diff options
author | Douglas Anderson <dianders@chromium.org> | 2019-03-14 16:41:59 -0700 |
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committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-03-17 12:56:30 +0900 |
commit | 0c22be0712b8771011880972aa30d3412aa3334e (patch) | |
tree | 514641da52c0df657f346be9cd6a971594d752ec /Makefile | |
parent | f6d9db6355227656108cb93dd8c74d9a9904c5fb (diff) | |
download | linux-0c22be0712b8771011880972aa30d3412aa3334e.tar.gz |
kbuild: Make NOSTDINC_FLAGS a simply expanded variable
During a simple no-op (nothing changed) build I saw 39 invocations of the C compiler with the argument "-print-file-name=include". We don't need to call the C compiler 39 times for this--one time will suffice. Let's change NOSTDINC_FLAGS to a simply expanded variable to avoid this since there doesn't appear to be any reason it should be recursively expanded. On my build this shaved ~400 ms off my "no-op" build. Note that the recursive expansion seems to date back to the (really old) commit e8f5bdb02ce0 ("[PATCH] Makefile include path ordering"). It's a little unclear to me if the point of that patch was to switch the variable to be recursively expanded (which it did) or to avoid directly assigning to NOSTDINC_FLAGS (AKA to switch to +=) because someone else (out of tree?) was setting it. I presume later since if the only goal was to switch to recursive expansion the patch would have just removed the ":". Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'Makefile')
-rw-r--r-- | Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Makefile b/Makefile index 1ef92d705984..08a01add09a6 100644 --- a/Makefile +++ b/Makefile @@ -412,7 +412,7 @@ CHECK = sparse CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \ -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF) -NOSTDINC_FLAGS = +NOSTDINC_FLAGS := CFLAGS_MODULE = AFLAGS_MODULE = LDFLAGS_MODULE = |