Re: [PATCH v2 2/2] kbuild: consolidate Clang compiler flags

On Mon, Nov 12, 2018 at 10:05 AM Michael Ellerman [off-list ref] wrote:

Masahiro Yamada [off-list ref] writes:

quoted

On Sat, Nov 10, 2018 at 3:35 AM Greg Hackmann [off-list ref] wrote:

quoted

On 11/09/2018 10:29 AM, Nick Desaulniers wrote:

quoted

On Mon, Nov 5, 2018 at 7:05 PM Masahiro Yamada
[off-list ref] wrote:

quoted

Collect basic Clang options such as --target, --prefix, --gcc-toolchain,
-no-integrated-as into a single variable CLANG_FLAGS so that it can be
easily reused in other parts of Makefile.

Signed-off-by: Masahiro Yamada <redacted>
---

Changes in v2:
  - Use := flavor instead of = because $(CLANG_FLAGS) is expanded soon anyway

  Makefile | 13 ++++++-------
  1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/Makefile b/Makefile
index da11700..e173a73 100644
--- a/Makefile
+++ b/Makefile

@@ -487,18 +487,17 @@ endif

  ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
  ifneq ($(CROSS_COMPILE),)
-CLANG_TARGET   := --target=$(notdir $(CROSS_COMPILE:%-=%))
+CLANG_FLAGS    := --target=$(notdir $(CROSS_COMPILE:%-=%))
  GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD)))
-CLANG_PREFIX   := --prefix=$(GCC_TOOLCHAIN_DIR)
+CLANG_FLAGS    += --prefix=$(GCC_TOOLCHAIN_DIR)
  GCC_TOOLCHAIN  := $(realpath $(GCC_TOOLCHAIN_DIR)/..)
  endif
  ifneq ($(GCC_TOOLCHAIN),)
-CLANG_GCC_TC   := --gcc-toolchain=$(GCC_TOOLCHAIN)
+CLANG_FLAGS    += --gcc-toolchain=$(GCC_TOOLCHAIN)
  endif
-KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX)
-KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX)
-KBUILD_CFLAGS += -no-integrated-as
-KBUILD_AFLAGS += -no-integrated-as
+CLANG_FLAGS    += -no-integrated-as
+KBUILD_CFLAGS  += $(CLANG_FLAGS)
+KBUILD_AFLAGS  += $(CLANG_FLAGS)
  endif

  RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
--

2.7.4

Thanks for this patch, Masahiro, it's a good simplification.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>

Would you mind waiting for a tested-by from Stefan, and maybe an ack
from Greg (added to cc)?

Acked-by: Greg Hackmann <redacted>

Thanks for your review!


So, how to organize this series, and Joel's one together?

I'd like Joel to use this series as a base for his work.
(https://lore.kernel.org/patchwork/patch/1006696/)

It will be much cleaner.


Shall I merge all the patches to kbuild tree, or
maybe will they go through powerpc tree?

Joel's changes are fairly small so you may as well merge them along with
the rest of the series, if that's OK with you and Joel.

OK, I will.


Joel,
If you send v2, I will merge it to kbuild tree.



Thanks.



-- 
Best Regards
Masahiro Yamada