Two fixes to get us closer to building with clang. With a one patch[1] on top of clang master I can build and boot a powernv kernel:
$ make ARCH=powerpc powernv_defconfig $ ./scripts/config -e PPC_DISABLE_WERROR -d FTRACE -d BTRFS_FS -d MD_RAID456 $ make CC=/scratch/joel/llvm-build/bin/clang-8 CLANG_TRIPLE=powerpc64le-linux-gnu -j128 $ qemu-system-ppc64 -M powernv -m 3G -nographic -kernel zImage.epapr \ -L ~/skiboot/ -initrd ~/rootfs.cpio.xz Linux version 4.19.0-rc3-00003-g728b25f26bce (joel@ozrom3) (clang version 8.0.0 (trunk 341773)) #12 SMP Mon Sep 10 17:32:05 ACST 2018 The DISABLE_WERROR is due to clang's -Wduplicate-decl-specifier. Some macros we have in arch/powerpc/include/asm/uaccess.h warn on 'const typeof(var)', where as the GCC version doesn't. Anton did fix this a while ago, but the fix was 'reverted' to resolve some sparse warnings. I think we should re-apply Anton's patch[2]. [1] https://reviews.llvm.org/D50965 [2] http://git.kernel.org/torvalds/c/b91c1e3e7a6f22a6b898e345b745b6a43273c973 Joel Stanley (2): powerpc/boot: Fix crt0.S syntax for clang powerpc/boot: Ensure _zimage_start is a weak symbol arch/powerpc/boot/crt0.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 2.17.1
