[oi-dev] Transitioning from Sun Studio to gcc & clang/llvm

[Alasdair Lumsden]

Hi All,

As per discussions on IRC, I'd like to formalise plans for the transition from Sun Studio to open source compiler suites. This is a medium-term transition plan, rather than a sweeping change.

So far the general working plan I've put together based on feedback is:

1. Add gcc 4.5.3 support (or gcc 4.6) with LinkTimeOptimization disabled
2. Follow the library layout guidelines set down by SFE
3. Compile gcc to use Sun ld, but GNU as
4. Use libstdc++ only where localisation is not affected
5. Compile and supply llvm/clang
6. Ensure software we transition from Sun Studio compiles with both gcc and llvm/clang
7. Use gcc as the shipping default with a view to switching to llvm/clang at a future date, but allow either to be picked easily when it achieves performance and feature parity

We can begin this process by applying the policy on new software we add to OI. How we transition our core consolidations can be discussed later on.

If anyone has any serious objections to the above, let me know, otherwise I'll get this written up on the wiki as a policy.

Cheers,

Alasdair