Stream: t-compiler/help

Topic: lto=fat vs lto=thin

semarie (Jun 17 2020 at 11:19, on Zulip):

I recently opened an issue on firefox ( about the use of -Clto (which is lto=fat) for build gkrust component, instead of the use of lto=thin which is advertized by cargo documentation as "takes substantially less time to run while still achieving performance gains similar to "fat". "

semarie (Jun 17 2020 at 11:20, on Zulip):

from testing, it seems that the use of lto=thin generate bunch of compilation and runtime failures:

semarie (Jun 17 2020 at 11:21, on Zulip):

does someone has some elements about these lto=thin failures ?

semarie (Jun 17 2020 at 11:22, on Zulip):

as firefox build heavy uses sccache, I wonder if it could be implied. but I have unsure.

semarie (Jun 21 2020 at 04:59, on Zulip):

where could I find the specific code for lto ? is it a rust code or a LLVM code ?

bjorn3 (Jun 21 2020 at 08:43, on Zulip):

LTO itself is an LLVM thing. The driver code at the rustc side is at and

Last update: Sep 27 2020 at 14:30UTC