On Tue, Feb 20, 2024 at 1:09 AM Eli Schwartz <eschwartz93@gmail.com> wrote:
>
> On 2/20/24 12:58 AM, Mike Gilbert wrote:
> > On Mon, Feb 19, 2024 at 11:26 PM Eli Schwartz <eschwartz93@gmail.com> wrote:
> >>
> >> meson's builtin LTO support allows meson to introspect whether LTO is
> >> enabled and do some fancy things, such as forcing LTO off for a single
> >> target that is known to be special(ly bad) and not support LTO.
> >
> > Please make sure to test this change with a multilib-enabled ebuild
> > with multiple ABIs enabled. I suspect the filter-lto call will cause
> > differing results for the ABIs after the first.
> >
> > If that is the case, we may need to declare the relevant FLAGS
> > variables with "local -x".
>
>
> >>> Configuring source in
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/work/zstd-1.5.5/build/meson ...
>  * abi_x86_32.x86: running multilib-minimal_abi_src_configure
> meson setup --libdir lib --localstatedir /var/lib --prefix /usr
> --sysconfdir /etc --wrap-mode nodownload --build.pkg-config-path
> /usr/share/pkgconfig:/usr/share/pkgconfig --pkg-config-path
> /usr/share/pkgconfig:/usr/share/pkgconfig --native-file
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.i686-pc-linux-gnu.x86.ini
> -Db_pch=false -Dwerror=false -Db_lto=true -Db_lto_threads=4
> -Dbuildtype=plain -Ddefault_library=shared -Dbin_programs=false
> -Dbin_contrib=false -Dbin_tests=false -Dzlib=disabled -Dlzma=disabled
> -Dlz4=disabled --native-file
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.i686-pc-linux-gnu.x86.ini.local
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/work/zstd-1.5.5/build/meson
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/work/zstd-1.5.5/build/meson-abi_x86_32.x86
> [...]
>     Native files         :
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.i686-pc-linux-gnu.x86.ini
>
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.i686-pc-linux-gnu.x86.ini.local
>     b_lto                : true
>     b_lto_threads        : 4
>
>
>
>
>  * abi_x86_64.amd64: running multilib-minimal_abi_src_configure
> meson setup --libdir lib64 --localstatedir /var/lib --prefix /usr
> --sysconfdir /etc --wrap-mode nodownload --build.pkg-config-path
> /usr/share/pkgconfig --pkg-config-path /usr/share/pkgconfig
> --native-file
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.x86_64-pc-linux-gnu.amd64.ini
> -Db_pch=false -Dwerror=false -Db_lto=true -Db_lto_threads=4
> -Dbuildtype=plain -Ddefault_library=shared -Dbin_programs=true
> -Dbin_contrib=true -Dbin_tests=false -Dzlib=enabled -Dlzma=enabled
> -Dlz4=disabled --native-file
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.x86_64-pc-linux-gnu.amd64.ini.local
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/work/zstd-1.5.5/build/meson
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/work/zstd-1.5.5/build/meson-abi_x86_64.amd64
> [...]
>     Native files         :
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.x86_64-pc-linux-gnu.amd64.ini
>
> /var/tmp/portage/app-arch/zstd-1.5.5-r1/temp/meson.x86_64-pc-linux-gnu.amd64.ini.local
>     b_lto                : true
>     b_lto_threads        : 4

I'm afraid I get different results. Build log attached. Happy to help
figure this out tomorrow.

To test, I applied this patch and ran this:

ABI_X86="32 x32 64" CFLAGS="-O2 -pipe -march=amdfam10 -flto=2" ebuild
zstd-1.5.5-r1.ebuild clean configure