Commit e8e69931 authored by Sam Ravnborg's avatar Sam Ravnborg Committed by Linus Torvalds

[PATCH] kbuild: Set NOSTDINC_FLAGS late to speed up compile (a little)

Move definition of NOSTDINC_FLAGS below inclusion of arch Makefile, so
any arch specific settings to $(CC) takes effect before looking up the
compiler include directory.

The previous solution that replaced ':=' with '=' caused gcc to be
invoked one additional time for each directory visited.

This decreases kernel compile time with 0.1 second (3.6 -> 3.5 seconds) when
running make on a fully built kernel
Signed-off-by: default avatarSam Ravnborg <>
Signed-off-by: default avatarLinus Torvalds <>
parent b3d9ae4b
......@@ -332,9 +332,7 @@ KALLSYMS = scripts/kallsyms
PERL = perl
CHECK = sparse
NOSTDINC_FLAGS = -nostdinc -isystem $(shell $(CC) -print-file-name=include)
CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__
......@@ -531,6 +529,10 @@ endif
include $(srctree)/arch/$(ARCH)/Makefile
# arch Makefile may override CC so keep this after arch Makefile is included
NOSTDINC_FLAGS := -nostdinc -isystem $(shell $(CC) -print-file-name=include)
# warn about C99 declaration after statement
CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
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