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* [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
@ 2018-10-30 13:26 Masahiro Yamada
  2018-10-30 13:26 ` [PATCH v2 2/2] kbuild: remove cc-name variable Masahiro Yamada
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Masahiro Yamada @ 2018-10-30 13:26 UTC (permalink / raw)
  To: linux-kbuild
  Cc: Masahiro Yamada, linux-mips, James Hogan, Michael Ellerman,
	Benjamin Herrenschmidt, linux-kernel, Michal Marek,
	Paul Mackerras, Paul Burton, Ralf Baechle, linuxppc-dev

Evaluating cc-name invokes the compiler every time even when you are
not compiling anything, like 'make help'. This is not efficient.

The compiler type has been already detected in the Kconfig stage.
Use CONFIG_CC_IS_CLANG, instead.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
---

Changes in v2:
 - Use ifdef/ifndef insteaed of ifeq/ifneq

 Makefile                   | 2 +-
 arch/mips/Makefile         | 2 +-
 arch/mips/vdso/Makefile    | 2 +-
 arch/powerpc/Makefile      | 4 ++--
 scripts/Makefile.extrawarn | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index 0a42d06..1c0696d 100644
--- a/Makefile
+++ b/Makefile
@@ -707,7 +707,7 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG)      := -fstack-protector-strong
 
 KBUILD_CFLAGS += $(stackp-flags-y)
 
-ifeq ($(cc-name),clang)
+ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
 KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 15a84cf..6841049 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -128,7 +128,7 @@ cflags-y += -ffreestanding
 # clang's output will be based upon the build machine. So for clang we simply
 # unconditionally specify -EB or -EL as appropriate.
 #
-ifeq ($(cc-name),clang)
+ifdef CONFIG_CC_IS_CLANG
 cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= -EB
 cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -EL
 else
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index 34605ca..58a0315 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -10,7 +10,7 @@ ccflags-vdso := \
 	$(filter -march=%,$(KBUILD_CFLAGS)) \
 	-D__VDSO__
 
-ifeq ($(cc-name),clang)
+ifdef CONFIG_CC_IS_CLANG
 ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
 endif
 
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 17be664..8a2ce14 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -96,7 +96,7 @@ aflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(call cc-option,-mabi=elfv1)
 aflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mabi=elfv2
 endif
 
-ifneq ($(cc-name),clang)
+ifndef CONFIG_CC_IS_CLANG
   cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= -mno-strict-align
 endif
 
@@ -175,7 +175,7 @@ endif
 # Work around gcc code-gen bugs with -pg / -fno-omit-frame-pointer in gcc <= 4.8
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44199
 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52828
-ifneq ($(cc-name),clang)
+ifndef CONFIG_CC_IS_CLANG
 CC_FLAGS_FTRACE	+= $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
 endif
 endif
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 24b2fb1..800a10f 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -64,7 +64,7 @@ endif
 KBUILD_CFLAGS += $(warning)
 else
 
-ifeq ($(cc-name),clang)
+ifdef CONFIG_CC_IS_CLANG
 KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
 KBUILD_CFLAGS += $(call cc-disable-warning, format)
-- 
2.7.4


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH v2 2/2] kbuild: remove cc-name variable
  2018-10-30 13:26 [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
@ 2018-10-30 13:26 ` Masahiro Yamada
  2018-10-30 16:51 ` [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Paul Burton
  2018-10-30 21:11 ` Joel Stanley
  2 siblings, 0 replies; 4+ messages in thread
From: Masahiro Yamada @ 2018-10-30 13:26 UTC (permalink / raw)
  To: linux-kbuild; +Cc: Masahiro Yamada, Michal Marek, linux-kernel

There is one more user of $(cc-name) in the top Makefile. It is supposed
to detect Clang before invoking Kconfig, so it should still be there
in the $(shell ...) form. All the other users of $(cc-name) have been
replaced with $(CONFIG_CC_IS_CLANG). Hence, scripts/Kbuild.include does
not need to define cc-name any more.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

Changes in v2: None

 Makefile               | 2 +-
 scripts/Kbuild.include | 4 ----
 2 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 1c0696d..25b1518 100644
--- a/Makefile
+++ b/Makefile
@@ -485,7 +485,7 @@ ifneq ($(KBUILD_SRC),)
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
 endif
 
-ifeq ($(cc-name),clang)
+ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
 ifneq ($(CROSS_COMPILE),)
 CLANG_TARGET	:= --target=$(notdir $(CROSS_COMPILE:%-=%))
 GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD)))
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index ca21a35..51703ae 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -140,10 +140,6 @@ cc-option-yn = $(call try-run,\
 cc-disable-warning = $(call try-run,\
 	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
 
-# cc-name
-# Expands to either gcc or clang
-cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc)
-
 # cc-version
 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 
-- 
2.7.4


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
  2018-10-30 13:26 [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
  2018-10-30 13:26 ` [PATCH v2 2/2] kbuild: remove cc-name variable Masahiro Yamada
@ 2018-10-30 16:51 ` Paul Burton
  2018-10-30 21:11 ` Joel Stanley
  2 siblings, 0 replies; 4+ messages in thread
From: Paul Burton @ 2018-10-30 16:51 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: linux-kbuild, linux-mips, James Hogan, Michael Ellerman,
	Benjamin Herrenschmidt, linux-kernel, Michal Marek,
	Paul Mackerras, Ralf Baechle, linuxppc-dev

Hi Masahiro,

On Tue, Oct 30, 2018 at 10:26:33PM +0900, Masahiro Yamada wrote:
> Evaluating cc-name invokes the compiler every time even when you are
> not compiling anything, like 'make help'. This is not efficient.
> 
> The compiler type has been already detected in the Kconfig stage.
> Use CONFIG_CC_IS_CLANG, instead.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

Looks good to me:

    Acked-by: Paul Burton <paul.burton@mips.com> (MIPS)

Thanks,
    Paul

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
  2018-10-30 13:26 [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
  2018-10-30 13:26 ` [PATCH v2 2/2] kbuild: remove cc-name variable Masahiro Yamada
  2018-10-30 16:51 ` [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Paul Burton
@ 2018-10-30 21:11 ` Joel Stanley
  2 siblings, 0 replies; 4+ messages in thread
From: Joel Stanley @ 2018-10-30 21:11 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: linux-kbuild, linux-mips, Michal Marek, jhogan,
	Linux Kernel Mailing List, ralf, paul.burton, Paul Mackerras,
	linuxppc-dev

On Tue, 30 Oct 2018 at 23:58, Masahiro Yamada
<yamada.masahiro@socionext.com> wrote:
>
> Evaluating cc-name invokes the compiler every time even when you are
> not compiling anything, like 'make help'. This is not efficient.
>
> The compiler type has been already detected in the Kconfig stage.
> Use CONFIG_CC_IS_CLANG, instead.

Thanks, I didn't know about this.

>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

Acked-by: Joel Stanley <joel@jms.id.au>

Cheers,

Joel

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2018-10-30 21:11 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-10-30 13:26 [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
2018-10-30 13:26 ` [PATCH v2 2/2] kbuild: remove cc-name variable Masahiro Yamada
2018-10-30 16:51 ` [PATCH v2 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Paul Burton
2018-10-30 21:11 ` Joel Stanley

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