lkml.org 
[lkml]   [2019]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 3/4] Makefile: lld: tell clang to use lld
On Tue, Feb 12, 2019 at 5:42 AM <ndesaulniers@google.com> wrote:
>
> This is needed because clang doesn't select which linker to use based on
> $LD but rather -fuse-ld=lld. This is problematic especially for
> cc-ldoption, which checks for linker flag support via invoking the
> compiler, rather than the linker.


Sorry, please explain what kind of problem
this patch solves.



[1] $(LD) is used to link vmlinux, modules, etc.

[2] $(CC) is used to link vdso, etc.
and -fuse-ld= selects which linker is invoked from $(CC)


Is it a problem to use a different
type of linker for [1] and [2] ?


Thanks.





> Link: https://github.com/ClangBuiltLinux/linux/issues/342
> Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> Changes V1->V2:
> * add reviewed and tested by tags.
> * move this addition up 2 statments so that it's properly added to
> KBUILD_*FLAGS as per Nathan.
>
> Makefile | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index d3b65e96d183..00e8e01d23fc 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -500,6 +500,9 @@ ifneq ($(GCC_TOOLCHAIN),)
> CLANG_FLAGS += --gcc-toolchain=$(GCC_TOOLCHAIN)
> endif
> CLANG_FLAGS += -no-integrated-as
> +ifneq ($(shell $(LD) --version 2>&1 | head -n 1 | grep LLD),)
> +CLANG_FLAGS += -fuse-ld=lld
> +endif
> KBUILD_CFLAGS += $(CLANG_FLAGS)
> KBUILD_AFLAGS += $(CLANG_FLAGS)
> export CLANG_FLAGS
> --
> 2.20.1.791.gb4d0f1c61a-goog
>


--
Best Regards
Masahiro Yamada

\
 
 \ /
  Last update: 2019-02-13 16:00    [W:0.102 / U:1.900 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site