[PATCH v2] ARM: error out if compiling ARMv6 using Clang before 8.0

[Stefan Agner]

The kernel passes the ArmV6K architecture to the compiler when
using the multi platform selection and enabling ARMv6. Clang
older than version 8.0 emit assembly with an non-existing CPU,
which then makes the GNU assembler fail. Warn users when
compiling ARMv6 using Clang before 8.0.

Suggested-by: Russell King <linux@xxxxxxxxxxxxxxx>
Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
Link: https://github.com/ClangBuiltLinux/linux/issues/55
---
 include/linux/compiler-clang.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index b1ce500fe8b3..9df8713bef38 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -3,6 +3,10 @@
 #error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
 #endif
 
+#if defined(CONFIG_ARCH_MULTI_V6) && CONFIG_CLANG_VERSION < 80000
+#error "Sorry, your compiler is too old - please upgrade it."
+#endif
+
 /* Some compiler specific definitions are overwritten here
  * for Clang compiler
  */
-- 
2.19.1