u-boot/doc/README.clang

1 The biggest problem when trying to compile U-Boot with clang is that
2 almost all archs rely on storing gd in a global register and clang user
7 Since version 3.4 the ARM backend can be instructed to leave r9 alone.
12 NOTE: target compilation only work for _some_ ARM boards at the moment.
15 in no strict reason to do so in the ARM world, since crt0.S takes care of this.
20 --------------
22 sudo apt-get install clang
25 CROSS_COMPILE. To compile U-Boot with clang on linux without IAS use e.g.:
27 make HOSTCC=clang CROSS_COMPILE=arm-linux-gnueabi- \
28     CC="clang -target arm-linux-gnueabi" -j8
32 make HOSTCC=clang CC=clang -j8
35 --------------------
37 incapable of building U-Boot. Therefore gas from devel/arm-gnueabi-binutils
40 ln -s /usr/local/bin/arm-gnueabi-freebsd-as /usr/bin/arm-freebsd-eabi-as
42 # The following commands compile U-Boot using the clang xdev toolchain.
44 export CROSS_COMPILE=arm-gnueabi-freebsd-
46 gmake CC="clang -target arm-freebsd-eabi --sysroot /usr/arm-freebsd" -j8
48 Given that U-Boot will default to gcc, above commands can be
51 /usr/local/bin/arm-gnueabi-freebsd-gcc
52 ---
55 exec clang -target arm-freebsd-eabi --sysroot /usr/arm-freebsd "$@"