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| author | Masahiro Yamada <masahiroy@kernel.org> | 2020-04-23 16:23:53 +0200 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2020-05-12 06:28:33 +0200 |
| commit | 30a7729771731971839cc969d2a321e6ea7a144b (patch) | |
| tree | 5ecc32acc767d02fde56084c435073be35ab3486 /scripts/Makefile.host | |
| parent | kbuild: ensure full rebuild when the compiler is updated (diff) | |
| download | linux-30a7729771731971839cc969d2a321e6ea7a144b.tar.xz linux-30a7729771731971839cc969d2a321e6ea7a144b.zip | |
kbuild: use -MMD instead of -MD to exclude system headers from dependency
This omits system headers from the generated header dependency.
System headers are not updated unless you upgrade the compiler. Nor do
they contain CONFIG options, so fixdep does not need to parse them.
Having said that, the effect of this optimization will be quite small
because the kernel code generally does not include system headers
except <stdarg.h>. Host programs include a lot of system headers,
but there are not so many in the kernel tree.
At first, keeping system headers in .*.cmd files might be useful to
detect the compiler update, but there is no guarantee that <stdarg.h>
is included from every file. So, I implemented a more reliable way in
the previous commit.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/Makefile.host')
| -rw-r--r-- | scripts/Makefile.host | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/scripts/Makefile.host b/scripts/Makefile.host index 2045855d0b75..c8a4a033dc3e 100644 --- a/scripts/Makefile.host +++ b/scripts/Makefile.host @@ -88,8 +88,8 @@ _hostcxx_flags += -I $(objtree)/$(obj) endif endif -hostc_flags = -Wp,-MD,$(depfile) $(_hostc_flags) -hostcxx_flags = -Wp,-MD,$(depfile) $(_hostcxx_flags) +hostc_flags = -Wp,-MMD,$(depfile) $(_hostc_flags) +hostcxx_flags = -Wp,-MMD,$(depfile) $(_hostcxx_flags) ##### # Compile programs on the host |