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: Behan Webster <behanw@converseincode.com>
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
diff --git a/Makefile b/Makefile
index 13270c0..5ccbb58 100644
--- a/Makefile
+++ b/Makefile
@@ -661,14 +661,7 @@
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 += $(call cc-disable-warning, unused-variable)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 05f464e..dfe8889 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -67,7 +67,7 @@
ifeq ($(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 @@
# - 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 @@
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 ' ; \
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index d3437b8..3523df6 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -128,6 +128,10 @@
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))
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index f734033..4efedcbe 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -56,7 +56,7 @@
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)