Re: [GSoC]Bypass assembler when generating LTO object files

[Jan Hubicka <hubicka@kam.mff.cuni.cz>]

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.
> 
> 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.  First is the
production of proper object file hearder (it encodes things like
architeture ELF is produced for), production of symbol table that is
necessary to mark the LTO object file and also we now need a way to
stream debug info (DWARF) directly to the object from dwarf2out.

So I think first step would be to produce object files w/o debug info
which can be consumed by unmodified linkers and then look into DWARF
bytecode streaming.

Honza
> 
> I am Ankur Saini, a B.Tech CSE 3rd year student at USICT, GGSIPU india
> and a former GSoC contributor at gcc ( worked on expanding gcc static
> analyzer's C++ support in GSoC 2021
> [https://gist.github.com/Arsenic-ATG/8f4ac194f460dd9b2c78cf51af39afef])
> 
> Thanks
> - Ankur