Messages in this thread Patch in this message | | | From | Sedat Dilek <> | Subject | [PATCH] kbuild: llvmlinux: Set appropriate compiler-flag for CONFIG_CC_OPTIMIZE_FOR_SIZE | Date | Tue, 15 Sep 2015 05:19:48 +0200 |
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Based on a patch of Behan Webster (see [1]).
CLANG (here: v3.7) requires '-Oz' as OptLevel to be set.
A Linux v4.3-rc1 kernel built fine with CONFIG_CC_OPTIMIZE_FOR_SIZE=y and boots on bare metal. This is a Ubuntu/precise AMD64 system.
Tested against Linux v4.3-rc1 and a refreshed llvmlinux patchset.
[1] http://git.linuxfoundation.org/?p=llvmlinux.git;a=blob;f=arch/all/patches/smaller.patch
CC: Behan Webster <behanw@converseincode.com> --- Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile index 4249441e535d..a57fb6b39ed7 100644 --- a/Makefile +++ b/Makefile @@ -622,7 +622,8 @@ KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) endif ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE -KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) +KBUILD_CFLAGS += $(call cc-option,-Oz,-Os) +KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) else KBUILD_CFLAGS += -O2 endif -- 2.5.2
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