[U-Boot] [RFC 10/10] README.clang: build command with clang

[Jeroen Hofstee]

---
 doc/README.clang | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 doc/README.clang

diff --git a/doc/README.clang b/doc/README.clang
new file mode 100644
index 0000000..59d39a4
--- /dev/null
+++ b/doc/README.clang
@@ -0,0 +1,15 @@
+NOTE: target compilation only work for (some) ARM boards
+at the moment. Also Aarch64 is not supported.
+
+The Debian clang package does not have ARM support. It must be
+compiled manually.
+
+To compile U-Boot with clang use e.g.:
+export CROSS_COMPILE=arm-linux-gnueabi-; make HOSTCC=clang CC="clang -no-integrated-as -target $CROSS_COMPILE -B/usr/arm-linux-gnueabi/lib/ -mllvm -arm-use-movt=0" V=1 twister_config all -j8
+
+If all is well you end up on the target with e.g.:
+
+ver
+U-Boot 2014.07-rc2-00067-gd410009 (May 31 2014 - 20:01:13)
+clang version 3.5.0 (https://github.com/llvm-mirror/clang.git 9d0a0d8e196610bb7fef57a5fa034b2f628f870f) (https://github.com/llvm-mirror/llvm.git f2928b9b5f3d2af68f724af16cdaed2628fddfc9)
+GNU ld (GNU Binutils for Ubuntu) 2.23.52.20130913
-- 
1.8.3.2