diff options
author | Masahiro Yamada <masahiroy@kernel.org> | 2020-04-08 04:36:23 +0300 |
---|---|---|
committer | Masahiro Yamada <masahiroy@kernel.org> | 2020-04-08 21:18:21 +0300 |
commit | a0d1c951ef08ed24f35129267e3595d86f57f5d3 (patch) | |
tree | 41fbfa682a7d5d1c9a93096063302963a68b5e70 /usr/include/Makefile | |
parent | 7e20e47c70f810d678d02941fa3c671209c4ca97 (diff) | |
download | linux-a0d1c951ef08ed24f35129267e3595d86f57f5d3.tar.xz |
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_IAS=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>
Diffstat (limited to 'usr/include/Makefile')
0 files changed, 0 insertions, 0 deletions