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 <[email protected]>
Acked-by: Michael Ellerman <[email protected]> (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
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 $(CONFIG_CC_IS_CLANG). Hence, scripts/Kbuild.include does
not need to define cc-name any more.
Signed-off-by: Masahiro Yamada <[email protected]>
---
Changes in v2: None
Makefile | 2 +-
scripts/Kbuild.include | 4 ----
2 files changed, 1 insertion(+), 5 deletions(-)
diff --git a/Makefile b/Makefile
index 1c0696d..25b1518 100644
--- a/Makefile
+++ b/Makefile
@@ -485,7 +485,7 @@ ifneq ($(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
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 <[email protected]>
> Acked-by: Michael Ellerman <[email protected]> (powerpc)
Looks good to me:
Acked-by: Paul Burton <[email protected]> (MIPS)
Thanks,
Paul
On Tue, 30 Oct 2018 at 23:58, Masahiro Yamada
<[email protected]> 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 <[email protected]>
> Acked-by: Michael Ellerman <[email protected]> (powerpc)
Acked-by: Joel Stanley <[email protected]>
Cheers,
Joel