Re: [Qemu-devel] [RFC 0/2] tcg-icount: Add and use tcg_set_insn_param to update tcg insn params

[Lluís Vilanova]

Peter Maydell writes:

> On 11 January 2016 at 20:16, Lluís Vilanova <address@hidden> wrote:
>> Great! I implemented a similar thing long time ago. In my case the machinery 
>> is
>> completely hidden under the concept of "value promises" in TCG (i.e., the 
>> user
>> does not need to know about TCG internals like tcg_op_buf_count):
>> 
>> // create promise
>> TCGv_promise_i32 imm_p;
>> TCGv_i32 imm = tcg_const_promise_i32(&imm_p); // akin to tcg_const_i32()
>> ...
>> // operate with promised immediate 'imm'
>> ...
>> // resolve promised value
>> tcg_set_promise_i32(imm_p, resolved_value);

> I think this is definitely a nicer API if we're going to
> have more than a very few uses -- gen_icount kind of gets
> away with looking under the hood of the tcg data structures
> because it's a sort of internal thing itself, but wider
> use would definitely benefit from a more formal API.

If this is not time-critical, I can prepare an updated patch by Friday, or let
Edgar do it. Both are fine by me.


Cheers,
  Lluis