POINTER_GUARD     572 mtcp/sysdep/sysdep-i386.h #  define PTR_MANGLE(reg)	xorl %gs:POINTER_GUARD, reg
POINTER_GUARD     331 mtcp/sysdep/sysdep-x86_64.h #  define PTR_MANGLE(reg)	xorq %fs:POINTER_GUARD, reg