[LLVMdev] Downstream distributions as first class citizens in the LLVM repository

[Joerg Sonnenberger]

Hi all,
I mentioned this idea yesterday on IRC already and would like to discuss
in the greater context of the mailing list. NetBSD is about to import
LLVM and Clang into its repository; FreeBSD already has done that a
while ago. This creates some interesting maintainance questions. FreeBSD
has followed the LLVM/Clang releases and backported various fixes
locally. NetBSD will after the 3.4 release likely end up doing the same.
In the past, this process has created some fragmentation for GCC as
various changed tended to accumulate over time. One part was always the
somewhat tidious process of getting those changes upstream, the other
problem was the difficulty of keeping track of who exactly had what
state.

Luckily with LLVM we are in much better position when it comes to
getting changes integrated, so that's not an issue. There is still the
problem of keeping track of who has which additional (bug fixing)
patches and release management in general. For this purpose I would like
to be able to create "vendor" branches in the main repository to reflect
exactly what it is used by the corresponding downstream repository.
This would increase the visibility of changes by any of the vendors
involved, so that others can pick up the same changes. The impact on
mailing list traffic should be low as changes are relatively rare
compared to the rest of the development speed. Code access should follow
similar practises as release management, e.g. every vendor branch has a
code owner responsible for it.

Joerg