Hi! My name is Carlos Barbosa, and I would like to participate in this year's GSoC with GCC. I'm a brazilian undergraduate student and I've been passionate about free software ever since I first heard of it. I'm most interested in OS level programming, language development, optimization and, of course, compiler development. I'm actually only starting to contribute to free software code now, but I have been active in other ways at local FOSS communities for a couple of years now.
About the GSoC proposal, the LTO now re-processes everything from scratch, for any changes in the code, no matter how small. So, the project idea is to make it work incrementally, avoiding unnecessary re-processing. In order to do so, I thought about focusing the most at WPA, first verifying and mapping still valid parts of the old ELF code, then building the new optimization_summary with them and with new code. Then, if LTRANS can't determine which files have been modified, this "diff" might be passed in the IPA to it, so only the modified files get re-optimized. During LTRANS, would using an analogous approach, trying to make local optimizations incremental too, be interesting? Do you have any suggestions about how to improve this approach idea? I apologize already if I misunderstood something in the docs and/or didn't make sense at some point. Regards, Carlos Barbosa