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

[Jack Mitchell]

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,