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author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2016-05-07 15:48:26 +0900 |
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committer | Michal Marek <mmarek@suse.com> | 2016-05-10 21:21:14 +0200 |
commit | 9c8fa9bc08f60ac657751daba9fccf828a36cfed (patch) | |
tree | 5f02b4935a701c7aa13adf75f2c58c77a9cb3772 /arch/nios2 | |
parent | a7c65b9729e4a5e9c0809784bc52466b0dbaafa7 (diff) | |
download | linux-9c8fa9bc08f60ac657751daba9fccf828a36cfed.tar.bz2 |
kbuild: fix if_change and friends to consider argument order
Currently, arg-check is implemented as follows:
arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
$(filter-out $(cmd_$@), $(cmd_$(1))) )
This does not care about the order of arguments that appear in
$(cmd_$(1)) and $(cmd_$@). So, if_changed and friends never rebuild
the target if only the argument order is changed. This is a problem
when the link order is changed.
Apparently,
obj-y += foo.o
obj-y += bar.o
and
obj-y += bar.o
obj-y += foo.o
should be distinguished because the link order determines the probe
order of drivers. So, built-in.o should be rebuilt when the order
of objects is changed.
This commit fixes arg-check to compare the old/current commands
including the argument order.
Of course, this change has a side effect; Kbuild will react to the
change of compile option order. For example, "-DFOO -DBAR" and
"-DBAR -DFOO" should give no difference to the build result, but
false positive should be better than false negative.
I am moving space_escape to the top of Kbuild.include just for a
matter of preference. In practical terms, space_escape can be
defined after arg-check because arg-check uses "=" flavor, not ":=".
Having said that, collecting convenient variables in one place makes
sense from the point of readability.
Chaining "%%%SPACE%%%" to "_-_SPACE_-_" is also a matter of taste
at this point. Actually, it can be arbitrary as long as it is an
unlikely used string. The only problem I see in "%%%SPACE%%%" is
that "%" is a special character in "$(patsubst ...)" context. This
commit just uses "$(subst ...)" for arg-check, but I am fixing it now
in case we might want to use it in $(patsubst ...) context in the
future.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Diffstat (limited to 'arch/nios2')
0 files changed, 0 insertions, 0 deletions