Re: kbuild: Fail if gold linker is detected

Thomas Gleixner
2019-07-16T18:59:51Z

On Tue, 16 Jul 2019, Nathan Chancellor wrote:
> On Tue, Jul 16, 2019 at 02:47:56PM +0200, Thomas Gleixner wrote:
> > The gold linker has known issues of failing the build in random and
> > predictible ways. H.J. stated:
> >
> > "Since building a workable kernel for different kernel configurations
> > isn't a requirement for gold, I don't recommend gold for kernel."
> >
> > So instead of dealing with attempts to duct tape gold support without
> > understanding the root cause, fail the build when gold is detected.
> >
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > Link: https://lore.kernel.org/r/CAMe9rOqMqkQ0LNpm25yE_Yt0FKp05WmHOrwc0aRDb53miFKM+w@mail.gmail.com
> > ---
> > scripts/Kconfig.include | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > --- a/scripts/Kconfig.include
> > +++ b/scripts/Kconfig.include
> > @@ -35,5 +35,8 @@ ld-option = $(success,$(LD) -v $(1))
> > $(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
> > $(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
> >
> > +# Fail if the linker is gold as it's not capable of linking the kernel proper
> > +$(error-if,$(success, command -v $(LD) -v | grep -q gold), gold linker '$(LD)' not supported)
>
> Why are there two '-v' flags here? The second one is ignored since
> command -v just prints out the path of the binary that is being used,
> which would work in most cases but not if gold is the default system
> linker.
>
> $ command -v ld.gold -v
> /usr/bin/ld.gold
>
> $ command -v ld.gold
> /usr/bin/ld.gold
>
> $ command ld.gold -v
> GNU gold (GNU Binutils 2.32) 1.16
>
> Thus, wouldn't it be better to just call $(LD) directly, like
> CC_IS_GCC and CC_IS_CLANG in init/Kconfig?
>
> $(success, $(LD) -v | grep -q gold)

Right you are. Copy and paste without brain ....