| From | Masahiro Yamada <> | Date | Fri, 11 Sep 2020 03:07:49 +0900 | Subject | Re: [PATCH v2 00/28] Add support for Clang LTO |
| |
On Fri, Sep 11, 2020 at 2:46 AM 'Nick Desaulniers' via Clang Built Linux <clang-built-linux@googlegroups.com> wrote: > > Hey Ian, > It was nice to meet you at Linux plumbers. You might want to take a > look at this series. It implements builds of the Linux kernel with > LTO. It would be good to get eyes on it and help review it from folks > working on this from the GCC angle. The series has some configs that > split where Clang specific changes need to be made; it might be of > interest to think about what would the similar changes be needed for > GCC. Also, congrats on your LWN article! > https://lwn.net/Articles/830300/
FYI.
Some people may remember GCC LTO was posted in 2014 (and rejected by Linus).
https://lore.kernel.org/linux-kbuild/20140407201919.GA15838@sepie.suse.cz/
In my understanding, GCC LTO does not work for relocatable objects because GNU linker is agnostic about LTO.
GCC LTO was implemented in the final link stage (i.e. vmlinux) by using $(CC) as a linker driver.
On the other hand, Clang LTO, in this series implementation, works in the pre-mospost stage (i.e. vmlinux.o).
-- Best Regards Masahiro Yamada
|