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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-07-29 18:15:17 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-07-31 01:00:58 +0900 |
| commit | 5241ab4cf42d3a93b933b55d3d53f43049081fa1 (patch) | |
| tree | 2af50c0e6f72de941b0dc130d7342b2556555750 /Makefile | |
| parent | 622445541b751ce70a952b8486ce4512a792c0a2 (diff) | |
| download | lwn-5241ab4cf42d3a93b933b55d3d53f43049081fa1.tar.gz lwn-5241ab4cf42d3a93b933b55d3d53f43049081fa1.zip | |
kbuild: initialize CLANG_FLAGS correctly in the top Makefile
CLANG_FLAGS is initialized by the following line:
CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
..., which is run only when CROSS_COMPILE is set.
Some build targets (bindeb-pkg etc.) recurse to the top Makefile.
When you build the kernel with Clang but without CROSS_COMPILE,
the same compiler flags such as -no-integrated-as are accumulated
into CLANG_FLAGS.
If you run 'make CC=clang' and then 'make CC=clang bindeb-pkg',
Kbuild will recompile everything needlessly due to the build command
change.
Fix this by correctly initializing CLANG_FLAGS.
Fixes: 238bcbc4e07f ("kbuild: consolidate Clang compiler flags")
Cc: <stable@vger.kernel.org> # v5.0+
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 3 |
1 files changed, 2 insertions, 1 deletions
@@ -472,6 +472,7 @@ KBUILD_CFLAGS_MODULE := -DMODULE KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds KBUILD_LDFLAGS := GCC_PLUGINS_CFLAGS := +CLANG_FLAGS := export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC export CPP AR NM STRIP OBJCOPY OBJDUMP PAHOLE KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS @@ -519,7 +520,7 @@ endif ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) ifneq ($(CROSS_COMPILE),) -CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%)) +CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR) GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..) |