Re: [PATCH] accel/tcg: assert insn_idx will always be valid before plugin_inject_cb

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 9/13/21 3:06 AM, Alex Bennée wrote:
>>> Also, existing strageness in insn_idx being incremented for non-insns?
>> It shouldn't be - it's just using the presence of the memory
>> instrumentation as a proxy for the start of a instruction and dealing
>> with the slightly different start of block boundary.
>> 
>>> Should it be named something else?  I haven't looked at how it's
>>> really used in the end.
>> We need the insn idx to find the registered callbacks for a given
>> instruction later. We could maybe embed a metadata TCGOp that could
>> track this for us but that might make TCG a bit more confusing as it
>> doesn't really need that information?
>
> We have a metadata op for marking instruction boundaries already:
> INDEX_op_insn_start.

Hmm so we have a separate list for speedy access:

    /* list to quickly access the injected ops */
    QSIMPLEQ_HEAD(, TCGOp) plugin_ops;

I wonder if we should drop that and just scan QTAILQ_HEAD(, TCGOp) ops
so we can be properly aligned with the current instruction.
Alternatively we could just emit INDEX_op_insn_start to the plugin list
as well?

>
>
> r~


-- 
Alex Bennée