On Tue, Apr 12, 2022 at 11:20 AM Jan Hubicka via Gcc <gcc@gcc.gnu.org> wrote: > > Hi, > > > > > > > On 08-Apr-2022, at 6:32 PM, Jan Hubicka <hubi...@kam.mff.cuni.cz> wrote: > > > > > > Ankur, > > >> I was browsing the list of submitted GSoC projects this year and the > > >> project regarding bypassing assembler when generating LTO object files > > >> caught my eye. > > > I apologize for late reply. I would be very happy to mentor this > > > project. > > > > Thanks for the reply, but unfortunately, due to some reasons, I would not > > be able to take part in GSoC this year. > > But the project seems interesting and would be amazing opportunity to > > learn a lot more things for me, so would it be okay if I try to give it a > > go outside GSoC if no-one else picks it as their GSoC project this year ? > > I would be still very happy to help with that! However it would be also > pity to not take part of GSoC, so if there is something I can help with > on that let me know. > > > > >> > > >> I already have a gcc built from source (sync-ed with trunk/master) and > > >> launched the test-suite on it. > > >> > > >> I am currently in process of understanding the primilary patch > > >> (https://gcc.gnu.org/legacy-ml/gcc/2014-09/msg00340.html), and > > >> experimenting with it. > > >> > > >> are there any other things I should be aware of (useful Doc/blog or a > > >> bug tracking the project) before proceeding further ? > > > > > > I think it is pretty much all that exists. Basically we will need to > > > implement everything that is necessary to stream out valid object file > > > directly from GCC rather than going through gas. The experimental > > > prototype sort of worked but it was lacking few things. > > > > When I try to apply that patch on my local branch ( branched from trunk ), > > it seem to be incompatible with the current working tree. Is there a > > specific branch that I have to apply it to ? or is it due to the recent > > file rename patch ( changing extensions from .c to .cc ) ? > > > > ``` > > $ git apply --check bypass_asm_patch > > > > error: patch failed: Makefile.in:1300 > > error: Makefile.in: patch does not apply > > error: common.opt: No such file or directory > > error: langhooks.c: No such file or directory > > error: lto/Make-lang.in: No such file or directory > > error: lto/lto-object.c: No such file or directory > > error: lto/lto.c: No such file or directory > > error: lto/lto.h: No such file or directory > > error: lto-streamer.h: No such file or directory > > error: toplev.c: No such file or directory > > ``` > > I can try to update the patch, or it probably should apply to trunk > checked out around the date I sent the patch. Indeed we need to change > c to cc but there are likely more changes since then - most importnatly > the early debug info. > At I will see how easy/hard is to make the patch build with current > trunk.
We do have ideas for the early debug with the asm-out abstraction to also solve a different issue (missing simple-object support for mingw/darwin). Namely assemble the early debug in a different file and include the resulting native object in binary form in the compile output - not needing to write assembly .data for that would be a good way to make this more viable. You might want to talk to Martin Liska for this who I think had some prototype on this? Richard. > Honza > > > > Thanks > > - Ankur > >
