfoo, I used -Wl,rpath-link
>>>> ${STAGING_SYSROOT}/usr/local/bar and -Wl,rpath /usr/local/bar. Now
>>>> when I
>>>> come to try link my app with libfoo, it fails to link as it can't find
>>>> libbar, which I assume means the rpath in libfoo isn't being properly
>>>> prepending with sysroot what is the proper way to support this in OE? My
>>>> library has the following rpath information:
>>>>
>>>> 0x0000000f (RPATH) Library rpath: [$ORIGIN/../lib:/usr/local/bar]
>>>>
>>>> So why isn't the rpath being prepended with the sysroot when I
>>>> compile my
>>>> app and link libfoo? The apps build system is using cmake, but this
>>>> should
>>>> be a built in linker feature, correct?
>>>
>>>
>>> Only first path ( before :) is relative to location of binary at runtime
>>>
>>
>> Exactly, so how can you make an OE build use the rpaths of libs that
>> point to the build sysroot. What I have at the moment is
>>
>> 0x0000000f (RPATH) Library rpath: [$ORIGIN/../lib:/usr/local/bar]
>>
>> Which would be correct if I was linking on the target. However when OE
>> sees the rpath in it's cross compile environment it should prepend it
>> with the build sysroot so you end up with something like
>>
>> 0x0000000f (RPATH) Library rpath:
>> [$ORIGIN/../lib:/path/to/build/sysroot/usr/local/bar]
>>
>> And then the SDK should end up with something like
>>
>> 0x0000000f (RPATH) Library rpath:
>> [$ORIGIN/../lib:/path/to/sdk/sysroot/usr/local/bar]
>>
>> Is this what is expected to happen, or am I stumbling into an
>> unsupported scenario.
>>
>> Cheers,
>
>
> I think basically what I'm saying is that does the linker prepend it's
> --sysroot value to absolute rpaths, and if not, should it?

having absolute build paths into rpaths is not a good thing. Linker
will search the libs during link in sysroot its configured to do so.

>
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