From 9e4140329ee9a787d0f96ac2829d618d47f7973f Mon Sep 17 00:00:00 2001 From: Masahiro Yamada <yamada.m@jp.panasonic.com> Date: Tue, 4 Feb 2014 17:24:24 +0900 Subject: kbuild: change out-of-tree build This commit changes the working directory where the build process occurs. Before this commit, build process occurred under the source tree for both in-tree and out-of-tree build. That's why we needed to add $(obj) prefix to all generated files in makefiles like follows: $(obj)u-boot.bin: $(obj)u-boot Here, $(obj) is empty for in-tree build, whereas it points to the output directory for out-of-tree build. And our old build system changes the current working directory with "make -C <sub-dir>" syntax when descending into the sub-directories. On the other hand, Kbuild uses a different idea to handle out-of-tree build and directory descending. The build process of Kbuild always occurs under the output tree. When "O=dir/to/store/output/files" is given, the build system changes the current working directory to that directory and restarts the make. Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>" syntax for descending into sub-directories. (We can write it like "make $(obj)=<sub-dir>" with a shorthand.) This means the current working directory is always the top of the output directory. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Tested-by: Gerhard Sittig <gsi@denx.de> --- arch/sandbox/cpu/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/sandbox/cpu') diff --git a/arch/sandbox/cpu/Makefile b/arch/sandbox/cpu/Makefile index b564294..c5f5426 100644 --- a/arch/sandbox/cpu/Makefile +++ b/arch/sandbox/cpu/Makefile @@ -10,7 +10,7 @@ obj-y := cpu.o os.o start.o state.o # os.c is build in the system environment, so needs standard includes -$(obj)os.o: CFLAGS := $(filter-out -nostdinc,\ +$(obj)/os.o: CFLAGS := $(filter-out -nostdinc,\ $(patsubst -I%,-idirafter%,$(CFLAGS))) -$(obj).depend.os: CPPFLAGS := $(filter-out -nostdinc,\ +$(obj)/.depend.os: CPPFLAGS := $(filter-out -nostdinc,\ $(patsubst -I%,-idirafter%,$(CPPFLAGS))) -- cgit v1.1