> -----Original Message----- > From: Matthew Fortune > Sent: 13 June 2016 16:55 > To: YunQiang Su; Pablo Oliveira > Cc: 826...@bugs.debian.org; Sylvestre Ledru; Daniel Sanders > Subject: RE: clang: enable FPXX for o32 by default > > YunQiang Su <wzss...@gmail.com> writes: > > On Fri, Jun 10, 2016 at 12:10 AM, Pablo Oliveira <pa...@sifflez.org> > > wrote: > > > Dear YunQiang Su, > > > > > > On Wed, 8 Jun 2016 23:49:17 +0800 YunQiang Su <wzss...@gmail.com> > > wrote: > > >> Package: src:llvm-toolchain-snapshot > > >> > > >> We are working on moving all packages mips/mipsel built with > > >> fpxx-enabled by default. > > >> > > >> While, now fpxx is not enabled by default in clang. > > >> So please apply the attached patch to 3.5/3.6/3.7/3.8/snapshot. > > >> > > >> About FPXX and the transaction, please see: > > >> > > >> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=825342 > > > > > > Are you sure it is ok to modify the default behavior of FPXXDefault > > > only for Debian clang packages (this could lead to surprise and hard > > > to track bugs for users) ? > > > > The clang guy in IMG told me that this the only way currently. > > > > > > > > To me it makes more sense to: > > > > > > 1) either submit this patch upstream, so that every clang distribution > > > has the same common behavior regarding FPXX > > > > I also prefer this way. > > We cannot do this as the topic we are discussing here is inherently a > decision for distributions and not upstream. Please note the setting for > this in GCC is a build time setting so upstream GCC does not set FPXX > by default. Fedora or other distros can choose different compatibility > levels that suit their user base and hence may not use FPXX. > > There is a longer term plan to get a build time configuration option into > CLANG/LLVM but this will take time to plan and implement. When ready > you can switch to it but there is no ETA.
My plan on this is a bit of a compromise between these two positions so I think I should elaborate a little. I aim to collect all the distribution specific behaviours upstream and have each distribution use a configure-time option to pick between them. This allows people to cross compile to specific distributions and should help limit any confusion caused by the configure-time option. One possible way of going about this is to have a mips-debian-linux-gnu triple in upstream clang that has all the Debian-specific behaviours and have Debian use a configure-time option to map mips-linux-gnu to mips-debian-linux-gnu. > > > 2) change the default flags used when building mips/mipsel packages, > > > and keep the default clang behavior. > > > > I don't this is ideal for us. > > It also will make people confused. > > The FPXX setting is almost entirely invisible to end users it is a > distro level decision on how compatible the resulting objects are. Only > a handful of packages will do special things depending on this setting > and they will be designed to cope with all possibilities eventually. > > > > Could you please clarify this issue ? > > > > CC'd the toolchain guys in IMG. > > Hope that clears it up a bit. > > Matthew
