On Thu, 28 Feb 2008 08:47:17 +0100 Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote: > Le Wed, 27 Feb 2008 23:35:27 +0000, > Wookey <wookey@wookware.org> a écrit : > > > emchain can only build 'latest' and from time to time 'latest' is > > broken for cross-builds. Now is such a time. > > Why can emchain only build 'latest', and not toolchains based on > earlier versions of gcc ? Building the latest version is the Debian default for any package. The idea behind emchain is that it doesn't continuously need to be updated just to handle the entry of gcc-4.foo into Debian unstable. It tries to work with the default gcc in Debian itself. (It tries to build a toolchain in much the same way as you or I would build any other set of packages.) We have a separate tool for building multiple versions of gcc in Emdebian SVN, buildcross, maintained by Hector but not released. The intention is that buildcross provides the basic set of toolchains (including ARM on i386 and ARM on amd64) for unstable and testing. emchain then 'helps out' for unusual combinations of build or target. emchain relies on the packages in Debian being fixed whereas buildcross provides mechanisms for Hector to apply patches to the Debian build to fix the build in the first place. Most people should not need emchain when buildcross is working. Unfortunately, if the gcc build is sufficiently broken, neither emchain nor buildcross can build a toolchain. > It sounds quite a big limitation, the 'latest' will always be broken as > some point in time, no ? So wouldn't it be better to be able to compile > a toolchain with a known-working gcc version at any time ? We don't rely on emchain, it is just an additional tool that can help when buildcross does not build a particular toolchain. The real problem is not emchain itself, it is that we have been unable to build *any* toolchains using *any* tools for some time for a variety of reasons. Have you tried 'emsetup --download 4.2; dpkg -force-....' ? That was written for this situation and it allowed me to get a working toolchain on amd64 for ARM. Also, Hector is building new versions currently, some of which are not yet in the repository. What is really needed is a toolchain autobuilder that will attempt to build every Debian version of every version of gcc in Debian for a full set of targets. This should provide three principle benefits: 1. Less reliance on someone (Hector) having time (and a working internet connection) to run every build, allowing Emdebian to have versions for all releases (necessary for 2). 2. Reliable migration into Emdebian testing. 3. Provide a testing ground for the gcc maintainers so that problems can be fixed in Debian, e.g. during the time that gcc spends in experimental. Please don't expect emchain to do any of that. Things are not ideal right now but cross-building does not have a particularly high priority in Debian (especially with the Lenny release coming up) and the small number of Emdebian developers can only do so much. If you fancy helping out, please do so. -- Neil Williams ============= http://www.data-freedom.org/ http://www.nosoftwarepatents.com/ http://www.linux.codehelp.co.uk/
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