# git rev-parse -q --verify 7d42223a874f7426b58792166fce20f78581b5c4^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/mirror/linux-kbuild.git for-next
# git rev-parse -q --verify 7d42223a874f7426b58792166fce20f78581b5c4^{commit}
7d42223a874f7426b58792166fce20f78581b5c4
# git checkout -q -f -B kisskb 7d42223a874f7426b58792166fce20f78581b5c4
# git clean -qxdf
# < git log -1
# commit 7d42223a874f7426b58792166fce20f78581b5c4
# Author: Masahiro Yamada <masahiroy@kernel.org>
# Date:   Wed Apr 8 03:43:36 2020 +0900
# 
#     kbuild: support LLVM=1 to switch the default tools to Clang/LLVM
#     
#     As Documentation/kbuild/llvm.rst implies, building the kernel with a
#     full set of LLVM tools gets very verbose and unwieldy.
#     
#     Provide a single switch LLVM=1 to use Clang and LLVM tools instead
#     of GCC and Binutils. You can pass it from the command line or as an
#     environment variable.
#     
#     Please note LLVM=1 does not turn on the integrated assembler. You need
#     to pass LLVM_IA=1 to use it. When the upstream kernel is ready for the
#     integrated assembler, I think we can make it default.
#     
#     We discussed what we need, and we agreed to go with a simple boolean
#     flag that switches both target and host tools:
#     
#       https://lkml.org/lkml/2020/3/28/494
#       https://lkml.org/lkml/2020/4/3/43
#     
#     Some items discussed, but not adopted:
#     
#     - LLVM_DIR
#     
#       When multiple versions of LLVM are installed, I just thought supporting
#       LLVM_DIR=/path/to/my/llvm/bin/ might be useful.
#     
#       CC      = $(LLVM_DIR)clang
#       LD      = $(LLVM_DIR)ld.lld
#         ...
#     
#       However, we can handle this by modifying PATH. So, we decided to not do
#       this.
#     
#     - LLVM_SUFFIX
#     
#       Some distributions (e.g. Debian) package specific versions of LLVM with
#       naming conventions that use the version as a suffix.
#     
#       CC      = clang$(LLVM_SUFFIX)
#       LD      = ld.lld(LLVM_SUFFIX)
#         ...
#     
#       will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc.,
#       but the suffixed versions in /usr/bin/ are symlinks to binaries in
#       /usr/lib/llvm-#/bin/, so this can also be handled by PATH.
#     
#     Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
#     Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
#     Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build
#     Tested-by: Nick Desaulniers <ndesaulniers@google.com>
#     Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-ld --version
# < git log --format=%s --max-count=1 7d42223a874f7426b58792166fce20f78581b5c4
# < make -s -j 8 ARCH=ia64 O=/kisskb/build/kbuild_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  defconfig
# < make -s -j 8 ARCH=ia64 O=/kisskb/build/kbuild_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  help
# make -s -j 8 ARCH=ia64 O=/kisskb/build/kbuild_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  olddefconfig
# make -s -j 8 ARCH=ia64 O=/kisskb/build/kbuild_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:401:21: note: 'pdeo' was declared here
/kisskb/src/mm/vmstat.c: In function 'sysctl_vm_numa_stat_handler':
/kisskb/src/mm/vmstat.c:90:5: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/futex.c: In function 'do_futex':
/kisskb/src/kernel/futex.c:1676:3: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/futex.c:1652:6: note: 'oldval' was declared here
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1741:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec':
/kisskb/src/fs/ext4/extents.c:5009:23: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_mst_dsc_aux_for_port':
/kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: missing braces around initializer [-Wmissing-braces]
/kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces]
/kisskb/src/fs/nfs/read.c: In function 'nfs_read_completion':
/kisskb/src/fs/nfs/read.c:196:5: warning: value computed is not used [-Wunused-value]
/kisskb/src/fs/nfs/read.c: In function 'nfs_readpage':
/kisskb/src/fs/nfs/read.c:353:2: warning: value computed is not used [-Wunused-value]
/kisskb/src/fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc':
/kisskb/src/fs/nfsd/nfs4xdr.c:2151:9: warning: 'str' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char':
/kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c: In function 'handle_dots':
/kisskb/src/fs/namei.c:1805:10: warning: 'inode' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c:1805:10: warning: 'seq' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/usb/core/devio.c: In function 'async_completed':
/kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update':
/kisskb/src/fs/io_uring.c:6617:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
No errors detected in 22336 functions.
Completed OK
# rm -rf /kisskb/build/kbuild_ia64-defconfig_ia64-gcc4.6
# Build took: 0:04:40.103628