Subzero: Work around another llvm-mc parser bug for relocatable symbols.

There's already a hack that emits asm like:
  lea eax, myglobal
instead of:
  mov eax, [myglobal]
because of an llvm-mc parser bug.  However, the lea hack still doesn't work if the symbol is a reserved word, e.g.:
  lea eax, flags

The extra hack is to drop into AT&T syntax temporarily:
.att_syntax
  leal flags, %eax
.intel_syntax

BUG= none
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/543803002
2 files changed