Hi Abhinav! Thanks for your interest in contributing to GCC, and thanks to Martin for all the information you already provided. Just a bit more, to get you started on developing a proper project proposal:
On 2024-03-13T14:54:52+0100, Martin Jambor <mjam...@suse.cz> wrote: > On Tue, Mar 12 2024, Abhinav Gupta wrote: >> I looked at all the links you provided in the reply and read the >> paper cited on the GCC page for GSoC. I also looked into the rust >> frontend project during this time, and the Offloading project >> interests me more, so I will focus solely on it in the remaining seven >> days before the deadline for GSoC application submission. > > AFAIU, in five days (from now) the application period *opens*, the > deadline is 2nd April. Still it is good idea not to lose any time. Indeed, no rush yet. :-) >> Are there other resources I can look at to better understand the whole >> process? At some point, no too late, you should spend some time on learning how to build GCC, and run the test suite. <https://gcc.gnu.org/wiki/SummerOfCode> and <https://gcc.gnu.org/wiki/#Getting_Started_with_GCC_Development> have some pointers to get started. If you have specific questions, we're happy to help, of course. >> Reading the git commit on the website is proving to be very >> slow. Yes, that's not going to be necessary. >> I think the git commit about Intel MIC would be like a >> "template" in loose terms Right, that's in fact a very good description. The idea here is not to bring back the whole Intel MIC emulator, but something very much simpler. >> to implement the host-ISA mode at least, but >> for the libgomp plugin, I need a better understanding. Find existing libgomp plugins as 'libgomp/plugin/plugin-*.c'. The 'GOMP_OFFLOAD_[...]' functions implement the entry points, the offloading plugin API. Actually also the very simple 'libgomp/oacc-host.c' should be helpful. That's essentially the API you need to care about (for OpenACC; but OpenMP 'target' also won't require much more, for a start). Make some thoughts (or actual experiments) about how we could use/implement a separate host process for code offloading. And otherwise, as Martin said: > You need to understand how OpenMP programs are internally represented. > > Look at the following (hopefully correct, at least as long as you try it > on a system without any Offloading enabled) simple testcase for OpenMP > target construct: > > ---------------------------------------------------------------------- > #include <stdio.h> > > volatile int v = 1; > > int main (int argc, char **argv) > { > int i = v; > > #pragma omp target map(to:i) > { > printf ("OpenMP target hello world, i is: %i\n", i); > } > > return 0; > } > ---------------------------------------------------------------------- > > and compile it with: > > gcc -fopenmp omptgt-hello.c -O2 -fdump-tree-optimized > > and then look at the generated optimized dump. This should give you an > idea how OpenMP regions are internally represented (as outlined > functions) and how calls into libgomp, the run-time library doing a lot > of the magic, look like. > > You can try to do more similar exercises with more OpenMP testcase which > you can find in sub-directory libgomp/testsuite/libgomp.c of in the GCC > repository. > > And then you should perhaps have a look into libgomp itself (you'll find > it in libgomp sub-directory) how GOMP_target_ext is implemented - though > don't worry if you don't understand many of the details, it is complex > stuff. At this point hopefully more of the contents of the Offloading > wiki page will make sense. > > Again, ask on the mailing list if you have any specific questions. Grüße Thomas >> On Thu, 7 Mar 2024 at 20:37, Martin Jambor <mjam...@suse.cz> wrote: >>> >>> Hello, >>> >>> On Wed, Mar 06 2024, Abhinav Gupta via Gcc wrote: >>> > Dear GCC Community, >>> > I hope this email finds you well. My name is Abhinav Gupta. I am a >>> > 3rd-year student at IIT Tirupati pursuing a bachelor's degree in >>> > computer science and engineering. I am writing to express my interest >>> > in contributing to the GCC project under GSoC. >>> >>> We are very happy that you find contributing to GCC interesting. >>> >>> > I am interested in two projects - Offloading to a separate process on >>> > the same host, I am already working in parallel computing, >>> > specifically parallelising tensor algorithms using various techniques >>> > as part of my research project at IIT Tirupati. Although this is not >>> > directly related to compilers, I will be able to get going with the >>> > project quickly. >>> >>> I'd personally very much like to see this project implemented. There is >>> a lot of information on offloading at >>> https://gcc.gnu.org/wiki/Offloading >>> >>> To give you a bit more context where the idea comes from, it was first >>> thought of in email thread starting with >>> https://gcc.gnu.org/pipermail/gcc-patches/2022-October/603984.html and >>> the patch that was "scrubbed" from the email archive eventually became >>> commit >>> https://gcc.gnu.org/cgit/gcc/commit/?id=e4cba49413ca429dc82f6aa2e88129ecb3fdd943 >>> >>> I hope these pointers will further help help you find out where to look >>> when planning the project. If you need more help, please feel free to >>> ask (I'm CCing Thomas who then is perhaps best placed to answer). >>> >>> > The second project is Rust Front-End - both the BIR location support >>> > and rustc testsuite adapter are of interest to me, >>> >>> Please note that Rust-GCC projects are a bit special in the sense that >>> they are often discussed primarily on Zulip of the gcc-rust team: >>> >>> https://gcc-rust.zulipchat.com/ >>> >>> So you may want to reach out to them there as well. >>> >>> > having worked on >>> > compiler front ends as part of my college's compiler design course >>> > combined with my experience in working with large libraries written in >>> > C++ (such as CTF) I believe that these two projects are something that >>> > I can do. >>> >>> You seem to be quite ready! >>> >>> > >>> > Proposed Timeline: >>> > I can start working as soon as my end-semester exams finish, i.e. 9th >>> > May 2024, and continue to work for however long it requires me to >>> > complete the project. >>> > Week 1-2 -> Knowing the existing code and understanding how it works. >>> >>> Right, but please try to do a bit of this, at least on the high level, >>> also now when preparing the proposal. There will be lots to learn in >>> the first weeks even so. Mainly because... >>> >>> > Week 3-8 -> Working on the implementation of whichever project we >>> > decide to move forward with >>> > Week 9-12 -> Testing and creating understandable documentation for the >>> > same. >>> > >>> > This is a very rough timeline, >>> >>> ...eventually the milestones in the application will have to be more >>> specific, mainly to demonstrate you have basic understanding of the >>> proposed project. >>> >>> > and I will refine it further as we >>> > discuss the project idea. This email is more of a call for guidance >>> > than an application, and I would appreciate any feedback you give me. >>> >>> This is a very good start. >>> >>> Good luck! >>> >>> Martin
