1. KAI-GCC Transition Status Report 11 March 2004 Marc Paterno

2. Project Overview Goal: make it possible for experiments to replace their use of the KAI C++ compiler with use of GCC Tasked to the C++ Working Group, consisting of representatives from: –experiments (CDF and DØ in the main) –OSS/CSI –ODS –CPD Note: These three groups were part of the previous CD organization. The C++WG does not reflect the current CD organization.

3. Work Completed ld executable locally patched to improve speed and reduce memory use Several GCC kits available through UPD Experiments have upgraded code to be compliant with the Standard. Consultation provided: –to aid experiments in transition to a more conformant compiler, and –to work around bugs in the new compiler.

4. Status We have a GCC implementation that works, and arguably can be used to replace KCC. –GCC is sufficiently conformant to the Standard. –a debugger (gdb) & “memory checker” (valgrind) exist. –build speed with GCC is (now) better than KCC. CDF and DØ have not yet verified that the optimization capability of GCC is sufficient, nor has detailed comparisons made of physics results. Some find the debugging tools for GCC inferior to those used for KCC.

5. Remaining Work Experiments need to complete any additional verification they deem necessary. Consultation regarding language issues will be available as needed. How do we know when we’re done?

6. Potential Future Project Investigation of other compilers, including: –conformance with Standard –licensing costs, packaging for distribution –performance of tools, quality of optimization, evaluation of impact of licensing costs. Is this a worthwhile task? Resources have not been identified.

7. Other Issues Transitional tools, having served their need, should be retired in a timely fashion (e.g. ISOcxx). Long-term support of GCC is needed –Experiments must be able to move to new versions of GCC as they arrive. –Experiments may require additional consultation for language issues when moving to a new GCC –Laboratory groups other than experiments may benefit from use of a common GCC. There is growing interest other compilers.

8. ISOcxx ISOcxx was produced to support the writing of Standard C++ when using pre-Standard compilers. –It met this need admirably. We are now using (nearly) Standard- conforming compilers. ISOcxx should move to legacy support, and its retirement should be scheduled.

9. Continuing CD Support for GCC How shall it be delivered? By whom? –This is a specific instance of a general question about delivering “standard” freeware *nix tools. Can GCC be delivered in the same fashion as other *nix products? Who shall keep SoftRelTools up-to-date? How shall language consulting continue? –The CEPA/APS/SLD group has, and is willing to supply, the appropriate expertise.

10. Interest in Other Compilers One compiler of recent interest: Intel C++ Resources must be identified for: –authorization of licensing and distribution agreements –consultation on language issues (CEPA/APS/SLD) –support of icc in SoftRelTools As with GCC, experiments must handle their own investigations at their own speed. –supporting tools also need evaluation by experiments.

11. KAI-GCC Transition Status Report 11 March 2004 Marc Paterno