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Diffstat (limited to 'Documentation/kbuild/llvm.rst')
| -rw-r--r-- | Documentation/kbuild/llvm.rst | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst index b18401d2ba82..d32616891dcf 100644 --- a/Documentation/kbuild/llvm.rst +++ b/Documentation/kbuild/llvm.rst @@ -38,7 +38,7 @@ Cross Compiling A single Clang compiler binary will typically contain all supported backends, which can help simplify cross compiling. :: - ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang + make ARCH=arm64 CC=clang CROSS_COMPILE=aarch64-linux-gnu- ``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead ``CROSS_COMPILE`` is used to set a command line flag: ``--target=<triple>``. For @@ -60,8 +60,27 @@ They can be enabled individually. The full list of the parameters: :: OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \ HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld -Currently, the integrated assembler is disabled by default. You can pass -``LLVM_IAS=1`` to enable it. +The integrated assembler is enabled by default. You can pass ``LLVM_IAS=0`` to +disable it. + +Omitting CROSS_COMPILE +---------------------- + +As explained above, ``CROSS_COMPILE`` is used to set ``--target=<triple>``. + +If ``CROSS_COMPILE`` is not specified, the ``--target=<triple>`` is inferred +from ``ARCH``. + +That means if you use only LLVM tools, ``CROSS_COMPILE`` becomes unnecessary. + +For example, to cross-compile the arm64 kernel:: + + make ARCH=arm64 LLVM=1 + +If ``LLVM_IAS=0`` is specified, ``CROSS_COMPILE`` is also used to derive +``--prefix=<path>`` to search for the GNU assembler and linker. :: + + make ARCH=arm64 LLVM=1 LLVM_IAS=0 CROSS_COMPILE=aarch64-linux-gnu- Supported Architectures ----------------------- @@ -111,9 +130,10 @@ Getting Help ------------ - `Website <https://clangbuiltlinux.github.io/>`_ -- `Mailing List <https://groups.google.com/forum/#!forum/clang-built-linux>`_: <clang-built-linux@googlegroups.com> +- `Mailing List <https://lore.kernel.org/llvm/>`_: <llvm@lists.linux.dev> +- `Old Mailing List Archives <https://groups.google.com/g/clang-built-linux>`_ - `Issue Tracker <https://github.com/ClangBuiltLinux/linux/issues>`_ -- IRC: #clangbuiltlinux on chat.freenode.net +- IRC: #clangbuiltlinux on irc.libera.chat - `Telegram <https://t.me/ClangBuiltLinux>`_: @ClangBuiltLinux - `Wiki <https://github.com/ClangBuiltLinux/linux/wiki>`_ - `Beginner Bugs <https://github.com/ClangBuiltLinux/linux/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22>`_ |