diff options
authorDouglas Anderson <dianders@chromium.org>2019-03-14 16:41:59 -0700
committerMasahiro Yamada <yamada.masahiro@socionext.com>2019-03-17 12:56:30 +0900
commit0c22be0712b8771011880972aa30d3412aa3334e (patch)
parentf6d9db6355227656108cb93dd8c74d9a9904c5fb (diff)
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>
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)

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