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* [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
@ 2018-10-30  4:21 Masahiro Yamada
  2018-10-30  4:21 ` [PATCH 2/2] kbuild: remove cc-name variable Masahiro Yamada
  2018-10-30 12:36 ` [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Michael Ellerman
  0 siblings, 2 replies; 5+ messages in thread
From: Masahiro Yamada @ 2018-10-30  4:21 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>
---

 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..bd93bc3 100644
--- a/Makefile
+++ b/Makefile
@@ -707,7 +707,7 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG)      := -fstack-protector-strong
 
 KBUILD_CFLAGS += $(stackp-flags-y)
 
-ifeq ($(cc-name),clang)
+ifeq ($(CONFIG_CC_IS_CLANG),y)
 KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
 KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 15a84cf..ad1c418 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -128,7 +128,7 @@ cflags-y += -ffreestanding
 # clang's output will be based upon the build machine. So for clang we simply
 # unconditionally specify -EB or -EL as appropriate.
 #
-ifeq ($(cc-name),clang)
+ifeq ($(CONFIG_CC_IS_CLANG),y)
 cflags-$(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..e2b055e 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -10,7 +10,7 @@ ccflags-vdso := \
 	$(filter -march=%,$(KBUILD_CFLAGS)) \
 	-D__VDSO__
 
-ifeq ($(cc-name),clang)
+ifeq ($(CONFIG_CC_IS_CLANG),y)
 ccflags-vdso += $(filter --target=%,$(KBUILD_CFLAGS))
 endif
 
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 17be664..338e827 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 ($(cc-name),clang)
+ifneq ($(CONFIG_CC_IS_CLANG),y)
   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 ($(cc-name),clang)
+ifneq ($(CONFIG_CC_IS_CLANG),y)
 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..88129e5 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -64,7 +64,7 @@ endif
 KBUILD_CFLAGS += $(warning)
 else
 
-ifeq ($(cc-name),clang)
+ifeq ($(CONFIG_CC_IS_CLANG),y)
 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 related	[flat|nested] 5+ messages in thread
* [PATCH 2/2] kbuild: remove cc-name variable
  2018-10-30  4:21 [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
@ 2018-10-30  4:21 ` Masahiro Yamada
  2018-10-30 12:36 ` [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Michael Ellerman
  1 sibling, 0 replies; 5+ messages in thread
From: Masahiro Yamada @ 2018-10-30  4:21 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>
---

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

diff --git a/Makefile b/Makefile
index bd93bc3..430f7de 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 related	[flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
  2018-10-30  4:21 [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
  2018-10-30  4:21 ` [PATCH 2/2] kbuild: remove cc-name variable Masahiro Yamada
@ 2018-10-30 12:36 ` Michael Ellerman
  2018-10-30 12:40   ` Masahiro Yamada
  1 sibling, 1 reply; 5+ messages in thread
From: Michael Ellerman @ 2018-10-30 12:36 UTC (permalink / raw)
  To: Masahiro Yamada, linux-kbuild
  Cc: Masahiro Yamada, linux-mips, James Hogan, Benjamin Herrenschmidt,
	linux-kernel, Michal Marek, Paul Mackerras, Paul Burton,
	Ralf Baechle, linuxppc-dev

Masahiro Yamada <yamada.masahiro@socionext.com> writes:
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 17be664..338e827 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 ($(cc-name),clang)
> +ifneq ($(CONFIG_CC_IS_CLANG),y)
>    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)
> +ifneq ($(CONFIG_CC_IS_CLANG),y)
>  CC_FLAGS_FTRACE	+= $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
>  endif
>  endif

Does this behave like other CONFIG variables, ie. it will not be defined
when it's false?

And if so can't we use ifdef/ifndef? eg:

ifndef CONFIG_CC_IS_CLANG
  CC_FLAGS_FTRACE	+= $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)

That reads cleaner to me.

Still this patch is fine as is:

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
  2018-10-30 12:36 ` [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Michael Ellerman
@ 2018-10-30 12:40   ` Masahiro Yamada
  2018-10-30 15:03     ` Michael Ellerman
  0 siblings, 1 reply; 5+ messages in thread
From: Masahiro Yamada @ 2018-10-30 12:40 UTC (permalink / raw)
  To: Michael Ellerman
  Cc: Linux Kbuild mailing list, Linux-MIPS, James Hogan,
	Benjamin Herrenschmidt, Linux Kernel Mailing List, Michal Marek,
	Paul Mackerras, Paul Burton, Ralf Baechle, linuxppc-dev

On Tue, Oct 30, 2018 at 9:36 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> Masahiro Yamada <yamada.masahiro@socionext.com> writes:
> > diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> > index 17be664..338e827 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 ($(cc-name),clang)
> > +ifneq ($(CONFIG_CC_IS_CLANG),y)
> >    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)
> > +ifneq ($(CONFIG_CC_IS_CLANG),y)
> >  CC_FLAGS_FTRACE      += $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
> >  endif
> >  endif
>
> Does this behave like other CONFIG variables, ie. it will not be defined
> when it's false?

Right.


> And if so can't we use ifdef/ifndef? eg:
>
> ifndef CONFIG_CC_IS_CLANG
>   CC_FLAGS_FTRACE       += $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
>
> That reads cleaner to me.


OK, will do respin if you prefer ifdef/ifndef style.




> Still this patch is fine as is:
>
> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
>
> cheers



-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG
  2018-10-30 12:40   ` Masahiro Yamada
@ 2018-10-30 15:03     ` Michael Ellerman
  0 siblings, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2018-10-30 15:03 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: Linux Kbuild mailing list, Linux-MIPS, James Hogan,
	Benjamin Herrenschmidt, Linux Kernel Mailing List, Michal Marek,
	Paul Mackerras, Paul Burton, Ralf Baechle, linuxppc-dev

Masahiro Yamada <yamada.masahiro@socionext.com> writes:
> On Tue, Oct 30, 2018 at 9:36 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>>
>> Masahiro Yamada <yamada.masahiro@socionext.com> writes:
>> > diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
>> > index 17be664..338e827 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 ($(cc-name),clang)
>> > +ifneq ($(CONFIG_CC_IS_CLANG),y)
>> >    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)
>> > +ifneq ($(CONFIG_CC_IS_CLANG),y)
>> >  CC_FLAGS_FTRACE      += $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
>> >  endif
>> >  endif
>>
>> Does this behave like other CONFIG variables, ie. it will not be defined
>> when it's false?
>
> Right.
>
>> And if so can't we use ifdef/ifndef? eg:
>>
>> ifndef CONFIG_CC_IS_CLANG
>>   CC_FLAGS_FTRACE       += $(call cc-ifversion, -lt, 0409, -mno-sched-epilog)
>>
>> That reads cleaner to me.
>
>
> OK, will do respin if you prefer ifdef/ifndef style.

I do prefer it, but I can also fix it up later if you're in a hurry to
get this merged.

cheers

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-10-30 15:03 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2018-10-30  4:21 [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Masahiro Yamada
2018-10-30  4:21 ` [PATCH 2/2] kbuild: remove cc-name variable Masahiro Yamada
2018-10-30 12:36 ` [PATCH 1/2] kbuild: replace cc-name test with CONFIG_CC_IS_CLANG Michael Ellerman
2018-10-30 12:40   ` Masahiro Yamada
2018-10-30 15:03     ` Michael Ellerman

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