Re: [dpdk-dev] weak functions in some drivers

[Ferruh Yigit <ferruh.yigit@intel.com>]

Hi Damjan,

On 6/21/2016 4:01 PM, Damjan Marion (damarion) wrote:
> 
> Hello,
> 
> We just spent few hours troubleshooting why vPMD is not working
> in i40e driver. Conclusion was that problem is caused by linker 
> linking the wrong instance of the i40e_rx_vec_dev_conf_condition_check(...).
> 
> That function is defined 2 times, once in i40e_rxtx.c and once in 
> i40e_rxtx_vec.c. First one is defined as weak and it just returns -1.
> 
> librte_pmd_i40e.a contains both versions:
> 
> $ objdump -x librte_pmd_i40e.a| grep i40e_rx_vec_dev_conf_condition_check
> 0000000000006ca0  w    F .text	0000000000000006 i40e_rx_vec_dev_conf_condition_check
> 00000000000007c1 g     F .text.unlikely	000000000000001c i40e_rx_vec_dev_conf_condition_check
> 
> However when we are linking our app, linker was picking 1st (weak) one and vPMD init was failing.
App is linking with correct instance of the function for me, how can I
reproduce this linkage issue?

> 
> Workaround we applied to get int working:  -Wl,--whole-archive <LIBS> -Wl,—no-whole-archive
These flags already wraps PMD libraries, can you please give more detail
about workaround?

Thanks,
ferruh