Messages in this thread | | | Date | Tue, 20 Sep 2022 10:06:46 +0200 | Subject | Re: [PATCH v2 2/2] kbuild: lto: preserve MAKEFLAGS for module linking | From | Jiri Slaby <> |
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On 19. 07. 22, 11:15, Masahiro Yamada wrote: > On Tue, Jul 19, 2022 at 5:41 PM Jiri Slaby <jslaby@suse.cz> wrote: >> >> From: Martin Liska <mliska@suse.cz> >> >> Prefix command in makefile run in order to preserve access to jobserver. >> This is needed for gcc at least. >> >> Fixes this warning: >> lto-wrapper: warning: jobserver is not available: ‘--jobserver-auth=’ is not present in ‘MAKEFLAGS’ > > > What is lto-wrapper ?
lto-wrapper is a part of gcc: https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/lto-wrapper.cc
And is invoked during the link of LTO objects (also to link in parallel if jobserver is available).
I am leaving the unanswered questions below for Martin to answer.
>> Cc: Sedat Dilek <sedat.dilek@gmail.com> >> Cc: Masahiro Yamada <masahiroy@kernel.org> >> Cc: Michal Marek <michal.lkml@markovi.net> >> Cc: Nick Desaulniers <ndesaulniers@google.com> >> Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o) >> Signed-off-by: Martin Liska <mliska@suse.cz> >> Signed-off-by: Jiri Slaby <jslaby@suse.cz> >> --- >> >> Notes: >> [v2] this is new in v2 >> >> scripts/Makefile.build | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/scripts/Makefile.build b/scripts/Makefile.build >> index bb63374fb055..493f3c4e8461 100644 >> --- a/scripts/Makefile.build >> +++ b/scripts/Makefile.build >> @@ -247,8 +247,8 @@ endef >> >> # Built-in and composite module parts >> $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE >> - $(call if_changed_rule,cc_o_c) >> - $(call cmd,force_checksrc) >> + +$(call if_changed_rule,cc_o_c) >> + +$(call cmd,force_checksrc) > > > cmd_force_checksrc invokes sparse. > How is it related to GCC? > > > > >> >> # To make this rule robust against "Argument list too long" error, >> # ensure to add $(obj)/ prefix by a shell command. >> @@ -457,7 +457,7 @@ endef >> $(multi-obj-m): objtool-enabled := $(delay-objtool) >> $(multi-obj-m): part-of-module := y >> $(multi-obj-m): %.o: %.mod FORCE >> - $(call if_changed_rule,ld_multi_m) >> + +$(call if_changed_rule,ld_multi_m) >> $(call multi_depend, $(multi-obj-m), .o, -objs -y -m) > > > cmd_ld_multi_m invokes $(LD) directly. > How is it related to gcc?
-- js suse labs
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