[oe] mono build error with swp instruction

[Cliff Brake]

I ran into an interesting build error this morning that might be worth
documenting ...

When building mono with the latest toolchains built with OE, I get:

/tmp/ccYsXwlg.s:3067: Error: selected processor does not support `swp
r2,r0,[r4]'
/tmp/ccYsXwlg.s:3161: Error: selected processor does not support `swp
r2,r0,[r4]'
/tmp/ccYsXwlg.s:3272: Error: selected processor does not support `swp
r3,r4,[r5]'

In the libgc code, there is the following:

#    ifdef ARM32
        inline static int GC_test_and_set(volatile unsigned int *addr) {
          int oldval;
          /* SWP on ARM is very similar to XCHG on x86.  Doesn't lock the
           * bus because there are no SMP ARM machines.  If/when there are,
           * this code will likely need to be updated. */
          /* See linuxthreads/sysdeps/arm/pt-machine.h in glibc-2.1 */
          __asm__ __volatile__("swp %0, %1, [%2]"
      		  	     : "=&r"(oldval)
      			     : "r"(1), "r"(addr)
			     : "memory");
          return oldval;
        }

The solution was to set ARM_INSTRUCTION_SET = "arm" in the mono recipe.

Thanks,
Cliff

-- 
=======================
Cliff Brake
http://bec-systems.com