Richard Henderson writes: > On 09/30/2016 08:13 AM, Lluís Vilanova wrote: >>> (2) an internal state change >>> to DisasContext, reflected in INDEX_op_insn_start, with no changes to any >>> TCG >>> registers. So you'll not actually be tracking eflags at all. >> >> I don't follow what you mean. AFAIK INDEX_op_insn_start does not change the >> guest eflags.
> It sets cc_op, which affects how eflags is computed. I see tcg_gen_insn_start() gets dc->cc_op as a second argument, but I really don't see where it gets modified (I'm looking at tcg_gen_code() on the INDEX_op_insn_start case). If you have the time, I'd like to understand that; I'm just curious. But regardless of this specific case, we still have all the instructions implemented with TCG helpers, which won't have any reguster usage information. I was pretty convinced that was enough for some basic analysis using the traces, but I might just as well keep proper register usage on my instrumentation tree. Thanks, Lluis
