Re: Underlinked libs and overlinked applications - an issue?

2016-05-19 17:38, Christian Ehrhardt:

Hi,
I was working on the new 16.04 build system to adapt deb packaging to it.
I remember somewhen back in the DPDK 2.2 and shared+combined library days I
had some issues with over/underlinking - but it seems those are still
existent or came back.

I would say it has always been like that.
Thanks for raising the issue.

After a build in almost default config (just disabled the kernel modules)
and set RTE_MACHINE to default I find the following.

#1
The libraries are all only linked against external things - even clearly
using internal structures:
ldd usr/lib/x86_64-linux-gnu/librte_lpm.so.2
       linux-vdso.so.1 =>  (0x00007fff7e7a5000)
       libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f175d4dd000)
       /lib64/ld-linux-x86-64.so.2 (0x0000558d3afbf000)

The DT_NEEDED entries are created only for external dependencies.
Probably we should create ones for internal dependencies based on the
variable DEPDIRS-y.

#2
The Application then seem to try to make up for that by realizing all that
is missing.
But looking at the app alone it seems overlinked by that - it is not using
all of these on its own.
ldd usr/bin/cmdline_test
       linux-vdso.so.1 =>  (0x00007ffeec9ea000)
       librte_distributor.so.1 => not found
       librte_reorder.so.1 => not found
[...]
       librte_jobstats.so.1 => not found
[...]
And for example none of the librte_jobstats.so.1 symbols are used
"directly" in there.

Yes every libraries are put for every apps in rte.app.mk.
Probably that we could better use DEPDIRS-y for apps.