On Mon, Jul 29, 2019 at 6:16 PM Masahiro Yamada yamada.masahiro@socionext.com wrote:
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 # v4.20+
This should be v5.0+
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com