Hi Terry, Thanks a lot for your reply! I suppose I have to introduce some new option like MULTILIB_COMPATIBLE to produce additional search locations for libraries. Does it sound reasonable? Any advice on implementation?
Thanks, Ilya 2013/8/12 Terry Guo <terry....@arm.com>: > > >> -----Original Message----- >> From: gcc-ow...@gcc.gnu.org [mailto:gcc-ow...@gcc.gnu.org] On Behalf Of >> Ilya Enkovich >> Sent: Friday, August 09, 2013 8:37 PM >> To: GCC Development >> Subject: How to specify multiple OSDIRNAME suffixes for multilib (Multilib >> usage with MPX)? >> >> Hi, >> >> I'm currently trying to create multilib libraries compiled with MPX. >> The main difference with existing multilib variants on i386 target is >> that new targets (32/mpx, 64/mpx) are compatible with old variants >> (32, 64). Also we should not prevent user from using mpx if he does >> not have MPX variants for some libraries - legacy versions should be >> used instead. Thus we need to check several suffixes instead of one. >> E.g. for 64bit MPX binary we should firstly check ../lib64/mpx, then >> check ../lib64 and finally the default one. >> >> I looked at MULTILIB_REUSE and thought it might solve my problem >> according to documentation: "And for some targets it is better to >> reuse an existing multilib than to fall back to default multilib when >> there is no corresponding multilib." [1]. So I tried following >> declarations: >> >> MULTILIB_OSDIRNAMES+= m64/fmpx=../lib64/mpx >> MULTILIB_REUSE = m64=m64/fmpx >> >> But it appeared that only the first entry for some options set counts >> when multilibs are parsed in gcc.c and my reuse here is just ignored. >> >> Is it a wrong implementation of MULTILIB_REUSE or my wrong >> understanding of this option? Is there a way to implement mpx >> multilibs still allowing legacy ones when some mpx libs are missing? >> >> [1] http://gcc.gnu.org/onlinedocs/gccint/Target-Fragment.html#Target- >> Fragment >> >> Thanks, >> Ilya > > Hi Ilya, > > Sorry for the later response. I am the author of MULTILIB_REUSE. So far this > feature is not flexible enough to meet your requirement. It can't > dynamically decide to choose m64/fmpx if such libraries are there, then > secondly choose m64 if m64/fmpx don't exist. This feature only makes a > static decision. The following statement: > MULTILIB_REUSE = m64=m64/fmpx > means that when options m64 and fmpx are given, we should reuse libraries > for m64 always. And for this purpose, we also need: > MULTILIB_EXCEPTIONS = m64/fmpx to make sure libraries for "m64 fmpx" won't > be built. > > If m64/fmpx isn't excluded, the MULTILIB_REUSE will think the required > libraries are there and no need to reuse. > > IMHO, the way used by gcc to select multilib is based on string match rather > than detecting the existence of libraries. So the flexible way like you > wanted isn't supported yet. > > BR, > Terry > > > >
