Re: [Qemu-devel] [RFC] [tcg] Idea on refactoring target code generation loop (gen_intermediate_code)

[Richard Henderson <rth@twiddle.net>]

On 03/09/2016 09:38 AM, Lluís Vilanova wrote:
> Hi,
>
> NOTE: I won't be throwing patches anytime soon, I just want to know if there's
>        interest in this for the future.
>
> While adding events for tracing guest instructions, I've found that the
> per-target "gen_intermediate_code()" function is very similar but not exactly
> the same for each of the targets. This makes architecture-agnostic features
> harder to maintain across targets, specially when it comes to their relative
> order.
>
> So, would it be worth it if I generalized part of that code into an
> architecture-agnostic function that calls into target-specific hooks wherever it
> needs extending? There are many ways to do it that we can discuss later.

It's worth talking about, since I do believe it would make long-term 
maintenance across the targets easier.

These "target-specific hooks" probably ought not be "hooks" in the
traditional sense of attaching them to CPUState.  I'd be more comfortable with 
a refactoring that used include files -- maybe .h or maybe .inc.c.  If we do 
the normal sort of hook, then we've got to either expose DisasContext in places 
we shouldn't, or dynamically allocate it.  Neither seems particularly appealing.


r~