Commit 5631d9c4 authored by Michal Marek's avatar Michal Marek
Browse files

kbuild: Fix clang detection 



We cannot detect clang before including the arch Makefile, because that
can set the default cross compiler. We also cannot detect clang after
including the arch Makefile, because powerpc wants to know about clang.
Solve this by using an deferred variable. This costs us a few shell
invocations, but this is only a constant number.

Reported-by: default avatarBehan Webster <behanw@converseincode.com>
Reported-by: default avatarAnton Blanchard <anton@samba.org>
Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
parent d179e227

Makefile

+1 −8
Original line number Diff line number Diff line
@@ -661,14 +661,7 @@ endif 
endif

KBUILD_CFLAGS += $(stackp-flag)



ifeq ($(shell $(CC) -v 2>&1 | grep -c "clang version"), 1)

COMPILER := clang

else

COMPILER := gcc

endif

export COMPILER



ifeq ($(COMPILER),clang)

ifeq ($(cc-name),clang)

KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)

KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)

KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)

arch/powerpc/Makefile

+4 −4
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ UTS_MACHINE := $(OLDARCH) 


ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y)

override CC	+= -mlittle-endian

ifneq ($(COMPILER),clang)

ifneq ($(cc-name),clang)

override CC	+= -mno-strict-align

endif

override AS	+= -mlittle-endian
@@ -333,7 +333,7 @@ TOUT := .tmp_gas_check 
# - Require gcc 4.0 or above on 64-bit

# - gcc-4.2.0 has issues compiling modules on 64-bit

checkbin:

	@if test "${COMPILER}" != "clang" \

	@if test "$(cc-name)" != "clang" \

	    && test "$(cc-version)" = "0304" ; then \

		if ! /bin/echo mftb 5 | $(AS) -v -mppc -many -o $(TOUT) >/dev/null 2>&1 ; then \

			echo -n '*** ${VERSION}.${PATCHLEVEL} kernels no longer build '; \
@@ -342,14 +342,14 @@ checkbin: 
			false; \

		fi ; \

	fi

	@if test "${COMPILER}" != "clang" \

	@if test "$(cc-name)" != "clang" \

	    && test "$(cc-version)" -lt "0400" \

	    && test "x${CONFIG_PPC64}" = "xy" ; then \

                echo -n "Sorry, GCC v4.0 or above is required to build " ; \

                echo "the 64-bit powerpc kernel." ; \

                false ; \

        fi

	@if test "${COMPILER}" != "clang" \

	@if test "$(cc-name)" != "clang" \

	    && test "$(cc-fullversion)" = "040200" \

	    && test "x${CONFIG_MODULES}${CONFIG_PPC64}" = "xyy" ; then \

		echo -n '*** GCC-4.2.0 cannot compile the 64-bit powerpc ' ; \

scripts/Kbuild.include

+4 −0
Original line number Diff line number Diff line
@@ -128,6 +128,10 @@ cc-option-align = $(subst -functions=0,,\ 
cc-disable-warning = $(call try-run,\

	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(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))

scripts/Makefile.extrawarn

+1 −1
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ endif 
KBUILD_CFLAGS += $(warning)

else



ifeq ($(COMPILER),clang)

ifeq ($(cc-name),clang)

KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)

KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)

KBUILD_CFLAGS += $(call cc-disable-warning, format)

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