On 21/07/16 19:58, bynes adam wrote: > On Wed, Jul 20, 2016 at 06:11:16PM +0100, Zoltan Kiss wrote: > Hi, Kiss >> Using weak symbols have a few issues with static linking: >> >> - normally the linker searches the .o files already linked, if your weak >> one is there, it won't check if there is a strong version >> - unless the symbol is directly referred, but it's not the right thing to >> rely on >> - or --whole-archive specified in the command line, which pulls in a lot >> of unwanted stuff > --whole-archive on the other hand can ensure all the object files are linked, > and the strong symbol will take precedence over weak symbol. So we don't need > to > take care of the sequence of the object files in the ar or between ar.
--whole-archive is primarily for shared libraries, just as weak symbols. When people do static linking, their reason is often to avoid carrying around a big library while they only use a fraction of it. >> - whole-archive also makes libtool dropping the library from the command >> line, which is what should happen with dynamic linking, but not with >> static (observed on Ubuntu 14.04). This is an important bug if you >> build a static library depending on DPDK > you mean the libtool bug for --whole-archive? > if it does, you shouldn't using the libtool, GNU libtool is a quite common tool for building libraries, it's a bit painful sometimes, but it works. What else do you recommend? I mean, something which is proven to be better? > BTW what's the circumstance you must use the libtool. using you own makefile > for > the library or APP. Building libraries which depend on DPDK >> >> This patch merges the two version and make the behaviour rely on the >> config. >> >> If we can agree in the concept, I can send a series to fix this for the >> other weak functions. >> >> Signed-off-by: Zoltan Kiss <zoltan.kiss at schaman.hu> >> --- >> >> Notes: >> v2: fix commit message >> >> drivers/net/i40e/i40e_rxtx.c | 36 +++++++++++++++++++++++++++++++++++- >> drivers/net/i40e/i40e_rxtx_vec.c | 36 ------------------------------------ >> 2 files changed, 35 insertions(+), 37 deletions(-) >> > From the original design, we follow the rule, we don't want the Macro in the > file > to seperate the different Rx/Tx path for disabled/enabled vector > configuration. And why is it better to compile two versions of the same function when you already know at the time of compilation which one do you want to use? > Adam Bynes >
