Documentation/kbuild/llvm.rst

11 -----
18 <https://www.chromium.org/chromium-os>`_, `OpenMandriva
20 <https://chimera-linux.org/>`_ use Clang built kernels. Google's and Meta's
24 objects <https://www.aosabook.org/en/llvm.html>`_. Clang is a front-end to LLVM
26 pronounced "klang," not "see-lang."
29 ------------------
35 to compile for the host target. For cross compiling::
37 	make LLVM=1 ARCH=arm64
40 ------------------
45 	make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \
46 	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \
47 	  HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld
65 	make LLVM=-14
67 which will use ``clang-14``, ``ld.lld-14``, etc.
72 	PATH=/path/to/llvm/:$PATH make LLVM=-14
83 Cross Compiling
84 ---------------
87 typically contain all supported back ends, which can help simplify cross
89 ``CROSS_COMPILE`` or target-triple-prefixes become unnecessary. Example::
91 	make LLVM=1 ARCH=arm64
94 which does not yet have ``ld.lld`` or ``llvm-objcopy`` support, you could
97 	make LLVM=1 ARCH=s390 LD=s390x-linux-gnu-ld.bfd \
98 	  OBJCOPY=s390x-linux-gnu-objcopy
100 This example will invoke ``s390x-linux-gnu-ld.bfd`` as the linker and
101 ``s390x-linux-gnu-objcopy``, so ensure those are reachable in your ``$PATH``.
108 ----------------------
111 behavior and have Clang invoke the corresponding non-integrated assembler
116 ``CROSS_COMPILE`` is necessary when cross compiling and ``LLVM_IAS=0``
117 is used in order to set ``--prefix=`` for the compiler to find the
118 corresponding non-integrated assembler (typically, you don't want to use the
119 system assembler when targeting another architecture). Example::
121 	make LLVM=1 ARCH=arm LLVM_IAS=0 CROSS_COMPILE=arm-linux-gnueabi-
125 ------
133 .. _KBUILD_BUILD_TIMESTAMP: kbuild.html#kbuild-build-timestamp
134 .. _Reproducible_builds: reproducible-builds.html#timestamps
137 -----------------------
151 .. list-table::
153    :header-rows: 1
155    * - Architecture
156      - Level of support
157      - ``make`` command
158    * - arm
159      - Supported
160      - ``LLVM=1``
161    * - arm64
162      - Supported
163      - ``LLVM=1``
164    * - hexagon
165      - Maintained
166      - ``LLVM=1``
167    * - loongarch
168      - Maintained
169      - ``LLVM=1``
170    * - mips
171      - Maintained
172      - ``LLVM=1``
173    * - powerpc
174      - Maintained
175      - ``LLVM=1``
176    * - riscv
177      - Supported
178      - ``LLVM=1``
179    * - s390
180      - Maintained
181      - ``CC=clang``
182    * - um (User Mode)
183      - Maintained
184      - ``LLVM=1``
185    * - x86
186      - Supported
187      - ``LLVM=1``
190 ------------
192 - `Website <https://clangbuiltlinux.github.io/>`_
193 - `Mailing List <https://lore.kernel.org/llvm/>`_: <llvm@lists.linux.dev>
194 - `Old Mailing List Archives <https://groups.google.com/g/clang-built-linux>`_
195 - `Issue Tracker <https://github.com/ClangBuiltLinux/linux/issues>`_
196 - IRC: #clangbuiltlinux on irc.libera.chat
197 - `Telegram <https://t.me/ClangBuiltLinux>`_: @ClangBuiltLinux
198 - `Wiki <https://github.com/ClangBuiltLinux/linux/wiki>`_
199 - `Beginner Bugs <https://github.com/ClangBuiltLinux/linux/issues?q=is%3Aopen+is%3Aissue+label%3A%2…
204 -------------
214 - https://releases.llvm.org/download.html
215 - https://github.com/llvm/llvm-project
216 - https://llvm.org/docs/GettingStarted.html
217 - https://llvm.org/docs/CMake.html
218 - https://apt.llvm.org/
219 - https://www.archlinux.org/packages/extra/x86_64/llvm/
220 - https://github.com/ClangBuiltLinux/tc-build
221 - https://github.com/ClangBuiltLinux/linux/wiki/Building-Clang-from-source
222 - https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/