Hello devs, I'm currently adding ppc64le to the list of platforms supported by icedtea-bin before we lose gcj to save me fudging around later. This addition presents a small problem.
I currently use the ARCH (e.g. amd64) and ABI (e.g. abi_x86_32) USE flags to fetch the relevant tarballs. The trouble is that there is no flag that decides the endianness. Both ppc64 and ppc64le share the "ppc64" ARCH and ABI. The only differing element between the two profiles is CHOST, which starts with powerpc64- and powerpc64le- respectively. This is sufficient when dealing with multilib-enabled source ebuilds. As far as I know, there is no such as thing as a mixed endian system on any architecture. They require different kernels. If a package doesn't work on one endian type, it can simply be masked in that profile. However, when dealing with binary ebuilds, you ideally want to split the different platforms into separate tarballs to reduce the download size. The platform-specific tarballs for icedtea-bin:8 currently weigh around 55MB each. It would be polite not to double this for ppc64. You can't use CHOST in SRC_URI so a new USE flag is the only way. I am therefore proposing a new global big-endian flag. This could be masked by default and unmasked + forced in the relevant profiles under arch. I will apply this according to the mapping defined in tc-endian of toolchain-funcs.eclass. There is just one package already this flag, dev-haskell/skein. I don't believe it would need to change though it might want to hard enable the force-endianness option or at least enable it by default. On the other hand, using tc-endian may be a better option here. If we're broadly agreed then I will submit a patch for review. On a side note, this problem also applies to soft vs hard float except that these can be mixed under the same kernel. We don't have profiles for these though and soft float seems to be a relic now anyway, at least on ARM. Cheers, -- James Le Cuirot (chewi) Gentoo Linux Developer
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