Commit 877417e6 authored Apr 25, 2016 by Arnd Bergmann Committed by Michal Marek May 10, 2016

Kbuild: change CC_OPTIMIZE_FOR_SIZE definition



CC_OPTIMIZE_FOR_SIZE disables the often useful -Wmaybe-unused warning,
because that causes a ridiculous amount of false positives when combined
with -Os.

This means a lot of warnings don't show up in testing by the developers
that should see them with an 'allmodconfig' kernel that has
CC_OPTIMIZE_FOR_SIZE enabled, but only later in randconfig builds
that don't.

This changes the Kconfig logic around CC_OPTIMIZE_FOR_SIZE to make
it a 'choice' statement defaulting to CC_OPTIMIZE_FOR_PERFORMANCE
that gets added for this purpose. The allmodconfig and allyesconfig
kernels now default to -O2 with the maybe-unused warning enabled.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michal Marek <mmarek@suse.com>

parent 51193b76

init/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -1283,6 +1283,17 @@ source "usr/Kconfig"

		endif

		choice
		prompt "Compiler optimization level"
		default CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE

		config CC_OPTIMIZE_FOR_PERFORMANCE
		bool "Optimize for performance"
		help
		This is the default optimization level for the kernel, building
		with the "-O2" compiler flag for best performance and most
		helpful compile-time warnings.

		config CC_OPTIMIZE_FOR_SIZE
		bool "Optimize for size"
		help
		@@ -1291,6 +1302,8 @@ config CC_OPTIMIZE_FOR_SIZE

		If unsure, say N.

		endchoice

		config SYSCTL
		bool

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