Invalid ARM instruction for clang-compiled Android code

[Michael Goffioul]

When running QEMU user mode on some code compiled by clang (dynamic linker from AOSP-10), the emulator chokes on this instruction:

   9aa92:       e8c0 2277       strexd  r7, r2, r2, [r0]

From debugging, I determined that op_strex() calls unallocated_encoding(), which I think leads to the SIGILL signal generated.

I run the emulator without specifying the ARM cpu type, I think it then defaults to "any", which should support all instructions, if I'm not mistaken.

Is this instruction really invalid? Or am I doing something wrong?

Thanks,

Michael.